Long-term exposure to close-proximity air pollution and asthma and allergies in urban children.

The aim of this study was to evaluate the impact of urban air pollution, assessed through reliable indicators of exposure, on asthma and allergies in schoolchildren. A validated dispersion model combining data on traffic conditions, topography, meteorology and background pollution was used to relate 3-yrs averaged concentrations of major urban pollutants at the sites of schools to skin prick tests, exercise-induced asthma and reported asthma and allergies in 6,683 children (9-11 yrs) attending 108 schools randomly selected in six French communities. For the 4,907 children who had resided at their current address for the past 3 yrs, asthma (exercise induced, past year and lifetime) was significantly positively associated with benzene, SO(2), particles with a 50% cut-off aerodynamic diameter of 10 microm (PM(10)), nitrogen oxides (NO(x)) and CO. In the same children, eczema (lifetime and past year) was significantly positively associated with benzene, PM(10), NO(2), NO(x) and CO, lifetime allergic rhinitis with PM(10) and sensitisation to pollens with benzene and PM(10). Among the 2,213 children residing at their current address since birth, the associations persisted for lifetime asthma with benzene (adjusted OR per interquartile range (95% CI) 1.3 (1.0-1.9)) and PM(10 )(1.4 (1.0-2.0)), and for sensitisation to pollens with volatile organic compounds (1.3 (1.0-1.9)) and PM(10) (1.2 (1.0-1.9)). Accurately modelled urban air pollution was associated with some measures of childhood asthma and allergies.

Alternaria sensitization and allergic rhinitis with or without asthma in the French Six Cities study.

BACKGROUND: Allergic sensitization to Alternaria has been related to asthma in various studies, but its association with allergic rhinitis is still controversial. OBJECTIVES: The aim of this study was to assess at the population level the relationships in childhood between Alternaria sensitization and 'past-year rhinoconjunctivitis' (PYRC), 'ever hay fever' (EHF) and 'ever allergic rhinitis caused by allergens other than pollens' (EAR) according to the presence or the absence of asthma. METHODS: This study is part of the Six Cities Study, the French contribution to the International Study of Asthma and Allergies in Childhood (ISAAC) Phase II. Children underwent skin prick test (SPT) to Alternaria and parents filled a standardized medical questionnaire. RESULTS: Some 6726 children with a mean age of 10 years were examined. The overall prevalence of Alternaria sensitization was 2.8%, 0.8% for monosensitization. Prevalences of symptoms in sensitized children were 27.7% for PYRC, 27.0% for EHF and 30.4% for EAR. Adjusted Odds Ratios (OR) between Alternaria sensitization and allergic rhinitis phenotypes were 2.34 (95% confidence interval: 1.51-3.63) for PYRC, 2.40 (1.65-3.50) for EHF and 2.95 (2.05-4.23) for EAR. The relationship still remained in the case of monosensitization to Alternaria for both PYRC and EAR when excluding the asthmatic children [OR = 3.87 (1.54-9.78) and 2.88 (1.10-7.55) respectively]. CONCLUSION: In our population-based sample of children, we found a link between Alternaria sensitization and allergic rhinitis, independently of asthma, which is compatible with the mechanisms of deposition of Alternaria in the upper airways.

Prevalence of food allergy and its relationship to asthma and allergic rhinitis in schoolchildren.

BACKGROUND: Food allergy (FA) is an important health problem. However, epidemiological studies at the population level are scarce. We assessed the prevalence of FA and its associations with respiratory manifestations among schoolchildren. METHODS: A total of 6672 schoolchildren aged 9-11 years recruited from 108 randomly chosen schools in six French cities underwent a clinical examination including skin prick test (SPT) to common food and aeroallergens and the standardized protocol of the run test to assess exercise-induced bronchial hyper-responsiveness (EIB). Asthma, allergic rhinitis (AR) and clinical symptoms of FA were determined using a standardized questionnaire completed by parents. RESULTS: About 2.1% of the children reported symptoms of FA, 1.9% were sensitized to food allergens, and 0.1% had SP-tested FA. The AR was more prevalent than asthma (20.0% lifetime, 11.9% past year vs 9.8%, 8.7% respectively). Reported FA, food sensitization and SP-tested FA were all positively associated with asthma and AR (P < 0.001). These associations persisted also for FA not manifesting as respiratory symptoms (P < 0.001). Asthma and AR remained significantly associated with reported symptoms of FA and allergic sensitization to food allergens after adjustment for confounders as well as for sensitization to aeroallergens. No relationship existed between EIB (9.0%) and FA. CONCLUSION: The relationships between FA and asthma and AR could be totally explained neither by the existence of respiratory manifestations of FA nor by sensitization to aeroallergens. The FA might intervene differently in asthma and AR.

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.

Increased prevalence of asthma and allied diseases among active adolescent tobacco smokers after controlling for passive smoking exposure. A cause for concern?

BACKGROUND: Whereas effects on allergic and respiratory health have been established for passive tobacco smoking, contradictory results still exist for active tobacco smoking. OBJECTIVE: Whether adolescents with asthma and allied diseases have higher rates of active smoking compared with adolescents without asthma was assessed after controlling for environmental tobacco smoking exposure. METHODS: A population-based sample of 14,578 adolescents was enrolled in an epidemiological survey on allergies in France. RESULTS: After controlling for age, sex, geographic region, familial allergy and passive smoking, current (in the past year) wheezing (12.4%), current asthma (5.6%), lifetime asthma (12.3%), current rhinoconjunctivitis (13.9%), lifetime hayfever (14.4%) and current eczema (9.3%) but not lifetime eczema (22.5%) were all significantly related to active smoking (>1 cigarette/day) (9.3%). A higher risk of current wheezing, current and lifetime asthma or current eczema was seen in smokers exposed to passive smoking compared with smokers not exposed to it using a polychotomous logistic regression model, in which the different modalities of exposure to active and passive smoking constituted the response variable. Passive smoking was significantly associated only with current diseases. Active smoking was also highly related to both severe asthma (OR=4.02; 95% confidence interval: 1.37, 11.79) and severe rhinoconjunctivitis (OR=2.95; 1.58, 5.49). The highest rate of adolescents suffering from the co-morbidity of lifetime asthma and hayfever (3.6%) was also seen in active smokers compared with passive and non-smokers (5.5% vs. 3.6% and 3.1%, respectively; P=0.001). CONCLUSIONS: Being asthmatic or allergic does not seem to act as a deterrent towards starting active smoking or continuing to smoke in adolescence. Results suggest the need for considering individual allergic status in programming health educational activities aimed at reducing smoking among adolescents.