A study has revealed that unusual cold spells lead to higher rates of death related to cardiovascular diseases, compared to extreme heat waves.
Researchers in a study published in the American Journal of Preventive Cardiology, a journal specializing in preventive cardiology, reported that unusually cold weather causes a greater increase in cardiovascular disease-related deaths than extreme heat. These findings are scheduled to be presented at the American College of Cardiology's annual scientific meeting.
The study was based on an analysis of average monthly temperatures and total deaths from cardiovascular diseases in 819 locations in the United States, covering about 80% of the population over the age of 25, during the period from 2000 to 2020. The results showed that the lowest mortality rate was recorded at a temperature of 23 degrees Celsius, while the number of deaths increases as temperatures deviate from this level, whether by rising or falling.
Based on this data, the researchers drew a curve illustrating the relationship between temperature and mortality, which came in the form of an asymmetrical (U) letter, where both extreme cold and high heat were associated with increased mortality, but the effect of cold was more severe and clear.
During the study period, it was estimated that cold weather caused approximately 40,000 additional deaths annually from cardiovascular disease (6.3% of the total), amounting to 800,000 deaths over two decades. In contrast, extreme heat was associated with approximately 2,000 additional deaths annually (0.33% of the total), totaling 40,000 deaths during the same period.
The effects of cold are attributed to a series of physiological responses in the human body, including inflammation and constriction of blood vessels, which increases the risk of heart disease. The elderly and those with chronic illnesses are most vulnerable to these risks, particularly given their growing numbers in the United States.
In this context, lead researcher Pedro Rafael Vieira de Oliveira Salerno said:
"We are used to focusing on the effects of climate change related to heat, but climate change also includes extreme cold waves. Therefore, measures should be taken to protect not only from the heat, but also from the cold."
Despite the increasing focus on the risks of rising temperatures, the findings indicate that the serious health effects of lower temperatures should not be overlooked.
