J Am Coll Cardiol

Wildfire smoke exposure linked to heart failure risk in older adults, especially women

July 22, 2025

Lengthy exposure to fine particulate matter from wildfire smoke was associated with higher heart failure risk in older patients compared with exposure to fine particulates from nonsmoke sources, according to this national retrospective cohort analysis of Medicare patient data. The association was stronger in women, Medicaid-eligible individuals, and patients living in areas with lower incomes. Targeted interventions and policies are needed to reduce the cardiovascular impact of wildfire smoke exposure.

Study details. This retrospective cohort study correlated incident heart failure data from approximately 22 million Medicare beneficiaries with high-resolution exposure estimates to both fire smoke-related and nonsmoke-related fine particulate matter over the past 2 years by ZIP code in the contiguous U.S. from 2007 to 2018. Cox proportional hazard models were adjusted for demographic characteristics and geographic area-level socioeconomic risk factors.

Results. Incident heart failure hazard ratios per 1 mcg/m³ increase in average fine particulate matter exposure over the past two years were 1.014 (95% confidence interval [CI], 1.007-1.020) for smoke and 1.005 (1.005; 95% CI, 1.003-1.006) for nonsmoke. This association with smoke exposure suggests an estimated 20,238 (95% CI, 10,727-29,612) additional heart failure cases per year among older adults in the U.S. Incident heart failure risk was also significantly adversely associated with the number of days exposed to fine particulate matter from smoke exceeding 1 mcg/m3 or 2.5 mcg/m3 over the past two years. Findings were notably stronger in women, Medicaid-eligible individuals, and individuals living in lower income areas.

Source:

Hao H, et al. (2025, July 1). J Am Coll Cardiol. Long-Term Wildfire Smoke Exposure and Increased Risk of Heart Failure in Older Adults. https://pubmed.ncbi.nlm.nih.gov/40562508/