Joel Schwartz, Ph.D., Antonella Zanobetti, Ph.D.
Harvard School of Public Health
R01ES024332, P30ES000002, R21ES024012, R01ES026217
An NIEHS-funded study of people who received Medicare showed that long-term exposure to ambient fine particulate matter (PM2.5) and ozone may increase the risk of premature death. Both are components of air pollution, and the risk occurred even at levels below the National Ambient Air Quality Standards.
The researchers examined Medicare claim records for the entire Medicare population of 60 million Americans age 65 years and older. They also estimated air pollution levels for every square kilometer in the U.S. The exposure data was then overlaid with the Medicare health records data. The team used a well-validated exposure prediction model that allowed them to include study participants who lived in unmonitored and less-populated areas.
The researchers reported a linear connection between ozone concentration and mortality. Based on their estimates, lowering ozone by 1 part per billion nationwide could save about 1,900 lives each year. Lowering PM2.5 by 1 microgram per cubic meter nationwide could save about 12,000 lives per year.
The enormous sample size also allowed the researchers to estimate risk among racial minorities and disadvantaged subgroups. The researchers found that men, blacks, and low-income groups were at higher risk from PM2.5 exposure compared with the national average. Blacks had mortality risks three times higher than the national average. The team also observed differences in the health effects of PM2.5 exposure between people in urban and rural settings, which could be due to differences in the particulate composition
Citation: Di Q, Wang Y, Zanobetti A, Wang Y, Koutrakis P, Choirat C, Dominici F, Schwartz JD. 2017. Air pollution and mortality in the Medicare population. N Engl J Med 376(26):2513-2522.