Characterizing Vulnerability for the Future Heat-Related Cardiovascular Morbidity Burden in U.S. Metropolitan Areas
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Objective: Climate change-driven increases in extreme heat events is associated with an increased burden of cardiovascular disease (CVD) morbidity among older adults. This study identifies urban areas with the largest expected change in heat-related excess burden of CVD hospitalizations in older adults under future temperature projections and assesses which measures of vulnerability modify future burden rates.
Material and methods: We assessed the excess risk and burden of CVD hospitalizations attributed to temperatures above the minimum hospitalization percentiles (MHP) among Medicare beneficiaries, aged 65 and older, in the 120 largest US cities between 2000-2017. Using future projections of population change and temperature, we estimated the average heat-attributed daily burden rates (HADB-rates) at early, mid, and late century for three climate scenarios (CESM with RCP4.5 [low emission] and RCP8.5 [high emission], GFDL with RCP8.5). Temperature projections from the Localized Constructed Analogs (LOCA) were used. Finally, we characterized how present-day indicators of vulnerability, including the frequency of exposure, population sensitivity, and adaptive capacity, modified future heat-related burden.
Results: By late century, the mean temperatures above the MHP are expected to increase by 1.9 (±0.5), 4.8 (±1.0), and 6.4 (±0.88) °C for CESM RCP4.5, CESM RCP8.5, GFDL RCP8.5, respectively. For early, mid, and late century, the respective HADB-rates are projected to increase by 1.2% (±4.5), 2.6% (±8.2), 3.1% (±11.3) under the low emission scenario, and by 1.4% (±5.0), 6.6% (±19.8), 22.5% (±65.3) under the high emission scenario. The greatest increase is expected in Florida. Preliminary results on characterizing vulnerability indicate that present-day tree cover and cooling centers are associated with decreased future HADB-rates.
Conclusion: Findings from this analysis indicate that the projected burden of heat-related CVD morbidity under climate change is significant. Future work includes identifying factors that are most relevant to reduce vulnerability to heat-related health burden and developing adaptation and resilience strategies. This abstract doesn’t reflect EPA’s policy.