by Ruggiero Corcella
Published in Circulation (American Heart Association) a study of over 200,000 people who died in China. The mix of extreme heat and Pm 2.5 particulates is fatal
That the heat, especially the extreme one we are experiencing, is a known cardiovascular risk factor. According to a new study of more than 202,000 heart attack deaths in China, the combination of sweltering heat and fine PM2.5 particulate matter pollution may even double the risk of death from heart attack. The study was published today in the journal Circulation dell’American Heart Association .
Extreme temperature events are becoming more frequent, longer and more intense, and their negative effects on health have caused growing concern. Another worldwide environmental problem is the presence of fine particulate matter in the air, which can synergistically interact with extreme temperatures to adversely affect cardiovascular health, says Yuewei Liu, senior author of the publication and an associate professor of epidemiology in the School of Public Health at Sun Yat-sen University in Guangzhou, China. However, it is unknown whether and how co-exposure to extreme temperatures and fine particulate pollution may interact to trigger a greater risk of death from heart attack, than an acute response potentially caused by an acute scenario and a major public health challenge due to its significant disease burden worldwide.
Research
To examine the impact of extreme temperatures with and without high levels of fine particulate pollution, the researchers analyzed 202,678 heart attack deaths between 2015 and 2020 that occurred in Jiangsu Province, a region with four distinct climate regions and a wide range of temperatures and fine particulate pollution levels. Deaths were among older adults with a mean age of 77.6 years; 52% were over 80 years old; and 52% were male. The analysis included exposure to particulate matter on the day of each death and one day before the death. Temperature extremes were measured based on the daily heat index (also known as apparent temperature) for an area, which captures the combined effect of heat and humidity.
Both the duration and peaks of heat (and cold) waves were evaluated. Heart attack deaths, or case days, during these periods were compared to control days on the same day of the week in the same month, meaning that if a death occurred on a Wednesday, all other Wednesdays in the same month would be considered control days. Particulate matter levels were considered high on any day with an average fine particulate level above 37.5 micrograms per cubic metre.
The results
Our findings provide evidence that reducing exposure to both extreme temperatures and fine particulate pollution may be helpful in preventing premature deaths from heart attacks, especially for women and the elderly, Liu said. Researchers have estimated that up to 2.8% of heart attack deaths can be attributed to the combination of extreme temperatures and high levels of fine particulate pollution.
(> 37.5 micrograms per cubic meter).
WHO goals
Strategies to avoid adverse health effects from extreme temperatures include following weather forecasts, staying indoors when temperatures are extreme, using fans and air conditioners during hot weather, dressing appropriately for the weather, proper hydration, and installing blinds to reduce indoor temperatures, according to World Health Organization goals, Liu said.
Using an air purifier indoors, wearing a mask outdoors, staying away from busy highways when walking, and choosing less strenuous outdoor activities can also help reduce air pollution exposure on days with high levels of fine particulate pollution. To improve public health, it is important to consider fine particulate pollution when providing warnings of extreme temperatures to the public, he concludes.
Further investigations are needed
In a scientific statement and in one political statement, in 2020, the American Heart Association details the latest scientific findings on air pollution exposure and individual, industry, and policy measures to reduce the negative impact of poor air quality on cardiovascular health. Reducing exposure to air pollution and reversing the negative impact of poor air quality on cardiovascular health, including heart disease and stroke, is essential to reducing health inequalities in historically marginalized and under-resourced communities and communities that have the highest levels of exposure to air pollution.
The researchers recommended further research into the possible interactive effects of extreme weather events and fine particulate pollution on heart attack deaths in areas with different temperature and pollution ranges to confirm their findings. The study did not include adjustments for any adaptive behaviors individuals engage in, such as using air conditioning and staying indoors, when temperatures are extreme or pollution levels are high, which could cause individuals’ exposure to weather conditions to be misclassified and alter their risk models. These results may also not be generalizable to other regions in China or other countries due to potential variations in adaptive capacity and temperature distribution.
What is fine particulate matter
The fine particles are less than 2.5 microns in size and can be inhaled deep into the lungs, where they can irritate the lungs and blood vessels around the heart. Most associated with fuel combustion, such as car exhaust particles, factory emissions or fires. Previous research has confirmed that exposure to particulate matter, including fine particulate matter, is linked to heart disease, stroke and other health problems. The World Health Organization’s target for the average annual exposure level of fine particulate pollution is no more than 5 micrograms per cubic meter and no more than 15 micrograms per cubic meter on more than 3-4 days per year.
July 24, 2023 (change July 24, 2023 | 18:16)
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