Climate Change and Health Resource Center

Climate Change and Health Resource Center

Disclosures: The authors report receiving support from the U.S. NIH, National Institute of Environmental Health Sciences and the Wellcome Trust. Wellenius reports receiving consulting income from the Health Effects Institution and Google.
December 02, 2021
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Younger adults more likely to go to ED on days of extreme heat

Disclosures: The authors report receiving support from the U.S. NIH, National Institute of Environmental Health Sciences and the Wellcome Trust. Wellenius reports receiving consulting income from the Health Effects Institution and Google.
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Adults aged 18 to 64 years may have a higher risk for an ED visit on extremely hot days compared with those older than 75 years, according to findings published in The BMJ.

“Younger adults may be at greater risk of exposure to extreme heat, particularly among workers that spend substantial time outdoors,” Shengzhi Sun, PhD, a research scientist in the department of environmental health at Boston University School of Public Health, said in a press release. “Younger adults may also not realize that they too can be at risk on days of extreme heat.”

Excess RR for ED visits during extreme heat, by cause.
Sun S, et al. BMJ. 2021;doi:10.1136/bmj-2021-065653.

Sun and colleagues conducted time-stratified crossover analyses of 74.2 million commercial and Medicare Advantage adult beneficiary claims that were filed between the months of May and September from 2010 to 2019. They compared daily rates of ED visits for any cause, heat-related illness, renal disease, CVD, respiratory disease and mental disorders with temperature distribution. Overall, they analyzed 21,996,670 ED visits in 2,939 counties in the U.S., stratifying by age, sex, low-income status, climate zone and geographic region.

The researchers defined “extreme heat” as days with a local temperature distribution in the 95th percentile or higher. The average extreme heat temperature nationally was 93.9°F compared with the national average temperature of 58.8°F.

Risks associated with extreme heat

Days of extreme heat were associated with an excess RR of 7.8% (95% CI, 7.3-8.2) for an ED visit due to any cause, 66.3% (95% CI, 60.2-72.7) for heat-related illness, 30.4% (95% CI, 23.4-37.8) for renal disease, and 7.9% (95% CI, 5.2-10.7) for mental disorders, according to Sun and colleagues. Moreover, there was an absolute excess risk for a heat-related ED visit of about 24.3 per 100,000 people for each day of extreme heat. However, extreme heat was not associated with a higher risk for ED visits related to CVD or respiratory diseases, according to the researchers. They also found that risk associations were more pronounced among men and in counties in the Northeast or with a continental climate.

Risks for younger vs. older adults

All adults, regardless of age, remained at increased risk for heat-related illness during extreme temperatures. Yet, Sun and colleagues observed stronger associations among young and middle-aged adults.

Specifically, individuals aged 18 to 24 years had a 9.5% (95% CI, 8-11) excess RR for an ED visit compared with 3.6% (95% CI, 2.7-4.6) among adults aged 75 years or older. Moreover, those aged 25 to 34 had a 9.9% (95% CI, 8.6-11.1) excess risk, those aged 35 to 44 years had a 7.4% (95% CI, 6.2-8.6) excess risk, those aged 45 to 54 years had a 10.3% (95% CI, 9.1-11.5) excess risk, those aged 55 to 64 years had a 8.8% (95% CI, 7.6-10) excess risk and those aged 65 to 74 years had a 7.6% (95% CI, 6.4-8.7) excess risk.

Gregory A. Wellenius

“The findings from this study highlight that heat poses a health risk for everyone, not just the elderly,” Gregory A. Wellenius, ScD, a professor of environmental health and director of the Program on Climate and Health at Boston University School of Public Health, told Healio Primary Care. “Individuals, community leaders and physicians need to be aware that heat increases the risk of needing emergency medical care for adults of any age and living in any region of the U.S. Clear communication of these risks and advice to stay well-hydrated and minimize exposure to heat will help reduce these risks.”

References:

Extreme heat may affect young and middle-aged adults more than older adults. https://www.bu.edu/sph/news/articles/2021/extreme-heat-may-affect-young-and-middle-aged-adults-more-than-older-adults/. Published Nov. 24, 2021. Accessed Dec. 1, 2021.

Sun S, et al. BMJ. 2021;doi:10.1136/bmj-2021-065653.