Wildfire smoke exposure ups risk of heart failure in older adults

Exposure to wildfire smoke for an extended period may increase the risk of heart failure (HF) in older adults, particularly women and socially vulnerable populations, suggests a study.

In this retrospective cohort study, the authors analysed data from Medicare fee-for-service beneficiaries between 2007 and 2018. They linked individuals to high-resolution exposure estimates of fire smoke and nonfire smoke fine particulate matter (PM2.5) at a 1 x 1-km spatial resolution aggregated to zip codes by averaging the values of all 1-km grid cells whose centroids fell within each zip code boundary and followed them for incident HF.

Cox proportional hazard models were used to explore the association between PM2.5 and incident HF, with adjustments for individual demographic characteristics and area-level socioeconomic risk factors.

The cohort involved about 22 million enrolees, with a follow-up of 115 million person-years. The mean smoke PM2.5 exposure was 0.51 μg/m3. Each 1-μg/m3 increase in the past 2-yer average smoke PM2.5 correlated with a significant increase in HF risk (hazard ratio [HR], 1.014, 95 percent confidence interval [CI], 1.007–1.020). This was higher than the risk associated with nonsmoke PM2.5 (HR, 1.005, 95 percent CI, 1.003–1.006).

This association indicated an estimated 10,238 (95 percent CI, 10,727–29,612) additional HF cases annually among older adults in the US.

Moreover, the number of days exposed to smoke PM2.5 exceeding 1 and 2.5 μg/m3 over the past 2 years significantly correlated with a higher HF risk. Notably, the association between smoke PM2.5 and HF was more pronounced among women, Medicaid-eligible individuals, and those living in lower income areas, suggesting greater vulnerability.

“These findings underscore the need for targeted interventions and policies to reduce wildfire smoke exposure and its cardiovascular impacts,” the authors said.