Long-term Air Pollution Exposure and Pneumonia-related Mortality in a Large Pooled European Cohort.

Abstract

<b>Rationale:</b> Ambient air pollution exposure has been linked to mortality from chronic cardiorespiratory diseases, while evidence on respiratory infections remains more limited. <b>Objectives:</b> We examined the association between long-term exposure to air pollution and pneumonia-related mortality in adults in a pool of eight European cohorts. <b>Methods:</b> Within the multicenter project ELAPSE (Effects of Low-Level Air Pollution: A Study in Europe), we pooled data from eight cohorts among six European countries. Annual mean residential concentrations in 2010 for fine particulate matter, nitrogen dioxide (NO₂), black carbon (BC), and ozone were estimated using Europe-wide hybrid land-use regression models. We applied stratified Cox proportional hazard models to investigate the associations between air pollution and pneumonia, influenza, and acute lower respiratory infections (ALRI) mortality. <b>Measurements and Main Results:</b> Of 325,367 participants, 712 died from pneumonia and influenza combined, 682 from pneumonia, and 695 from ALRI during a mean follow-up of 19.5 years. NO₂ and BC were associated with 10-12% increases in pneumonia and influenza combined mortality, but 95% confidence intervals included unity (hazard ratios, 1.12 [0.99-1.26] per 10 μg/m³ for NO₂; 1.10 [0.97-1.24] per 0.5 10^-5m^-1 for BC). Associations with pneumonia and ALRI mortality were almost identical. We detected effect modification suggesting stronger associations with NO₂ or BC in overweight, employed, or currently smoking participants compared with normal weight, unemployed, or nonsmoking participants. <b>Conclusions:</b> Long-term exposure to combustion-related air pollutants NO₂ and BC may be associated with mortality from lower respiratory infections, but larger studies are needed to estimate these associations more precisely.