Environmental research, health : ERH
Impact of wildfire smoke waves on the association between long-term exposure to fine particulate matter and cardiovascular hospitalizations among older adults in the United States
By Zhang S, Wang Y, Wei J and 3 others.
Abstract
Background
Fine particulate matter (PM2.5) is a risk factor for cardiovascular disease (CVD), even at concentrations below U.S. air quality standards. The frequency and severity of wildfires are increasing, causing episodic PM2.5 spikes. Our study examined whether associations between long-term exposure to PM2.5 and cardiovascular hospitalizations differed in the presence and absence of wildfire smoke waves.
Methods
We conducted a cohort study of 65.2 million U.S. Medicare beneficiaries aged ≥ 65 years across the contiguous U.S. during 2017-2022. Daily total and wildfire smoke PM2.5 concentrations were estimated at 1 km and 10 km spatial resolutions, respectively, using validated machine learning models that incorporated satellite, meteorological, emission, and land-use data. Exposure estimates were aggregated to beneficiaries' residential ZIP codes by population-weighted averaging. Wildfire smoke waves were defined as ≥ 2 consecutive days with daily smoke PM2.5 > 10 μg/m3. We applied quasi-Poisson regressions to estimate relative risks (RR) of first hospitalizations for overall CVD, ischemic heart disease, cerebrovascular disease, and hypertension in ZIP-years with and without smoke waves.