Excessive Heat Increases Hospital Visits for Children with Asthma | 2024 ATS

Extreme heat is associated with increased hospital visits for children with asthma, finds new research presented at the American Thoracic Society 2024 International Conference. 

Morgan Ye, MPH

“We found that both daily high heat events and extreme temperatures that lasted several days increased the risk of asthma hospital visits,” corresponding author Morgan Ye, MPH, research data analyst, Division of Pulmonary and Critical Care Medicine, University of California, San Francisco School of Medicine, said in a news release. “Understanding the impacts of climate-sensitive events such as extreme heat on a vulnerable population is the key to reducing the burden of disease due to climate change.”

Asthma is a respiratory condition in which a person’s airways narrow, making it difficult to breathe. In the United States, about 8.7% of adults over the age of 18 have asthma, and about 6.2% of children have asthma, according to the CDC. The CDC estimates that as many as 939,000 people with asthma visited the emergency room in 2021. Additionally, about 6.3% of visits to physicians’ offices are for asthma.

Harold Wimmer

Climate change is resulting in extreme weather, increased ozone pollution, increased allergens, more frequent and intense wildfires, and more cases of excessive heat, Harold Wimmer, president and CEO of the American Lung Association, said recently in a news release. May is Asthma Awareness Month.

“Thanks to decades of research into better asthma management techniques and treatments, most people with asthma lead normal, active and healthy lives. Unfortunately, climate change threatens this progress,” Wimmer said.

Ye and her colleagues looked at data from electronic health records from the UCSF Benioff Children’s Hospital Oakland from 2017 to 2020. They assessed data on asthma hospital visits during the June to September months, as well as data from the PRISM Climate Group of Oregon State University to determine the timing of day- and night-time heat for the San Francisco Bay area and central California.

Researchers found that daytime heat waves were associated with 19% higher odds of children’s asthma hospital visits, and longer duration of heat waves doubled the odds of hospital visits. They did not observe any associations for nighttime heat waves.

Heat is known to worsen asthma symptoms, but researchers said previous studies looking at hospital and emergency room visits have shown conflicting results, and few studies have looked at the hospitalization of children with asthma during extreme heat.

This follows other research published last year about the impact of heart and climate change on those with asthma. One study published in January 2023 in Environment Research, found that both extreme heat and extreme cold increased the risk of asthma. Researchers in this analysis assessed 37 articles about extreme heat, extreme cold and temperature variation. Their review looked at epidemiological evidence and biological plausibility.

This review found that extreme cold increased hospital visits for asthma more than extreme heat; cold-related asthma hospital visits lasted up to 30 days. Hospital visits for heat-related asthma appeared to be acute and lasted about a week.

A second study published in June 2023 in the European Respiratory Review also was a review study that found that extreme weather increased the risk of morbidity and mortality in people with, especially women and children. These researchers analyzed 31 articles that looked at weather and asthma and found that extreme weather increased the risk ratio of asthma symptoms by 1.10 fold and also increased the risk of emergency department visits by 1.25 fold.

In April, the CDC and the National Oceanic and Atmospheric Administration (NOAA) released a new heat forecast tool to help for those with asthma or who have cardiovascular disease or for women who are pregnant assess risk. HeatRisk identifies both daytime and nighttime temperatures over a 24-hour period.