An observational study by Australian researchers has found that about 1.8 million people from 32 countries around the world are dying every year from heart problems associated with cold or hot weather.
The study by Monash University and the Queensland University of Technology (QUT) estimated that more people (8.2%) died between 2000-2019 from heart deaths related to cold weather compared to hot weather (0.66%).
During this same 19-year period the study found there was an overall decline in heart deaths due to cold, while heart-related deaths increased.
The data analysis was published in the Journal of the American College of Cardiology on Tuesday.
Another series of papers published in the same journal this week, including by researchers from the Victor Chang Cardiac Research Institute (VCCRI), UNSW, and the University of Western Australia (UWA), has highlighted some man-made drivers of heart disease.
The series examines the effects of global warming, air pollution, exposure to wildfire smoke, toxic chemicals, soil, noise and light pollution to call for regulators to improve monitoring pollutant levels to better understand who is at risk of cardiovascular disease.
Victor Chang Cardiac Research Institute CEO Professor Jason Kovacic said the dangers of pollution and the extent to which they caused approximately 9 million annual deaths worldwide should be better recognised.
One model to consider in future would be to routinely test people for their exposure to pollutants in the same way the US tests children for lead exposure.
“Our bodies are being bombarded with pollutants from every angle and they are taking a toll on our heart health,” Kovacic said.
“The evidence suggests that the number of people dying prematurely because of these very different forms of pollution is far higher than currently recognised.”
While about 20 million people are dying each year from cardiovascular diseases, pollutants are increasingly contributing to illness.
Professor Kovacic explained pollutants impacted all people in “every corner of the globe” and affected the body in different ways.
For example, smoke and toxins could reach the blood by being inhaled deep into the lower respiratory tract and then transported to other organs in the body. Damage to the heart and other organs could be caused by cell damage due to oxidative stress, he said.
“There are hundreds of thousands of chemicals that haven’t even been tested for their safety or toxicity, let alone their impact on our health,” Kovacic said.
“We also need to discover if there are other risk factors that make people more susceptible – such as pre-existing conditions, lifestyle factors or where they live.”
The researchers found other factors disrupting human sleep patterns and contributing to inflammation in the body had the potential to contribute to blood pressure and weight gain.
Extreme heat, for example, was capable of causing dehydration, decreased blood volume, cardiovascular strain and acute kidney failure.
During heat waves in particular, cardiovascular-related mortality can escalate by more than 10%.
The challenge for the government to solve is for a more consistent and less sporadic approach, most urgently with respect to stemming the effects of climate change.
“Urgent action is required as climate change strides forward and pollution infiltrates the air we breathe, the water we drink, the food we eat, and the places we live in,” the researchers said.
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