Journal of Urban Health Bulletin of the New York Academy of Medicine Vol 84 No 6

doi101007s11524-007-9216-0

2007 The New York Academy of Medicine

Prevalence of Indoor Allergen Exposuresamong New Orleans Children with Asthma

Felicia A Rabito Shahed Iqbal Elizabeth HoltL Faye Grimsley Tareq M S Islam and Susanne K Scott

ABSTRACT Studies of inner-city asthmatic children have shown significant regionalvariation in dust allergen exposures The home environment of asthmatic children inthe Gulf South region of the USA has not been characterized This study describesindoor dust allergen levels in the homes of 86 asthmatic children in New Orleans andexplores regional variability in dust allergen exposure Data were used from baselinehome visits of children in the New Orleans Healthy Homes Initiative Interview visualobservation and environmental dust sampling data of 86 children between 4 and17 years of age were analyzed Seventy-seven percent of households had moderate(920ndash99 mgg) or high (Q100 mgg) levels of either Der p 1 or Der f 1 dust miteallergen and 566 had moderate (920ndash80 Ug) or high (980 Ug) levels ofcockroach allergen (Bla g 1) The prevalence of high (910 mgg) levels of dog (Can f 1)allergen was 265 and few households (60) had high cat allergen (Fel d 1) levels(980 mgg) Households with average humidity levels 950 were three times morelikely to have elevated dust mite levels (odds ratio=32 95 confidence interval=1193 p=003) Home ownership and education level were inversely associated withcockroach and dust mite allergen levels respectively Our findings reinforce theevidence of regional variability in dust allergen exposure levels Asthmatic childrenliving in the Gulf South are exposed to multiple indoor allergen exposures and live in ahighly allergenic environment

KEYWORDS Child health Asthma Allergens Environmental health Dog allergenHouse dust

Abbreviations NOHHI ndash The New Orleans Healthy Homes Initiative ICAS ndashInner City Asthma Study DACI ndash Dermatology Allergy and Clinical ImmunologyReference Laboratory CI ndash Confidence Interval IOM ndash Institute of Medicine

INTRODUCTION

Asthma is the most common chronic disease in childhood It affects more than onein five children in many poor neighborhoods and non-Hispanic black childrenliving in inner cities have the highest reported prevalence1ndash4 There has been an

Rabito Iqbal Holt and Islam are with the Department of Epidemiology Tulane University School of

Public Health amp Tropical Medicine New Orleans LA USA Grimsley is with the Department of

Environmental Health Sciences Tulane University School of Public Health amp Tropical Medicine NewOrleans LA USA Scott is with the Division of Epidemiology College of Public Health Ohio State

University Columbus OH USA

Correspondence Felicia A Rabito Department of Epidemiology Tulane University School of Public

Health amp Tropical Medicine New Orleans LA USA (E-mail rabitotulaneedu)

782

increase in asthma prevalence despite a reduction in outdoor air pollutant levelsleading researchers to focus on the home environment as a key risk factor for thedevelopment and exacerbation of asthma5 It is postulated that more time spentindoors translates into prolonged exposure to indoor allergens which mayexacerbate asthma particularly among sensitized individuals6

Allergen exposure is dependent on many factors including local climaticconditions7ndash9 The Inner City Asthma Study (ICAS) characterized the homeenvironment of asthmatic children in seven low-income urban areas in the USA10

An important finding was that indoor allergen levels and skin test reactivity amonginner-city asthmatics vary significantly by geographic location Northeastern homes(New York and the Bronx) had the highest concentration of cockroach allergenwhereas homes in the South (Dallas) and Northwest (Seattle) had high levels of dustmite allergens911 Because regional differences in allergen exposure levels cancontribute to varying sensitization profiles among asthmatic children it isimportant to describe allergen exposure profiles of homes located in geographicareas with distinctive climatic conditions

The home environment of asthmatic children living in urban areas of the USGulf South and the factors associated with elevated allergen levels has not beendescribed The semitropical climate with high humidity and lack of winter frostmay increase the risk of multiple allergen exposure812 To fill the data gap onexposure to home dust allergens in asthmatic children living in the Gulf South wemeasured level of dust mite (Der p 1 Der f 1) cockroach (Bla g 1) dog (Can f 1)and cat (Fel d 1) allergen in homes of children with asthma living in inner-cityNew Orleans

METHODS

Participants and Study DesignThe New Orleans Healthy Homes Initiative was a randomized intervention trialaimed at reducing allergen exposure asthma morbidity and lead burden in childrenages 4ndash17 years living in inner-city New Orleans Eligibility criteria included havingno plans to relocate within 7 months of enrollment in the study medical recordevidence of physician-diagnosed asthma and a positive skin test for any indoorallergen (pet dander dust mite cockroach or mold) This cross-sectional analysischaracterizes the baseline prevalence of dust allergen levels in the child_s primaryresidence

Children were recruited from 15 March 2004 to 30 June 2005 through targetedradio and newspaper advertising and during routine clinic visits to the MedicalCenter of Louisiana New Orleans Asthma and Allergy Clinic Tulane AllergyClinic Children_s Hospital and Louisiana State University Health Sciences CenterLions Clinic At the time of the study these clinics served the majority of inner-cityNew Orleans residents Parental informed consent was obtained and uponcompletion of the baseline home visit 86 children were enrolled in the study

The baseline home visit included an interviewer-administered questionnaire onsociodemographic factors and home characteristics Vacuum dust samples hometemperature and relative humidity was measured and evidence of mold moistureand cockroachrodent infestation was recorded as part of a systematic visualobservation In situations with multiple eligible children in a household only one

783INDOOR ALLERGEN EXPOSURES AMONG CHILDREN WITH ASTHMA

child was enrolled in the study For children recruited from clinics the childpresenting with symptoms was enrolled in the study For children recruited from thecommunity one eligible child per household was randomly selected for inclusionThe study received approval from the Institutional Review Board of the TulaneUniversity Office of Human Research Protection

Environmental Sampling and MeasurementsFive vacuum dust allergen samples were taken from each household from 8 April2004 through 30 July 2005 Samples were taken from the living room floor andupholstery child_s bedroom floor and bed and kitchen floor using separate dustcollection bags [Dermatology Allergy and Clinical Immunology Reference Labo-ratory (DACI) Baltimore MD] attached to a Kenmore (12-amp high-efficiencyparticulate air-filtered canister) electric-powered portable hand-held vacuumcleaner with optional wand extension Trained environmental health paraprofes-sionals vacuumed each sample area for 5 min The vacuum cleaner hose andheadpiece was wiped clean and gloves were replaced after each sample wascollected to prevent contamination The selection of sample areas and the overallsampling process followed a standardized protocol13 Samples were kept in separatebags after collection labeled and mailed to the appropriate laboratory Sampleswere analyzed for dust mite (Der p 1 and Der f 1) cat (Fel d 1) dog (Can f 1) andGerman cockroach (Bla g 1) allergens Temperature and relative humidity weremeasured at the time of dust sample collection using a BK Precision thermo-hygrometer in the living room kitchen and child_s bedroom

Environmental Sample AnalysisEnvironmental dust samples were sent to Aerotech PampK Microbiology Services(Cherry Hill NJ) (543 samples) and the Johns Hopkins University DACI(Baltimore MD) (457 samples) for analysis At the DACI laboratory theaeroallergens in sieved reservoir dust were extracted [100 mg in 2 ml of phosphate-buffered saline (PBS)ndash5 bovine serum albumin] and quantified using a monoclo-nal antibody-based two-site immunoenzymetric assay All monoclonal antibodyreagents and allergen standards were purchased from Indoor Biotechnology(Charlottesville VA USA) The Aerotech PampK laboratory extracted sieved dustsamples (100 mg in 2 ml) in PBS pH 74 with 005 Tween 20 (PBS-T) and mixedend over end for 2 h on an orbital rotator at room temperature The samples werethen centrifuged for 20 min at 2500 rpm at 4-C and the supernatants were usedfor detection of Der p 1 Der f 1 Can f 1 Fel d 1 and Bla g 1 by ELISA method

Both laboratories reported values below the laboratory detection levels PampKreported Bbelow detection limit^ and Bminimum quantification limit (MQL)^ andDACI laboratory reported values less than the minimum detection limit for thegiven quantity We assigned half of the MQL values to PampK laboratory sampleshalf of the highest minimum detection limit value was assigned to samples from theDACI laboratory as per instruction by the service provider (personal communica-tion May 2006)

Statistical AnalysisBased on the literature lower and upper cut-off points for dust allergens were set at92 and Q10 mgg for Der p 1 and Der f 1 Q1 and 98 mgg for Fel d1 Q2 and 910 mggfor Can f 1 and 92 and 98 Ug for Bla g 191415 Average household relative humiditywas calculated by taking an average of baseline relative humidity levels in the

784 RABITO ET AL

kitchen living room and bedroom Descriptive statistics were performed toexamine frequencies of study variables Chi-square tests were used to examinedifferences in allergen exposure by levels of relative humidity (e50 and 950) andother pertinent household characteristics Odds ratios 95 confidence intervals(CIs) and exact p values were reported for bivariate analysis All analyses wereperformed using SAS software (version 91 SAS Institute Cary NC USA)

RESULTS

Of 116 eligible children 86 (74) were enrolled in the study After acquiringinformed consent 16 families could not be contacted to schedule the baseline homevisit 12 refused to participate (eg busy schedule family medical emergencies)one mother refused to have blood drawn on her child and one family moved

Complete sociodemographic characteristics of the study population are de-scribed in Table 1 The majority of the study sample was African American (977)

TABLE 1 Sociodemographic characteristics of study population (N=86)

Variable n ()

SexFemale 30 (353)Male 55 (647)

RaceAfrican American 84 (977)White 2 (23)

Age in years4 to 11 years 63 (733)6 to 17 years 22 (267)

Other asthmatic children in householdYes 20 (233)No 66 (767)

Health insurancePrivate 3 (55)Medicaid 52 (945)

Home ownershipOwner 31 (360)Renter 55 (640)

EmploymentYes 60 (698)No 26 (322)

Education level of primary caregiverLess than high school graduate 4 (47)High school graduate and some college 63 (733)College graduate or more 18 (209)Refused to answer 1 (12)

Annual household incomeLess than $10000 51 (600)$10000 to $15000 12 (141)$15001 to $25000 10 (118)$25001 to $50000 8 (94)Refused to answer 4 (47)

Some variables do not add up to 86 due to missing data

785INDOOR ALLERGEN EXPOSURES AMONG CHILDREN WITH ASTHMA

and male (647) and most children were between the ages of 4 and 11 years Inmost homes the primary caregiver was employed and 94 had at least a high schooleducation Average household income for 74 of the families was less than $15000Results from the survey questionnaire on home environment and residential char-acteristics are described in Table 2 The average relative humidity () was between51 and 53 Twenty four percent of children were exposed to environmentaltobacco smoke defined as having one or more regular smokers smoking inside thehouse Visual observation by health paraprofessionals found evidence of cock-roachesrodents (eg eggs droppings) in 17 out of 86 homes Whereas very fewhouseholds had evidence of visible mold (7) or standing water (5) some werefound to have water damage moisture and leaks (13)

Environmental dust results from kitchen floors living room floor andupholstery and child_s bedroom floor and bed were available for analysis in 83 ofthe enrolled households The prevalence of households having moderate and high

TABLE 2 Residential characteristics of the study population (N=86)

Variable Mean (TSD)

Temperature (-F)Kitchen 736 (111)Living room 731 (114)Bedroom 733 (112)

Relative humidityKitchen 733 (112)Living room 517 (110)Bedroom 515 (108)

Number of rooms in household 66 (21)N ()

Total number of people in householdLess than 5 64 (744)5 or more 22 (256)

Smoking inside the houseNone 65 (744)1 to 3 people 19 (221)4 or more 2 (23)

Pets (cat dog bird rodent)None 63 (733)Single 14 (163)Multiple 9 (104)

Evidence or water damage moisture or leaksYes 11 (134)No 71 (866)

Visible evidence of moldYes 6 (71)No 79 (929)

Presence of standing waterYes 4 (47)No 82 (953)

Evidence of cockroach or rodentsYes 17 (202)No 67 (798)

786 RABITO ET AL

levels of allergens in at least one of these samples (Table 3) was estimated We foundthat 771 of households had 920 mgg of either dust mite allergen (Der p 1 or Derf 1) and 566 had 920 Ug of cockroach allergen (Bla g 1) Dog allergen levels(Can f 1) Q20 mgg were found in 554 of households Among the five indoorallergens cat allergen (Fel d 1) levels were the lowest

Average household humidity greater than 50 was associated with 920 mggof either Der p 1 or Der f 1 dust mite allergen (odds ratio=32 95 CI=11 93 pvalue=003) but was not associated with any other dust allergen (Table 4)Homeownership was associated with low levels of Bla g 1 (odds ratio=261 95CI=103 66 p value=004) and households where research staff reported seeingevidence of cockroaches during home visits were significantly more likely to haveBla g 1 levels above 80 Ug in the kitchen (OR=140 95 CI=33 595 pvalue=G0001) Homes in which the primary caretaker had at least some collegeeducation were less likely to have Der p 1 levels 920 mgg (odds ratio=028 95CI=010 075 p value=001) Household income and the number of people livingin the household were not associated with dust allergen levels

DISCUSSION

Previous research has shown substantial regional variability in home dust allergenlevels among asthmatic children living in US inner cities9 Whereas a number ofstudies have been published which describe the urban and suburban environmentsof asthmatics living in the densely populated northeast areas of the USA there hasbeen little data published on home dust allergen levels of asthmatic children livingin urban areas of the Gulf South914 Climatic conditions in this region of thecountry are distinguished by high temperature and year-round elevated humiditycreating a damp environment suitable for allergen growth The Institute of

TABLE 3 Distribution of allergen levels in the household floor bed and upholstery (N=83)

Allergens n ()

Der p 1 (mgg)920 38(458)Q100 15(181)

Der f 1 (mgg)920 49(590)Q100 13(157)

Either dust mite (mgg)920 64(771)Q100 27(325)

Fel d 1 (mgg)10ndash80 8(96)980 5(60)

Can f 1 (mgg)20ndash100 24(289)9100 22(265)

Bla g 1 (Ug)920 47(566)980 28(337)

787INDOOR ALLERGEN EXPOSURES AMONG CHILDREN WITH ASTHMA

Medicine concluded that a damp indoor environment is related to asthmaexacerbation and increased morbidity acting primarily through the proliferationof moisture-sensitive allergens16

Our findings revealed a highly allergenic home environment Seventy-sevenpercent of children were exposed to two or more indoor allergens above establishedcutpoints and 434 were exposed to three or more allergens (data not shown)Over a quarter of homes had moderate or high exposure to three of four dustallergens tested (dust mite cockroach and dog) Our data show that asthmaticchildren in New Orleans may be exposed to a greater number of allergens atmoderate to high levels compared to asthmatic children living in other inner citiesand to the general population Of particular note is the rate of exposure to highlevels of cockroaches and dust mites (Table 5)

Findings from ICAS established that the homes of inner-city asthmatics living inthe Northeast have a higher concentration of cockroach allergen (specifically NewYork where 622 of homes had levels 92 Ug) than any other region likelybecause of the high number of children living in high-rise apartments wherecockroach extermination is difficult9 In our study where no child lived in a high-rise apartment 566 of the homes had cockroach allergens above 2 Ug and onethird of the households had levels 98 Ug Home humidity level was not associatedwith the presence of cockroach allergens and of the various household character-istics measured only home ownership was associated with cockroach allergens andthe association was weak This leads us to conclude that the high rate of cockroachallergen is related to features of the general ambient rather than the homeenvironment

Dust mites were also a pervasive allergen Seventy-seven percent of NewOrleans homes had levels 92 mgg of dust mite allergen Considering a cutpoint of10 mgg the prevalence of residential dust mite exposure was 325 These levelsare substantially higher than those found both in the homes of asthmatics in theICAS sample and levels in beds in the general population29 Our findings supportan association between high humidity and dust mite exposure suggesting that anintervention that reduces home humidity levels may be warranted New Orleans

TABLE 4 Unadjusted association between average household humidity and dust allergenlevels (N=83)

Allergens 950 humidity [n ()] OR (95 CI) p value

Either dust mite 32 (11 93) 003a

e20 mgg 7 (146)920 mgg 41 (854)

Fel d 1 06 (02 18) 032G10 mgg 42 (875)Q10 mgg 6 (125)

Can f 1 14 (06 34) 046G20 mgg 20 (417)Q20 mgg 28 (583)

Bla g 1 10 (04 25) 097e20 Ug 21 (438)920 Ug 27 (563)

aStatistically significant (p valueG005)

788 RABITO ET AL

TABLE

5Co

mparisonofhomeallergen

levels()betweenNew

Orleansan

dother

cities

Allergens

New

Orleans

(n=83)

Dallasa

(n=135)

Seattlea

(n=127)

Bostona

(n=119)

Bronxa

(n=134)

Chicagoa

(n=141)

Tucson

a

(n=140)

New

York

a

(n=141)

Either

dustmite

920

mgg

771

699

651

398

214

167

245

82

Feld1

980

mgg

48

16

328

140

124

59

58

126

Canf1

9100

mgg

253

97

254

91

175

77

199

138

Bla

g1

920Ug

566

477

76

368

543

551

110

622

aGruchalla

etal(2005)9

789INDOOR ALLERGEN EXPOSURES AMONG CHILDREN WITH ASTHMA

has a humid environment with an average morning relative humidity of 8817

Our dust mite findings may have been a conservative estimate of home allergenexposure because potentially relevant species of dust mites were not sampledResearch has shown that in addition to Der p 1 and Der f 1 the dust miteEuroglyphus maynei is prevalent in humid climates and is a cause of allergensensitization around the world1819 Euroglyphus maynei is a primary source of Tcell sensitization and is present in levels that cause sensitization in temperateclimates It is often found in high concentration in beddings providing a pathwayfor exposure2021 A study conducted in New Orleans and seven other geographicareas of the USA found that in New Orleans E maynei was prevalent in 31 ofsampled homes It was also found in a significant number of homes in GalvestonTX and Delray Beach FL suggesting an affinity for southern climates22 Furtherresearch is needed to establish whether E maynei species of house dust is asignificant source of home allergen exposure in New Orleans homes

A quarter of homes had levels of dog (Can f 1) allergen 9100 mgdl comparableto the highest ICAS sitemdashSeattle Fifty-four percent of homes with dog allergenlevels 9100 mgdl reported currently having a dog Although five homes had catallergen levels above 80 mgdl only one of those homes reported currently havingcats Cat allergen levels in homes without cats ranged from 80 to 1474 mgdlThese findings suggest that allergens from previous pets still lingered in the home orwere being tracked in from outdoors Whereas levels of cat and dog allergens werecomparable to levels found in the homes of other inner-city asthmatics they werelower than levels present in the general population Approximately one-third(347) of homes in the National Survey of Lead and Allergens in Housing studyhad dog allergens 9100 mgdl and 349 of homes had detectable cat allergenlevels above 80 mgdl23

In addition to the climatic disposition indoor allergen exposure also dependson socioeconomic and sociodemographic factors7 The demographic characteristicsof our study population are similar to those in the ICAS study however the majorityof our sample was African-American and had a lower annual incomemdashdespite asimilar educational level10 The majority of families reported receiving an asthmamanagement plan home cleaning advice and advice on trigger avoidance fromtheir medical provider Furthermore most families reported taking steps to reducehome allergen levels by ceasing to smoke attempting to eliminate pests andvacuuming regularly (data not shown) Despite these efforts home dust allergenlevels were very high A combination of an environment conducive to allergengrowth and poverty may be a plausible explanation for these findings Approxi-mately 70 of caregivers were employed but the majority of families had annualincomes of G$15000 Few families reported using mattress covers or air filters andfew reported removing carpets or drapes (data not shown) A lack of resourcescould be the primary barrier to purchasing allergen avoidance supplies Kitch et alreported that in the greater Boston area low family income was associated withgreater risk of exposure to high levels of cockroach allergen and a lower risk of dustmite allergen exposure in the home24 In our sample of low-income families bothdust mite and cockroach were prevalent household allergens

Asthmatic children in New Orleans are at high risk of exposure to multipleindoor allergens Overall our study homes showed higher levels for three out offour allergens namely dust mites cockroach and dog dander compared to allICAS sites Compared to the general population levels of cockroach and dust miteallergens were consistently higher yet levels of cat and dog allergens were lower

790 RABITO ET AL

Our findings reinforce evidence of substantial regional variability in the indoorallergen levels of asthmatic children In an ideal situation allergen avoidance adviceshould be tailored to a child_s specific home environment However individualhome allergen testing is not feasible in the clinical setting making regional exposuredata an important resource for clinicians This study fills a data gap on the homeexposure profile of asthmatic children in the Gulf South region of the USA

ACKNOWLEDGMENTS

This study was funded by the US Department of Housing and Urban DevelopmentOffice of Healthy Homes and Lead Hazard Control Healthy Homes program grant LALHH0121-03

We thank Dr Peter Ashley and Kyla Leon MPH for their assistance inpreparing this manuscript

REFERENCES

1 Bashir SA Home is where the harm is Inadequate housing as a public health crisis Am JPub Health 200292733ndash738

2 Arbes SJ Cohn RD Yin M et al House dust mite allergen in US beds results from theFirst National Survey of Lead and Allergens in Housing J Allergy Clin Immunol2003111408ndash414

3 Institute of Medicine (IOM) Committee on the Assessment of Asthma and Indoor AirCleaning the Air Asthma and Indoor Air Exposures Division of Health Promotion andDisease Prevention Washington DC IOM 2000

4 Gold DR Wright R Population disparities in asthma Annu Rev Public Health20052689ndash113

5 Custovic A Indoor allergens are a primary cause of asthma Eur Respir Rev19988155ndash158

6 Sporik R Holgate T Platts-Mills T et al Exposure to house-dust mite allergen (Der p I)and the development of asthma in childhood N Engl J Med 1990323502ndash507

7 Platts-Mills TAE Vervloet D Thomas WR Aalberse RC Chapman MD Indoorallergens and asthma Report of the Third International Workshop J Allergy ClinImmunol 1997100(6 pt 1)S2ndashS24

8 Huss K Adkinson N Eggleston PA Dawson C Van Natta ML Hamilton RG Housedust mite and cockroach exposure are strong risk factors for positive allergy skin testresponses in the Childhood Asthma Management Program J Allergy Clin Immunol200110748ndash54

9 Gruchalla RS Pongracic J Plaut M et al Inner city asthma study Relationships amongsensitivity allergen exposure and asthma morbidity J Allergy Clin Immunol2005115478ndash485

10 Crain EF Walter M O_Connor GT et al Home and allergic characteristics of childrenwith asthma in seven US urban communities and design of and environmentalintervention The Inner City Asthma Study Environ Health Perspect 2002110939ndash945

11 Eggleston PA Rosenstreich D Lynn H et al Relationship of indoor allergen exposure toskin test sensitivity in inner-city children with asthma J Allergy Clin Immunol1998102563ndash570

12 Mvula M Larzelere M Kraus M et al Prevalence of asthma and asthma-like symptomsin inner-city school children J Asthma 200519ndash16

791INDOOR ALLERGEN EXPOSURES AMONG CHILDREN WITH ASTHMA

13 US Department of Housing and Urban Development (HUD) First National Environ-mental Health Survey of Child Care Centers Final Report Volume II Analysis ofAllergen Levels on Floors Office of Healthy Homes and Lead Hazard ControlWashington DC HUD 2003

14 Leaderer BP Belanger K Triche E et al Dust mite cockroach cat and dog allergenconcentrations in homes of asthmatic children in the northeastern United States impactof socioeconomic factors and population density Environ Health Perspect2002110419ndash425

15 Rosenstreich DL Eggleston P Katten M et al The role of cockroach allergy andexposure to cockroach allergen in causing morbidity among inner-city children withasthma N Engl J Med 19973361356ndash1363

16 Institute of Medicine (IOM) 2004 Damp Indoor Spaces and Health National Academyof Sciences Washington DC National Academy Press Available at http wwwnapedubooks0309091934html Accessed March 5 2007

17 Washington Post 2006 WeatherPost New Orleans La Historical Weather DataAvailable at httpwwwwashingtonpostcomwp-srvweatherlongtermhistoricaldatanew_orleans_lahtm Accessed March 5 2007

18 Arlian LG Water balance and humidity requirements of house dust mites Exp ApplAcarol 19921615ndash35

19 Smith W Mills K Hazell L Hart B Thomas W Molecular analysis of the group 1 and 2allergens from the house dust mite Euroglyphus maynei Int Arch Allergy Immunol199911815ndash22

20 Hales BJ Thomas WR T-cell sensitization to epitopes from the house dust mitesDermatophagoides pteronyssinus and Euroglyphus maynei Exp Allergy 199727868ndash875

21 Colloff MJ Stewart GA Thompson PJ House dust acarofauna and Der p I equivalent inAustralia the relative importance of Dermatophagoides pteronyssinus and Euroglyphusmaynei Clin Exp Allergy 1991121225ndash230

22 Arlian LG Bernstein D Bernstein IL et al Prevalence of dust mites in the homes ofpeople with asthma living in eight different geographic areas of the United States JAllergy Clin Immunol 199290292ndash300

23 Arbes SJ Cohn RD Yin M et al Dog allergen (Can F 1) and cat allergen (Fel d 1) inUS homes Results from the National Survey of Lead and Allergens in Housing JAllergy Clin Immunol 2004114111ndash117

24 Kitch BT Chew G Burge HA et al Socioeconomic predictors of high allergen levels inhomes in the greater Boston area Environ Health Perspect 2000108301ndash307

792 RABITO ET AL

increase in asthma prevalence despite a reduction in outdoor air pollutant levelsleading researchers to focus on the home environment as a key risk factor for thedevelopment and exacerbation of asthma5 It is postulated that more time spentindoors translates into prolonged exposure to indoor allergens which mayexacerbate asthma particularly among sensitized individuals6

Allergen exposure is dependent on many factors including local climaticconditions7ndash9 The Inner City Asthma Study (ICAS) characterized the homeenvironment of asthmatic children in seven low-income urban areas in the USA10

An important finding was that indoor allergen levels and skin test reactivity amonginner-city asthmatics vary significantly by geographic location Northeastern homes(New York and the Bronx) had the highest concentration of cockroach allergenwhereas homes in the South (Dallas) and Northwest (Seattle) had high levels of dustmite allergens911 Because regional differences in allergen exposure levels cancontribute to varying sensitization profiles among asthmatic children it isimportant to describe allergen exposure profiles of homes located in geographicareas with distinctive climatic conditions

The home environment of asthmatic children living in urban areas of the USGulf South and the factors associated with elevated allergen levels has not beendescribed The semitropical climate with high humidity and lack of winter frostmay increase the risk of multiple allergen exposure812 To fill the data gap onexposure to home dust allergens in asthmatic children living in the Gulf South wemeasured level of dust mite (Der p 1 Der f 1) cockroach (Bla g 1) dog (Can f 1)and cat (Fel d 1) allergen in homes of children with asthma living in inner-cityNew Orleans

METHODS

Participants and Study DesignThe New Orleans Healthy Homes Initiative was a randomized intervention trialaimed at reducing allergen exposure asthma morbidity and lead burden in childrenages 4ndash17 years living in inner-city New Orleans Eligibility criteria included havingno plans to relocate within 7 months of enrollment in the study medical recordevidence of physician-diagnosed asthma and a positive skin test for any indoorallergen (pet dander dust mite cockroach or mold) This cross-sectional analysischaracterizes the baseline prevalence of dust allergen levels in the child_s primaryresidence

Children were recruited from 15 March 2004 to 30 June 2005 through targetedradio and newspaper advertising and during routine clinic visits to the MedicalCenter of Louisiana New Orleans Asthma and Allergy Clinic Tulane AllergyClinic Children_s Hospital and Louisiana State University Health Sciences CenterLions Clinic At the time of the study these clinics served the majority of inner-cityNew Orleans residents Parental informed consent was obtained and uponcompletion of the baseline home visit 86 children were enrolled in the study

The baseline home visit included an interviewer-administered questionnaire onsociodemographic factors and home characteristics Vacuum dust samples hometemperature and relative humidity was measured and evidence of mold moistureand cockroachrodent infestation was recorded as part of a systematic visualobservation In situations with multiple eligible children in a household only one

783INDOOR ALLERGEN EXPOSURES AMONG CHILDREN WITH ASTHMA

child was enrolled in the study For children recruited from clinics the childpresenting with symptoms was enrolled in the study For children recruited from thecommunity one eligible child per household was randomly selected for inclusionThe study received approval from the Institutional Review Board of the TulaneUniversity Office of Human Research Protection

Environmental Sampling and MeasurementsFive vacuum dust allergen samples were taken from each household from 8 April2004 through 30 July 2005 Samples were taken from the living room floor andupholstery child_s bedroom floor and bed and kitchen floor using separate dustcollection bags [Dermatology Allergy and Clinical Immunology Reference Labo-ratory (DACI) Baltimore MD] attached to a Kenmore (12-amp high-efficiencyparticulate air-filtered canister) electric-powered portable hand-held vacuumcleaner with optional wand extension Trained environmental health paraprofes-sionals vacuumed each sample area for 5 min The vacuum cleaner hose andheadpiece was wiped clean and gloves were replaced after each sample wascollected to prevent contamination The selection of sample areas and the overallsampling process followed a standardized protocol13 Samples were kept in separatebags after collection labeled and mailed to the appropriate laboratory Sampleswere analyzed for dust mite (Der p 1 and Der f 1) cat (Fel d 1) dog (Can f 1) andGerman cockroach (Bla g 1) allergens Temperature and relative humidity weremeasured at the time of dust sample collection using a BK Precision thermo-hygrometer in the living room kitchen and child_s bedroom

Environmental Sample AnalysisEnvironmental dust samples were sent to Aerotech PampK Microbiology Services(Cherry Hill NJ) (543 samples) and the Johns Hopkins University DACI(Baltimore MD) (457 samples) for analysis At the DACI laboratory theaeroallergens in sieved reservoir dust were extracted [100 mg in 2 ml of phosphate-buffered saline (PBS)ndash5 bovine serum albumin] and quantified using a monoclo-nal antibody-based two-site immunoenzymetric assay All monoclonal antibodyreagents and allergen standards were purchased from Indoor Biotechnology(Charlottesville VA USA) The Aerotech PampK laboratory extracted sieved dustsamples (100 mg in 2 ml) in PBS pH 74 with 005 Tween 20 (PBS-T) and mixedend over end for 2 h on an orbital rotator at room temperature The samples werethen centrifuged for 20 min at 2500 rpm at 4-C and the supernatants were usedfor detection of Der p 1 Der f 1 Can f 1 Fel d 1 and Bla g 1 by ELISA method

Both laboratories reported values below the laboratory detection levels PampKreported Bbelow detection limit^ and Bminimum quantification limit (MQL)^ andDACI laboratory reported values less than the minimum detection limit for thegiven quantity We assigned half of the MQL values to PampK laboratory sampleshalf of the highest minimum detection limit value was assigned to samples from theDACI laboratory as per instruction by the service provider (personal communica-tion May 2006)

Statistical AnalysisBased on the literature lower and upper cut-off points for dust allergens were set at92 and Q10 mgg for Der p 1 and Der f 1 Q1 and 98 mgg for Fel d1 Q2 and 910 mggfor Can f 1 and 92 and 98 Ug for Bla g 191415 Average household relative humiditywas calculated by taking an average of baseline relative humidity levels in the

784 RABITO ET AL

kitchen living room and bedroom Descriptive statistics were performed toexamine frequencies of study variables Chi-square tests were used to examinedifferences in allergen exposure by levels of relative humidity (e50 and 950) andother pertinent household characteristics Odds ratios 95 confidence intervals(CIs) and exact p values were reported for bivariate analysis All analyses wereperformed using SAS software (version 91 SAS Institute Cary NC USA)

RESULTS

Of 116 eligible children 86 (74) were enrolled in the study After acquiringinformed consent 16 families could not be contacted to schedule the baseline homevisit 12 refused to participate (eg busy schedule family medical emergencies)one mother refused to have blood drawn on her child and one family moved

Complete sociodemographic characteristics of the study population are de-scribed in Table 1 The majority of the study sample was African American (977)

TABLE 1 Sociodemographic characteristics of study population (N=86)

Variable n ()

SexFemale 30 (353)Male 55 (647)

RaceAfrican American 84 (977)White 2 (23)

Age in years4 to 11 years 63 (733)6 to 17 years 22 (267)

Other asthmatic children in householdYes 20 (233)No 66 (767)

Health insurancePrivate 3 (55)Medicaid 52 (945)

Home ownershipOwner 31 (360)Renter 55 (640)

EmploymentYes 60 (698)No 26 (322)

Education level of primary caregiverLess than high school graduate 4 (47)High school graduate and some college 63 (733)College graduate or more 18 (209)Refused to answer 1 (12)

Annual household incomeLess than $10000 51 (600)$10000 to $15000 12 (141)$15001 to $25000 10 (118)$25001 to $50000 8 (94)Refused to answer 4 (47)

Some variables do not add up to 86 due to missing data

785INDOOR ALLERGEN EXPOSURES AMONG CHILDREN WITH ASTHMA

and male (647) and most children were between the ages of 4 and 11 years Inmost homes the primary caregiver was employed and 94 had at least a high schooleducation Average household income for 74 of the families was less than $15000Results from the survey questionnaire on home environment and residential char-acteristics are described in Table 2 The average relative humidity () was between51 and 53 Twenty four percent of children were exposed to environmentaltobacco smoke defined as having one or more regular smokers smoking inside thehouse Visual observation by health paraprofessionals found evidence of cock-roachesrodents (eg eggs droppings) in 17 out of 86 homes Whereas very fewhouseholds had evidence of visible mold (7) or standing water (5) some werefound to have water damage moisture and leaks (13)

Environmental dust results from kitchen floors living room floor andupholstery and child_s bedroom floor and bed were available for analysis in 83 ofthe enrolled households The prevalence of households having moderate and high

TABLE 2 Residential characteristics of the study population (N=86)

Variable Mean (TSD)

Temperature (-F)Kitchen 736 (111)Living room 731 (114)Bedroom 733 (112)

Relative humidityKitchen 733 (112)Living room 517 (110)Bedroom 515 (108)

Number of rooms in household 66 (21)N ()

Total number of people in householdLess than 5 64 (744)5 or more 22 (256)

Smoking inside the houseNone 65 (744)1 to 3 people 19 (221)4 or more 2 (23)

Pets (cat dog bird rodent)None 63 (733)Single 14 (163)Multiple 9 (104)

Evidence or water damage moisture or leaksYes 11 (134)No 71 (866)

Visible evidence of moldYes 6 (71)No 79 (929)

Presence of standing waterYes 4 (47)No 82 (953)

Evidence of cockroach or rodentsYes 17 (202)No 67 (798)

786 RABITO ET AL

levels of allergens in at least one of these samples (Table 3) was estimated We foundthat 771 of households had 920 mgg of either dust mite allergen (Der p 1 or Derf 1) and 566 had 920 Ug of cockroach allergen (Bla g 1) Dog allergen levels(Can f 1) Q20 mgg were found in 554 of households Among the five indoorallergens cat allergen (Fel d 1) levels were the lowest

Average household humidity greater than 50 was associated with 920 mggof either Der p 1 or Der f 1 dust mite allergen (odds ratio=32 95 CI=11 93 pvalue=003) but was not associated with any other dust allergen (Table 4)Homeownership was associated with low levels of Bla g 1 (odds ratio=261 95CI=103 66 p value=004) and households where research staff reported seeingevidence of cockroaches during home visits were significantly more likely to haveBla g 1 levels above 80 Ug in the kitchen (OR=140 95 CI=33 595 pvalue=G0001) Homes in which the primary caretaker had at least some collegeeducation were less likely to have Der p 1 levels 920 mgg (odds ratio=028 95CI=010 075 p value=001) Household income and the number of people livingin the household were not associated with dust allergen levels

DISCUSSION

Previous research has shown substantial regional variability in home dust allergenlevels among asthmatic children living in US inner cities9 Whereas a number ofstudies have been published which describe the urban and suburban environmentsof asthmatics living in the densely populated northeast areas of the USA there hasbeen little data published on home dust allergen levels of asthmatic children livingin urban areas of the Gulf South914 Climatic conditions in this region of thecountry are distinguished by high temperature and year-round elevated humiditycreating a damp environment suitable for allergen growth The Institute of

TABLE 3 Distribution of allergen levels in the household floor bed and upholstery (N=83)

Allergens n ()

Der p 1 (mgg)920 38(458)Q100 15(181)

Der f 1 (mgg)920 49(590)Q100 13(157)

Either dust mite (mgg)920 64(771)Q100 27(325)

Fel d 1 (mgg)10ndash80 8(96)980 5(60)

Can f 1 (mgg)20ndash100 24(289)9100 22(265)

Bla g 1 (Ug)920 47(566)980 28(337)

787INDOOR ALLERGEN EXPOSURES AMONG CHILDREN WITH ASTHMA

Medicine concluded that a damp indoor environment is related to asthmaexacerbation and increased morbidity acting primarily through the proliferationof moisture-sensitive allergens16

Our findings revealed a highly allergenic home environment Seventy-sevenpercent of children were exposed to two or more indoor allergens above establishedcutpoints and 434 were exposed to three or more allergens (data not shown)Over a quarter of homes had moderate or high exposure to three of four dustallergens tested (dust mite cockroach and dog) Our data show that asthmaticchildren in New Orleans may be exposed to a greater number of allergens atmoderate to high levels compared to asthmatic children living in other inner citiesand to the general population Of particular note is the rate of exposure to highlevels of cockroaches and dust mites (Table 5)

Findings from ICAS established that the homes of inner-city asthmatics living inthe Northeast have a higher concentration of cockroach allergen (specifically NewYork where 622 of homes had levels 92 Ug) than any other region likelybecause of the high number of children living in high-rise apartments wherecockroach extermination is difficult9 In our study where no child lived in a high-rise apartment 566 of the homes had cockroach allergens above 2 Ug and onethird of the households had levels 98 Ug Home humidity level was not associatedwith the presence of cockroach allergens and of the various household character-istics measured only home ownership was associated with cockroach allergens andthe association was weak This leads us to conclude that the high rate of cockroachallergen is related to features of the general ambient rather than the homeenvironment

Dust mites were also a pervasive allergen Seventy-seven percent of NewOrleans homes had levels 92 mgg of dust mite allergen Considering a cutpoint of10 mgg the prevalence of residential dust mite exposure was 325 These levelsare substantially higher than those found both in the homes of asthmatics in theICAS sample and levels in beds in the general population29 Our findings supportan association between high humidity and dust mite exposure suggesting that anintervention that reduces home humidity levels may be warranted New Orleans

TABLE 4 Unadjusted association between average household humidity and dust allergenlevels (N=83)

Allergens 950 humidity [n ()] OR (95 CI) p value

Either dust mite 32 (11 93) 003a

e20 mgg 7 (146)920 mgg 41 (854)

Fel d 1 06 (02 18) 032G10 mgg 42 (875)Q10 mgg 6 (125)

Can f 1 14 (06 34) 046G20 mgg 20 (417)Q20 mgg 28 (583)

Bla g 1 10 (04 25) 097e20 Ug 21 (438)920 Ug 27 (563)

aStatistically significant (p valueG005)

788 RABITO ET AL

TABLE

5Co

mparisonofhomeallergen

levels()betweenNew

Orleansan

dother

cities

Allergens

New

Orleans

(n=83)

Dallasa

(n=135)

Seattlea

(n=127)

Bostona

(n=119)

Bronxa

(n=134)

Chicagoa

(n=141)

Tucson

a

(n=140)

New

York

a

(n=141)

Either

dustmite

920

mgg

771

699

651

398

214

167

245

82

Feld1

980

mgg

48

16

328

140

124

59

58

126

Canf1

9100

mgg

253

97

254

91

175

77

199

138

Bla

g1

920Ug

566

477

76

368

543

551

110

622

aGruchalla

etal(2005)9

789INDOOR ALLERGEN EXPOSURES AMONG CHILDREN WITH ASTHMA

has a humid environment with an average morning relative humidity of 8817

Our dust mite findings may have been a conservative estimate of home allergenexposure because potentially relevant species of dust mites were not sampledResearch has shown that in addition to Der p 1 and Der f 1 the dust miteEuroglyphus maynei is prevalent in humid climates and is a cause of allergensensitization around the world1819 Euroglyphus maynei is a primary source of Tcell sensitization and is present in levels that cause sensitization in temperateclimates It is often found in high concentration in beddings providing a pathwayfor exposure2021 A study conducted in New Orleans and seven other geographicareas of the USA found that in New Orleans E maynei was prevalent in 31 ofsampled homes It was also found in a significant number of homes in GalvestonTX and Delray Beach FL suggesting an affinity for southern climates22 Furtherresearch is needed to establish whether E maynei species of house dust is asignificant source of home allergen exposure in New Orleans homes

A quarter of homes had levels of dog (Can f 1) allergen 9100 mgdl comparableto the highest ICAS sitemdashSeattle Fifty-four percent of homes with dog allergenlevels 9100 mgdl reported currently having a dog Although five homes had catallergen levels above 80 mgdl only one of those homes reported currently havingcats Cat allergen levels in homes without cats ranged from 80 to 1474 mgdlThese findings suggest that allergens from previous pets still lingered in the home orwere being tracked in from outdoors Whereas levels of cat and dog allergens werecomparable to levels found in the homes of other inner-city asthmatics they werelower than levels present in the general population Approximately one-third(347) of homes in the National Survey of Lead and Allergens in Housing studyhad dog allergens 9100 mgdl and 349 of homes had detectable cat allergenlevels above 80 mgdl23

In addition to the climatic disposition indoor allergen exposure also dependson socioeconomic and sociodemographic factors7 The demographic characteristicsof our study population are similar to those in the ICAS study however the majorityof our sample was African-American and had a lower annual incomemdashdespite asimilar educational level10 The majority of families reported receiving an asthmamanagement plan home cleaning advice and advice on trigger avoidance fromtheir medical provider Furthermore most families reported taking steps to reducehome allergen levels by ceasing to smoke attempting to eliminate pests andvacuuming regularly (data not shown) Despite these efforts home dust allergenlevels were very high A combination of an environment conducive to allergengrowth and poverty may be a plausible explanation for these findings Approxi-mately 70 of caregivers were employed but the majority of families had annualincomes of G$15000 Few families reported using mattress covers or air filters andfew reported removing carpets or drapes (data not shown) A lack of resourcescould be the primary barrier to purchasing allergen avoidance supplies Kitch et alreported that in the greater Boston area low family income was associated withgreater risk of exposure to high levels of cockroach allergen and a lower risk of dustmite allergen exposure in the home24 In our sample of low-income families bothdust mite and cockroach were prevalent household allergens

Asthmatic children in New Orleans are at high risk of exposure to multipleindoor allergens Overall our study homes showed higher levels for three out offour allergens namely dust mites cockroach and dog dander compared to allICAS sites Compared to the general population levels of cockroach and dust miteallergens were consistently higher yet levels of cat and dog allergens were lower

790 RABITO ET AL

Our findings reinforce evidence of substantial regional variability in the indoorallergen levels of asthmatic children In an ideal situation allergen avoidance adviceshould be tailored to a child_s specific home environment However individualhome allergen testing is not feasible in the clinical setting making regional exposuredata an important resource for clinicians This study fills a data gap on the homeexposure profile of asthmatic children in the Gulf South region of the USA

ACKNOWLEDGMENTS

This study was funded by the US Department of Housing and Urban DevelopmentOffice of Healthy Homes and Lead Hazard Control Healthy Homes program grant LALHH0121-03

We thank Dr Peter Ashley and Kyla Leon MPH for their assistance inpreparing this manuscript

REFERENCES

1 Bashir SA Home is where the harm is Inadequate housing as a public health crisis Am JPub Health 200292733ndash738

2 Arbes SJ Cohn RD Yin M et al House dust mite allergen in US beds results from theFirst National Survey of Lead and Allergens in Housing J Allergy Clin Immunol2003111408ndash414

3 Institute of Medicine (IOM) Committee on the Assessment of Asthma and Indoor AirCleaning the Air Asthma and Indoor Air Exposures Division of Health Promotion andDisease Prevention Washington DC IOM 2000

4 Gold DR Wright R Population disparities in asthma Annu Rev Public Health20052689ndash113

5 Custovic A Indoor allergens are a primary cause of asthma Eur Respir Rev19988155ndash158

6 Sporik R Holgate T Platts-Mills T et al Exposure to house-dust mite allergen (Der p I)and the development of asthma in childhood N Engl J Med 1990323502ndash507

7 Platts-Mills TAE Vervloet D Thomas WR Aalberse RC Chapman MD Indoorallergens and asthma Report of the Third International Workshop J Allergy ClinImmunol 1997100(6 pt 1)S2ndashS24

8 Huss K Adkinson N Eggleston PA Dawson C Van Natta ML Hamilton RG Housedust mite and cockroach exposure are strong risk factors for positive allergy skin testresponses in the Childhood Asthma Management Program J Allergy Clin Immunol200110748ndash54

9 Gruchalla RS Pongracic J Plaut M et al Inner city asthma study Relationships amongsensitivity allergen exposure and asthma morbidity J Allergy Clin Immunol2005115478ndash485

10 Crain EF Walter M O_Connor GT et al Home and allergic characteristics of childrenwith asthma in seven US urban communities and design of and environmentalintervention The Inner City Asthma Study Environ Health Perspect 2002110939ndash945

11 Eggleston PA Rosenstreich D Lynn H et al Relationship of indoor allergen exposure toskin test sensitivity in inner-city children with asthma J Allergy Clin Immunol1998102563ndash570

12 Mvula M Larzelere M Kraus M et al Prevalence of asthma and asthma-like symptomsin inner-city school children J Asthma 200519ndash16

791INDOOR ALLERGEN EXPOSURES AMONG CHILDREN WITH ASTHMA

13 US Department of Housing and Urban Development (HUD) First National Environ-mental Health Survey of Child Care Centers Final Report Volume II Analysis ofAllergen Levels on Floors Office of Healthy Homes and Lead Hazard ControlWashington DC HUD 2003

14 Leaderer BP Belanger K Triche E et al Dust mite cockroach cat and dog allergenconcentrations in homes of asthmatic children in the northeastern United States impactof socioeconomic factors and population density Environ Health Perspect2002110419ndash425

15 Rosenstreich DL Eggleston P Katten M et al The role of cockroach allergy andexposure to cockroach allergen in causing morbidity among inner-city children withasthma N Engl J Med 19973361356ndash1363

16 Institute of Medicine (IOM) 2004 Damp Indoor Spaces and Health National Academyof Sciences Washington DC National Academy Press Available at http wwwnapedubooks0309091934html Accessed March 5 2007

17 Washington Post 2006 WeatherPost New Orleans La Historical Weather DataAvailable at httpwwwwashingtonpostcomwp-srvweatherlongtermhistoricaldatanew_orleans_lahtm Accessed March 5 2007

18 Arlian LG Water balance and humidity requirements of house dust mites Exp ApplAcarol 19921615ndash35

19 Smith W Mills K Hazell L Hart B Thomas W Molecular analysis of the group 1 and 2allergens from the house dust mite Euroglyphus maynei Int Arch Allergy Immunol199911815ndash22

20 Hales BJ Thomas WR T-cell sensitization to epitopes from the house dust mitesDermatophagoides pteronyssinus and Euroglyphus maynei Exp Allergy 199727868ndash875

21 Colloff MJ Stewart GA Thompson PJ House dust acarofauna and Der p I equivalent inAustralia the relative importance of Dermatophagoides pteronyssinus and Euroglyphusmaynei Clin Exp Allergy 1991121225ndash230

22 Arlian LG Bernstein D Bernstein IL et al Prevalence of dust mites in the homes ofpeople with asthma living in eight different geographic areas of the United States JAllergy Clin Immunol 199290292ndash300

23 Arbes SJ Cohn RD Yin M et al Dog allergen (Can F 1) and cat allergen (Fel d 1) inUS homes Results from the National Survey of Lead and Allergens in Housing JAllergy Clin Immunol 2004114111ndash117

24 Kitch BT Chew G Burge HA et al Socioeconomic predictors of high allergen levels inhomes in the greater Boston area Environ Health Perspect 2000108301ndash307

792 RABITO ET AL

child was enrolled in the study For children recruited from clinics the childpresenting with symptoms was enrolled in the study For children recruited from thecommunity one eligible child per household was randomly selected for inclusionThe study received approval from the Institutional Review Board of the TulaneUniversity Office of Human Research Protection

Environmental Sampling and MeasurementsFive vacuum dust allergen samples were taken from each household from 8 April2004 through 30 July 2005 Samples were taken from the living room floor andupholstery child_s bedroom floor and bed and kitchen floor using separate dustcollection bags [Dermatology Allergy and Clinical Immunology Reference Labo-ratory (DACI) Baltimore MD] attached to a Kenmore (12-amp high-efficiencyparticulate air-filtered canister) electric-powered portable hand-held vacuumcleaner with optional wand extension Trained environmental health paraprofes-sionals vacuumed each sample area for 5 min The vacuum cleaner hose andheadpiece was wiped clean and gloves were replaced after each sample wascollected to prevent contamination The selection of sample areas and the overallsampling process followed a standardized protocol13 Samples were kept in separatebags after collection labeled and mailed to the appropriate laboratory Sampleswere analyzed for dust mite (Der p 1 and Der f 1) cat (Fel d 1) dog (Can f 1) andGerman cockroach (Bla g 1) allergens Temperature and relative humidity weremeasured at the time of dust sample collection using a BK Precision thermo-hygrometer in the living room kitchen and child_s bedroom

Environmental Sample AnalysisEnvironmental dust samples were sent to Aerotech PampK Microbiology Services(Cherry Hill NJ) (543 samples) and the Johns Hopkins University DACI(Baltimore MD) (457 samples) for analysis At the DACI laboratory theaeroallergens in sieved reservoir dust were extracted [100 mg in 2 ml of phosphate-buffered saline (PBS)ndash5 bovine serum albumin] and quantified using a monoclo-nal antibody-based two-site immunoenzymetric assay All monoclonal antibodyreagents and allergen standards were purchased from Indoor Biotechnology(Charlottesville VA USA) The Aerotech PampK laboratory extracted sieved dustsamples (100 mg in 2 ml) in PBS pH 74 with 005 Tween 20 (PBS-T) and mixedend over end for 2 h on an orbital rotator at room temperature The samples werethen centrifuged for 20 min at 2500 rpm at 4-C and the supernatants were usedfor detection of Der p 1 Der f 1 Can f 1 Fel d 1 and Bla g 1 by ELISA method

Both laboratories reported values below the laboratory detection levels PampKreported Bbelow detection limit^ and Bminimum quantification limit (MQL)^ andDACI laboratory reported values less than the minimum detection limit for thegiven quantity We assigned half of the MQL values to PampK laboratory sampleshalf of the highest minimum detection limit value was assigned to samples from theDACI laboratory as per instruction by the service provider (personal communica-tion May 2006)

Statistical AnalysisBased on the literature lower and upper cut-off points for dust allergens were set at92 and Q10 mgg for Der p 1 and Der f 1 Q1 and 98 mgg for Fel d1 Q2 and 910 mggfor Can f 1 and 92 and 98 Ug for Bla g 191415 Average household relative humiditywas calculated by taking an average of baseline relative humidity levels in the

784 RABITO ET AL

kitchen living room and bedroom Descriptive statistics were performed toexamine frequencies of study variables Chi-square tests were used to examinedifferences in allergen exposure by levels of relative humidity (e50 and 950) andother pertinent household characteristics Odds ratios 95 confidence intervals(CIs) and exact p values were reported for bivariate analysis All analyses wereperformed using SAS software (version 91 SAS Institute Cary NC USA)

RESULTS

Of 116 eligible children 86 (74) were enrolled in the study After acquiringinformed consent 16 families could not be contacted to schedule the baseline homevisit 12 refused to participate (eg busy schedule family medical emergencies)one mother refused to have blood drawn on her child and one family moved

Complete sociodemographic characteristics of the study population are de-scribed in Table 1 The majority of the study sample was African American (977)

TABLE 1 Sociodemographic characteristics of study population (N=86)

Variable n ()

SexFemale 30 (353)Male 55 (647)

RaceAfrican American 84 (977)White 2 (23)

Age in years4 to 11 years 63 (733)6 to 17 years 22 (267)

Other asthmatic children in householdYes 20 (233)No 66 (767)

Health insurancePrivate 3 (55)Medicaid 52 (945)

Home ownershipOwner 31 (360)Renter 55 (640)

EmploymentYes 60 (698)No 26 (322)

Education level of primary caregiverLess than high school graduate 4 (47)High school graduate and some college 63 (733)College graduate or more 18 (209)Refused to answer 1 (12)

Annual household incomeLess than $10000 51 (600)$10000 to $15000 12 (141)$15001 to $25000 10 (118)$25001 to $50000 8 (94)Refused to answer 4 (47)

Some variables do not add up to 86 due to missing data

785INDOOR ALLERGEN EXPOSURES AMONG CHILDREN WITH ASTHMA

and male (647) and most children were between the ages of 4 and 11 years Inmost homes the primary caregiver was employed and 94 had at least a high schooleducation Average household income for 74 of the families was less than $15000Results from the survey questionnaire on home environment and residential char-acteristics are described in Table 2 The average relative humidity () was between51 and 53 Twenty four percent of children were exposed to environmentaltobacco smoke defined as having one or more regular smokers smoking inside thehouse Visual observation by health paraprofessionals found evidence of cock-roachesrodents (eg eggs droppings) in 17 out of 86 homes Whereas very fewhouseholds had evidence of visible mold (7) or standing water (5) some werefound to have water damage moisture and leaks (13)

Environmental dust results from kitchen floors living room floor andupholstery and child_s bedroom floor and bed were available for analysis in 83 ofthe enrolled households The prevalence of households having moderate and high

TABLE 2 Residential characteristics of the study population (N=86)

Variable Mean (TSD)

Temperature (-F)Kitchen 736 (111)Living room 731 (114)Bedroom 733 (112)

Relative humidityKitchen 733 (112)Living room 517 (110)Bedroom 515 (108)

Number of rooms in household 66 (21)N ()

Total number of people in householdLess than 5 64 (744)5 or more 22 (256)

Smoking inside the houseNone 65 (744)1 to 3 people 19 (221)4 or more 2 (23)

Pets (cat dog bird rodent)None 63 (733)Single 14 (163)Multiple 9 (104)

Evidence or water damage moisture or leaksYes 11 (134)No 71 (866)

Visible evidence of moldYes 6 (71)No 79 (929)

Presence of standing waterYes 4 (47)No 82 (953)

Evidence of cockroach or rodentsYes 17 (202)No 67 (798)

786 RABITO ET AL

levels of allergens in at least one of these samples (Table 3) was estimated We foundthat 771 of households had 920 mgg of either dust mite allergen (Der p 1 or Derf 1) and 566 had 920 Ug of cockroach allergen (Bla g 1) Dog allergen levels(Can f 1) Q20 mgg were found in 554 of households Among the five indoorallergens cat allergen (Fel d 1) levels were the lowest

Average household humidity greater than 50 was associated with 920 mggof either Der p 1 or Der f 1 dust mite allergen (odds ratio=32 95 CI=11 93 pvalue=003) but was not associated with any other dust allergen (Table 4)Homeownership was associated with low levels of Bla g 1 (odds ratio=261 95CI=103 66 p value=004) and households where research staff reported seeingevidence of cockroaches during home visits were significantly more likely to haveBla g 1 levels above 80 Ug in the kitchen (OR=140 95 CI=33 595 pvalue=G0001) Homes in which the primary caretaker had at least some collegeeducation were less likely to have Der p 1 levels 920 mgg (odds ratio=028 95CI=010 075 p value=001) Household income and the number of people livingin the household were not associated with dust allergen levels

DISCUSSION

Previous research has shown substantial regional variability in home dust allergenlevels among asthmatic children living in US inner cities9 Whereas a number ofstudies have been published which describe the urban and suburban environmentsof asthmatics living in the densely populated northeast areas of the USA there hasbeen little data published on home dust allergen levels of asthmatic children livingin urban areas of the Gulf South914 Climatic conditions in this region of thecountry are distinguished by high temperature and year-round elevated humiditycreating a damp environment suitable for allergen growth The Institute of

TABLE 3 Distribution of allergen levels in the household floor bed and upholstery (N=83)

Allergens n ()

Der p 1 (mgg)920 38(458)Q100 15(181)

Der f 1 (mgg)920 49(590)Q100 13(157)

Either dust mite (mgg)920 64(771)Q100 27(325)

Fel d 1 (mgg)10ndash80 8(96)980 5(60)

Can f 1 (mgg)20ndash100 24(289)9100 22(265)

Bla g 1 (Ug)920 47(566)980 28(337)

787INDOOR ALLERGEN EXPOSURES AMONG CHILDREN WITH ASTHMA

Medicine concluded that a damp indoor environment is related to asthmaexacerbation and increased morbidity acting primarily through the proliferationof moisture-sensitive allergens16

Our findings revealed a highly allergenic home environment Seventy-sevenpercent of children were exposed to two or more indoor allergens above establishedcutpoints and 434 were exposed to three or more allergens (data not shown)Over a quarter of homes had moderate or high exposure to three of four dustallergens tested (dust mite cockroach and dog) Our data show that asthmaticchildren in New Orleans may be exposed to a greater number of allergens atmoderate to high levels compared to asthmatic children living in other inner citiesand to the general population Of particular note is the rate of exposure to highlevels of cockroaches and dust mites (Table 5)

Findings from ICAS established that the homes of inner-city asthmatics living inthe Northeast have a higher concentration of cockroach allergen (specifically NewYork where 622 of homes had levels 92 Ug) than any other region likelybecause of the high number of children living in high-rise apartments wherecockroach extermination is difficult9 In our study where no child lived in a high-rise apartment 566 of the homes had cockroach allergens above 2 Ug and onethird of the households had levels 98 Ug Home humidity level was not associatedwith the presence of cockroach allergens and of the various household character-istics measured only home ownership was associated with cockroach allergens andthe association was weak This leads us to conclude that the high rate of cockroachallergen is related to features of the general ambient rather than the homeenvironment

Dust mites were also a pervasive allergen Seventy-seven percent of NewOrleans homes had levels 92 mgg of dust mite allergen Considering a cutpoint of10 mgg the prevalence of residential dust mite exposure was 325 These levelsare substantially higher than those found both in the homes of asthmatics in theICAS sample and levels in beds in the general population29 Our findings supportan association between high humidity and dust mite exposure suggesting that anintervention that reduces home humidity levels may be warranted New Orleans

TABLE 4 Unadjusted association between average household humidity and dust allergenlevels (N=83)

Allergens 950 humidity [n ()] OR (95 CI) p value

Either dust mite 32 (11 93) 003a

e20 mgg 7 (146)920 mgg 41 (854)

Fel d 1 06 (02 18) 032G10 mgg 42 (875)Q10 mgg 6 (125)

Can f 1 14 (06 34) 046G20 mgg 20 (417)Q20 mgg 28 (583)

Bla g 1 10 (04 25) 097e20 Ug 21 (438)920 Ug 27 (563)

aStatistically significant (p valueG005)

788 RABITO ET AL

TABLE

5Co

mparisonofhomeallergen

levels()betweenNew

Orleansan

dother

cities

Allergens

New

Orleans

(n=83)

Dallasa

(n=135)

Seattlea

(n=127)

Bostona

(n=119)

Bronxa

(n=134)

Chicagoa

(n=141)

Tucson

a

(n=140)

New

York

a

(n=141)

Either

dustmite

920

mgg

771

699

651

398

214

167

245

82

Feld1

980

mgg

48

16

328

140

124

59

58

126

Canf1

9100

mgg

253

97

254

91

175

77

199

138

Bla

g1

920Ug

566

477

76

368

543

551

110

622

aGruchalla

etal(2005)9

789INDOOR ALLERGEN EXPOSURES AMONG CHILDREN WITH ASTHMA

has a humid environment with an average morning relative humidity of 8817

Our dust mite findings may have been a conservative estimate of home allergenexposure because potentially relevant species of dust mites were not sampledResearch has shown that in addition to Der p 1 and Der f 1 the dust miteEuroglyphus maynei is prevalent in humid climates and is a cause of allergensensitization around the world1819 Euroglyphus maynei is a primary source of Tcell sensitization and is present in levels that cause sensitization in temperateclimates It is often found in high concentration in beddings providing a pathwayfor exposure2021 A study conducted in New Orleans and seven other geographicareas of the USA found that in New Orleans E maynei was prevalent in 31 ofsampled homes It was also found in a significant number of homes in GalvestonTX and Delray Beach FL suggesting an affinity for southern climates22 Furtherresearch is needed to establish whether E maynei species of house dust is asignificant source of home allergen exposure in New Orleans homes

A quarter of homes had levels of dog (Can f 1) allergen 9100 mgdl comparableto the highest ICAS sitemdashSeattle Fifty-four percent of homes with dog allergenlevels 9100 mgdl reported currently having a dog Although five homes had catallergen levels above 80 mgdl only one of those homes reported currently havingcats Cat allergen levels in homes without cats ranged from 80 to 1474 mgdlThese findings suggest that allergens from previous pets still lingered in the home orwere being tracked in from outdoors Whereas levels of cat and dog allergens werecomparable to levels found in the homes of other inner-city asthmatics they werelower than levels present in the general population Approximately one-third(347) of homes in the National Survey of Lead and Allergens in Housing studyhad dog allergens 9100 mgdl and 349 of homes had detectable cat allergenlevels above 80 mgdl23

In addition to the climatic disposition indoor allergen exposure also dependson socioeconomic and sociodemographic factors7 The demographic characteristicsof our study population are similar to those in the ICAS study however the majorityof our sample was African-American and had a lower annual incomemdashdespite asimilar educational level10 The majority of families reported receiving an asthmamanagement plan home cleaning advice and advice on trigger avoidance fromtheir medical provider Furthermore most families reported taking steps to reducehome allergen levels by ceasing to smoke attempting to eliminate pests andvacuuming regularly (data not shown) Despite these efforts home dust allergenlevels were very high A combination of an environment conducive to allergengrowth and poverty may be a plausible explanation for these findings Approxi-mately 70 of caregivers were employed but the majority of families had annualincomes of G$15000 Few families reported using mattress covers or air filters andfew reported removing carpets or drapes (data not shown) A lack of resourcescould be the primary barrier to purchasing allergen avoidance supplies Kitch et alreported that in the greater Boston area low family income was associated withgreater risk of exposure to high levels of cockroach allergen and a lower risk of dustmite allergen exposure in the home24 In our sample of low-income families bothdust mite and cockroach were prevalent household allergens

Asthmatic children in New Orleans are at high risk of exposure to multipleindoor allergens Overall our study homes showed higher levels for three out offour allergens namely dust mites cockroach and dog dander compared to allICAS sites Compared to the general population levels of cockroach and dust miteallergens were consistently higher yet levels of cat and dog allergens were lower

790 RABITO ET AL

Our findings reinforce evidence of substantial regional variability in the indoorallergen levels of asthmatic children In an ideal situation allergen avoidance adviceshould be tailored to a child_s specific home environment However individualhome allergen testing is not feasible in the clinical setting making regional exposuredata an important resource for clinicians This study fills a data gap on the homeexposure profile of asthmatic children in the Gulf South region of the USA

ACKNOWLEDGMENTS

This study was funded by the US Department of Housing and Urban DevelopmentOffice of Healthy Homes and Lead Hazard Control Healthy Homes program grant LALHH0121-03

We thank Dr Peter Ashley and Kyla Leon MPH for their assistance inpreparing this manuscript

REFERENCES

1 Bashir SA Home is where the harm is Inadequate housing as a public health crisis Am JPub Health 200292733ndash738

2 Arbes SJ Cohn RD Yin M et al House dust mite allergen in US beds results from theFirst National Survey of Lead and Allergens in Housing J Allergy Clin Immunol2003111408ndash414

3 Institute of Medicine (IOM) Committee on the Assessment of Asthma and Indoor AirCleaning the Air Asthma and Indoor Air Exposures Division of Health Promotion andDisease Prevention Washington DC IOM 2000

4 Gold DR Wright R Population disparities in asthma Annu Rev Public Health20052689ndash113

5 Custovic A Indoor allergens are a primary cause of asthma Eur Respir Rev19988155ndash158

6 Sporik R Holgate T Platts-Mills T et al Exposure to house-dust mite allergen (Der p I)and the development of asthma in childhood N Engl J Med 1990323502ndash507

7 Platts-Mills TAE Vervloet D Thomas WR Aalberse RC Chapman MD Indoorallergens and asthma Report of the Third International Workshop J Allergy ClinImmunol 1997100(6 pt 1)S2ndashS24

8 Huss K Adkinson N Eggleston PA Dawson C Van Natta ML Hamilton RG Housedust mite and cockroach exposure are strong risk factors for positive allergy skin testresponses in the Childhood Asthma Management Program J Allergy Clin Immunol200110748ndash54

9 Gruchalla RS Pongracic J Plaut M et al Inner city asthma study Relationships amongsensitivity allergen exposure and asthma morbidity J Allergy Clin Immunol2005115478ndash485

10 Crain EF Walter M O_Connor GT et al Home and allergic characteristics of childrenwith asthma in seven US urban communities and design of and environmentalintervention The Inner City Asthma Study Environ Health Perspect 2002110939ndash945

11 Eggleston PA Rosenstreich D Lynn H et al Relationship of indoor allergen exposure toskin test sensitivity in inner-city children with asthma J Allergy Clin Immunol1998102563ndash570

12 Mvula M Larzelere M Kraus M et al Prevalence of asthma and asthma-like symptomsin inner-city school children J Asthma 200519ndash16

791INDOOR ALLERGEN EXPOSURES AMONG CHILDREN WITH ASTHMA

13 US Department of Housing and Urban Development (HUD) First National Environ-mental Health Survey of Child Care Centers Final Report Volume II Analysis ofAllergen Levels on Floors Office of Healthy Homes and Lead Hazard ControlWashington DC HUD 2003

14 Leaderer BP Belanger K Triche E et al Dust mite cockroach cat and dog allergenconcentrations in homes of asthmatic children in the northeastern United States impactof socioeconomic factors and population density Environ Health Perspect2002110419ndash425

15 Rosenstreich DL Eggleston P Katten M et al The role of cockroach allergy andexposure to cockroach allergen in causing morbidity among inner-city children withasthma N Engl J Med 19973361356ndash1363

16 Institute of Medicine (IOM) 2004 Damp Indoor Spaces and Health National Academyof Sciences Washington DC National Academy Press Available at http wwwnapedubooks0309091934html Accessed March 5 2007

17 Washington Post 2006 WeatherPost New Orleans La Historical Weather DataAvailable at httpwwwwashingtonpostcomwp-srvweatherlongtermhistoricaldatanew_orleans_lahtm Accessed March 5 2007

18 Arlian LG Water balance and humidity requirements of house dust mites Exp ApplAcarol 19921615ndash35

19 Smith W Mills K Hazell L Hart B Thomas W Molecular analysis of the group 1 and 2allergens from the house dust mite Euroglyphus maynei Int Arch Allergy Immunol199911815ndash22

20 Hales BJ Thomas WR T-cell sensitization to epitopes from the house dust mitesDermatophagoides pteronyssinus and Euroglyphus maynei Exp Allergy 199727868ndash875

21 Colloff MJ Stewart GA Thompson PJ House dust acarofauna and Der p I equivalent inAustralia the relative importance of Dermatophagoides pteronyssinus and Euroglyphusmaynei Clin Exp Allergy 1991121225ndash230

22 Arlian LG Bernstein D Bernstein IL et al Prevalence of dust mites in the homes ofpeople with asthma living in eight different geographic areas of the United States JAllergy Clin Immunol 199290292ndash300

23 Arbes SJ Cohn RD Yin M et al Dog allergen (Can F 1) and cat allergen (Fel d 1) inUS homes Results from the National Survey of Lead and Allergens in Housing JAllergy Clin Immunol 2004114111ndash117

24 Kitch BT Chew G Burge HA et al Socioeconomic predictors of high allergen levels inhomes in the greater Boston area Environ Health Perspect 2000108301ndash307

792 RABITO ET AL

kitchen living room and bedroom Descriptive statistics were performed toexamine frequencies of study variables Chi-square tests were used to examinedifferences in allergen exposure by levels of relative humidity (e50 and 950) andother pertinent household characteristics Odds ratios 95 confidence intervals(CIs) and exact p values were reported for bivariate analysis All analyses wereperformed using SAS software (version 91 SAS Institute Cary NC USA)

RESULTS

Of 116 eligible children 86 (74) were enrolled in the study After acquiringinformed consent 16 families could not be contacted to schedule the baseline homevisit 12 refused to participate (eg busy schedule family medical emergencies)one mother refused to have blood drawn on her child and one family moved

Complete sociodemographic characteristics of the study population are de-scribed in Table 1 The majority of the study sample was African American (977)

TABLE 1 Sociodemographic characteristics of study population (N=86)

Variable n ()

SexFemale 30 (353)Male 55 (647)

RaceAfrican American 84 (977)White 2 (23)

Age in years4 to 11 years 63 (733)6 to 17 years 22 (267)

Other asthmatic children in householdYes 20 (233)No 66 (767)

Health insurancePrivate 3 (55)Medicaid 52 (945)

Home ownershipOwner 31 (360)Renter 55 (640)

EmploymentYes 60 (698)No 26 (322)

Education level of primary caregiverLess than high school graduate 4 (47)High school graduate and some college 63 (733)College graduate or more 18 (209)Refused to answer 1 (12)

Annual household incomeLess than $10000 51 (600)$10000 to $15000 12 (141)$15001 to $25000 10 (118)$25001 to $50000 8 (94)Refused to answer 4 (47)

Some variables do not add up to 86 due to missing data

785INDOOR ALLERGEN EXPOSURES AMONG CHILDREN WITH ASTHMA

and male (647) and most children were between the ages of 4 and 11 years Inmost homes the primary caregiver was employed and 94 had at least a high schooleducation Average household income for 74 of the families was less than $15000Results from the survey questionnaire on home environment and residential char-acteristics are described in Table 2 The average relative humidity () was between51 and 53 Twenty four percent of children were exposed to environmentaltobacco smoke defined as having one or more regular smokers smoking inside thehouse Visual observation by health paraprofessionals found evidence of cock-roachesrodents (eg eggs droppings) in 17 out of 86 homes Whereas very fewhouseholds had evidence of visible mold (7) or standing water (5) some werefound to have water damage moisture and leaks (13)

Environmental dust results from kitchen floors living room floor andupholstery and child_s bedroom floor and bed were available for analysis in 83 ofthe enrolled households The prevalence of households having moderate and high

TABLE 2 Residential characteristics of the study population (N=86)

Variable Mean (TSD)

Temperature (-F)Kitchen 736 (111)Living room 731 (114)Bedroom 733 (112)

Relative humidityKitchen 733 (112)Living room 517 (110)Bedroom 515 (108)

Number of rooms in household 66 (21)N ()

Total number of people in householdLess than 5 64 (744)5 or more 22 (256)

Smoking inside the houseNone 65 (744)1 to 3 people 19 (221)4 or more 2 (23)

Pets (cat dog bird rodent)None 63 (733)Single 14 (163)Multiple 9 (104)

Evidence or water damage moisture or leaksYes 11 (134)No 71 (866)

Visible evidence of moldYes 6 (71)No 79 (929)

Presence of standing waterYes 4 (47)No 82 (953)

Evidence of cockroach or rodentsYes 17 (202)No 67 (798)

786 RABITO ET AL

levels of allergens in at least one of these samples (Table 3) was estimated We foundthat 771 of households had 920 mgg of either dust mite allergen (Der p 1 or Derf 1) and 566 had 920 Ug of cockroach allergen (Bla g 1) Dog allergen levels(Can f 1) Q20 mgg were found in 554 of households Among the five indoorallergens cat allergen (Fel d 1) levels were the lowest

Average household humidity greater than 50 was associated with 920 mggof either Der p 1 or Der f 1 dust mite allergen (odds ratio=32 95 CI=11 93 pvalue=003) but was not associated with any other dust allergen (Table 4)Homeownership was associated with low levels of Bla g 1 (odds ratio=261 95CI=103 66 p value=004) and households where research staff reported seeingevidence of cockroaches during home visits were significantly more likely to haveBla g 1 levels above 80 Ug in the kitchen (OR=140 95 CI=33 595 pvalue=G0001) Homes in which the primary caretaker had at least some collegeeducation were less likely to have Der p 1 levels 920 mgg (odds ratio=028 95CI=010 075 p value=001) Household income and the number of people livingin the household were not associated with dust allergen levels

DISCUSSION

Previous research has shown substantial regional variability in home dust allergenlevels among asthmatic children living in US inner cities9 Whereas a number ofstudies have been published which describe the urban and suburban environmentsof asthmatics living in the densely populated northeast areas of the USA there hasbeen little data published on home dust allergen levels of asthmatic children livingin urban areas of the Gulf South914 Climatic conditions in this region of thecountry are distinguished by high temperature and year-round elevated humiditycreating a damp environment suitable for allergen growth The Institute of

TABLE 3 Distribution of allergen levels in the household floor bed and upholstery (N=83)

Allergens n ()

Der p 1 (mgg)920 38(458)Q100 15(181)

Der f 1 (mgg)920 49(590)Q100 13(157)

Either dust mite (mgg)920 64(771)Q100 27(325)

Fel d 1 (mgg)10ndash80 8(96)980 5(60)

Can f 1 (mgg)20ndash100 24(289)9100 22(265)

Bla g 1 (Ug)920 47(566)980 28(337)

787INDOOR ALLERGEN EXPOSURES AMONG CHILDREN WITH ASTHMA

Medicine concluded that a damp indoor environment is related to asthmaexacerbation and increased morbidity acting primarily through the proliferationof moisture-sensitive allergens16

Our findings revealed a highly allergenic home environment Seventy-sevenpercent of children were exposed to two or more indoor allergens above establishedcutpoints and 434 were exposed to three or more allergens (data not shown)Over a quarter of homes had moderate or high exposure to three of four dustallergens tested (dust mite cockroach and dog) Our data show that asthmaticchildren in New Orleans may be exposed to a greater number of allergens atmoderate to high levels compared to asthmatic children living in other inner citiesand to the general population Of particular note is the rate of exposure to highlevels of cockroaches and dust mites (Table 5)

Findings from ICAS established that the homes of inner-city asthmatics living inthe Northeast have a higher concentration of cockroach allergen (specifically NewYork where 622 of homes had levels 92 Ug) than any other region likelybecause of the high number of children living in high-rise apartments wherecockroach extermination is difficult9 In our study where no child lived in a high-rise apartment 566 of the homes had cockroach allergens above 2 Ug and onethird of the households had levels 98 Ug Home humidity level was not associatedwith the presence of cockroach allergens and of the various household character-istics measured only home ownership was associated with cockroach allergens andthe association was weak This leads us to conclude that the high rate of cockroachallergen is related to features of the general ambient rather than the homeenvironment

Dust mites were also a pervasive allergen Seventy-seven percent of NewOrleans homes had levels 92 mgg of dust mite allergen Considering a cutpoint of10 mgg the prevalence of residential dust mite exposure was 325 These levelsare substantially higher than those found both in the homes of asthmatics in theICAS sample and levels in beds in the general population29 Our findings supportan association between high humidity and dust mite exposure suggesting that anintervention that reduces home humidity levels may be warranted New Orleans

TABLE 4 Unadjusted association between average household humidity and dust allergenlevels (N=83)

Allergens 950 humidity [n ()] OR (95 CI) p value

Either dust mite 32 (11 93) 003a

e20 mgg 7 (146)920 mgg 41 (854)

Fel d 1 06 (02 18) 032G10 mgg 42 (875)Q10 mgg 6 (125)

Can f 1 14 (06 34) 046G20 mgg 20 (417)Q20 mgg 28 (583)

Bla g 1 10 (04 25) 097e20 Ug 21 (438)920 Ug 27 (563)

aStatistically significant (p valueG005)

788 RABITO ET AL

TABLE

5Co

mparisonofhomeallergen

levels()betweenNew

Orleansan

dother

cities

Allergens

New

Orleans

(n=83)

Dallasa

(n=135)

Seattlea

(n=127)

Bostona

(n=119)

Bronxa

(n=134)

Chicagoa

(n=141)

Tucson

a

(n=140)

New

York

a

(n=141)

Either

dustmite

920

mgg

771

699

651

398

214

167

245

82

Feld1

980

mgg

48

16

328

140

124

59

58

126

Canf1

9100

mgg

253

97

254

91

175

77

199

138

Bla

g1

920Ug

566

477

76

368

543

551

110

622

aGruchalla

etal(2005)9

789INDOOR ALLERGEN EXPOSURES AMONG CHILDREN WITH ASTHMA

has a humid environment with an average morning relative humidity of 8817

Our dust mite findings may have been a conservative estimate of home allergenexposure because potentially relevant species of dust mites were not sampledResearch has shown that in addition to Der p 1 and Der f 1 the dust miteEuroglyphus maynei is prevalent in humid climates and is a cause of allergensensitization around the world1819 Euroglyphus maynei is a primary source of Tcell sensitization and is present in levels that cause sensitization in temperateclimates It is often found in high concentration in beddings providing a pathwayfor exposure2021 A study conducted in New Orleans and seven other geographicareas of the USA found that in New Orleans E maynei was prevalent in 31 ofsampled homes It was also found in a significant number of homes in GalvestonTX and Delray Beach FL suggesting an affinity for southern climates22 Furtherresearch is needed to establish whether E maynei species of house dust is asignificant source of home allergen exposure in New Orleans homes

A quarter of homes had levels of dog (Can f 1) allergen 9100 mgdl comparableto the highest ICAS sitemdashSeattle Fifty-four percent of homes with dog allergenlevels 9100 mgdl reported currently having a dog Although five homes had catallergen levels above 80 mgdl only one of those homes reported currently havingcats Cat allergen levels in homes without cats ranged from 80 to 1474 mgdlThese findings suggest that allergens from previous pets still lingered in the home orwere being tracked in from outdoors Whereas levels of cat and dog allergens werecomparable to levels found in the homes of other inner-city asthmatics they werelower than levels present in the general population Approximately one-third(347) of homes in the National Survey of Lead and Allergens in Housing studyhad dog allergens 9100 mgdl and 349 of homes had detectable cat allergenlevels above 80 mgdl23

In addition to the climatic disposition indoor allergen exposure also dependson socioeconomic and sociodemographic factors7 The demographic characteristicsof our study population are similar to those in the ICAS study however the majorityof our sample was African-American and had a lower annual incomemdashdespite asimilar educational level10 The majority of families reported receiving an asthmamanagement plan home cleaning advice and advice on trigger avoidance fromtheir medical provider Furthermore most families reported taking steps to reducehome allergen levels by ceasing to smoke attempting to eliminate pests andvacuuming regularly (data not shown) Despite these efforts home dust allergenlevels were very high A combination of an environment conducive to allergengrowth and poverty may be a plausible explanation for these findings Approxi-mately 70 of caregivers were employed but the majority of families had annualincomes of G$15000 Few families reported using mattress covers or air filters andfew reported removing carpets or drapes (data not shown) A lack of resourcescould be the primary barrier to purchasing allergen avoidance supplies Kitch et alreported that in the greater Boston area low family income was associated withgreater risk of exposure to high levels of cockroach allergen and a lower risk of dustmite allergen exposure in the home24 In our sample of low-income families bothdust mite and cockroach were prevalent household allergens

Asthmatic children in New Orleans are at high risk of exposure to multipleindoor allergens Overall our study homes showed higher levels for three out offour allergens namely dust mites cockroach and dog dander compared to allICAS sites Compared to the general population levels of cockroach and dust miteallergens were consistently higher yet levels of cat and dog allergens were lower

790 RABITO ET AL

Our findings reinforce evidence of substantial regional variability in the indoorallergen levels of asthmatic children In an ideal situation allergen avoidance adviceshould be tailored to a child_s specific home environment However individualhome allergen testing is not feasible in the clinical setting making regional exposuredata an important resource for clinicians This study fills a data gap on the homeexposure profile of asthmatic children in the Gulf South region of the USA

ACKNOWLEDGMENTS

This study was funded by the US Department of Housing and Urban DevelopmentOffice of Healthy Homes and Lead Hazard Control Healthy Homes program grant LALHH0121-03

We thank Dr Peter Ashley and Kyla Leon MPH for their assistance inpreparing this manuscript

REFERENCES

1 Bashir SA Home is where the harm is Inadequate housing as a public health crisis Am JPub Health 200292733ndash738

2 Arbes SJ Cohn RD Yin M et al House dust mite allergen in US beds results from theFirst National Survey of Lead and Allergens in Housing J Allergy Clin Immunol2003111408ndash414

3 Institute of Medicine (IOM) Committee on the Assessment of Asthma and Indoor AirCleaning the Air Asthma and Indoor Air Exposures Division of Health Promotion andDisease Prevention Washington DC IOM 2000

4 Gold DR Wright R Population disparities in asthma Annu Rev Public Health20052689ndash113

5 Custovic A Indoor allergens are a primary cause of asthma Eur Respir Rev19988155ndash158

6 Sporik R Holgate T Platts-Mills T et al Exposure to house-dust mite allergen (Der p I)and the development of asthma in childhood N Engl J Med 1990323502ndash507

7 Platts-Mills TAE Vervloet D Thomas WR Aalberse RC Chapman MD Indoorallergens and asthma Report of the Third International Workshop J Allergy ClinImmunol 1997100(6 pt 1)S2ndashS24

8 Huss K Adkinson N Eggleston PA Dawson C Van Natta ML Hamilton RG Housedust mite and cockroach exposure are strong risk factors for positive allergy skin testresponses in the Childhood Asthma Management Program J Allergy Clin Immunol200110748ndash54

9 Gruchalla RS Pongracic J Plaut M et al Inner city asthma study Relationships amongsensitivity allergen exposure and asthma morbidity J Allergy Clin Immunol2005115478ndash485

10 Crain EF Walter M O_Connor GT et al Home and allergic characteristics of childrenwith asthma in seven US urban communities and design of and environmentalintervention The Inner City Asthma Study Environ Health Perspect 2002110939ndash945

11 Eggleston PA Rosenstreich D Lynn H et al Relationship of indoor allergen exposure toskin test sensitivity in inner-city children with asthma J Allergy Clin Immunol1998102563ndash570

12 Mvula M Larzelere M Kraus M et al Prevalence of asthma and asthma-like symptomsin inner-city school children J Asthma 200519ndash16

791INDOOR ALLERGEN EXPOSURES AMONG CHILDREN WITH ASTHMA

13 US Department of Housing and Urban Development (HUD) First National Environ-mental Health Survey of Child Care Centers Final Report Volume II Analysis ofAllergen Levels on Floors Office of Healthy Homes and Lead Hazard ControlWashington DC HUD 2003

14 Leaderer BP Belanger K Triche E et al Dust mite cockroach cat and dog allergenconcentrations in homes of asthmatic children in the northeastern United States impactof socioeconomic factors and population density Environ Health Perspect2002110419ndash425

15 Rosenstreich DL Eggleston P Katten M et al The role of cockroach allergy andexposure to cockroach allergen in causing morbidity among inner-city children withasthma N Engl J Med 19973361356ndash1363

16 Institute of Medicine (IOM) 2004 Damp Indoor Spaces and Health National Academyof Sciences Washington DC National Academy Press Available at http wwwnapedubooks0309091934html Accessed March 5 2007

17 Washington Post 2006 WeatherPost New Orleans La Historical Weather DataAvailable at httpwwwwashingtonpostcomwp-srvweatherlongtermhistoricaldatanew_orleans_lahtm Accessed March 5 2007

18 Arlian LG Water balance and humidity requirements of house dust mites Exp ApplAcarol 19921615ndash35

19 Smith W Mills K Hazell L Hart B Thomas W Molecular analysis of the group 1 and 2allergens from the house dust mite Euroglyphus maynei Int Arch Allergy Immunol199911815ndash22

20 Hales BJ Thomas WR T-cell sensitization to epitopes from the house dust mitesDermatophagoides pteronyssinus and Euroglyphus maynei Exp Allergy 199727868ndash875

21 Colloff MJ Stewart GA Thompson PJ House dust acarofauna and Der p I equivalent inAustralia the relative importance of Dermatophagoides pteronyssinus and Euroglyphusmaynei Clin Exp Allergy 1991121225ndash230

22 Arlian LG Bernstein D Bernstein IL et al Prevalence of dust mites in the homes ofpeople with asthma living in eight different geographic areas of the United States JAllergy Clin Immunol 199290292ndash300

23 Arbes SJ Cohn RD Yin M et al Dog allergen (Can F 1) and cat allergen (Fel d 1) inUS homes Results from the National Survey of Lead and Allergens in Housing JAllergy Clin Immunol 2004114111ndash117

24 Kitch BT Chew G Burge HA et al Socioeconomic predictors of high allergen levels inhomes in the greater Boston area Environ Health Perspect 2000108301ndash307

792 RABITO ET AL

and male (647) and most children were between the ages of 4 and 11 years Inmost homes the primary caregiver was employed and 94 had at least a high schooleducation Average household income for 74 of the families was less than $15000Results from the survey questionnaire on home environment and residential char-acteristics are described in Table 2 The average relative humidity () was between51 and 53 Twenty four percent of children were exposed to environmentaltobacco smoke defined as having one or more regular smokers smoking inside thehouse Visual observation by health paraprofessionals found evidence of cock-roachesrodents (eg eggs droppings) in 17 out of 86 homes Whereas very fewhouseholds had evidence of visible mold (7) or standing water (5) some werefound to have water damage moisture and leaks (13)

Environmental dust results from kitchen floors living room floor andupholstery and child_s bedroom floor and bed were available for analysis in 83 ofthe enrolled households The prevalence of households having moderate and high

TABLE 2 Residential characteristics of the study population (N=86)

Variable Mean (TSD)

Temperature (-F)Kitchen 736 (111)Living room 731 (114)Bedroom 733 (112)

Relative humidityKitchen 733 (112)Living room 517 (110)Bedroom 515 (108)

Number of rooms in household 66 (21)N ()

Total number of people in householdLess than 5 64 (744)5 or more 22 (256)

Smoking inside the houseNone 65 (744)1 to 3 people 19 (221)4 or more 2 (23)

Pets (cat dog bird rodent)None 63 (733)Single 14 (163)Multiple 9 (104)

Evidence or water damage moisture or leaksYes 11 (134)No 71 (866)

Visible evidence of moldYes 6 (71)No 79 (929)

Presence of standing waterYes 4 (47)No 82 (953)

Evidence of cockroach or rodentsYes 17 (202)No 67 (798)

786 RABITO ET AL

levels of allergens in at least one of these samples (Table 3) was estimated We foundthat 771 of households had 920 mgg of either dust mite allergen (Der p 1 or Derf 1) and 566 had 920 Ug of cockroach allergen (Bla g 1) Dog allergen levels(Can f 1) Q20 mgg were found in 554 of households Among the five indoorallergens cat allergen (Fel d 1) levels were the lowest

Average household humidity greater than 50 was associated with 920 mggof either Der p 1 or Der f 1 dust mite allergen (odds ratio=32 95 CI=11 93 pvalue=003) but was not associated with any other dust allergen (Table 4)Homeownership was associated with low levels of Bla g 1 (odds ratio=261 95CI=103 66 p value=004) and households where research staff reported seeingevidence of cockroaches during home visits were significantly more likely to haveBla g 1 levels above 80 Ug in the kitchen (OR=140 95 CI=33 595 pvalue=G0001) Homes in which the primary caretaker had at least some collegeeducation were less likely to have Der p 1 levels 920 mgg (odds ratio=028 95CI=010 075 p value=001) Household income and the number of people livingin the household were not associated with dust allergen levels

DISCUSSION

Previous research has shown substantial regional variability in home dust allergenlevels among asthmatic children living in US inner cities9 Whereas a number ofstudies have been published which describe the urban and suburban environmentsof asthmatics living in the densely populated northeast areas of the USA there hasbeen little data published on home dust allergen levels of asthmatic children livingin urban areas of the Gulf South914 Climatic conditions in this region of thecountry are distinguished by high temperature and year-round elevated humiditycreating a damp environment suitable for allergen growth The Institute of

TABLE 3 Distribution of allergen levels in the household floor bed and upholstery (N=83)

Allergens n ()

Der p 1 (mgg)920 38(458)Q100 15(181)

Der f 1 (mgg)920 49(590)Q100 13(157)

Either dust mite (mgg)920 64(771)Q100 27(325)

Fel d 1 (mgg)10ndash80 8(96)980 5(60)

Can f 1 (mgg)20ndash100 24(289)9100 22(265)

Bla g 1 (Ug)920 47(566)980 28(337)

787INDOOR ALLERGEN EXPOSURES AMONG CHILDREN WITH ASTHMA

Medicine concluded that a damp indoor environment is related to asthmaexacerbation and increased morbidity acting primarily through the proliferationof moisture-sensitive allergens16

Our findings revealed a highly allergenic home environment Seventy-sevenpercent of children were exposed to two or more indoor allergens above establishedcutpoints and 434 were exposed to three or more allergens (data not shown)Over a quarter of homes had moderate or high exposure to three of four dustallergens tested (dust mite cockroach and dog) Our data show that asthmaticchildren in New Orleans may be exposed to a greater number of allergens atmoderate to high levels compared to asthmatic children living in other inner citiesand to the general population Of particular note is the rate of exposure to highlevels of cockroaches and dust mites (Table 5)

Findings from ICAS established that the homes of inner-city asthmatics living inthe Northeast have a higher concentration of cockroach allergen (specifically NewYork where 622 of homes had levels 92 Ug) than any other region likelybecause of the high number of children living in high-rise apartments wherecockroach extermination is difficult9 In our study where no child lived in a high-rise apartment 566 of the homes had cockroach allergens above 2 Ug and onethird of the households had levels 98 Ug Home humidity level was not associatedwith the presence of cockroach allergens and of the various household character-istics measured only home ownership was associated with cockroach allergens andthe association was weak This leads us to conclude that the high rate of cockroachallergen is related to features of the general ambient rather than the homeenvironment

Dust mites were also a pervasive allergen Seventy-seven percent of NewOrleans homes had levels 92 mgg of dust mite allergen Considering a cutpoint of10 mgg the prevalence of residential dust mite exposure was 325 These levelsare substantially higher than those found both in the homes of asthmatics in theICAS sample and levels in beds in the general population29 Our findings supportan association between high humidity and dust mite exposure suggesting that anintervention that reduces home humidity levels may be warranted New Orleans

TABLE 4 Unadjusted association between average household humidity and dust allergenlevels (N=83)

Allergens 950 humidity [n ()] OR (95 CI) p value

Either dust mite 32 (11 93) 003a

e20 mgg 7 (146)920 mgg 41 (854)

Fel d 1 06 (02 18) 032G10 mgg 42 (875)Q10 mgg 6 (125)

Can f 1 14 (06 34) 046G20 mgg 20 (417)Q20 mgg 28 (583)

Bla g 1 10 (04 25) 097e20 Ug 21 (438)920 Ug 27 (563)

aStatistically significant (p valueG005)

788 RABITO ET AL

TABLE

5Co

mparisonofhomeallergen

levels()betweenNew

Orleansan

dother

cities

Allergens

New

Orleans

(n=83)

Dallasa

(n=135)

Seattlea

(n=127)

Bostona

(n=119)

Bronxa

(n=134)

Chicagoa

(n=141)

Tucson

a

(n=140)

New

York

a

(n=141)

Either

dustmite

920

mgg

771

699

651

398

214

167

245

82

Feld1

980

mgg

48

16

328

140

124

59

58

126

Canf1

9100

mgg

253

97

254

91

175

77

199

138

Bla

g1

920Ug

566

477

76

368

543

551

110

622

aGruchalla

etal(2005)9

789INDOOR ALLERGEN EXPOSURES AMONG CHILDREN WITH ASTHMA

has a humid environment with an average morning relative humidity of 8817

Our dust mite findings may have been a conservative estimate of home allergenexposure because potentially relevant species of dust mites were not sampledResearch has shown that in addition to Der p 1 and Der f 1 the dust miteEuroglyphus maynei is prevalent in humid climates and is a cause of allergensensitization around the world1819 Euroglyphus maynei is a primary source of Tcell sensitization and is present in levels that cause sensitization in temperateclimates It is often found in high concentration in beddings providing a pathwayfor exposure2021 A study conducted in New Orleans and seven other geographicareas of the USA found that in New Orleans E maynei was prevalent in 31 ofsampled homes It was also found in a significant number of homes in GalvestonTX and Delray Beach FL suggesting an affinity for southern climates22 Furtherresearch is needed to establish whether E maynei species of house dust is asignificant source of home allergen exposure in New Orleans homes

A quarter of homes had levels of dog (Can f 1) allergen 9100 mgdl comparableto the highest ICAS sitemdashSeattle Fifty-four percent of homes with dog allergenlevels 9100 mgdl reported currently having a dog Although five homes had catallergen levels above 80 mgdl only one of those homes reported currently havingcats Cat allergen levels in homes without cats ranged from 80 to 1474 mgdlThese findings suggest that allergens from previous pets still lingered in the home orwere being tracked in from outdoors Whereas levels of cat and dog allergens werecomparable to levels found in the homes of other inner-city asthmatics they werelower than levels present in the general population Approximately one-third(347) of homes in the National Survey of Lead and Allergens in Housing studyhad dog allergens 9100 mgdl and 349 of homes had detectable cat allergenlevels above 80 mgdl23

In addition to the climatic disposition indoor allergen exposure also dependson socioeconomic and sociodemographic factors7 The demographic characteristicsof our study population are similar to those in the ICAS study however the majorityof our sample was African-American and had a lower annual incomemdashdespite asimilar educational level10 The majority of families reported receiving an asthmamanagement plan home cleaning advice and advice on trigger avoidance fromtheir medical provider Furthermore most families reported taking steps to reducehome allergen levels by ceasing to smoke attempting to eliminate pests andvacuuming regularly (data not shown) Despite these efforts home dust allergenlevels were very high A combination of an environment conducive to allergengrowth and poverty may be a plausible explanation for these findings Approxi-mately 70 of caregivers were employed but the majority of families had annualincomes of G$15000 Few families reported using mattress covers or air filters andfew reported removing carpets or drapes (data not shown) A lack of resourcescould be the primary barrier to purchasing allergen avoidance supplies Kitch et alreported that in the greater Boston area low family income was associated withgreater risk of exposure to high levels of cockroach allergen and a lower risk of dustmite allergen exposure in the home24 In our sample of low-income families bothdust mite and cockroach were prevalent household allergens

Asthmatic children in New Orleans are at high risk of exposure to multipleindoor allergens Overall our study homes showed higher levels for three out offour allergens namely dust mites cockroach and dog dander compared to allICAS sites Compared to the general population levels of cockroach and dust miteallergens were consistently higher yet levels of cat and dog allergens were lower

790 RABITO ET AL

Our findings reinforce evidence of substantial regional variability in the indoorallergen levels of asthmatic children In an ideal situation allergen avoidance adviceshould be tailored to a child_s specific home environment However individualhome allergen testing is not feasible in the clinical setting making regional exposuredata an important resource for clinicians This study fills a data gap on the homeexposure profile of asthmatic children in the Gulf South region of the USA

ACKNOWLEDGMENTS

This study was funded by the US Department of Housing and Urban DevelopmentOffice of Healthy Homes and Lead Hazard Control Healthy Homes program grant LALHH0121-03

We thank Dr Peter Ashley and Kyla Leon MPH for their assistance inpreparing this manuscript

REFERENCES

1 Bashir SA Home is where the harm is Inadequate housing as a public health crisis Am JPub Health 200292733ndash738

2 Arbes SJ Cohn RD Yin M et al House dust mite allergen in US beds results from theFirst National Survey of Lead and Allergens in Housing J Allergy Clin Immunol2003111408ndash414

3 Institute of Medicine (IOM) Committee on the Assessment of Asthma and Indoor AirCleaning the Air Asthma and Indoor Air Exposures Division of Health Promotion andDisease Prevention Washington DC IOM 2000

4 Gold DR Wright R Population disparities in asthma Annu Rev Public Health20052689ndash113

5 Custovic A Indoor allergens are a primary cause of asthma Eur Respir Rev19988155ndash158

6 Sporik R Holgate T Platts-Mills T et al Exposure to house-dust mite allergen (Der p I)and the development of asthma in childhood N Engl J Med 1990323502ndash507

7 Platts-Mills TAE Vervloet D Thomas WR Aalberse RC Chapman MD Indoorallergens and asthma Report of the Third International Workshop J Allergy ClinImmunol 1997100(6 pt 1)S2ndashS24

8 Huss K Adkinson N Eggleston PA Dawson C Van Natta ML Hamilton RG Housedust mite and cockroach exposure are strong risk factors for positive allergy skin testresponses in the Childhood Asthma Management Program J Allergy Clin Immunol200110748ndash54

9 Gruchalla RS Pongracic J Plaut M et al Inner city asthma study Relationships amongsensitivity allergen exposure and asthma morbidity J Allergy Clin Immunol2005115478ndash485

10 Crain EF Walter M O_Connor GT et al Home and allergic characteristics of childrenwith asthma in seven US urban communities and design of and environmentalintervention The Inner City Asthma Study Environ Health Perspect 2002110939ndash945

11 Eggleston PA Rosenstreich D Lynn H et al Relationship of indoor allergen exposure toskin test sensitivity in inner-city children with asthma J Allergy Clin Immunol1998102563ndash570

12 Mvula M Larzelere M Kraus M et al Prevalence of asthma and asthma-like symptomsin inner-city school children J Asthma 200519ndash16

791INDOOR ALLERGEN EXPOSURES AMONG CHILDREN WITH ASTHMA

13 US Department of Housing and Urban Development (HUD) First National Environ-mental Health Survey of Child Care Centers Final Report Volume II Analysis ofAllergen Levels on Floors Office of Healthy Homes and Lead Hazard ControlWashington DC HUD 2003

14 Leaderer BP Belanger K Triche E et al Dust mite cockroach cat and dog allergenconcentrations in homes of asthmatic children in the northeastern United States impactof socioeconomic factors and population density Environ Health Perspect2002110419ndash425

15 Rosenstreich DL Eggleston P Katten M et al The role of cockroach allergy andexposure to cockroach allergen in causing morbidity among inner-city children withasthma N Engl J Med 19973361356ndash1363

16 Institute of Medicine (IOM) 2004 Damp Indoor Spaces and Health National Academyof Sciences Washington DC National Academy Press Available at http wwwnapedubooks0309091934html Accessed March 5 2007

17 Washington Post 2006 WeatherPost New Orleans La Historical Weather DataAvailable at httpwwwwashingtonpostcomwp-srvweatherlongtermhistoricaldatanew_orleans_lahtm Accessed March 5 2007

18 Arlian LG Water balance and humidity requirements of house dust mites Exp ApplAcarol 19921615ndash35

19 Smith W Mills K Hazell L Hart B Thomas W Molecular analysis of the group 1 and 2allergens from the house dust mite Euroglyphus maynei Int Arch Allergy Immunol199911815ndash22

20 Hales BJ Thomas WR T-cell sensitization to epitopes from the house dust mitesDermatophagoides pteronyssinus and Euroglyphus maynei Exp Allergy 199727868ndash875

21 Colloff MJ Stewart GA Thompson PJ House dust acarofauna and Der p I equivalent inAustralia the relative importance of Dermatophagoides pteronyssinus and Euroglyphusmaynei Clin Exp Allergy 1991121225ndash230

22 Arlian LG Bernstein D Bernstein IL et al Prevalence of dust mites in the homes ofpeople with asthma living in eight different geographic areas of the United States JAllergy Clin Immunol 199290292ndash300

23 Arbes SJ Cohn RD Yin M et al Dog allergen (Can F 1) and cat allergen (Fel d 1) inUS homes Results from the National Survey of Lead and Allergens in Housing JAllergy Clin Immunol 2004114111ndash117

24 Kitch BT Chew G Burge HA et al Socioeconomic predictors of high allergen levels inhomes in the greater Boston area Environ Health Perspect 2000108301ndash307

792 RABITO ET AL

levels of allergens in at least one of these samples (Table 3) was estimated We foundthat 771 of households had 920 mgg of either dust mite allergen (Der p 1 or Derf 1) and 566 had 920 Ug of cockroach allergen (Bla g 1) Dog allergen levels(Can f 1) Q20 mgg were found in 554 of households Among the five indoorallergens cat allergen (Fel d 1) levels were the lowest

Average household humidity greater than 50 was associated with 920 mggof either Der p 1 or Der f 1 dust mite allergen (odds ratio=32 95 CI=11 93 pvalue=003) but was not associated with any other dust allergen (Table 4)Homeownership was associated with low levels of Bla g 1 (odds ratio=261 95CI=103 66 p value=004) and households where research staff reported seeingevidence of cockroaches during home visits were significantly more likely to haveBla g 1 levels above 80 Ug in the kitchen (OR=140 95 CI=33 595 pvalue=G0001) Homes in which the primary caretaker had at least some collegeeducation were less likely to have Der p 1 levels 920 mgg (odds ratio=028 95CI=010 075 p value=001) Household income and the number of people livingin the household were not associated with dust allergen levels

DISCUSSION

Previous research has shown substantial regional variability in home dust allergenlevels among asthmatic children living in US inner cities9 Whereas a number ofstudies have been published which describe the urban and suburban environmentsof asthmatics living in the densely populated northeast areas of the USA there hasbeen little data published on home dust allergen levels of asthmatic children livingin urban areas of the Gulf South914 Climatic conditions in this region of thecountry are distinguished by high temperature and year-round elevated humiditycreating a damp environment suitable for allergen growth The Institute of

TABLE 3 Distribution of allergen levels in the household floor bed and upholstery (N=83)

Allergens n ()

Der p 1 (mgg)920 38(458)Q100 15(181)

Der f 1 (mgg)920 49(590)Q100 13(157)

Either dust mite (mgg)920 64(771)Q100 27(325)

Fel d 1 (mgg)10ndash80 8(96)980 5(60)

Can f 1 (mgg)20ndash100 24(289)9100 22(265)

Bla g 1 (Ug)920 47(566)980 28(337)

787INDOOR ALLERGEN EXPOSURES AMONG CHILDREN WITH ASTHMA

Medicine concluded that a damp indoor environment is related to asthmaexacerbation and increased morbidity acting primarily through the proliferationof moisture-sensitive allergens16

Our findings revealed a highly allergenic home environment Seventy-sevenpercent of children were exposed to two or more indoor allergens above establishedcutpoints and 434 were exposed to three or more allergens (data not shown)Over a quarter of homes had moderate or high exposure to three of four dustallergens tested (dust mite cockroach and dog) Our data show that asthmaticchildren in New Orleans may be exposed to a greater number of allergens atmoderate to high levels compared to asthmatic children living in other inner citiesand to the general population Of particular note is the rate of exposure to highlevels of cockroaches and dust mites (Table 5)

Findings from ICAS established that the homes of inner-city asthmatics living inthe Northeast have a higher concentration of cockroach allergen (specifically NewYork where 622 of homes had levels 92 Ug) than any other region likelybecause of the high number of children living in high-rise apartments wherecockroach extermination is difficult9 In our study where no child lived in a high-rise apartment 566 of the homes had cockroach allergens above 2 Ug and onethird of the households had levels 98 Ug Home humidity level was not associatedwith the presence of cockroach allergens and of the various household character-istics measured only home ownership was associated with cockroach allergens andthe association was weak This leads us to conclude that the high rate of cockroachallergen is related to features of the general ambient rather than the homeenvironment

Dust mites were also a pervasive allergen Seventy-seven percent of NewOrleans homes had levels 92 mgg of dust mite allergen Considering a cutpoint of10 mgg the prevalence of residential dust mite exposure was 325 These levelsare substantially higher than those found both in the homes of asthmatics in theICAS sample and levels in beds in the general population29 Our findings supportan association between high humidity and dust mite exposure suggesting that anintervention that reduces home humidity levels may be warranted New Orleans

TABLE 4 Unadjusted association between average household humidity and dust allergenlevels (N=83)

Allergens 950 humidity [n ()] OR (95 CI) p value

Either dust mite 32 (11 93) 003a

e20 mgg 7 (146)920 mgg 41 (854)

Fel d 1 06 (02 18) 032G10 mgg 42 (875)Q10 mgg 6 (125)

Can f 1 14 (06 34) 046G20 mgg 20 (417)Q20 mgg 28 (583)

Bla g 1 10 (04 25) 097e20 Ug 21 (438)920 Ug 27 (563)

aStatistically significant (p valueG005)

788 RABITO ET AL

TABLE

5Co

mparisonofhomeallergen

levels()betweenNew

Orleansan

dother

cities

Allergens

New

Orleans

(n=83)

Dallasa

(n=135)

Seattlea

(n=127)

Bostona

(n=119)

Bronxa

(n=134)

Chicagoa

(n=141)

Tucson

a

(n=140)

New

York

a

(n=141)

Either

dustmite

920

mgg

771

699

651

398

214

167

245

82

Feld1

980

mgg

48

16

328

140

124

59

58

126

Canf1

9100

mgg

253

97

254

91

175

77

199

138

Bla

g1

920Ug

566

477

76

368

543

551

110

622

aGruchalla

etal(2005)9

789INDOOR ALLERGEN EXPOSURES AMONG CHILDREN WITH ASTHMA

has a humid environment with an average morning relative humidity of 8817

Our dust mite findings may have been a conservative estimate of home allergenexposure because potentially relevant species of dust mites were not sampledResearch has shown that in addition to Der p 1 and Der f 1 the dust miteEuroglyphus maynei is prevalent in humid climates and is a cause of allergensensitization around the world1819 Euroglyphus maynei is a primary source of Tcell sensitization and is present in levels that cause sensitization in temperateclimates It is often found in high concentration in beddings providing a pathwayfor exposure2021 A study conducted in New Orleans and seven other geographicareas of the USA found that in New Orleans E maynei was prevalent in 31 ofsampled homes It was also found in a significant number of homes in GalvestonTX and Delray Beach FL suggesting an affinity for southern climates22 Furtherresearch is needed to establish whether E maynei species of house dust is asignificant source of home allergen exposure in New Orleans homes

A quarter of homes had levels of dog (Can f 1) allergen 9100 mgdl comparableto the highest ICAS sitemdashSeattle Fifty-four percent of homes with dog allergenlevels 9100 mgdl reported currently having a dog Although five homes had catallergen levels above 80 mgdl only one of those homes reported currently havingcats Cat allergen levels in homes without cats ranged from 80 to 1474 mgdlThese findings suggest that allergens from previous pets still lingered in the home orwere being tracked in from outdoors Whereas levels of cat and dog allergens werecomparable to levels found in the homes of other inner-city asthmatics they werelower than levels present in the general population Approximately one-third(347) of homes in the National Survey of Lead and Allergens in Housing studyhad dog allergens 9100 mgdl and 349 of homes had detectable cat allergenlevels above 80 mgdl23

In addition to the climatic disposition indoor allergen exposure also dependson socioeconomic and sociodemographic factors7 The demographic characteristicsof our study population are similar to those in the ICAS study however the majorityof our sample was African-American and had a lower annual incomemdashdespite asimilar educational level10 The majority of families reported receiving an asthmamanagement plan home cleaning advice and advice on trigger avoidance fromtheir medical provider Furthermore most families reported taking steps to reducehome allergen levels by ceasing to smoke attempting to eliminate pests andvacuuming regularly (data not shown) Despite these efforts home dust allergenlevels were very high A combination of an environment conducive to allergengrowth and poverty may be a plausible explanation for these findings Approxi-mately 70 of caregivers were employed but the majority of families had annualincomes of G$15000 Few families reported using mattress covers or air filters andfew reported removing carpets or drapes (data not shown) A lack of resourcescould be the primary barrier to purchasing allergen avoidance supplies Kitch et alreported that in the greater Boston area low family income was associated withgreater risk of exposure to high levels of cockroach allergen and a lower risk of dustmite allergen exposure in the home24 In our sample of low-income families bothdust mite and cockroach were prevalent household allergens

Asthmatic children in New Orleans are at high risk of exposure to multipleindoor allergens Overall our study homes showed higher levels for three out offour allergens namely dust mites cockroach and dog dander compared to allICAS sites Compared to the general population levels of cockroach and dust miteallergens were consistently higher yet levels of cat and dog allergens were lower

790 RABITO ET AL

Our findings reinforce evidence of substantial regional variability in the indoorallergen levels of asthmatic children In an ideal situation allergen avoidance adviceshould be tailored to a child_s specific home environment However individualhome allergen testing is not feasible in the clinical setting making regional exposuredata an important resource for clinicians This study fills a data gap on the homeexposure profile of asthmatic children in the Gulf South region of the USA

ACKNOWLEDGMENTS

This study was funded by the US Department of Housing and Urban DevelopmentOffice of Healthy Homes and Lead Hazard Control Healthy Homes program grant LALHH0121-03

We thank Dr Peter Ashley and Kyla Leon MPH for their assistance inpreparing this manuscript

REFERENCES

1 Bashir SA Home is where the harm is Inadequate housing as a public health crisis Am JPub Health 200292733ndash738

2 Arbes SJ Cohn RD Yin M et al House dust mite allergen in US beds results from theFirst National Survey of Lead and Allergens in Housing J Allergy Clin Immunol2003111408ndash414

3 Institute of Medicine (IOM) Committee on the Assessment of Asthma and Indoor AirCleaning the Air Asthma and Indoor Air Exposures Division of Health Promotion andDisease Prevention Washington DC IOM 2000

4 Gold DR Wright R Population disparities in asthma Annu Rev Public Health20052689ndash113

5 Custovic A Indoor allergens are a primary cause of asthma Eur Respir Rev19988155ndash158

6 Sporik R Holgate T Platts-Mills T et al Exposure to house-dust mite allergen (Der p I)and the development of asthma in childhood N Engl J Med 1990323502ndash507

7 Platts-Mills TAE Vervloet D Thomas WR Aalberse RC Chapman MD Indoorallergens and asthma Report of the Third International Workshop J Allergy ClinImmunol 1997100(6 pt 1)S2ndashS24

8 Huss K Adkinson N Eggleston PA Dawson C Van Natta ML Hamilton RG Housedust mite and cockroach exposure are strong risk factors for positive allergy skin testresponses in the Childhood Asthma Management Program J Allergy Clin Immunol200110748ndash54

9 Gruchalla RS Pongracic J Plaut M et al Inner city asthma study Relationships amongsensitivity allergen exposure and asthma morbidity J Allergy Clin Immunol2005115478ndash485

10 Crain EF Walter M O_Connor GT et al Home and allergic characteristics of childrenwith asthma in seven US urban communities and design of and environmentalintervention The Inner City Asthma Study Environ Health Perspect 2002110939ndash945

11 Eggleston PA Rosenstreich D Lynn H et al Relationship of indoor allergen exposure toskin test sensitivity in inner-city children with asthma J Allergy Clin Immunol1998102563ndash570

12 Mvula M Larzelere M Kraus M et al Prevalence of asthma and asthma-like symptomsin inner-city school children J Asthma 200519ndash16

791INDOOR ALLERGEN EXPOSURES AMONG CHILDREN WITH ASTHMA

13 US Department of Housing and Urban Development (HUD) First National Environ-mental Health Survey of Child Care Centers Final Report Volume II Analysis ofAllergen Levels on Floors Office of Healthy Homes and Lead Hazard ControlWashington DC HUD 2003

14 Leaderer BP Belanger K Triche E et al Dust mite cockroach cat and dog allergenconcentrations in homes of asthmatic children in the northeastern United States impactof socioeconomic factors and population density Environ Health Perspect2002110419ndash425

15 Rosenstreich DL Eggleston P Katten M et al The role of cockroach allergy andexposure to cockroach allergen in causing morbidity among inner-city children withasthma N Engl J Med 19973361356ndash1363

16 Institute of Medicine (IOM) 2004 Damp Indoor Spaces and Health National Academyof Sciences Washington DC National Academy Press Available at http wwwnapedubooks0309091934html Accessed March 5 2007

17 Washington Post 2006 WeatherPost New Orleans La Historical Weather DataAvailable at httpwwwwashingtonpostcomwp-srvweatherlongtermhistoricaldatanew_orleans_lahtm Accessed March 5 2007

18 Arlian LG Water balance and humidity requirements of house dust mites Exp ApplAcarol 19921615ndash35

19 Smith W Mills K Hazell L Hart B Thomas W Molecular analysis of the group 1 and 2allergens from the house dust mite Euroglyphus maynei Int Arch Allergy Immunol199911815ndash22

20 Hales BJ Thomas WR T-cell sensitization to epitopes from the house dust mitesDermatophagoides pteronyssinus and Euroglyphus maynei Exp Allergy 199727868ndash875

21 Colloff MJ Stewart GA Thompson PJ House dust acarofauna and Der p I equivalent inAustralia the relative importance of Dermatophagoides pteronyssinus and Euroglyphusmaynei Clin Exp Allergy 1991121225ndash230

22 Arlian LG Bernstein D Bernstein IL et al Prevalence of dust mites in the homes ofpeople with asthma living in eight different geographic areas of the United States JAllergy Clin Immunol 199290292ndash300

23 Arbes SJ Cohn RD Yin M et al Dog allergen (Can F 1) and cat allergen (Fel d 1) inUS homes Results from the National Survey of Lead and Allergens in Housing JAllergy Clin Immunol 2004114111ndash117

24 Kitch BT Chew G Burge HA et al Socioeconomic predictors of high allergen levels inhomes in the greater Boston area Environ Health Perspect 2000108301ndash307

792 RABITO ET AL

Medicine concluded that a damp indoor environment is related to asthmaexacerbation and increased morbidity acting primarily through the proliferationof moisture-sensitive allergens16

Our findings revealed a highly allergenic home environment Seventy-sevenpercent of children were exposed to two or more indoor allergens above establishedcutpoints and 434 were exposed to three or more allergens (data not shown)Over a quarter of homes had moderate or high exposure to three of four dustallergens tested (dust mite cockroach and dog) Our data show that asthmaticchildren in New Orleans may be exposed to a greater number of allergens atmoderate to high levels compared to asthmatic children living in other inner citiesand to the general population Of particular note is the rate of exposure to highlevels of cockroaches and dust mites (Table 5)

Findings from ICAS established that the homes of inner-city asthmatics living inthe Northeast have a higher concentration of cockroach allergen (specifically NewYork where 622 of homes had levels 92 Ug) than any other region likelybecause of the high number of children living in high-rise apartments wherecockroach extermination is difficult9 In our study where no child lived in a high-rise apartment 566 of the homes had cockroach allergens above 2 Ug and onethird of the households had levels 98 Ug Home humidity level was not associatedwith the presence of cockroach allergens and of the various household character-istics measured only home ownership was associated with cockroach allergens andthe association was weak This leads us to conclude that the high rate of cockroachallergen is related to features of the general ambient rather than the homeenvironment

Dust mites were also a pervasive allergen Seventy-seven percent of NewOrleans homes had levels 92 mgg of dust mite allergen Considering a cutpoint of10 mgg the prevalence of residential dust mite exposure was 325 These levelsare substantially higher than those found both in the homes of asthmatics in theICAS sample and levels in beds in the general population29 Our findings supportan association between high humidity and dust mite exposure suggesting that anintervention that reduces home humidity levels may be warranted New Orleans

TABLE 4 Unadjusted association between average household humidity and dust allergenlevels (N=83)

Allergens 950 humidity [n ()] OR (95 CI) p value

Either dust mite 32 (11 93) 003a

e20 mgg 7 (146)920 mgg 41 (854)

Fel d 1 06 (02 18) 032G10 mgg 42 (875)Q10 mgg 6 (125)

Can f 1 14 (06 34) 046G20 mgg 20 (417)Q20 mgg 28 (583)

Bla g 1 10 (04 25) 097e20 Ug 21 (438)920 Ug 27 (563)

aStatistically significant (p valueG005)

788 RABITO ET AL

TABLE

5Co

mparisonofhomeallergen

levels()betweenNew

Orleansan

dother

cities

Allergens

New

Orleans

(n=83)

Dallasa

(n=135)

Seattlea

(n=127)

Bostona

(n=119)

Bronxa

(n=134)

Chicagoa

(n=141)

Tucson

a

(n=140)

New

York

a

(n=141)

Either

dustmite

920

mgg

771

699

651

398

214

167

245

82

Feld1

980

mgg

48

16

328

140

124

59

58

126

Canf1

9100

mgg

253

97

254

91

175

77

199

138

Bla

g1

920Ug

566

477

76

368

543

551

110

622

aGruchalla

etal(2005)9

789INDOOR ALLERGEN EXPOSURES AMONG CHILDREN WITH ASTHMA

has a humid environment with an average morning relative humidity of 8817

Our dust mite findings may have been a conservative estimate of home allergenexposure because potentially relevant species of dust mites were not sampledResearch has shown that in addition to Der p 1 and Der f 1 the dust miteEuroglyphus maynei is prevalent in humid climates and is a cause of allergensensitization around the world1819 Euroglyphus maynei is a primary source of Tcell sensitization and is present in levels that cause sensitization in temperateclimates It is often found in high concentration in beddings providing a pathwayfor exposure2021 A study conducted in New Orleans and seven other geographicareas of the USA found that in New Orleans E maynei was prevalent in 31 ofsampled homes It was also found in a significant number of homes in GalvestonTX and Delray Beach FL suggesting an affinity for southern climates22 Furtherresearch is needed to establish whether E maynei species of house dust is asignificant source of home allergen exposure in New Orleans homes

A quarter of homes had levels of dog (Can f 1) allergen 9100 mgdl comparableto the highest ICAS sitemdashSeattle Fifty-four percent of homes with dog allergenlevels 9100 mgdl reported currently having a dog Although five homes had catallergen levels above 80 mgdl only one of those homes reported currently havingcats Cat allergen levels in homes without cats ranged from 80 to 1474 mgdlThese findings suggest that allergens from previous pets still lingered in the home orwere being tracked in from outdoors Whereas levels of cat and dog allergens werecomparable to levels found in the homes of other inner-city asthmatics they werelower than levels present in the general population Approximately one-third(347) of homes in the National Survey of Lead and Allergens in Housing studyhad dog allergens 9100 mgdl and 349 of homes had detectable cat allergenlevels above 80 mgdl23

In addition to the climatic disposition indoor allergen exposure also dependson socioeconomic and sociodemographic factors7 The demographic characteristicsof our study population are similar to those in the ICAS study however the majorityof our sample was African-American and had a lower annual incomemdashdespite asimilar educational level10 The majority of families reported receiving an asthmamanagement plan home cleaning advice and advice on trigger avoidance fromtheir medical provider Furthermore most families reported taking steps to reducehome allergen levels by ceasing to smoke attempting to eliminate pests andvacuuming regularly (data not shown) Despite these efforts home dust allergenlevels were very high A combination of an environment conducive to allergengrowth and poverty may be a plausible explanation for these findings Approxi-mately 70 of caregivers were employed but the majority of families had annualincomes of G$15000 Few families reported using mattress covers or air filters andfew reported removing carpets or drapes (data not shown) A lack of resourcescould be the primary barrier to purchasing allergen avoidance supplies Kitch et alreported that in the greater Boston area low family income was associated withgreater risk of exposure to high levels of cockroach allergen and a lower risk of dustmite allergen exposure in the home24 In our sample of low-income families bothdust mite and cockroach were prevalent household allergens

Asthmatic children in New Orleans are at high risk of exposure to multipleindoor allergens Overall our study homes showed higher levels for three out offour allergens namely dust mites cockroach and dog dander compared to allICAS sites Compared to the general population levels of cockroach and dust miteallergens were consistently higher yet levels of cat and dog allergens were lower

790 RABITO ET AL

Our findings reinforce evidence of substantial regional variability in the indoorallergen levels of asthmatic children In an ideal situation allergen avoidance adviceshould be tailored to a child_s specific home environment However individualhome allergen testing is not feasible in the clinical setting making regional exposuredata an important resource for clinicians This study fills a data gap on the homeexposure profile of asthmatic children in the Gulf South region of the USA

ACKNOWLEDGMENTS

This study was funded by the US Department of Housing and Urban DevelopmentOffice of Healthy Homes and Lead Hazard Control Healthy Homes program grant LALHH0121-03

We thank Dr Peter Ashley and Kyla Leon MPH for their assistance inpreparing this manuscript

REFERENCES

1 Bashir SA Home is where the harm is Inadequate housing as a public health crisis Am JPub Health 200292733ndash738

2 Arbes SJ Cohn RD Yin M et al House dust mite allergen in US beds results from theFirst National Survey of Lead and Allergens in Housing J Allergy Clin Immunol2003111408ndash414

3 Institute of Medicine (IOM) Committee on the Assessment of Asthma and Indoor AirCleaning the Air Asthma and Indoor Air Exposures Division of Health Promotion andDisease Prevention Washington DC IOM 2000

4 Gold DR Wright R Population disparities in asthma Annu Rev Public Health20052689ndash113

5 Custovic A Indoor allergens are a primary cause of asthma Eur Respir Rev19988155ndash158

6 Sporik R Holgate T Platts-Mills T et al Exposure to house-dust mite allergen (Der p I)and the development of asthma in childhood N Engl J Med 1990323502ndash507

7 Platts-Mills TAE Vervloet D Thomas WR Aalberse RC Chapman MD Indoorallergens and asthma Report of the Third International Workshop J Allergy ClinImmunol 1997100(6 pt 1)S2ndashS24

8 Huss K Adkinson N Eggleston PA Dawson C Van Natta ML Hamilton RG Housedust mite and cockroach exposure are strong risk factors for positive allergy skin testresponses in the Childhood Asthma Management Program J Allergy Clin Immunol200110748ndash54

9 Gruchalla RS Pongracic J Plaut M et al Inner city asthma study Relationships amongsensitivity allergen exposure and asthma morbidity J Allergy Clin Immunol2005115478ndash485

10 Crain EF Walter M O_Connor GT et al Home and allergic characteristics of childrenwith asthma in seven US urban communities and design of and environmentalintervention The Inner City Asthma Study Environ Health Perspect 2002110939ndash945

11 Eggleston PA Rosenstreich D Lynn H et al Relationship of indoor allergen exposure toskin test sensitivity in inner-city children with asthma J Allergy Clin Immunol1998102563ndash570

12 Mvula M Larzelere M Kraus M et al Prevalence of asthma and asthma-like symptomsin inner-city school children J Asthma 200519ndash16

791INDOOR ALLERGEN EXPOSURES AMONG CHILDREN WITH ASTHMA

13 US Department of Housing and Urban Development (HUD) First National Environ-mental Health Survey of Child Care Centers Final Report Volume II Analysis ofAllergen Levels on Floors Office of Healthy Homes and Lead Hazard ControlWashington DC HUD 2003

14 Leaderer BP Belanger K Triche E et al Dust mite cockroach cat and dog allergenconcentrations in homes of asthmatic children in the northeastern United States impactof socioeconomic factors and population density Environ Health Perspect2002110419ndash425

15 Rosenstreich DL Eggleston P Katten M et al The role of cockroach allergy andexposure to cockroach allergen in causing morbidity among inner-city children withasthma N Engl J Med 19973361356ndash1363

16 Institute of Medicine (IOM) 2004 Damp Indoor Spaces and Health National Academyof Sciences Washington DC National Academy Press Available at http wwwnapedubooks0309091934html Accessed March 5 2007

17 Washington Post 2006 WeatherPost New Orleans La Historical Weather DataAvailable at httpwwwwashingtonpostcomwp-srvweatherlongtermhistoricaldatanew_orleans_lahtm Accessed March 5 2007

18 Arlian LG Water balance and humidity requirements of house dust mites Exp ApplAcarol 19921615ndash35

19 Smith W Mills K Hazell L Hart B Thomas W Molecular analysis of the group 1 and 2allergens from the house dust mite Euroglyphus maynei Int Arch Allergy Immunol199911815ndash22

20 Hales BJ Thomas WR T-cell sensitization to epitopes from the house dust mitesDermatophagoides pteronyssinus and Euroglyphus maynei Exp Allergy 199727868ndash875

21 Colloff MJ Stewart GA Thompson PJ House dust acarofauna and Der p I equivalent inAustralia the relative importance of Dermatophagoides pteronyssinus and Euroglyphusmaynei Clin Exp Allergy 1991121225ndash230

22 Arlian LG Bernstein D Bernstein IL et al Prevalence of dust mites in the homes ofpeople with asthma living in eight different geographic areas of the United States JAllergy Clin Immunol 199290292ndash300

23 Arbes SJ Cohn RD Yin M et al Dog allergen (Can F 1) and cat allergen (Fel d 1) inUS homes Results from the National Survey of Lead and Allergens in Housing JAllergy Clin Immunol 2004114111ndash117

24 Kitch BT Chew G Burge HA et al Socioeconomic predictors of high allergen levels inhomes in the greater Boston area Environ Health Perspect 2000108301ndash307

792 RABITO ET AL

TABLE

5Co

mparisonofhomeallergen

levels()betweenNew

Orleansan

dother

cities

Allergens

New

Orleans

(n=83)

Dallasa

(n=135)

Seattlea

(n=127)

Bostona

(n=119)

Bronxa

(n=134)

Chicagoa

(n=141)

Tucson

a

(n=140)

New

York

a

(n=141)

Either

dustmite

920

mgg

771

699

651

398

214

167

245

82

Feld1

980

mgg

48

16

328

140

124

59

58

126

Canf1

9100

mgg

253

97

254

91

175

77

199

138

Bla

g1

920Ug

566

477

76

368

543

551

110

622

aGruchalla

etal(2005)9

789INDOOR ALLERGEN EXPOSURES AMONG CHILDREN WITH ASTHMA

has a humid environment with an average morning relative humidity of 8817

Our dust mite findings may have been a conservative estimate of home allergenexposure because potentially relevant species of dust mites were not sampledResearch has shown that in addition to Der p 1 and Der f 1 the dust miteEuroglyphus maynei is prevalent in humid climates and is a cause of allergensensitization around the world1819 Euroglyphus maynei is a primary source of Tcell sensitization and is present in levels that cause sensitization in temperateclimates It is often found in high concentration in beddings providing a pathwayfor exposure2021 A study conducted in New Orleans and seven other geographicareas of the USA found that in New Orleans E maynei was prevalent in 31 ofsampled homes It was also found in a significant number of homes in GalvestonTX and Delray Beach FL suggesting an affinity for southern climates22 Furtherresearch is needed to establish whether E maynei species of house dust is asignificant source of home allergen exposure in New Orleans homes

A quarter of homes had levels of dog (Can f 1) allergen 9100 mgdl comparableto the highest ICAS sitemdashSeattle Fifty-four percent of homes with dog allergenlevels 9100 mgdl reported currently having a dog Although five homes had catallergen levels above 80 mgdl only one of those homes reported currently havingcats Cat allergen levels in homes without cats ranged from 80 to 1474 mgdlThese findings suggest that allergens from previous pets still lingered in the home orwere being tracked in from outdoors Whereas levels of cat and dog allergens werecomparable to levels found in the homes of other inner-city asthmatics they werelower than levels present in the general population Approximately one-third(347) of homes in the National Survey of Lead and Allergens in Housing studyhad dog allergens 9100 mgdl and 349 of homes had detectable cat allergenlevels above 80 mgdl23

In addition to the climatic disposition indoor allergen exposure also dependson socioeconomic and sociodemographic factors7 The demographic characteristicsof our study population are similar to those in the ICAS study however the majorityof our sample was African-American and had a lower annual incomemdashdespite asimilar educational level10 The majority of families reported receiving an asthmamanagement plan home cleaning advice and advice on trigger avoidance fromtheir medical provider Furthermore most families reported taking steps to reducehome allergen levels by ceasing to smoke attempting to eliminate pests andvacuuming regularly (data not shown) Despite these efforts home dust allergenlevels were very high A combination of an environment conducive to allergengrowth and poverty may be a plausible explanation for these findings Approxi-mately 70 of caregivers were employed but the majority of families had annualincomes of G$15000 Few families reported using mattress covers or air filters andfew reported removing carpets or drapes (data not shown) A lack of resourcescould be the primary barrier to purchasing allergen avoidance supplies Kitch et alreported that in the greater Boston area low family income was associated withgreater risk of exposure to high levels of cockroach allergen and a lower risk of dustmite allergen exposure in the home24 In our sample of low-income families bothdust mite and cockroach were prevalent household allergens

Asthmatic children in New Orleans are at high risk of exposure to multipleindoor allergens Overall our study homes showed higher levels for three out offour allergens namely dust mites cockroach and dog dander compared to allICAS sites Compared to the general population levels of cockroach and dust miteallergens were consistently higher yet levels of cat and dog allergens were lower

790 RABITO ET AL

Our findings reinforce evidence of substantial regional variability in the indoorallergen levels of asthmatic children In an ideal situation allergen avoidance adviceshould be tailored to a child_s specific home environment However individualhome allergen testing is not feasible in the clinical setting making regional exposuredata an important resource for clinicians This study fills a data gap on the homeexposure profile of asthmatic children in the Gulf South region of the USA

ACKNOWLEDGMENTS

This study was funded by the US Department of Housing and Urban DevelopmentOffice of Healthy Homes and Lead Hazard Control Healthy Homes program grant LALHH0121-03

We thank Dr Peter Ashley and Kyla Leon MPH for their assistance inpreparing this manuscript

REFERENCES

1 Bashir SA Home is where the harm is Inadequate housing as a public health crisis Am JPub Health 200292733ndash738

2 Arbes SJ Cohn RD Yin M et al House dust mite allergen in US beds results from theFirst National Survey of Lead and Allergens in Housing J Allergy Clin Immunol2003111408ndash414

3 Institute of Medicine (IOM) Committee on the Assessment of Asthma and Indoor AirCleaning the Air Asthma and Indoor Air Exposures Division of Health Promotion andDisease Prevention Washington DC IOM 2000

4 Gold DR Wright R Population disparities in asthma Annu Rev Public Health20052689ndash113

5 Custovic A Indoor allergens are a primary cause of asthma Eur Respir Rev19988155ndash158

6 Sporik R Holgate T Platts-Mills T et al Exposure to house-dust mite allergen (Der p I)and the development of asthma in childhood N Engl J Med 1990323502ndash507

7 Platts-Mills TAE Vervloet D Thomas WR Aalberse RC Chapman MD Indoorallergens and asthma Report of the Third International Workshop J Allergy ClinImmunol 1997100(6 pt 1)S2ndashS24

8 Huss K Adkinson N Eggleston PA Dawson C Van Natta ML Hamilton RG Housedust mite and cockroach exposure are strong risk factors for positive allergy skin testresponses in the Childhood Asthma Management Program J Allergy Clin Immunol200110748ndash54

9 Gruchalla RS Pongracic J Plaut M et al Inner city asthma study Relationships amongsensitivity allergen exposure and asthma morbidity J Allergy Clin Immunol2005115478ndash485

10 Crain EF Walter M O_Connor GT et al Home and allergic characteristics of childrenwith asthma in seven US urban communities and design of and environmentalintervention The Inner City Asthma Study Environ Health Perspect 2002110939ndash945

11 Eggleston PA Rosenstreich D Lynn H et al Relationship of indoor allergen exposure toskin test sensitivity in inner-city children with asthma J Allergy Clin Immunol1998102563ndash570

12 Mvula M Larzelere M Kraus M et al Prevalence of asthma and asthma-like symptomsin inner-city school children J Asthma 200519ndash16

791INDOOR ALLERGEN EXPOSURES AMONG CHILDREN WITH ASTHMA

13 US Department of Housing and Urban Development (HUD) First National Environ-mental Health Survey of Child Care Centers Final Report Volume II Analysis ofAllergen Levels on Floors Office of Healthy Homes and Lead Hazard ControlWashington DC HUD 2003

14 Leaderer BP Belanger K Triche E et al Dust mite cockroach cat and dog allergenconcentrations in homes of asthmatic children in the northeastern United States impactof socioeconomic factors and population density Environ Health Perspect2002110419ndash425

15 Rosenstreich DL Eggleston P Katten M et al The role of cockroach allergy andexposure to cockroach allergen in causing morbidity among inner-city children withasthma N Engl J Med 19973361356ndash1363

16 Institute of Medicine (IOM) 2004 Damp Indoor Spaces and Health National Academyof Sciences Washington DC National Academy Press Available at http wwwnapedubooks0309091934html Accessed March 5 2007

17 Washington Post 2006 WeatherPost New Orleans La Historical Weather DataAvailable at httpwwwwashingtonpostcomwp-srvweatherlongtermhistoricaldatanew_orleans_lahtm Accessed March 5 2007

18 Arlian LG Water balance and humidity requirements of house dust mites Exp ApplAcarol 19921615ndash35

19 Smith W Mills K Hazell L Hart B Thomas W Molecular analysis of the group 1 and 2allergens from the house dust mite Euroglyphus maynei Int Arch Allergy Immunol199911815ndash22

20 Hales BJ Thomas WR T-cell sensitization to epitopes from the house dust mitesDermatophagoides pteronyssinus and Euroglyphus maynei Exp Allergy 199727868ndash875

21 Colloff MJ Stewart GA Thompson PJ House dust acarofauna and Der p I equivalent inAustralia the relative importance of Dermatophagoides pteronyssinus and Euroglyphusmaynei Clin Exp Allergy 1991121225ndash230

22 Arlian LG Bernstein D Bernstein IL et al Prevalence of dust mites in the homes ofpeople with asthma living in eight different geographic areas of the United States JAllergy Clin Immunol 199290292ndash300

23 Arbes SJ Cohn RD Yin M et al Dog allergen (Can F 1) and cat allergen (Fel d 1) inUS homes Results from the National Survey of Lead and Allergens in Housing JAllergy Clin Immunol 2004114111ndash117

24 Kitch BT Chew G Burge HA et al Socioeconomic predictors of high allergen levels inhomes in the greater Boston area Environ Health Perspect 2000108301ndash307

792 RABITO ET AL

has a humid environment with an average morning relative humidity of 8817

Our dust mite findings may have been a conservative estimate of home allergenexposure because potentially relevant species of dust mites were not sampledResearch has shown that in addition to Der p 1 and Der f 1 the dust miteEuroglyphus maynei is prevalent in humid climates and is a cause of allergensensitization around the world1819 Euroglyphus maynei is a primary source of Tcell sensitization and is present in levels that cause sensitization in temperateclimates It is often found in high concentration in beddings providing a pathwayfor exposure2021 A study conducted in New Orleans and seven other geographicareas of the USA found that in New Orleans E maynei was prevalent in 31 ofsampled homes It was also found in a significant number of homes in GalvestonTX and Delray Beach FL suggesting an affinity for southern climates22 Furtherresearch is needed to establish whether E maynei species of house dust is asignificant source of home allergen exposure in New Orleans homes

A quarter of homes had levels of dog (Can f 1) allergen 9100 mgdl comparableto the highest ICAS sitemdashSeattle Fifty-four percent of homes with dog allergenlevels 9100 mgdl reported currently having a dog Although five homes had catallergen levels above 80 mgdl only one of those homes reported currently havingcats Cat allergen levels in homes without cats ranged from 80 to 1474 mgdlThese findings suggest that allergens from previous pets still lingered in the home orwere being tracked in from outdoors Whereas levels of cat and dog allergens werecomparable to levels found in the homes of other inner-city asthmatics they werelower than levels present in the general population Approximately one-third(347) of homes in the National Survey of Lead and Allergens in Housing studyhad dog allergens 9100 mgdl and 349 of homes had detectable cat allergenlevels above 80 mgdl23

In addition to the climatic disposition indoor allergen exposure also dependson socioeconomic and sociodemographic factors7 The demographic characteristicsof our study population are similar to those in the ICAS study however the majorityof our sample was African-American and had a lower annual incomemdashdespite asimilar educational level10 The majority of families reported receiving an asthmamanagement plan home cleaning advice and advice on trigger avoidance fromtheir medical provider Furthermore most families reported taking steps to reducehome allergen levels by ceasing to smoke attempting to eliminate pests andvacuuming regularly (data not shown) Despite these efforts home dust allergenlevels were very high A combination of an environment conducive to allergengrowth and poverty may be a plausible explanation for these findings Approxi-mately 70 of caregivers were employed but the majority of families had annualincomes of G$15000 Few families reported using mattress covers or air filters andfew reported removing carpets or drapes (data not shown) A lack of resourcescould be the primary barrier to purchasing allergen avoidance supplies Kitch et alreported that in the greater Boston area low family income was associated withgreater risk of exposure to high levels of cockroach allergen and a lower risk of dustmite allergen exposure in the home24 In our sample of low-income families bothdust mite and cockroach were prevalent household allergens

Asthmatic children in New Orleans are at high risk of exposure to multipleindoor allergens Overall our study homes showed higher levels for three out offour allergens namely dust mites cockroach and dog dander compared to allICAS sites Compared to the general population levels of cockroach and dust miteallergens were consistently higher yet levels of cat and dog allergens were lower

790 RABITO ET AL

Our findings reinforce evidence of substantial regional variability in the indoorallergen levels of asthmatic children In an ideal situation allergen avoidance adviceshould be tailored to a child_s specific home environment However individualhome allergen testing is not feasible in the clinical setting making regional exposuredata an important resource for clinicians This study fills a data gap on the homeexposure profile of asthmatic children in the Gulf South region of the USA

ACKNOWLEDGMENTS

This study was funded by the US Department of Housing and Urban DevelopmentOffice of Healthy Homes and Lead Hazard Control Healthy Homes program grant LALHH0121-03

We thank Dr Peter Ashley and Kyla Leon MPH for their assistance inpreparing this manuscript

REFERENCES

1 Bashir SA Home is where the harm is Inadequate housing as a public health crisis Am JPub Health 200292733ndash738

2 Arbes SJ Cohn RD Yin M et al House dust mite allergen in US beds results from theFirst National Survey of Lead and Allergens in Housing J Allergy Clin Immunol2003111408ndash414

3 Institute of Medicine (IOM) Committee on the Assessment of Asthma and Indoor AirCleaning the Air Asthma and Indoor Air Exposures Division of Health Promotion andDisease Prevention Washington DC IOM 2000

4 Gold DR Wright R Population disparities in asthma Annu Rev Public Health20052689ndash113

5 Custovic A Indoor allergens are a primary cause of asthma Eur Respir Rev19988155ndash158

6 Sporik R Holgate T Platts-Mills T et al Exposure to house-dust mite allergen (Der p I)and the development of asthma in childhood N Engl J Med 1990323502ndash507

7 Platts-Mills TAE Vervloet D Thomas WR Aalberse RC Chapman MD Indoorallergens and asthma Report of the Third International Workshop J Allergy ClinImmunol 1997100(6 pt 1)S2ndashS24

8 Huss K Adkinson N Eggleston PA Dawson C Van Natta ML Hamilton RG Housedust mite and cockroach exposure are strong risk factors for positive allergy skin testresponses in the Childhood Asthma Management Program J Allergy Clin Immunol200110748ndash54

9 Gruchalla RS Pongracic J Plaut M et al Inner city asthma study Relationships amongsensitivity allergen exposure and asthma morbidity J Allergy Clin Immunol2005115478ndash485

10 Crain EF Walter M O_Connor GT et al Home and allergic characteristics of childrenwith asthma in seven US urban communities and design of and environmentalintervention The Inner City Asthma Study Environ Health Perspect 2002110939ndash945

11 Eggleston PA Rosenstreich D Lynn H et al Relationship of indoor allergen exposure toskin test sensitivity in inner-city children with asthma J Allergy Clin Immunol1998102563ndash570

12 Mvula M Larzelere M Kraus M et al Prevalence of asthma and asthma-like symptomsin inner-city school children J Asthma 200519ndash16

791INDOOR ALLERGEN EXPOSURES AMONG CHILDREN WITH ASTHMA

13 US Department of Housing and Urban Development (HUD) First National Environ-mental Health Survey of Child Care Centers Final Report Volume II Analysis ofAllergen Levels on Floors Office of Healthy Homes and Lead Hazard ControlWashington DC HUD 2003

14 Leaderer BP Belanger K Triche E et al Dust mite cockroach cat and dog allergenconcentrations in homes of asthmatic children in the northeastern United States impactof socioeconomic factors and population density Environ Health Perspect2002110419ndash425

15 Rosenstreich DL Eggleston P Katten M et al The role of cockroach allergy andexposure to cockroach allergen in causing morbidity among inner-city children withasthma N Engl J Med 19973361356ndash1363

16 Institute of Medicine (IOM) 2004 Damp Indoor Spaces and Health National Academyof Sciences Washington DC National Academy Press Available at http wwwnapedubooks0309091934html Accessed March 5 2007

17 Washington Post 2006 WeatherPost New Orleans La Historical Weather DataAvailable at httpwwwwashingtonpostcomwp-srvweatherlongtermhistoricaldatanew_orleans_lahtm Accessed March 5 2007

18 Arlian LG Water balance and humidity requirements of house dust mites Exp ApplAcarol 19921615ndash35

19 Smith W Mills K Hazell L Hart B Thomas W Molecular analysis of the group 1 and 2allergens from the house dust mite Euroglyphus maynei Int Arch Allergy Immunol199911815ndash22

20 Hales BJ Thomas WR T-cell sensitization to epitopes from the house dust mitesDermatophagoides pteronyssinus and Euroglyphus maynei Exp Allergy 199727868ndash875

21 Colloff MJ Stewart GA Thompson PJ House dust acarofauna and Der p I equivalent inAustralia the relative importance of Dermatophagoides pteronyssinus and Euroglyphusmaynei Clin Exp Allergy 1991121225ndash230

22 Arlian LG Bernstein D Bernstein IL et al Prevalence of dust mites in the homes ofpeople with asthma living in eight different geographic areas of the United States JAllergy Clin Immunol 199290292ndash300

23 Arbes SJ Cohn RD Yin M et al Dog allergen (Can F 1) and cat allergen (Fel d 1) inUS homes Results from the National Survey of Lead and Allergens in Housing JAllergy Clin Immunol 2004114111ndash117

24 Kitch BT Chew G Burge HA et al Socioeconomic predictors of high allergen levels inhomes in the greater Boston area Environ Health Perspect 2000108301ndash307

792 RABITO ET AL

Our findings reinforce evidence of substantial regional variability in the indoorallergen levels of asthmatic children In an ideal situation allergen avoidance adviceshould be tailored to a child_s specific home environment However individualhome allergen testing is not feasible in the clinical setting making regional exposuredata an important resource for clinicians This study fills a data gap on the homeexposure profile of asthmatic children in the Gulf South region of the USA

ACKNOWLEDGMENTS

This study was funded by the US Department of Housing and Urban DevelopmentOffice of Healthy Homes and Lead Hazard Control Healthy Homes program grant LALHH0121-03

We thank Dr Peter Ashley and Kyla Leon MPH for their assistance inpreparing this manuscript

REFERENCES

1 Bashir SA Home is where the harm is Inadequate housing as a public health crisis Am JPub Health 200292733ndash738

2 Arbes SJ Cohn RD Yin M et al House dust mite allergen in US beds results from theFirst National Survey of Lead and Allergens in Housing J Allergy Clin Immunol2003111408ndash414

3 Institute of Medicine (IOM) Committee on the Assessment of Asthma and Indoor AirCleaning the Air Asthma and Indoor Air Exposures Division of Health Promotion andDisease Prevention Washington DC IOM 2000

4 Gold DR Wright R Population disparities in asthma Annu Rev Public Health20052689ndash113

5 Custovic A Indoor allergens are a primary cause of asthma Eur Respir Rev19988155ndash158

6 Sporik R Holgate T Platts-Mills T et al Exposure to house-dust mite allergen (Der p I)and the development of asthma in childhood N Engl J Med 1990323502ndash507

7 Platts-Mills TAE Vervloet D Thomas WR Aalberse RC Chapman MD Indoorallergens and asthma Report of the Third International Workshop J Allergy ClinImmunol 1997100(6 pt 1)S2ndashS24

8 Huss K Adkinson N Eggleston PA Dawson C Van Natta ML Hamilton RG Housedust mite and cockroach exposure are strong risk factors for positive allergy skin testresponses in the Childhood Asthma Management Program J Allergy Clin Immunol200110748ndash54

9 Gruchalla RS Pongracic J Plaut M et al Inner city asthma study Relationships amongsensitivity allergen exposure and asthma morbidity J Allergy Clin Immunol2005115478ndash485

10 Crain EF Walter M O_Connor GT et al Home and allergic characteristics of childrenwith asthma in seven US urban communities and design of and environmentalintervention The Inner City Asthma Study Environ Health Perspect 2002110939ndash945

11 Eggleston PA Rosenstreich D Lynn H et al Relationship of indoor allergen exposure toskin test sensitivity in inner-city children with asthma J Allergy Clin Immunol1998102563ndash570

12 Mvula M Larzelere M Kraus M et al Prevalence of asthma and asthma-like symptomsin inner-city school children J Asthma 200519ndash16

791INDOOR ALLERGEN EXPOSURES AMONG CHILDREN WITH ASTHMA

13 US Department of Housing and Urban Development (HUD) First National Environ-mental Health Survey of Child Care Centers Final Report Volume II Analysis ofAllergen Levels on Floors Office of Healthy Homes and Lead Hazard ControlWashington DC HUD 2003

14 Leaderer BP Belanger K Triche E et al Dust mite cockroach cat and dog allergenconcentrations in homes of asthmatic children in the northeastern United States impactof socioeconomic factors and population density Environ Health Perspect2002110419ndash425

15 Rosenstreich DL Eggleston P Katten M et al The role of cockroach allergy andexposure to cockroach allergen in causing morbidity among inner-city children withasthma N Engl J Med 19973361356ndash1363

16 Institute of Medicine (IOM) 2004 Damp Indoor Spaces and Health National Academyof Sciences Washington DC National Academy Press Available at http wwwnapedubooks0309091934html Accessed March 5 2007

17 Washington Post 2006 WeatherPost New Orleans La Historical Weather DataAvailable at httpwwwwashingtonpostcomwp-srvweatherlongtermhistoricaldatanew_orleans_lahtm Accessed March 5 2007

18 Arlian LG Water balance and humidity requirements of house dust mites Exp ApplAcarol 19921615ndash35

19 Smith W Mills K Hazell L Hart B Thomas W Molecular analysis of the group 1 and 2allergens from the house dust mite Euroglyphus maynei Int Arch Allergy Immunol199911815ndash22

20 Hales BJ Thomas WR T-cell sensitization to epitopes from the house dust mitesDermatophagoides pteronyssinus and Euroglyphus maynei Exp Allergy 199727868ndash875

21 Colloff MJ Stewart GA Thompson PJ House dust acarofauna and Der p I equivalent inAustralia the relative importance of Dermatophagoides pteronyssinus and Euroglyphusmaynei Clin Exp Allergy 1991121225ndash230

22 Arlian LG Bernstein D Bernstein IL et al Prevalence of dust mites in the homes ofpeople with asthma living in eight different geographic areas of the United States JAllergy Clin Immunol 199290292ndash300

23 Arbes SJ Cohn RD Yin M et al Dog allergen (Can F 1) and cat allergen (Fel d 1) inUS homes Results from the National Survey of Lead and Allergens in Housing JAllergy Clin Immunol 2004114111ndash117

24 Kitch BT Chew G Burge HA et al Socioeconomic predictors of high allergen levels inhomes in the greater Boston area Environ Health Perspect 2000108301ndash307

792 RABITO ET AL

13 US Department of Housing and Urban Development (HUD) First National Environ-mental Health Survey of Child Care Centers Final Report Volume II Analysis ofAllergen Levels on Floors Office of Healthy Homes and Lead Hazard ControlWashington DC HUD 2003

14 Leaderer BP Belanger K Triche E et al Dust mite cockroach cat and dog allergenconcentrations in homes of asthmatic children in the northeastern United States impactof socioeconomic factors and population density Environ Health Perspect2002110419ndash425

15 Rosenstreich DL Eggleston P Katten M et al The role of cockroach allergy andexposure to cockroach allergen in causing morbidity among inner-city children withasthma N Engl J Med 19973361356ndash1363

16 Institute of Medicine (IOM) 2004 Damp Indoor Spaces and Health National Academyof Sciences Washington DC National Academy Press Available at http wwwnapedubooks0309091934html Accessed March 5 2007

17 Washington Post 2006 WeatherPost New Orleans La Historical Weather DataAvailable at httpwwwwashingtonpostcomwp-srvweatherlongtermhistoricaldatanew_orleans_lahtm Accessed March 5 2007

18 Arlian LG Water balance and humidity requirements of house dust mites Exp ApplAcarol 19921615ndash35

19 Smith W Mills K Hazell L Hart B Thomas W Molecular analysis of the group 1 and 2allergens from the house dust mite Euroglyphus maynei Int Arch Allergy Immunol199911815ndash22

20 Hales BJ Thomas WR T-cell sensitization to epitopes from the house dust mitesDermatophagoides pteronyssinus and Euroglyphus maynei Exp Allergy 199727868ndash875

21 Colloff MJ Stewart GA Thompson PJ House dust acarofauna and Der p I equivalent inAustralia the relative importance of Dermatophagoides pteronyssinus and Euroglyphusmaynei Clin Exp Allergy 1991121225ndash230

22 Arlian LG Bernstein D Bernstein IL et al Prevalence of dust mites in the homes ofpeople with asthma living in eight different geographic areas of the United States JAllergy Clin Immunol 199290292ndash300

23 Arbes SJ Cohn RD Yin M et al Dog allergen (Can F 1) and cat allergen (Fel d 1) inUS homes Results from the National Survey of Lead and Allergens in Housing JAllergy Clin Immunol 2004114111ndash117

24 Kitch BT Chew G Burge HA et al Socioeconomic predictors of high allergen levels inhomes in the greater Boston area Environ Health Perspect 2000108301ndash307

792 RABITO ET AL