Unless greenhouse gas emissions are reduced, heat-related cardiovascular deaths in the United States are projected to double or triple by mid-century.
On a national scale, older adults and black adults are at the highest risk of cardiovascular death from extreme heat, a new study published in the same journal found. Circulation.
- Based on a hypothetical scenario if currently proposed policies to reduce U.S. greenhouse gas emissions are successfully implemented, heat-related cardiovascular deaths in the United States are projected to increase by 162% by mid-century.
- In an even more dire scenario, it is projected that cardiovascular deaths from extreme heat could increase by 233% over the next 13 to 47 years if minimal efforts are made to reduce emissions.
- In either scenario, the rate of increase in mortality would be greater among older adults and non-Hispanic black adults.
Deaths from heat-related cardiovascular disease in the United States could more than double by mid-century. Without cuts in greenhouse gas emissions, that number could triple again, according to a new NIH-funded study published Oct. 30 in 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 author of the study and assistant professor of medicine at the University of Pennsylvania. said Sameed Katana, MD, and his staff. Cardiologist at the Philadelphia Veterans Affairs Medical Center, both in Philadelphia. “Climate change is also a health equity issue because it may disproportionately impact certain individuals and groups and exacerbate existing health disparities in the United States.”
A study published in the Journal of the American Heart Association found that cardiovascular deaths in the United States due to extreme heat could double or even triple by mid-century if greenhouse gas emissions remain unchecked. I’m warning you. There are also proposals to introduce infrastructure interventions such as increasing tree cover, but further research is needed to test their effectiveness.
Effects of greenhouse gas emissions on health
How much and how quickly greenhouse gas emissions increase in the coming decades will determine the health effects of extreme heat. Katana said more aggressive policies to reduce greenhouse gas emissions could reduce the number of people who could experience the negative health effects of extreme heat.
Previously, the authors examined county-by-county data in the continental United States and demonstrated an association between an increase in extremely hot days and an increase in deaths from cardiovascular disease from 2008 to 2017. This data served as the benchmark for analysis in this new study. Researchers used models of future greenhouse gas emissions and the future socio-economic and demographic composition of the U.S. population to predict the impact of extreme heat on cardiovascular mortality in mid-century (2036-2065). estimated the possibility. They estimated the excess cardiovascular deaths associated with heat waves by comparing the predicted number of deaths for each county if the heat wave had not occurred and the expected number of heat days had occurred.
Key findings include:
- From 2008 to 2019, extreme heat was associated with 1,651 excess deaths from cardiovascular disease per year.
- Even if currently proposed reductions in greenhouse gas emissions are fully implemented, excess cardiovascular deaths due to heat waves will increase by 162% by mid-century compared to 2008-2019 baselines. is predicted to increase.
- However, if these greenhouse gas emissions reduction policies are not implemented, excess deaths from cardiovascular disease due to extreme heat are projected to increase by 233% in the coming decades.
- Depending on how aggressively greenhouse gas emission reduction policies are implemented, adults aged 65 years and older are 2.9 to 3.5 times more likely to die from cardiovascular diseases due to extreme heat compared to adults aged 20 to 64 years. It is predicted to double.
- Depending on the extent of greenhouse policy implementation, non-Hispanic black adults are predicted to experience a 3.8- to 4.6-fold increase in heat-induced cardiovascular mortality compared to non-Hispanic white adults.
- The predicted increase in heat-related deaths did not differ significantly among adults of other races or ethnicities or between men and women.
“The magnitude of the percentage increase was surprising. This increase not only accounts for the known association between cardiovascular disease deaths and extreme heat, but also reflects the aging of the population in the United States and the proportional “The increase in the population of other races and ethnic groups is also having an impact,” Katana said.
Underlying factors and responses
Both medical and environmental factors can influence the greater impact of heatwaves on people in these population groups, he said. Neighborhood disparities and environmental factors are also important factors to consider.
“Previous research suggests that Black residents may have less access to air conditioning; less tree cover; and a higher degree of “urban heat island effect,” meaning that built-up areas may have less access to surrounding woodlands. “The temperature increase is greater than in developed areas,” Katana said. “Living conditions may also influence social isolation, which some older people experience and which has been previously associated with increased odds of death from extreme heat.”
The results are unfortunately not surprising, according to American Heart Association volunteer Robert Brook, MD, FAHA, co-author of several associations. Scientific statement on air pollution and was not involved in this study.
“Even under this study’s more optimistic moderate scenario, greenhouse gas emissions will continue to increase for some time before declining,” said Dr. McConlogue, professor of medicine and executive director of cardiovascular prevention at Wayne State University School of Medicine in Detroit. Brook said. “Furthermore, because most pollutants remain in the atmosphere for many years, the frequency of heatwave events tends to increase significantly despite short-term measures.
“As more susceptible and vulnerable populations increase, such as older adults and people moving to warmer areas, they become more susceptible to heat-related impacts. cardiovascular disease The number of deaths is expected to increase in the coming decades. Nevertheless, this study shows that taking early steps to reduce the greenhouse gas emissions that cause climate change may alleviate some of the magnitude of the negative impact on cardiovascular disease. is showing. ”
Brook noted that while this prediction may seem alarming, it is likely conservative.
“This study’s projections focus on deaths from cardiovascular disease and therefore represent a conservative estimate of the negative effects of extreme heat on cardiovascular health,” he said. “Non-fatal heart attacks, strokes and hospitalizations for heart failure outnumber fatal events and are very likely linked to extremely hot days. The full extent of the public health threat is Cardiovascular mortality alone is likely to be much greater than what is shown in this study.
While this projection raises the question of whether infrastructure interventions such as increasing tree cover in nearby areas will lead to improvements in heat-affected populations in the United States, results from several studies in Europe suggest that this Research suggests this may be the case, but research is lacking in the United States.
Brooke also mentioned the role of pollution from excessive heat. “Air pollution (PM) due to fine particulate matter2.5) more than 6 million people die each year. This study adds to evidence that the full range of harmful effects caused by air pollutants extends beyond PM.2.5. With a significant increase in the number of extremely hot days, greenhouse air pollutants pose an additional threat to our health. ”
Research details and background:
- Researchers compared excess cardiovascular deaths due to extreme heat under two scenarios used by the Intergovernmental Panel on Climate Change, an international organization that assesses the science related to climate change caused by human activities. did. The scenario is:
- The implementation of currently proposed moderate emission reduction policies will be successful and the increase in greenhouse gas emissions will be contained.or
- There are no significant emissions reduction efforts, and greenhouse gas emissions continue to increase at the same rate as they have for the past 20 years.
- As a baseline, researchers looked at county-by-county records of summer deaths from leading causes of cardiovascular disease (including heart attacks and strokes) from 2008 to 2019, including age, sex, race, and sex. relevant data were used. Ethnicity of each person who died and the hottest day (day when the maximum heat index was 90)ahF or higher) during the month of death. Heat index takes into account both heat and humidity. This reflects how the human body experiences high temperatures, as high humidity interferes with the body’s ability to release heat through sweating.
These results are from data from the continental United States and may not apply to people living in other parts of the United States or other parts of the world. This study is also limited by employing two plausible projections for heat waves and population change, and actual changes in the United States may differ.
For more information on this study, please see:
Reference: “Projected Changes in the Burden of Excess Cardiovascular Deaths Associated with Extreme Heat by Mid-Century (2036-2065) in the Continental United States” Sameed Ahmed M. Katana, Lauren A. Everly, Ashwin Written by S. Nathan and Peter W. Groh, October 30, 2023.Circulation.
DOI: 10.1161/CirculationAHA.123.066017
Co-authors and their disclosure information are provided in the manuscript. The study was funded by the American Heart Association and the National Heart, Lung, and Blood Institute, a division of the American Heart, Lung, and Blood Institute. National Institutes of Health.
