New research connects climate change to increasing heat-related heart disease nationally

CLEVELAND - A new study by researchers at Case Western Reserve University, University Hospitals and the Louis Stokes Cleveland VA Medical Center predicts rising temperatures driven by climate change will dramatically increase heat-related heart disease in the United States.

More specifically, the study, published today in JAMA Cardiology, estimates the higher temperatures could increase heat-related heart disease by 200% by 2050.

Researchers analyzed heart disease data in each county in the contiguous U.S. from 2010 to 2016 to develop projections through 2050.

Scientists used the Global Burden of Disease database for cardiovascular burden estimates, a NASA-derived global climate model for historical and future temperature projections and U.S. Census Bureau data for baseline and future population calculations. They combined this data to perform county-level calculations.
"We already knew that extreme heat could trigger heart attacks and other cardiovascular events," said Gokul Parameswaran, research associate at the Case Western Reserve School of Medicine's Cardiovascular Research Institute and the study's lead author. "But this study is the first to map out exactly how bad the problem could get-county by county, across the U.S. It also highlighted how states with lower median household incomes are likely to face higher heat-related heart disease burden."

According to the Centers for Disease Control and Prevention, when temperatures rise, the heart must work harder to keep the body cool and the likelihood of developing sudden clots in the bloodstream increases. This extra stress on the heart due to high heat may lead to heart attacks or sudden worsening of heart disease, especially in the elderly or those with prior heart conditions.

Researchers found that the Pacific Northwest has the highest heat-related heart disease rate in the country. Southern states, however, are projected to see the steepest increases by 2050.

"We believe this increase in the South could possibly be driven by three converging factors: The region already carries one of the highest heart disease burdens in the nation, it faces some of the fastest projected temperature increases in the country and presently contains many counties among the poorest in U.S. with the least healthcare infrastructure to cope with the projected crisis," said Salil Deo, associate professor in the Department of Surgery and one of the study's senior authors. "Climate change is not just an environmental issue-it is a health equity crisis, and prioritizing vulnerable communities must be at the center of any heat mitigation strategy."

The study also found that aging-independent of temperature increases-will contribute an additional 34% increase in heat-related heart disease by 2050-simply because there will be more older adults by then.

Expanding green spaces and tree cover in urban areas could help reduce temperature-related adverse effects. Expanding access to cooling centers and air-conditioning assistance programs for low-income communities can also help bridge the gap in underserved communities.

"Climate change is not a distant, abstract threat," said Sanjay Rajagopalan, director of the Cardiovascular Research Institute and chief of Cardiovascular Medicine at University Hospitals Harrington Heart & Vascular Institute. "It is a present and growing danger to the hearts of every American, and it is coming for the most vulnerable among us first. The choices made today about greenhouse gas emissions, urban planning and healthcare policy will determine whether tens of thousands of Americans live or die from heart-related heart disease by 2050."

Rajagopalan's lab has helped transform global perceptions and understanding of the impact of environmental risk factors on cardiovascular disease. The lab has published numerous high-impact studies highlighting the critical role environmental factors play in cardiovascular health.