Ambient ozone exposure and depressive symptoms in adolescents: Results of the GINIplus and LISA birth cohorts

Background: Depression has been associated with air pollution, as reported by animal and epidemiological studies. However, the relationship between ozone exposure and depression, especially among adolescents, is scarcely investigated. Objectives: The study aimed to analyze associations between ozone exposure and depressive symptoms among German adolescents. Methods: The analyses were based on 2827 adolescents aged 15 from Munich and Wesel areas of the GINIplus and LISA birth cohorts. The depressive symptoms were assessed by the Depression Screener for Teenagers (DesTeen). Long-term ozone exposure was estimated by optimal interpolation techniques and assigned to home addresses. Nitrogen dioxide (NO2) and particulate matter with an aerodynamic diameter < 10 mu m (PM10) were assessed by land use regression models. For short-term exposure, maximum 8-h averages of ozone and daily average concentrations of NO2 and PM10 from the background monitoring sites 0 (same day), 1, 2, 3, and 7 days prior to depressive symptoms assessment were adopted. The cross-sectional analyses were conducted by adjusted logistic regression models controlling for residuals of NO2 and PM10, and covariates identified by a directed acyclic graph. Results: The prevalence of depressive symptoms ranged from 10.9% to 13.8% depending on regions. Overall, long- and short-term exposure to ozone were not statistically significantly associated with depressive symptoms. However, subgroup analysis showed inconsistent significant protective associations for short-term exposure to ozone lag 0 day (same day) and depressive symptoms in Wesel (OR = 0.76, 95% CI: (0.59, 0.98)), but not in Munich (OR = 1.00, 95% CI: (0.83, 1.21)). Conclusions: Our study does not support the hypothesis that ambient ozone exposure might increase the prevalence of depressive symptoms in German adolescents. Nevertheless, due to a lack of similar studies, these results need to be replicated in other samples.