A new study highlights the substantial risk wildfire smoke poses to heart health, emphasizing an urgent call for enhanced environmental policies and healthcare preparedness.
Long-term exposure to wildfire smoke incrementally raises the risk of heart failure, particularly impacting older adults, women and other vulnerable groups, according to new research published in the Journal of the American College of Cardiology (JACC).
The study, the first of its kind to analyze the impact of prolonged wildfire smoke on heart failure risk across a national population, observed that a slight increase in air pollution due to wildfire smoke correlates with a noteworthy rise in heart failure cases.
“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,” lead author Hua Hao, a research scientist at Emory University’s Rollins School of Public Health, said in a news release. “Even a small individual risk translates into a large public health impact.”
The Impact of PM2.5 Pollution
Wildfires emit PM2.5, tiny particles less than 2.5 micrometers in diameter, which can deeply penetrate the lungs and reach the bloodstream.
PM2.5 originates from various sources like vehicle emissions, industrial activities and fossil fuel burning, but wildfire smoke is increasingly becoming a global health concern.
The researchers studied data from Medicare beneficiaries enrolled in the Fee-For-Service program between 2007 and 2018.
They discovered that each time the PM2.5 levels in wildfire smoke increased by 1 microgram per cubic meter over a two-year period, there was a 1.4% rise in heart failure risk. This translates to potentially over 20,000 additional heart failure cases annually in the United States among older adults.
“We also found that the association between smoke PM2.5 and HF was stronger in women, Medicaid eligible individuals and those living in lower-income areas, indicating higher susceptibility,” added Hao.
Compared to similar increases in non-smoke-related air pollution, the rise in heart failure risk was just 0.5%, suggesting that wildfire smoke could be more harmful than other pollution types.
The Growing Frequency of Wildfires
“By century’s end, under a high greenhouse gas emission scenario, we expect 74% of the globe to experience substantial increases in the length of wildfire season and the frequency of wildfire events,” added Joan A. Casey, an associate professor of epidemiology in the University of Washington’s Department of Environmental and Occupational Health Sciences and an author of the accompanying editorial comment. “This is already the case in the United States, where wildfire smoke days, once rare, now happen several times per year.”
These findings signal a critical need for policy interventions.
“This study highlights a growing and underappreciated threat to heart health,” added Harlan M. Krumholz, a professor at Yale School of Medicine and the editor-in-chief of JACC. “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.”
Study Limitations
The study acknowledges certain limitations, including potential measurement errors in predicting smoke PM2.5 concentrations, misclassifications due to reliance on Medicare claims data, and unmeasured confounding variables like individual lifestyle habits or family history. Geographical variations could also play a role.
Source: American College of Cardiology