Associations of long-term exposure to air pollution and greenness with incidence of chronic obstructive pulmonary disease in Northern Europe: The Life-GAP project

Background: Prolonged exposure to air pollution has been linked to adverse respiratory health, yet the evidence concerning its association with chronic obstructive pulmonary disease (COPD) is inconsistent. The evidence of a greenness effect on chronic respiratory diseases is limited. Objective: This study aimed to investigate the association between long-term exposure to particulate matter (PM 2.5 and PM 10 ), black carbon (BC), nitrogen dioxide (NO 2 ), ozone (O 3 ) and greenness (as measured by the normalized difference vegetation index - NDVI) and incidence of self -reported chronic bronchitis or COPD (CB/ COPD). Methods: We analyzed data from 5355 adults from 7 centers participating in the Respiratory Health in Northern Europe (RHINE) study. Mean exposures to air pollution and greenness were assessed at available residential addresses in 1990, 2000 and 2010 using air dispersion models and satellite data, respectively. Poisson regression with log person -time as an offset was employed to analyze the association between air pollution, greenness, and CB/COPD incidence, adjusting for confounders. Results: Overall, there were 328 incident cases of CB/COPD during 2010 -2023. Despite wide statistical uncertainty, we found a trend for a positive association between NO 2 exposure and CB/COPD incidence, with incidence rate ratios (IRRs) per 10 mu g/m 3 difference ranging between 1.13 (95% CI: 0.90 -1.41) in 1990 and 1.18 (95% CI: 0.96 -1.45) in 2000. O 3 showed a tendency for inverse association with CB/COPD incidence (IRR from 0.84 (95% CI: 0.66-1.07) in 2000 to 0.88 (95% CI: 0.69-1.14) in 2010. No consistent association was found between PM, BC and greenness with CB/COPD incidence across different exposure time windows. Conclusion: Consistent with prior research, our study suggests that individuals exposed to higher concentrations of NO 2 may face an elevated risk of developing COPD, although evidence remains inconclusive. Greenness was not associated with CB/COPD incidence, while O 3 showed a tendency for an inverse association with the outcome.