Long-term exposures to PM2.5, black carbon and NO2 and prevalence of current rhinitis in French adults: the constances cohort

BACKGROUND: Rhinitis is one of the most common disease worldwide with a high and increasing prevalence. There is limited knowledge on the link between long-term exposure to air pollution and rhinitis. OBJECTIVES: We aim to study the associations between long-term exposure to air pollutants and self-reported current rhinitis among adults from Constances, a large French population-based cohort. METHODS: Current rhinitis was defined at inclusion from questionnaire by the presence of sneezing, runny or blocked nose in the last 12 months without a cold or the flu. Annual concentrations of nitrogen dioxide (NO2), particulate matter </= 2.5 microm (PM2.5) and black carbon (BC) were estimated at the participants' residential address by European land-use regression models. Cross-sectional associations between annual exposure to each air pollutant and current rhinitis were estimated using logistic models adjusted for age, sex, smoking, education level and French deprivation index. The health prevention centers were taken into account by marginal models with generalized estimating equations. Several supplementary analyses were performed. RESULTS: Analyses were performed on 127,108 participants (47 years old on average, 54% women, 19% current smokers). The prevalence of current rhinitis, allergic (AR) and non-allergic (NAR) rhinitis were 36%, 25% and 11% respectively. Adjusted ORs for current rhinitis were 1.13 (1.08, 1.17), 1.12 (1.07, 1.17), and 1.11 (1.06, 1.17) per one interquartile range increase of PM2.5 (4.85 microg/m(3)), BC (0.88 . 10(-5) m(-1)) and NO2 (17.3 microg/m(3)) respectively. Significant and positive associations were also found for both AR and NAR. Results were similar in men and women, and in the different smoking strata, and were consistent with meta-analysis or after imputing missing covariates. DISCUSSION: An increase of modeled annual average residential exposure to PM2.5, BC, and NO2 was significantly associated with an increase of prevalence of current rhinitis in adults in the French general population. The results suggest that among air pollutants, BC may be of special interest.