Associations of Long-term Particulate Matter and Ozone Air Pollution Exposures with Pulmonary Function: Does Excess Weight Increase Risk of Enhanced Decrements?

Abstract

Few studies evaluate how long-term air pollution exposures affects lung function among young adults. Data from existing epidemiologic and toxicologic studies support the hypothesis that obese adults’ lung function responds more negatively to long-term air pollution exposure compared to non-obese adults. 5,026 Black and White participants in the Coronary Artery Risk Development In Young Adults Study (CARDIA), aged 18 to 30 years in 1985-86, provided lung function measurements, demographic and clinical data, and were followed 2, 5, 10 and 20 years later. Using air quality monitoring data and residential history, for each participant we estimated one long-term average exposure over the period of study attendance for particulate matter (PM10) and ozone. We fit linear mixed effects models to estimate associations between long-term air pollution and level and rate of change per year in forced expiratory volume in one second (FEV1), forced vital capacity (FVC) and FEV1/FVC, adjusting for confounders. We examined effect modification by obesity status using body mass index (BMI) ≥ 30.0 kg/m2. An increase of 10 µg/m3 in long-term (1984-2006) PM10 exposure was associated with a decreased rate of change in FEV1 of 1.7 ml per year of followup (p-value 0.04) and a decrease in level of FVC of 56.0 ml (p-value 0.04). Associations with rate of change were stronger among women than men. No associations were observed between long-term PM10 exposure and FEV1/FVC, nor between long-term ozone exposures and any lung function measure, for all participants. For the most part, obesity status did not modify the association between long-term PM10 and ozone exposures and FEV1, FVC, or FEV1/FVC. Only ozone associations with FEV1 and FVC differed by obesity status as participants aged. In CARDIA, long-term PM10 exposures were associated with decreases in lung function but ozone exposures were not. We did not observe effect modification in level by obesity status; however, BMI and obesity status are imprecise measures. Research with more precise obesity and exposure estimation and different designs in CARDIA and other cohorts is needed to understand how air pollution exposure may affect pulmonary health in young adults as they age and gain weight.