Long-Term Ozone Exposure Associated With Increased Mortality Risk

Long-term exposure to ozone (O₃) is associated with an increased risk for mortality, according to study findings published in the American Journal of Respiratory and Critical Care Medicine.

Individuals from the National Institutes of Health-American Association of Retired Persons (NIH-AARP) Diet and Health Study (age range, 50-71 years), a prospective study with 17-year follow-up data, were included in the analysis (N=548,780). Researchers evaluated associations between mortality and long-term exposure to O₃, with an average value exposure from 2002 and 2010. The EPA Fused Air Quality Surface Using Downscaling (FAQSD) data was used to evaluate annual O₃ concentrations that were assigned to each participant’s residence census tract. Multiple causes of death were analyzed, including cardiovascular disease (n=39,529), ischemic heart disease (n=22,327), cerebrovascular disease (n=5592), cardiac arrest (n=6811), respiratory diseases (n=12,459), chronic obstructive pulmonary disease (n=7748), pneumonia (n=1889), and lung cancer (n=13,529).

In single-pollutant models, long-term average per-year exposure to O₃ was associated with mortality as a result of cardiovascular disease (hazard ratio [HR], 1.03; 95% CI, 1.01-1.06), ischemic heart disease (HR, 1.06; 95% CI, 1.02-1.09), respiratory disease (HR, 1.04; 95% CI, 1.00-1.09), and chronic obstructive pulmonary disease (HR, 1.09; 95% CI, 1.03-1.15). Individuals living in high-temperature locations who had long-term O₃ exposure also had a higher risk for respiratory disease mortality (P interaction <.05).

Study limitations included the predominantly white and black non-Hispanic participants, as well as the lack of control for smoking duration.

“This study provides additional evidence linking excess mortality to long-term O₃ exposure,” the researchers wrote, “suggesting that policies aimed at lowering the long-term O₃ concentration level are important in alleviating the public health burden associated with ambient O₃ exposures.”

Reference

Lim CC, Hayes RB, Ahn J, et al. Long-term exposure to ozone and cause-specific mortality risk in the U.S [published online May 3, 2019]. Am J Respir Crit Care Med. doi:10.1164/rccm.201806-1161OC