VITAMIN A, C, E AND D VITAMIN A, C, E AND D INSUFFICIENCY INSUFFICIENCY

LINKED TOLINKED TO ASTHMA / WHEEZE AND ASTHMA / WHEEZE AND

ASTHMA SEVERITYASTHMA SEVERITY

DEFINITION OF ASTHMADEFINITION OF ASTHMA A chronic inflammatory disorder of A chronic inflammatory disorder of

the bronchial tubes (bronchi) the bronchial tubes (bronchi) makes them swell, narrowing the makes them swell, narrowing the airways.airways.

Asthma involves only the bronchial Asthma involves only the bronchial tubes and does not affect the air tubes and does not affect the air sacs (alveoli) or the lung tissue sacs (alveoli) or the lung tissue (the parenchyma of the lung) itself. (the parenchyma of the lung) itself.

DEFINITION OF ASTHMADEFINITION OF ASTHMA

Airway narrowing in asthma is due Airway narrowing in asthma is due to three major processes acting on to three major processes acting on the bronchi:the bronchi:

inflammation inflammation spasm spasm hyper reactivityhyper reactivity

CAUSES CAUSES 1. Airborne allergens, such as pollen, 1. Airborne allergens, such as pollen,

animal dander, mold, cockroaches animal dander, mold, cockroaches and dust mites and dust mites

2. Respiratory infections, such as the 2. Respiratory infections, such as the common cold common cold

3. Physical activity (exercise-induced 3. Physical activity (exercise-induced asthma) asthma)

4. Cold air 4. Cold air

CAUSES CAUSES

5. Air pollutants and irritants such as 5. Air pollutants and irritants such as smoke smoke

6. Certain medications, including 6. Certain medications, including beta blockers, aspirin and other no beta blockers, aspirin and other no steroidal anti-inflammatory drugs steroidal anti-inflammatory drugs

7. Strong emotions and stress 7. Strong emotions and stress

CAUSESCAUSES8. 8. Sulfites, preservatives added Sulfites, preservatives added

to some perishable foods to some perishable foods

9. 9. Gastro esophageal reflux Gastro esophageal reflux disease disease

10. 10. Allergic reactions to foods Allergic reactions to foods such as peanuts or shellfish such as peanuts or shellfish

RISK FACTORSRISK FACTORS

1. A family history of asthma 1. A family history of asthma

2. Frequent respiratory infections as 2. Frequent respiratory infections as a child a child

3. Exposure to secondhand smoke 3. Exposure to secondhand smoke

4. Living in an urban area, especially 4. Living in an urban area, especially if there's a lot of air pollution if there's a lot of air pollution

RISK FACTORSRISK FACTORS

5. Exposure to occupational triggers, 5. Exposure to occupational triggers, such as chemicals used in farming, such as chemicals used in farming, hairdressing and manufacturing hairdressing and manufacturing

6. Low birth weight 6. Low birth weight

7. Being overweight 7. Being overweight

8. ????8. ????

HYPOTHESISHYPOTHESIS

DIET LOW IN VITAMINS A, C DIET LOW IN VITAMINS A, C AND E LINKED TO ASTHMA AND E LINKED TO ASTHMA AND WHEEZEAND WHEEZE

VITAMIN D INSUFFICIENCY IS VITAMIN D INSUFFICIENCY IS LINKED TO ASTHMA LINKED TO ASTHMA SEVERITYSEVERITY

The results of a systematic review and The results of a systematic review and meta-analysis reported in the April 16meta-analysis reported in the April 16thth 2009 Online First issue of Thorax:2009 Online First issue of Thorax:

Relatively Relatively low dietary intakes of low dietary intakes of vitamins A and Cvitamins A and C are associated are associated

with statistically significant with statistically significant increased odds of asthma and increased odds of asthma and

wheeze wheeze

The American Journal of Respiratory The American Journal of Respiratory and Critical Care Medicine (May 1, and Critical Care Medicine (May 1, 2009):2009):

Vitamin D insufficiency is linked to Vitamin D insufficiency is linked to asthma severity asthma severity

S. Allen, from the University of S. Allen, from the University of Nottingham in Nottingham, United Nottingham in Nottingham, United Kingdom, and colleagues carried out Kingdom, and colleagues carried out epidemiological studies:epidemiological studies:

““Dietary intake of vitamins A, C and Dietary intake of vitamins A, C and E may be associated with the E may be associated with the

occurrence of asthma”occurrence of asthma”

The reviewers searched MEDLINE, The reviewers searched MEDLINE, EMBASE, CINAHL, CAB abstracts, EMBASE, CINAHL, CAB abstracts, and AMED up to November 2007 and AMED up to November 2007 included 40 studies:included 40 studies:asthma, wheeze, or airway asthma, wheeze, or airway responsiveness in association with responsiveness in association with dietary intakes and serum dietary intakes and serum concentrations of vitamins A, C, concentrations of vitamins A, C, and Eand E. .

Compared with people without Compared with people without asthma, those with asthma, those with asthma had asthma had significantly lower dietary vitamin A significantly lower dietary vitamin A intake intake (mean difference, –182 µg/day; 95% CI, –288 to –75 µg/day; 3 (mean difference, –182 µg/day; 95% CI, –288 to –75 µg/day; 3 studies).studies).

In addition, people with In addition, people with severe severe asthma had significantly lower asthma had significantly lower dietary vitamin A intakedietary vitamin A intake vs. those vs. those with mild asthmawith mild asthma(mean difference, –344 µg/day; 2 studies).(mean difference, –344 µg/day; 2 studies).

The odds of asthma were also The odds of asthma were also increased inincreased in patients with patients with lower lower quantize dietary quantize dietary intakesintakes and in and in those with those with lower serumlower serum levels of levels of vitamin C.vitamin C.(OR, 1.12; 95% CI, 1.04 - 1.21; 9 studies)(OR, 1.12; 95% CI, 1.04 - 1.21; 9 studies)

Vitamin E intakeVitamin E intake was generally was generally not associated with asthma statusnot associated with asthma status..

ButBut it was it was significantly lowersignificantly lower in in patients with patients with severe asthmasevere asthma vs. vs. those with mild asthmathose with mild asthma

(mean difference, –1.20 µg/day; 95% CI, –2.3 to –0.1 µg/day; (mean difference, –1.20 µg/day; 95% CI, –2.3 to –0.1 µg/day; 2 studies).2 studies).

The study authors write: The study authors write: "Relatively low dietary intakes of "Relatively low dietary intakes of

vitamins A and C are associated vitamins A and C are associated with statistically significant with statistically significant increased odds of asthma and increased odds of asthma and wheeze, wheeze, and and Vitamin E intake does Vitamin E intake does not appear to be related to asthma not appear to be related to asthma status."status."

Erick Forno, from Brigham and Erick Forno, from Brigham and Women's Hospital in Boston, Women's Hospital in Boston, Massachusetts, and colleagues: Massachusetts, and colleagues:

"Maternal vitamin D intake during "Maternal vitamin D intake during pregnancy has been inversely pregnancy has been inversely

associated with asthma symptoms associated with asthma symptoms in early childhood," in early childhood,"

The study carried out in 616 Costa The study carried out in 616 Costa Rican children aged 6 to 14 years Rican children aged 6 to 14 years to evaluate the association to evaluate the association between measured levels of 25 between measured levels of 25 hydroxyvitamin D and markers of hydroxyvitamin D and markers of asthma severity and allergy asthma severity and allergy

Levels of vitamin D were insufficientLevels of vitamin D were insufficient (< 30 ng/mL) in 175 (28%) of 616 (< 30 ng/mL) in 175 (28%) of 616 children with asthma.children with asthma.

Vitamin D levelsVitamin D levels were significantly were significantly and and inverselyinversely associated with total associated with total immunoglobulin E (IgE) and immunoglobulin E (IgE) and eosinophileosinophil count, based on count, based on multivariate linear regression multivariate linear regression models. models.

Increase in vitamin D levels was Increase in vitamin D levels was associated with: associated with:

Lower odds of any hospitalization Lower odds of any hospitalization in the previous yearin the previous year(OR, 0.05; 95% confidence interval [CI], 0.004 - 0.71; P = .03),(OR, 0.05; 95% confidence interval [CI], 0.004 - 0.71; P = .03),

Lower use of anti-inflammatory Lower use of anti-inflammatory medications in the previous year medications in the previous year (OR, 0.18; 95% CI, 0.05 - 0.67; P = .01),(OR, 0.18; 95% CI, 0.05 - 0.67; P = .01),

increased airway responsivenessincreased airway responsiveness (OR, 0.15; 95% CI, 0.024 - 0.97; (OR, 0.15; 95% CI, 0.024 - 0.97; PP = .05), = .05),

The study authors write: The study authors write:

“ “ Vitamin D insufficiency is relatively Vitamin D insufficiency is relatively frequent in an equatorial frequent in an equatorial population of children with asthma. population of children with asthma. Lower vitamin D levels are Lower vitamin D levels are associated with increased markers associated with increased markers of allergy and asthma severity." of allergy and asthma severity."

Limitations Limitations of this study include:of this study include:• lack of a control group, lack of a control group,

• cross-sectional design, cross-sectional design,

• possible residual confounding by possible residual confounding by socioeconomic status.socioeconomic status.

Authors conclude:Authors conclude:should include in vitro and animal should include in vitro and animal studies to further elucidate the studies to further elucidate the mechanisms for the role of vitamin Dmechanisms for the role of vitamin D

CONCLUSION:CONCLUSION:

1.1. Lower dietary intakes of vitamins A Lower dietary intakes of vitamins A and C, but not vitamin E, were and C, but not vitamin E, were associated with increased odds of associated with increased odds of asthma. asthma.

2.2. Vitamin E was significantly lower in Vitamin E was significantly lower in patients with severe asthma patients with severe asthma

3.3. Lower vitamin D level was associated Lower vitamin D level was associated with increased markers of allergy and with increased markers of allergy and asthma severity uncertainly.asthma severity uncertainly.

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