Extreme weather heightens risk of death from heart disease

A new study has identified connections between cold weather and deaths from heart disease, particularly in poor neighborhoods. Hot weather was also linked with excess deaths from heart disease and stroke in patients with heart conditions.

“Climate change is leading to a rise in the average global temperature but also extreme cold in some regions. More than 70,000 excess deaths occurred across Europe during the summer of 2003 due to intense heatwaves,” said Professor Stefan Agewall of the University of Oslo, Norway.

“Cold weather also accounts for excess deaths and hospital admissions. Previously studies on the cardiovascular effects of heat and cold mainly used aggregated data, such as daily deaths in a city. The EXHAUSTION project used individual data, enabling us to identify vulnerable subgroups for protective interventions, thereby increasing resilience for future weather events.”

The analysis included 2.28 million adults from five cohort studies conducted in Italy, Germany, the UK, Norway, and Sweden between 1994 and 2010. Participants with and without cardiovascular disease were included. 

The relationships between temperature and cardiovascular conditions and death were analyzed for all participants. 

The researchers compared the temperature on the day of the week an adverse event occurred (e.g. Monday) with the temperature on the same day without an adverse event (e.g. all remaining Mondays) within the same month.

In particular, the experts found increased risks of death from cardiovascular disease and heart disease associated with cold weather. 

With a temperature drop of 10°C, from 5°C to -5°C, there was a 19 percent greater risk of death from cardiovascular disease and a 22 percent elevated likelihood of death from heart disease. 

The relationship between cold temperature and death was pronounced in men and people living in poor neighborhoods. Meanwhile, the relationship between cold and new-onset heart disease was stronger among women and those older than 65.

Interestingly, heat was not related to detrimental effects in the overall study population. However, temperature rises from 15°C to 24°C were associated with 25 to 30 percent elevated risks of death from cardiovascular disease and stroke in people with heart disease.

“Clinicians can use this information to provide tailored advice to those most at risk of adverse health outcomes during hot and cold days,” said Professor Agewall.

“Patients with heart conditions should stay hydrated in hot weather and adhere to advice from their cardiologist on medication use. We can all check the news for extreme heat and cold alerts and follow safety tips from local authorities.”

The research will be presented at the annual meeting of the European Society of Cardiology, ESC Congress 2022.

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By Katherine Bucko, Earth.com Staff Writer