A National Study of the Mortality Effects of PM2.5 on All-Cause and Cause-Specific Mortality in the Contiguous U.S.

摘要

Background The adverse health effects of air pollution are established at the individual level, and at the population level in major metropolitan areas. However, the effect on all-cause and cause-specific mortality for the entire country has not been directly evaluated. We investigate the effects of air pollution on mortality for the entire population in the contiguous USA. Methods We used number of deaths for 1999-2011 from the U.S. National Center for Health Statistics (NCHS). Corresponding age-sex-specific population counts were from the US Census Bureau and the NCHS. Annual mean PM2.5 concentrations were estimated by incorporating remotely-sensed and in-situ observations into a land-use regression model. We applied a Bayesian spatiotemporal model to age-sex-county-specific death rates, to estimate the effects of county annual mean PM2.5 concentration on all-cause and cardiopulmonary mortality. The model was formulated to empirically smooth death rates over age and county of residence. We adjusted for poverty, race, income and lung-cancer mortality as a proxy for smoking. Results In unadjusted analysis, all-cause death rates increased by 4.4% (95%CI 3.9-4.9%) for males and 2.5% (95%CI 2.0-3.0%) for females, per 10pgm-3 higher PM2.5. Age-specific rate ratios smoothly varied with age, with rate ratios highest in males aged 60-64 years and females 65-69 years. Cardiopulmonary death rates increased by 2.2% (95%CI 1.1 to 3.1%) for males and 0.5% (95%CI -0.4 to 1.4%) for females (all confounders and education). Age-specific proportional effects were largest for males aged 45-49 and females 50-54 per 10ugm-3 higher PM2.5. Conclusion In this first direct population-level study for an entire country we found that air pollution increases the risk of deaths from major cause of death.