Study: Long-Term Exposure to Wildfire Smoke Increases Risk of Heart Failure

A new study led by researchers at Emory University’s Rollins School of Public Health found that long-term exposure to wildfire smoke increases the risk of heart failure, especially among women, older adults, and lower-income individuals.
The study—published Monday in JACC, the flagship journal of the American College of Cardiology—was the first national population-based study to examine the association between long-term wildfire exposure and heart failure risk.

What Was Studied

The study analyzed data from approximately 22 million Medicare beneficiaries ages 68 and older across the contiguous United States to estimate people's exposure to fine particulate matter (PM2.5) found in two common sources of air pollution: wildfire smoke and non-smoke sources, such as traffic or industry. Researchers used Medicare records from 2007 to 2018 to track how many individuals developed heart failure. The data also provided insights into individual demographics and community-level factors, such as income, region, and temperature.

Key Findings

• A slight increase in wildfire smoke PM2.5 (1 microgram increase per cubic meter of air) was linked to over 20,000 more heart failure cases annually in the U.S. among older adults. The risk of heart failure went up by 1.4%.
• There were stronger links between smoke PM2.5 and heart failure in women, Medicaid-eligible individuals, and those living in lower-income areas.
• PM2.5 in wildfire smoke was found to be more harmful to heart health than PM2.5 from other types of air pollution, such as traffic or industry. Wildfire smoke was associated with a 1.4% increased risk of heart failure, while the heart failure risk for the same level of exposure to non-smoke sources increased just 0.5%.
• Heart failure risks from smoke exposure were present nationwide, but were especially high in parts of the southeastern and southwestern U.S.

What the Experts Say

“Over time, the average smoke pollution someone breathes in can increase very slightly. But that slight increase matters a lot for heart health, especially for vulnerable populations. Even a small individual risk translates into a large public health impact,” says the study’s lead author Hua Hao, PhD, a research scientist in the Gangarosa Department of Environmental Health at Rollins. 

“This study highlights a growing and underappreciated threat to heart health. As wildfire smoke becomes more frequent and intense, we are learning that even small, long-term exposures can raise the risk of heart failure, especially among the most vulnerable. These findings elevate the urgency of protecting communities through both environmental policy and health care preparedness,” Harlan M. Krumholz, MD, Harold H. Hines Jr. Professor at Yale School of Medicine and editor-in-chief of JACC said in a release.