Long-term exposure to background air pollution related to respiratory and allergic health in schoolchildren.
BACKGROUND
The impact of air pollution on asthma and allergies still remains a debate.


OBJECTIVE
Our cross-sectional study was intended to analyse the associations between long-term exposure to background air pollution and atopic and respiratory outcomes in a large population-based sample of schoolchildren.


METHODS
Six thousand six hundred and seventy-two children aged 9-11 years recruited from 108 randomly schools in six French cities underwent a clinical examination including a skin prick test (SPT) to common allergens, exercise-induced bronchial reactivity (EIB) and skin examination for flexural dermatitis. The prevalence of asthma, allergic rhinitis (AR) and atopic dermatitis was assessed by a standardized health questionnaire completed by the parents. Three-year-averaged concentrations of air pollutants (NO2, SO2, PM10 and O3) were calculated at children' schools using measurements of background monitoring stations.


RESULTS
After adjusting for confounders, EIB, lifetime asthma and lifetime AR were found to be positively related to an increase in the exposure to SO2, PM10 and O3. The adjusted odds ratios (aOR) per increase of 5 microg/m3 of SO2 was 1.39 (95% confidence interval (CI)=1.15-1.66) for EIB and 1.19 (1.00-1.41) for lifetime asthma. The aOR for lifetime AR per increase of 10 microg/m3 of PM10 was 1.32 (CI=1.04-1.68). Moreover, SPT positivity was associated with O3 (aOR=1.34; CI=1.24-1.46). Associations with past year symptoms were consistent, even if not always statistically significant. Results persisted in long-term resident (current address for at least 8 years) children. However, no consistent positive association was found with NO2.


CONCLUSIONS
A moderate increase in long-term exposure to background ambient air pollution was associated with an increased prevalence of respiratory and atopic indicators in children.
Pénard-Morand
C
C
INSERM U472, Epidemiology of Allergic and Respiratory Diseases, Villejuif, France. celine.morand@polytechnique.org
Charpin
D
D
Raherison
C
C
Kopferschmitt
C
C
Caillaud
D
D
Lavaud
F
F
Annesi-Maesano
I
I
D000393:Air Pollutants / Q000009:adverse effects* / Q000032:analysis; D000397:Air Pollution / Q000009:adverse effects; D001249:Asthma / Q000453:epidemiology / Q000209:etiology; D016535:Bronchial Hyperreactivity / Q000453:epidemiology / Q000209:etiology; D002648:Child; D003430:Cross-Sectional Studies; D003876:Dermatitis, Atopic / Q000453:epidemiology / Q000209:etiology; D004784:Environmental Monitoring / Q000379:methods; D062665:Epidemiological Monitoring; D005260:Female; D005602:France / Q000453:epidemiology; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000209:etiology*; D008297:Male; D009585:Nitrogen Dioxide / Q000009:adverse effects / Q000032:analysis; D010126:Ozone / Q000009:adverse effects / Q000032:analysis; D015995:Prevalence; D012220:Rhinitis / Q000453:epidemiology / Q000209:etiology; D012574:Schools; D012882:Skin Tests / Q000379:methods; D013458:Sulfur Dioxide / Q000009:adverse effects / Q000032:analysis; D001335:Vehicle Emissions / Q000009:adverse effects / Q000032:analysis
D000393:Air Pollutants; D001335:Vehicle Emissions; D013458:Sulfur Dioxide; D010126:Ozone; D009585:Nitrogen Dioxide