Incidence and burden of cardiovascular disease attributable to extreme heat in China

Aim The increasing frequency of heat events driven by climate change poses a serious challenge to cardiovascular health. This study aimed to investigate the relationship between high temperature and acute cardiovascular disease (CVD) incidence in China, and to quantify the heat-related burden of CVD.

Methods 856,357 incident acute CVD cases were used from CVD surveillance in China in 2023. A distributed lag non-linear model was applied to evaluate the dose-response relationship between temperature and CVD incidence, as well as the best linear unbiased prediction of the minimum incidence temperature (MIT). The heat-related burden was quantified using attributable fraction and attributable number for two temperature ranges: all heat and extreme heat.

Results Higher temperatures were associated with an increased risk of acute CVD incidence. Extreme heat exposure resulted in a cumulative relative risk (RR) of 1.17 (95% confidence interval[CI] 1.05-1.30), with the highest cumulative risk observed on the fourth day following exposure. All heat exposure accounted for 3.19% of CVD cases, while extreme heat contributed to 0.08%. The burden was particularly pronounced among individuals aged≥65 years (RR = 1.20, 95% CI 1.05-1.37), rural populations (RR = 1.18, 95% CI 1.01-1.37), and those living in temperate monsoon and temperate continental climates (RR = 1.25, 95% CI 1.05-1.49). MIT varied geographically, ranging from 16.0 ℃ in northern regions to 26.2 ℃ in southern regions, with the highest MITs concentrated in tropical areas.

Conclusions These findings emphasize the urgent need for region-specific public health strategies that integrate climate change adaptation and CVD prevention to mitigate the growing health risks associated with rising temperatures.