Polusi Udara Dan Anemia Sebagai Faktor Risiko Pneumonia Pada Anak Ekuador, Sebuah Analisis Cohort Retrospektif

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<ul><li><p>RESEARCH Open Access</p><p>Air Pollution and Anemia as Risk Factors forPneumonia in Ecuadorian Children: ARetrospective Cohort AnalysisAaron M Harris1, Fernando Semprtegui1,2,3, Bertha Estrella1,2,3, Ximena Narvez2, Juan Egas2, Mark Woodin1,4*,John L Durant4, Elena N Naumova1,4,5 and Jeffrey K Griffiths1,4,5,6</p><p>Abstract</p><p>Background: Ambient air pollution and malnutrition, particularly anemia, are risk factors for pneumonia, a leadingcause of death in children under five. We simultaneously assessed these risk factors in Quito, Ecuador.</p><p>Methods: In 2005, we studied two socioeconomically similar neighborhoods in Quito: Lucha de los Pobres (LP)and Jaime Roldos (JR). LP had relatively high levels of air pollution (annual median PM2.5 = 20.4 g/m</p><p>3; NO2 = 29.5g/m3) compared to JR (annual median PM2.5 = 15.3 g/m</p><p>3; NO2 = 16.6 g/m3). We enrolled 408 children from LP</p><p>(more polluted) and 413 children from JR (less polluted). All subjects were aged 18-42 months. We obtainedmedical histories of prior physician visits and hospitalizations during the previous year, anthropometric nutritiondata, hemoglobin levels, and hemoglobin oxygen saturation via oximetry.</p><p>Results: In anemic children, higher pollution exposure was significantly associated with pneumonia hospitalization(OR = 6.82, 95%CI = 1.45-32.00; P = 0.015). In non-anemic children, no difference in hospitalizations by pollutionexposure status was detected (OR = 1.04, NS). Children exposed to higher levels of air pollution had morepneumonia hospitalizations (OR = 3.68, 1.09-12.44; P = 0.036), total respiratory illness (OR = 2.93, 95% CI 1.92-4.47; P&lt; 0.001), stunting (OR = 1.88, 1.36-2.60; P &lt; 0.001) and anemia (OR = 1.45, 1.09-1.93; P = 0.013) compared tochildren exposed to lower levels of air pollution. Also, children exposed to higher levels of air pollution hadsignificantly lower oxygen saturation (92.2% 2.6% vs. 95.8% 2.2%; P &lt; 0.0001), consistent with air pollutionrelated dyshemoglobinemia.</p><p>Conclusions: Ambient air pollution is associated with rates of hospitalization for pneumonia and with physiciansconsultations for acute respiratory infections. Anemia may interact with air pollution to increase pneumoniahospitalizations. If confirmed in larger studies, improving nutrition-related anemia, as well as decreasing the levelsof air pollution in Quito, may reduce pneumonia incidence.</p><p>BackgroundPneumonia is the leading cause of childhood death [1,2].The pathogenesis of pneumonia includes environmentaland host factors, such as air pollution and malnutrition[2]. Air pollutants are respiratory irritants and increasesusceptibility to acute respiratory infections (ARI) [3,4].Air pollution increases morbidity and mortality largelyfrom respiratory diseases [5], and reducing ambient airpollution increases lifespan [6]. Particulate air pollution</p><p>(PM), especially particles &lt; 10 m (PM10) and &lt; 2.5 m(PM2.5) in aerodynamic diameter, and nitrogen oxides(NOx) are specifically linked to childhood ARI [7-9].Outdoor (ambient) air pollution, and indoor pollutionfrom biofuel use, have been identified as major pneumo-nia risk factors [2,3].Globally, many malnourished children are exposed to</p><p>high levels of air pollution. Also, because malnourishedchildren are known to be at increased risk for pneumo-nia [1,2,10,11], a synergistic relationship between ambi-ent air pollution and malnutrition has been postulated[2]. Previous studies of pneumonia have examined either</p><p>* Correspondence: mark.woodin@tufts.edu1Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA, USAFull list of author information is available at the end of the article</p><p>Harris et al. Environmental Health 2011, 10:93http://www.ehjournal.net/content/10/1/93</p><p> 2011 Harris et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative CommonsAttribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction inany medium, provided the original work is properly cited.</p></li><li><p>air pollution or malnutrition [e.g. [12-15]] but not bothrisk factors simultaneously. We explored the relation-ship between air pollution and malnutrition in Quito,Ecuador where both risk factors are prevalent. Our pri-mary objective was to determine if interaction betweenmalnutrition and air pollution was evident. To ourknowledge this is the first study of possible interactioneffects between ambient air pollution and malnutritionas risk factors for pneumonia in children.</p><p>MethodsEthics ApprovalThis study was approved by the Tufts University Institu-tional Review Board and the Ethical Committee of theCorporacin Ecuatoriana de Biotechnologa (CEB).</p><p>Study SiteQuito is a high-altitude (2830 m) city with significantambient air pollution largely due to vehicular traffic andcombustion [16]. The city is flanked by volcanic moun-tains that act to trap air pollutants by reducing atmo-spheric mixing [17]. Quitos urban slums have high ratesof pneumonia and malnutrition [15,18,19]. We identifiedtwo neighborhoods, Jaime Roldos (JR) and Lucha de losPobres (LP), of closely comparable socioeconomic status(SES) (Figure 1, Table 1), but which differ in levels ofambient air pollution. The Instituto Nacional de Estadis-tica Y Censos (INEC) provided SES and census data for2001 and the Corporacin Para el Mejoramiento delAire de Quito (CORPAIRE) provided hourly air pollu-tion measurements for 2005 for two monitoring stationslocated adjacent to the studied neighborhoods.</p><p>Study DesignBetween February and May 2006 we enrolled 408 and413 children aged 18-42 months in LP and JR, respec-tively, after using a neighborhood census to identify eli-gible children. For each child we obtained a medicalhistory using a standardized, pre-tested questionnairefor parents asking if the child was hospitalized orreceived medical attention for a respiratory illness in theprior year, including diagnoses and treatments. Anthro-pometric measurements included height, weight, andmid-upper arm circumference (MUAC). Length (age</p></li></ul>