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).

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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