Abstract

Background: Few studies have examined exposure to air pollution and greenness over three decades and incidence of symptoms common in obstructive respiratory disease.

Aim: We investigated incidence of protracted cough in relation to exposure to particulate matter (PM2.5 and PM10), black carbon (BC), nitrogen dioxide (NO2), ozone (O3) and greenness (normalized difference vegetation index (NDVI)).

Methods: We analyzed outcome data from the fourth Respiratory Health in Northern Europe (RHINE IV) study in 2022 (n = 9910 participants aged 50-75 years) as related to modelled air pollution and greenness exposure from 1990, 2000 and 2010. We used Poisson regression model with log person-year at risk as the offset, adjusting for covariates in 2010 (age, sex, smoking status, pack-years smoking, body mass index, education and marital status).

Results: We identified 624 incident cases of protracted cough during 13.0 years mean follow-up. The adjusted incidence rate ratios (IRR) (95% confidence interval (CI)) for protracted cough were 1.29 (1.05-1.57) and 1.23 (1.07-1.42) per 9.7 µg/m3 increase in PM2.5 and per 0.6 µg/m3 in BC, respectively in 1990 exposure. Similar associations were seen for PM10 and NO2, but not statistically significant. No association was seen for NDVI whereas O3 was inversely associated with protracted cough across all time points, the adjusted IRR was 0.80 (0.69-0.94) per 10.9 ?g/m3 increase in O3 in 1990 exposure.

Conclusion: Long-term exposure to low-level PM2.5 and BC increased risk for incident symptoms of protracted cough, while O3 had an inverse association. Living in green neighborhoods was not associated with cough in our study.