Cardiovascular Deaths Due to Extreme Heat May Double in Coming Decades

In the United States, cardiovascular deaths from extreme heat may more than double by the middle of the current century, and could potentially triple, if greenhouse gas emissions are not reduced, according to new research published by the American Heart Association’s flagship journal, Circulation.

“Climate change and its many manifestations will play an increasingly important role [in] the health of communities around the world in the coming decades,” said lead study author Sameed Khatana, MD, MPH, an assistant professor of medicine at the University of Pennsylvania and a staff cardiologist at the Philadelphia Veterans Affairs Medical Center, both in Philadelphia. “Climate change is also a health equity issue as it will impact certain individuals and populations to a disproportionate degree and may exacerbate preexisting health disparities in the [United States].”

Previous county-by-county data regarding the link between a greater number of extreme heat days and an increase in cardiovascular deaths between 2008 and 2017 was used as this current study’s benchmark. The investigators used models for future greenhouse gas emissions, as well as future socioeconomic and demographic makeup of the US population to assess the potential impact of extreme heat on cardiovascular deaths in the middle years of the current century (2036-2065).

Critical Need to Reduce Greenhouse Gas Emissions

The study found that between 2008 and 2019, extreme heat was linked to 1651 excess cardiovascular deaths per year. Troublingly, the analysis showed that even if proposed reductions to greenhouse gas emissions are fully implemented, cardiovascular deaths owing to extreme heat are projected to be 162% higher in the middle of this century. Moreover, if greenhouse gas emission reduction policies are not implemented, excess cardiovascular deaths could spike to 233% in the coming decades. Also, depending on the extent of greenhouse gas emissions, both older individuals (aged 65 years and above) and Black adults are at significantly higher risk of heat-related cardiovascular deaths.

“The projections of this study focus on cardiovascular disease deaths, and, therefore, they represent conservative estimations of the adverse effects on cardiovascular health due to extreme heat,” he said. “Nonfatal heart attacks, strokes, and heart failure hospitalizations outnumber fatal events and are also highly likely to be linked with extreme heat days. The full extent of the public health threat, even just due to cardiovascular death, is likely much greater than presented in this study. “