Childhood Air Pollution Exposure Associated with Self-Reported Bronchitic Symptoms in Adulthood.

Abstract

Few studies have examined the effects of long-term childhood air pollution exposure on adult respiratory health, including whether childhood respiratory effects underlie this relation. To evaluate associations between childhood air pollution exposure and self-reported adult bronchitic symptoms, while considering child respiratory health, in the Southern California Children's Health Study. Nitrogen dioxide (NO2), ozone, particulate matter<2.5μm (PM2.5) and <10μm (PM10) exposures assessed using inverse-distance-squared spatial interpolation based on childhood (birth-17 years) residential histories. Bronchitic symptoms (bronchitis, cough, or phlegm in last 12 months) were ascertained via questionnaire in adulthood. Associations between mean air pollution exposure across childhood and self-reported adult bronchitic symptoms were estimated using logistic regression. We further adjusted for childhood bronchitic symptoms and asthma to understand whether associations operated beyond childhood respiratory health impacts. Effect modification was assessed for family history of asthma, childhood asthma, and adult allergies. 1308 participants were included (mostly non-Hispanic White [56%] or Hispanic [32%]). At adult assessment (age mean=32.0 years, standard deviation [SD]=4.7) 25% reported bronchitic symptoms. Adult bronchitic symptoms were associated with NO2 and PM10 childhood exposures. Odds ratios per SD increase: 1.69 (95%CI:1.14,2.49) for NO2 (SD=11.1ppb); 1.51 (95%CI:1.00,2.27) for PM10 (SD=14.2µg/m3). Adjusting for childhood bronchitic symptoms or asthma produced similar results. NO2 and PM10 associations were modified by childhood asthma, with larger associations among asthmatics. Childhood NO2 and PM10 exposures were associated with adult bronchitic symptoms. Associations were not explained by childhood respiratory health impacts; however, participants with childhood asthma had stronger associations.