Climate change worsens cardiovascular health risks

Cardiovascular disease (CVD) remains the leading cause of death globally, responsible for approximately one in three deaths. There were over 20 million CVD fatalities reported in 2021, according to a 2024 World Heart Federation report.

Despite significant advancements in heart disease prevention, treatment, and intervention, climate change threatens to reverse these gains.

NASA confirms that the average global temperature has risen by more than two degrees Fahrenheit over the last century, resulting in long-term shifts in weather patterns, disturbed ecosystems, and rising sea levels. Alarmingly, the ten hottest years on record have all occurred within the past decade.

Climate change and cardiovascular health

A new study conducted by researchers at Beth Israel Deaconess Medical Center (BIDMC) has delved into the connection between climate change-related environmental stressors and cardiovascular disease. The team systematically reviewed 492 observational studies to explore this critical issue.

The findings reveal a strong association between extreme temperatures, hurricanes, and increased CVD mortality and incidence.

Vulnerable populations, such as older adults, racial and ethnic minorities, and those from lower-income communities, are disproportionately affected.

The impact of environmental stressors

“Climate change is already affecting our cardiovascular health,” said Dhruv S. Kazi, associate director of the Richard A. and Susan F. Smith Center for Outcomes Research at BIDMC and the study’s corresponding author.

“Exposure to extreme heat can adversely affect heart rate and blood pressure, ozone or wildfire smog can trigger systemic inflammation, and living through a natural disaster can cause psychological distress.”

“Hurricanes and floods may disrupt healthcare delivery through power outages and supply chain disruptions. In the long term, the changing climate is projected to reduce agricultural productivity and the nutritional quality of the food supply, which could also compromise cardiovascular health.”

The research team screened nearly 21,000 peer-reviewed studies published between 1970 and 2023.

These studies evaluated the associations between acute cardiovascular events, CVD mortality, healthcare utilization, and various climate change-related phenomena, including extreme temperatures, wildfires, air pollution, ground-level ozone, extreme weather events, sea level rise, salt-water intrusion, and climate-related migration.

Extreme weather linked to cardiovascular risks

Out of the 492 global observational studies included in the review, 182 examined extreme temperature, 210 focused on ground-level ozone effects, 45 investigated wildfire smoke, and 63 studied extreme weather events such as hurricanes, dust storms, and droughts.

These studies spanned 30 high-income countries, 17 middle-income countries, and one low-income country.

The researchers found that exposure to extreme temperature was strongly linked to increased incidence of cardiovascular disease and mortality, with the impact varying based on temperature and exposure duration.

Extreme weather events, including tropical storms, hurricanes, floods, and mudslides, were also associated with heightened cardiovascular risk, often lasting months or even years beyond the severe weather event.

One study on Hurricane Sandy, which caused nearly $20 billion in damage in New York City alone in 2012, showed that the risk of death from cardiovascular disease remained elevated for up to 12 months after the storm.

Addressing knowledge gaps

The researchers also identified significant gaps in knowledge regarding the impact of climate change on cardiovascular risk in lower-income nations.

Only one study was conducted in a low-income country, and just five were based in Africa, where climate change is expected to have disproportionate effects.

“Though data on outcomes in low-income countries are lacking, our study shows that several environmental stressors already increasing in frequency and intensity with climate change are linked with increased cardiovascular risk,” noted senior author Dr. Mary B. Rice, a pulmonary and critical care physician at BIDMC.

Recommendations for health systems

These findings suggest that clinicians should be aware of climate-related cardiovascular risk in their community, whether related to extreme temperatures, wildfire smoke, or extreme weather events.

For instance, in areas prone to hurricanes or flooding, clinicians should help patients develop contingency plans to ensure uninterrupted access to medications and healthcare as needed.

Health systems should also evaluate the resilience of their infrastructure to climate change.

“Climate change is already adversely affecting cardiovascular health in the U.S. and worldwide,” the researchers concluded. “Urgent action is needed to mitigate climate change-related cardiovascular risk, particularly among our most vulnerable populations.”

The study is published in the journal JAMA Cardiology.

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