Long-term exposure to air pollution and incidence of asthma and chronic obstructive pulmonary disease among adults aged 50 years and older: the English Longitudinal Study of Ageing

Air pollution is a recognised risk factor for respiratory diseases, but its long-term effect on obstructive lung diseases in older adults remains inconclusive. We investigated the associations between long-term air pollution exposure and asthma and chronic obstructive pulmonary disease (COPD) incidence in 11,391 respondents (aged ≥ 50 years) in the English Longitudinal Study of Ageing, recruited in 2002–03 and followed up to 2017 for new asthma and COPD diagnoses or hospital records. Annual mean levels of fine particulate matter (PM 2.5 ), nitrogen dioxide (NO 2 ) and ozone (O 3 ) with a one-year lag were assessed at respondents’ residential addresses. Time-varying Cox models adjusted for confounders were used and effect modifiers were tested. Over the 15 follow-up years, we observed 343 asthma diagnoses, 531 COPD diagnoses and 236 COPD hospitalisations. PM 2.5 was associated with asthma and COPD diagnosis and COPD hospitalisations. O 3 was associated with COPD diagnosis and hospitalisation. Stronger associations of PM 2.5 with asthma diagnosis were observed in ever-smokers, and stronger associations of PM 2.5 and NO 2 with COPD hospitalisation were observed in people aged 65+ and those in deprived areas; stronger associations of O 3 with COPD hospitalisation were observed in men. These findings underscore the significant risk of air pollution exposure in developing asthma and COPD in adults, highlighting the need for further studies to strengthen the evidence and identify susceptible populations.