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Study finds Heart attacks more likely due to extreme temperature variation

March 7, 2018 at 4:13 pm John Englart 2 comments

It is not only heatwaves that pose a health problem with global warming but extreme temperature variation and single extreme heat days is increasing the likelihood of heart attacks new research shows.

A study presented at the American College of Cardiology’s 67th Annual Scientific Session showed that heart attacks were more frequent with large temperature variations.

The study examined data from 30,000 hospital patients from at 45 Michigan hospitals between 2010-2016 and compared it to daily temperature variation extremes.

“Global warming is expected to cause extreme weather events, which may, in turn, result in large day-to-day fluctuations in temperature,” said Hedvig Andersson, MD, a cardiology researcher at the University of Michigan and the study’s lead author. “Our study suggests that such fluctuations in outdoor temperature could potentially lead to an increased number of heart attacks and affect global cardiac health in the future.”

While there is much academic research on extreme heat and health impact, this new study is among the first to examine associations between heart attacks and sudden temperature changes.

“While the body has effective systems for responding to changes in temperature, it might be that more rapid and extreme fluctuations create more stress on those systems, which could contribute to health problems,” Andersson said, noting that the underlying mechanism for this association remains unknown.

Accordng to the media release:

“Overall, the results showed the risk of a heart attack increased by about 5 percent for every five-degree jump in temperature differential, in degrees Celsius (9 degrees Fahrenheit). Swings of more than 25 degrees Celsius (45 degrees Fahrenheit) were associated with a greater increase in heart attack rates compared to a smaller increase with temperature swings of 10 to 25 degrees Celsius (18-45 degrees Fahrenheit). The effect was more pronounced on days with a higher average temperature; in other words, a sudden temperature swing seemed to have a greater impact on warmer days.”

According to the study, on extremely hot summer days, nearly twice as many heart attacks were predicted on days with a temperature fluctuation of 35-40 degrees Celsius (63-72 degrees Fahrenheit) than on days with no fluctuation.

“Generally, we think of heart attack risk factors as those that apply to individual patients and we have, consequently, identified lifestyle changes or medications to modify them. Population-level risk factors need a similar approach,” said Hitinder Gurm, MD, professor of medicine and associate chief clinical officer at Michigan Medicine and the study’s senior author. “Temperature fluctuations are common and [often] predictable. More research is needed to better understand the underlying mechanisms for how temperature fluctuations increase the risk of heart attacks, which would allow us to perhaps devise a successful prevention approach.”

Climate Action Moreland would argue strongly that the National Health and Medical Research Council (NHMRC) should be funding similar medical and climate change research in Australia on the health implications for rising temperatures due to global warming and the adaptations in lifestyle, social behaviour and medical treatments needed.

In March 2016 I wrote about the lack of funding by the National Health and Medical Research Council on climate and health research projects. (Is poor funding of climate and health research by NHMRC political bias?)

A quick perusal of the latest funding to date shows that only two new climate and health studies have been approved for research grants commencing in 2018:

• Identifying optimal sustainable cooling strategies for the most vulnerable during heatwaves to Dr Ollie Jay. Funding from 2018 to 2022. Plain description of the research: “Current guidance warns against electric fan use in heatwaves without any supporting evidence. This Project aims to identify how fans and other parallel low-resource strategies can reduce the risk of heat-related illness in the most vulnerable during simulated hot/humid and very hot/dry heat wave conditions. This information will be used to develop simple heat adaptation strategies that also mitigate unsustainable energy demands and the destructive environmental impact of air conditioning.”
• Forecasting the impact of climate change on dengue transmission to A/Pr Wenbiao Hu. Funding from 2018-2020. The plain description of the research: “Dengue fever (DF) is the most important mosquito-transmitted viral disease in the world. The large-scale re-emergence of DF in the Asia-Pacific region during the past few decades has renewed its status as a serious international public health problem. Global climate change is anticipated to impact upon the biology and ecology of vectors and consequently the risk of DF transmission. The principal research aim of this study is to project the impact of future climate change on DF.”

While we need strong and rapid emissions reduction, we also need to be addressing the health risks and implications of rising temperatures and extreme heat events, and increase in disease vectors.

This includes emergency preparedness of our health system to deal with health crises associated with extreme heat events and extreme temperature fluctuations: from our local GPs, community health networks, Victorian Ambulance Service, to our hospitals.

Entry filed under: climate change info, news. Tags: extreme heat, health, heart attack, NHMRC, research, temperature variation.