Climate change linked to higher risk of cardiovascular deaths, study suggests

By Lois Zoppi, B.A.Mar 30 2020

Kuwait recorded the highest temperature on Earth in the last 76 years, of 129 degrees Fahrenheit, and researchers have found that as temperatures climb to a daily average temperature of 109 degrees Fahrenheit in the country, the number of deaths from cardiovascular disease can double or triple.

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In a study published in Circulation, March 30, 2020, researchers analyzed the association between temperature and over 15,000 cardiovascular-related deaths across Kuwait. Included in the study were all death certificates from 2010 to 2016 that cited “any cardiovascular cause” for anyone over the age of 15.

Effects of heat on cardiovascular health are different for each demographic

The study revealed that average daily temperature was 94.5 degrees Fahrenheit when the fewest people died. However, when the 24-hour average temperature was extreme 109 degrees Fahrenheit or higher, the death risk was three-times higher due to a cardiovascular disease and men were affected by a 3.5 times higher death rate, with the death rate standing at 2.5 times higher for women.

People aged 15 to 64 years, classed as “working age”, had a death rate that was 3.8 times higher. Those aged 65 and older had a death rate of two times higher.

Barrack Alahmad, M.B.Ch.B, M.P.H., a mission scholar from Kuwait University and a PhD candidate in environmental health at the Harvard T.H. Chan School of Public Health in Boston, said that, “While cardiologists and other medical doctors have rightly focused on traditional risk factors, such as diet, blood pressure and tobacco use, climate change may exacerbate the burden of cardiovascular mortality, especially in very hot regions of the world.”

In order to examine the effects of temperature independently, the researchers adjusted for environmental factors including air pollution and humidity. It was found that higher temperatures affected all age groups and genders differently.

Hotter climates are at risk of high rates of cardiovascular deaths

The body redirects blood from the organs to underneath the skin when its core temperatures increase. When this happens, the heart pumps more blood and exerts more stress on the organ. In hotter climates, where the temperature is regularly increasing, it is possible that deaths due to cardiovascular disease could increase, according to a hypothesis posited by cardiologists environmental health specialists and epidemiologists.

Barrack Alahmad said:

“The warming of our planet is not evenly distributed. Regions that are inherently hot, like Kuwait and the Arabian Peninsula, are witnessing soaring temperatures unlike ever before.

“We are sounding the alarm that populations in this part of the world could be at higher risk of dying from cardiovascular causes due to heat.”

More research will reveal the effects of hot climates on specific heart conditions

The study was subject to some limitations, because there was only information on deaths from cardiovascular disease in general, and no specific heart conditions were identified as being more susceptible from complications due to high heat.

Despite this, Alahmad concluded:

Although we cannot conclude it from this analysis, men and working-age people may have been at greater increased risk because of spending more time outside. We need to explore this relationship further and consider serious preventive strategies that could reduce the impact of rising temperatures on our health.”

Barrack Alahmad, Kuwait University

Although there were strong associations were found between heat and cardiovascular deaths, the study, which was funded by the United States Environmental Protection Agency and the Kuwait Foundation for the Advancement of Sciences, requires more research in order to definitively prove causality between higher cardiovascular death rates and higher temperatures.