Abstract
Introduction. While the health effects of air pollution are well-established, there are very few studies looking at very long term follow-up of >25 years and most do not look at more than one exposure time point.
Methods. This study investigated modelled air pollution exposures to particulate matter measured as black smoke (BS) in 1971, 1981, 1991 and PM10 in 2001, in relation to respiratory mortality up to 2009 in 368,000 individuals in the ONS Longitudinal Study cohort in England and Wales.
Results. Mean BS exposure in 1971 was 42.7 (SD 20.4) and mean PM10 exposure in 2001 was 20.7 (SD 2.5) μg/m3. 72% of the population moved during the study period and correlations between air pollution exposure in different decades were moderate (r<0.5).
BS exposure in 1971 was associated with a 5% increased risk (95% 4 to 10) in respiratory mortality per 10 μg/m3 in 1972-2009, a 7% (3 to 11) increased risk for COPD, 6% (2 to 11) risk for respiratory infections and 5% (2 to 9) for lung cancer mortality. Analysis by decade demonstrated that mortality risks associated with 1971 exposures were persistent to 2002-9 for COPD (>30 years after exposure) but reduced slightly and became non-significant for respiratory infections and lung cancer. PM10 in 2001 was associated with increased risk of respiratory mortality in 2002-9 with OR 1.23 (95% CI 1.05-1.45), but this reduced to 1.19 (0.99-1.42) after adjustment for air pollution in past decades. In line with past UK and several European studies, respiratory mortality risks were higher than those for cardiovascular conditions.
Conclusions. Air pollution effects on respiratory health may persist for decades after exposure.
- Copyright ©the authors 2016