Extreme heat can hit adults aged 18 to 64 more severely than older people

A new study found that days of extreme heat were associated with a higher risk of emergency room visits in adults aged 18 to 64 than in adults over 75.

Extreme heat – a leading cause of weather-related deaths in the United States – poses a growing threat to the public as days of extreme heat are likely to be more frequent, intense, and longer-lasting due to the ongoing effects of climate change. Although the adverse health effects of heat in older adults are well documented, less is known about the potential effects of heat on young and middle-aged adults.

Now, a new study, led by researchers from Boston University School of Public Health (BUSPH), has found that complications from extreme heat appear to be more pronounced in young and middle adults in the United States than in older adults.

Published in Das British Medical Journal, the study examined the association between extreme temperatures and emergency room (ED) visits and found that days of extreme heat were associated with a higher risk of ED visits from any cause, heat-related illness, kidney disease, and mental disorders among all adults , but the strongest association was in adults aged 18 to 64 years.

Previous studies of the health effects of heat have mainly focused on senior mortality or hospital admissions. This study is the first nationwide assessment of the effects of extreme heat on adults of all ages and the first national study to look at emergency medical visits as markers of adverse effects of heat on all adults.

“Many illnesses that lead to the use of the emergency room do not lead to a hospital stay because they can be treated in a short time, especially in the younger adult population,” says study director Dr. Gregory Wellenius, Professor of Environmental Health and Director of the Climate and Health Program at BUSPH. “By examining emergency rooms, we wanted to get a more complete picture of the real burden of disease that could be attributed to the hot days.”

Wellenius and colleagues analyzed anonymous data on health care utilization to quantify the risk of ED visits from any cause and for specific conditions that may come with rising temperatures during the warm season (between May and September) in nearly 3,000 US states 2010 to 2019 are connected.

The data was provided by OptumLabs, a collaborative research and innovation center with its central linked databases in the OptumLabs Data Warehouse (OLDW). This database contains anonymized longitudinal health information – including medical and pharmaceutical claims, laboratory results, and registration records – from more than 200 million commercial and Medicare Advantage registrants and patients representing a range of age groups and geographic regions in the United States.

For the study, the researchers analyzed harm data from 74 million adults, including more than 22 million ED visits. They found that days of extreme heat (vary by location but averaged around 93 degrees).


The Fahrenheit scale is a temperature scale named after the German physicist Daniel Gabriel Fahrenheit and is based on one he proposed in 1724. On the Fahrenheit temperature scale, the freezing point of water freezes at 32 ° F and water boils at 212 ° F, with a 180 ° F separation, as defined at sea level and standard atmospheric pressure.

“> Fahrenheit) were associated with a 66 percent increased risk of ED visits for heat-related illnesses and a 30 percent increased risk of kidney disease compared to ED visits on cooler days. But the risk associated with extreme heat varies by age. A day of extreme heat was associated with a 10.3 percent higher risk of ED visits in people ages 45 to 54 compared to a 3.6 percent higher risk in people over 75 years of age.

“Younger adults can be at greater risk of exposure to extreme heat, especially for workers who spend a lot of time outdoors,” says study leader Dr. Shengzhi Sun, research fellow at BUSPH’s Department of Environmental Health. “Younger adults may also fail to realize that they too can be at risk on days of extreme heat.”

The results also agreed with previous research that showed that people in US states with lower temperatures during the warm season are still at higher risk of heat-related complications. Days of extreme heat were associated with a 12 percent increased risk of ED visits in the northeast region and nearly 10 percent increased risk in the Midwest and Northwest, compared with 4.3 percent in the warmer Southeast.

“While extreme heat threatens the health of everyone, this study provides further evidence that it is particularly dangerous in regions with cooler climates that may be less heat-adapted,” says Dr. Kate Weinberger, study co-author, assistant professor at the University of British Columbia 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 of crucial importance.”

Many of these heat-related complications can be prevented through policy changes that reduce heat exposure or make people more vulnerable and adaptable to heat, say the researchers, but emphasize that effective policies will differ between regions, states, and counties.

“Although climate change is a global problem and heat threatens the health of all people around the world, the effects are felt locally and the solutions have to be tailored to local needs,” says Dr. Wellenius citing the geographical infrastructure and the vulnerability of the population, and available resources. “What works for heat wave preparation in the Pacific Northwest is really different from what works in the Southeast, so the solutions need to be localized to meet the needs of the local community.”

By considering emergency room visits for various causes and for several age groups, we were able to characterize


How close the measured value corresponds to the correct value.

“> Accurate the different health effects of different populations,” says Dr. Francesca Dominici, study co-author, Clarence James Gamble Professor of Biostatistics at Harvard TH Chan School of Public Health, and Co-Director of the Harvard Data Science Initiative. “A key objective of this study is to provide clinicians and public health professionals with actionable information on how to prevent these emergency room visits, also taking into account the fact that we can predict when these extreme heat events are likely to occur. “

Reference: “Ambient Heat and Risks of Adult Emergency Room Visits in the United States: Time-Stratified Crossover Case Study” November 24, 2021, BMJ.
DOI: 10.1136 / BMJ-2021-065653

The study was also co-authored by other faculties and staff in the Department of Environmental Health at BUSPH, including Amruta Nori-Sarma, Assistant Professor of Environmental Health; Keith Spangler, postdoc; and Yuantong Sun, research data analyst.


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