Global Estimation of the Effect of Fine Particulate Air Pollution on Life Expectancy at the Age of 60

Abstract

Background: Previous studies evaluating the association between particulate matter less than 2·5 μm in diameter (PM2·5) and life expectancy were conducted in a single country, assuming a linear relationship. In our study, we evaluated the association using global country-level data accounting for a non-linear relationship between PM2·5 concentration and life expectancy. Methods: A total of 17 years (from 2000 to 2016) data of country-level population-weighted PM2·5 concentration and life expectancy at age 60 were extracted from the Global Burden of Disease Study 2017 database and the World Health Organization Global Health Observatory. A generalized estimating equation with a compound symmetry covariance structure was used to evaluate the linear association between a reduction in annual PM2·5 concentration and an increase in life expectancy. Non-parametric analyses using generalized additive mixed model and piecewise linear regression were conducted for analyses of repeated measures data with non-linear assumption. Findings: Seventeen years of data from 176 countries were included in our analysis. With a linear assumption, 10 μg/m3 reduction in annual PM2·5 concentration was associated with 0·34 years (95%CI, 0·20, 0·49) of increase in life expectancy. By assuming a non-linear relationship, life expectancy increased by 0·72 years (95%CI: 0·49, 0·96) per 10 μg/m3 reduction in 0-24·0 μg/m3 PM2·5 concentration range. However, life expectancy increased by 0·01 years (95%CI: -0·06, 0·08) per 10 μg/m3 reduction in PM2·5 above 24·0 μg/m3 concentration. Interpretation: There was a non-linear relationship between country-level population-weighted annual PM2·5 concentration and life expectancy at age 60. Expected life expectancy gain for a unit decrease in PM2·5 was greater at low PM2·5 concentration range (0-24·0μg/m3) than that over 24·0 μg/m3. Future individual and multi-level studies are needed to confirm our ecologic study findings. Funding Statement: Ministry of Science, ICT, and Future Planning, Korea Centre for Disease Control and Prevention, and the Centre for Environmental Health, Ministry of Environment, Korea Declaration of Interests: The authors declare no competing interests. Ethics Approval Statement: Not required.