Title : Incident COPD and Its Disparity Associated with Air Pollution in American Older Adults: A National Cohort Study
RATIONALE: Risk of Chronic Obstructive Pulmonary Disease (COPD) and its disparities associated with air pollution exposures are less clear and warrant more evidence.
OBJECTIVES: To examine the association between long-term exposure to air pollution and COPD incidence.
METHODS: We constructed a nationwide population-based open cohort (2000-2016), by leveraging the Medicare Chronic Conditions Warehouse database and high-resolution population-weighted air pollution data, to estimate COPD incidence associated with annual mean particulate matter (PM2.5), nitrogen dioxide (NO2), and warm-season ozone (O3) using Cox proportional hazards models. We further tested effect modifications by individual- and community-level characteristics.
MAIN RESULTS: Of 18.8 million participants, ~3.9 million developed COPD during the follow-up with a mean of 8 years. The adjusted hazard ratios (HRs) and 95% confidence intervals for associations with COPD incidence were 1.032 (1.023-1.041) per 5 μg/m3 for PM2.5, 1.017 (1.014-1.020) per 5 part per billion (ppb) for NO2, and 1.032 (1.028-1.037) per 5 ppb for warm-season O3. HRs for NO2 and O3 remained robust in three-pollutant models with co-pollutants, whereas the HR for PM2.5 was attenuated. Further, individuals in communities with lower physician-per-population ratio, higher percent of ever smokers, higher average BMI, or lower population density experienced higher risk.
CONCLUSIONS: Long-term exposure to air pollution was significantly associated with the development of COPD among the U.S. older adults. Subgroup differences suggested contextual factors contributed to COPD disparities under effects of air pollutant exposures.