Tag: extreme heat

Categories : Environmental EffectsTags :

Increase in Excessively Hot Nights Will Raise Mortality Rate

On By ModernMedia
Sleeping woman
Photo by Cottonbro on Pexels

With the number of excessively hot nights expected to double due to climate change, it is predicted that their associated mortality rate will rise by up to 60% by the end of the century, according to the latest research published in published in The Lancet Planetary Health.

Ambient heat during the night may interrupt the normal physiology of sleep, leading to immune system damage and a higher risk of cardiovascular disease, chronic illnesses, inflammation and mental health conditions. The average intensity of hot night events will nearly double by 2090, from 20.4℃ to 39.7℃ across 28 cities from east Asia, increasing the burden of disease due to excessive heat that disrupts normal sleeping patterns.

This is the first study to estimate the impact of hotter nights on climate change-related mortality risk. The findings show that the burden of mortality could be significantly higher than estimated by average daily temperature increase, suggesting that warming from climate change could have a troubling impact, even under restrictions from the Paris Climate Agreement.

“The risks of increasing temperature at night were frequently neglected,” said study co-author Yuqiang Zhang, PhD, a climate scientist in the Department of Environmental Sciences and Engineering at the Gillings School. “However, in our study, we found that the occurrences of hot night excess are projected to occur more rapidly than the daily mean temperature changes. The frequency and mean intensity of hot nights would increase more than 30% and 60% by the 2100s, respectively, compared with less than 20% increase for the daily mean temperature.”

The team estimated the mortality due to excess heat in 28 cities in China, South Korea and Japan between 1980 and 2015 and applied it to two climate change modelling scenarios that aligned with carbon-reduction scenarios adapted by the respective national governments.

Through this model, the team was able to estimate that between 2016 and 2100, the risk of death from excessively hot nights would increase nearly six-fold. This prediction is much higher than the mortality risk from daily average warming suggested by climate change models.

“From our study, we highlight that, in assessing the disease burden due to non-optimum temperature, governments and local policymakers should consider the extra health impacts of the disproportional intra-day temperature variations. A more complete health risk assessment of future climate change can help policymakers for better resource allocation and priority setting,” said Haidong Kan, PhD, who is a professor at Fudan University in China and the study’s corresponding author.

In this study, the authors also found that regional differences in temperature accounted for many of the variances in nighttime temperature, and areas with the lowest average temperature were projected to have the largest warming potential.

“To combat the health risk raised by the temperature increases from climate change, we should design efficient ways to help people adapt,” said Dr Zhang. “Locally, heat during the night should be taken into account when designing the future heatwave warning system, especially for vulnerable populations and low-income communities who may not be able to afford the additional expense of air conditioning. Also, stronger mitigation strategies, including global collaborations, should be considered to reduce future impacts of warming.”

Since the study only included 28 cities from three countries, Dr Zhang said that “extrapolation of these results to the whole East Asia region or other regions should be cautious. Currently, based on these findings, authors are trying to extend the analysis to a global dataset. Then we could have a global picture of the deadly nighttime heat on health under climate change scenarios.”

Source: University of North Carolina at Chapel Hill

Categories : Cardiovascular DiseaseTags :

Beta Blockers and Antiplatelet Drugs Tied to Heat-related MI Risk

On By ModernMedia
Photo by Camilo Jimenez on Unsplash

During hot weather events, people taking beta blockers and antiplatelet medications such as aspirin could be at increased risk of a myocardial infarction (MI), amplifying the risk already present from hot weather.

A new study published in Nature Cardiovascular Research found that, among people suffering non-fatal MI associated with hot weather, a greater portion are taking these heart drugs.

“Patients taking these two medications have higher risk,” said Assistant Professor Kai Chen, first author of the study. “During heat waves, they should really take precautions.”

External environmental factors like air pollution and cold weather can trigger MIs, and there is growing evidence to suggest that hot weather can do so, too. But epidemiologists are still working to identify which groups of people are most vulnerable to these environmental extremes.

The authors looked at 2494 cases sourced from a registry, in which individuals experienced a non-fatal MI in Augsburg, Germany during the hot-weather months (May–September) between 2001 and 2014.

In previous research, they had shown that exposure to either heat or cold made heart attacks more likely, and they calculated that heat-related MI rates would rise once the planet has warmed by 2–3°C.

The current study built on that research by examining patients’ medication use prior to their MI.

They analysed the data in a way that let patients serve as their own controls, by comparing heat exposure on the day of the MI versus the same days of the week within the same month. That is, if a person had an NI on the third Thursday in June, the authors compared their temperature exposure that day to their temperature exposure on other, “control” Thursdays in June.

It turned out that users of beta-blockers or antiplatelet medications were likelier to have an MI during the hottest days compared to control days. Antiplatelet medication use was associated with a 63% increase in risk and beta-blockers with a 65% increase. People taking both drugs had a 75% higher risk. Non-users of those medications were not more likely to have a heart attack on hot days.

When researchers compared younger patients (25–59 years) to older ones (60–74 years), they found, as expected, that the younger ones were a healthier group, with lower rates of coronary heart disease. Yet younger patients taking beta-blockers and antiplatelet medications were more susceptible to heat-related heart attack than older patients, despite the older ones having more heart disease.

Another clue that these two medication types may render people more vulnerable is that, other heart medications generally didn’t show a connection to heat-related heart attacks. An exception was statins, which taken by younger people, were associated with an over threefold risk of a heart attack on hot days.

“We hypothesise that some of the medications may make it hard to regulate body temperature,” Asst Prof Chen said. He plans to find out why in future studies.

The results suggest that as climate change progresses, heart attacks might become a greater hazard to some people with cardiovascular disease.

Source: Yale School of Public Health

Categories : Environmental EffectsTags :

Extreme Heat Health Risks Are Higher for Younger Adults

On By ModernMedia
Photo by Ketut Subiyanto on Pexels

A new study in the US has found that complications from extreme heat appear to be more pronounced among young and middle-aged adults than older adults.

Extreme heat poses an increasing threat to the public, due to the continued effects of climate change. Although the adverse health impacts of heat have been well documented among older adults, less is known about the potential impacts of heat on young and middle-aged adults.

Published in the BMJ, the study examined the relationship between extreme temperatures and emergency department (ED) visits, and found that days of extreme heat were associated with an increase risk of ED visits for any cause, heat-related illness, renal disease, and mental disorders among all adults, but the strongest association was found among adults ages 18-64.

Prior research on heat’s health impacts have mostly focused on mortality or hospital admissions among seniors. This study is the first national-scale assessment of extreme heat effects on adults of all ages, measured with ED visits.

“Many illnesses that lead to utilisation of the ED do not lead to hospitalisation because they can be treated in a short amount of time, particularly among the younger adult population,” said study senior author Gregory Wellenius, professor of environmental health and director of the Program on Climate and Health at SPH. “By looking at emergency room visits, we aimed to obtain a more comprehensive picture of the true burden of disease that might be attributed to the days of high heat.”

Prof Wellenius and colleagues analysed healthcare claims data to quantify the risk of ED visits for any cause and for heat-associated conditions during the warm season (between May and September) from 2010 to 2019.

For the study, the researchers analysed claims data among 74 million adults, including more than 22 million ED visits. They found that days of extreme heat (varying by location, but averaging about 34°C), were associated with a 66% greater risk of ED visits for heat-related illness, as well as a 30% increased risk for renal disease, compared to ED visits on cooler days. But the risk according to extreme heat varied by age. A day of extreme heat was associated with a 10.3% higher risk of ED visits among people ages 45 to 54 years old, compared to a 3.6% higher risk among those older than 75.

“Younger adults may be at greater risk of exposure to extreme heat, particularly among workers that spend substantial time outdoors,” says study lead author Shengzhi Sun, research scientist in the Department of Environmental Health at SPH. “Younger adults may also not realise that they too can be at risk on days of extreme heat.”

Prior studies had shown that people in US counties with lower warm-season temperatures still experience higher risks of heat-related complications.
“While extreme heat threatens everyone’s health, this study provides further evidence that it is especially dangerous in regions with cooler climates that may be less adapted to heat,” says study co-author Kate Weinberger, assistant professor at the University of British Columbia’s School of Population and Public Health. “As temperatures continue to rise due to climate change, the implementation of heat adaptation measures in these regions will be critically important.”

According to the researchers, many of these heat-related complications can be prevented through policy changes that reduce exposure to heat, or improve people’s susceptibility and adaptivity to heat.

“By looking at emergency department visits for different causes and for several age groups, we were able to characterise with accuracy the varying impact on health on different populations,” said study co-author, Professor Francesca Dominici. “An important goal of this study is to provide actionable information to clinicians and public health experts regarding how to prevent these emergency department visits, also considering that we can anticipate when these extreme heat events are likely to occur.”

Source: Boston University