Heart Disease Mortality Increases With Combined Day-Night Heatwaves

TUESDAY, April 15, 2025 (HealthDay News) -- Exposure-response curves reveal the impacts of daytime-only, nighttime-only, and compound heatwaves on cause-specific heart disease mortality, according to study published in the April 8 issue of the Journal of the American College of Cardiology.Xue Yu, M.D., from Beijing Hospital, and colleagues collected heart disease death records for individuals across Mainland China from 2013 to 2019. Daytime-only, nighttime-only, and day-night compound heatwaves were defined, and the excess cumulative temperatures in heatwaves (ECT-HW) metric was calculated. Exposure-response curves were explored and used to estimate the corresponding mortality burden.A total of 2,392,254 heart disease deaths were evaluated. The researchers found that across the entire range of ECT-HW, mortality risks associated with compound heatwaves exhibited a steady increase, without a discernible threshold. Risks from nighttime-only heatwaves were seen beyond the 25th percentile of ECT-HW and stabilized after the 90th percentile, while risks from daytime-only heatwaves were stable between the 50th and 95th percentile and then increased. Significantly higher heart disease mortality risk was seen for compound heatwaves versus nighttime-only and daytime-only heatwaves (odds ratios, 1.86, 1.16, and 1.19, respectively). Overall, 41,869, 9,092, and 9,809 excess cardiac deaths were estimated to be associated with compound, nighttime-only, and daytime-only heatwaves, respectively, which accounted for 1.75, 0.38, and 0.41 percent of total heart disease deaths.“As climate change accelerates, the shifting and emerging heatwave exposure pattern demands better metrics and targeted interventions,” coauthor Renjie Chen, Ph.D., of Fudan University in Shanghai, China, said in a statement. “Given the increasing frequency and intensity of compound heatwaves due to climate change, our findings highlight the need for disease-specific prevention strategies and revised public health guidelines to better protect at-risk populations.”Abstract/Full Text (subscription or payment may be required)Editorial (subscription or payment may be required).Sign up for our weekly HealthDay newsletter