Lifetime urban exposure, socioeconomic position and respiratory health among adolescents

INTRODUCTION: Early-life exposure to urban environmental factors, including air pollution, greenness or climate-related factors, is suspected to be associated with respiratory health but evidence among adolescents is scarce. We estimated the association between early-life exposure to urban factors and respiratory health among adolescents and addressed whether the socioeconomic position (SEP) could modify these associations. METHODS: This study was based on 3731 mother-child pairs from the HELIX and Generation R cohorts with 29 exposures from 6 domains (air pollution, built environment, natural spaces, climate-related factors, road traffic, light and noise) assessed during pregnancy, early (1-6 years) and middle childhood (7-12 years). Ever-asthma, wheezing and lung function parameters were assessed in adolescents (13-18 years). Associations between urban exposure profiles, defined at each period separately, and respiratory health were estimated through regression models. Models were further stratified by SEP levels during pregnancy. RESULTS: At each period, 2 exposure profiles were identified: high (high exposure to air pollutants, built environment, road traffic, noise and light and reduced access to green/blue spaces) vs. low urbanicity. High urbanicity in each period was associated with a lower risk of asthma and wheezing. SEP did not modify these associations. High urbanicity profile was associated with higher forced vital capacity (FVC) and forced respiratory volume in 1 s (FEV1) in the HELIX population and with higher FVC among adolescents with higher SEP. CONCLUSION: These findings reflect the complex, context-dependent nature of the urban exposome, where both beneficial and harmful components coexist and interact in shaping respiratory health trajectories.