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Potential climate change scenarios could nearly double the global incidence of obstructive sleep apnea (OSA), based on estimates from a new study presented at American Thoracic Society (ATS) 2025 International Conference.

Although high ambient temperatures have been linked to negative health outcomes including reduced sleep duration and quality, the association between increased average ambient temperatures and the severity of OSA remains unclear, wrote Bastien Lechat, PhD, a research fellow in sleep health at Flinders University, Adelaide, Australia, and colleagues, in their abstract.

Previous cross-sectional studies have shown an association between temperature and OSA severity, which prompted the idea for the current study, Lechat said in an interview. “We have access to a consumer database (125,295 users) of an FDA-cleared wearable device validated to estimate OSA severity,” he said. Given the unique nature of this dataset (with approximately 500 repeat measurements per user), the researchers believed that the data would be ideal for estimating the effect of temperature on OSA severity, he said. “Additionally, considering the impact of obstructive sleep apnea on health and productivity, we aimed to estimate the burden associated with a potential increase in OSA prevalence due to rising temperatures, and this novel contribution from our group allowed us to quantify the societal and economic costs for different climate scenarios from the Intergovernmental Panel on Climate Change,” he noted.

In their new cross-sectional study, the researchers reviewed data from 116,200 adults in 41 countries who used an FDA-approved under-mattress sensor to estimate the severity of their OSA. The dataset included a median of 509 OSA measurements per individual; these were compared against 24-hour ambient temperature data from climate models. The mean age of the study population was 49 years; 77% were men. OSA was defined as an apnea hypopnea index score ≥ 15.

The prevalence of OSA ranged from 15% to 32% across the countries. Overall, temperatures in the 99^th percentile vs the 25^th percentile were associated with a 70% increased risk for OSA (mean odds ratio, 1.70) and a 45% increase in odds of having OSA on any given night (mean odds ratio, 1.45).

The association was significant in 29 countries, including the United States and the United Kingdom, but was stronger in European countries compared to the United States or Australia. However, across the 29 countries, the increase in OSA in 2023 associated with higher temperatures was estimated to account for an average of nearly 800,000 healthy life years lost because of death or disability, as well a mean loss of $32 billion USD in workplace productivity.

The researchers also developed scenarios based on projected temperature increases of at least 1.8°C or higher above pre-industrial levels. They determined that this increase would result in an additional 1.5- to 3-fold increase in the global burden of OSA by 2100.

“We were surprised by the magnitude of the association between ambient temperature and OSA severity,” Lechat told Medscape Medical News. “The effect size was higher than in previous studies, which we believe is likely due to our longitudinal data and robust time-series analysis design. This provides support for a potential causal association between high temperature exposure and OSA severity,” he noted.

Takeaways and Implications

Lechat emphasized the two main findings from the study: That extreme temperatures are associated with an increased likelihood of having OSA on a given night, and the burden of OSA on society in terms of wellbeing loss and economic loss.

“To put this into context, by 2100, under the most likely climate scenario, the wellbeing burden of OSA is estimated to nearly double in most countries because of rising temperature,” Lechat told Medscape Medical News. “These results highlight the critical urgency of limiting global warming in alignment with the Paris Agreement. Our findings also emphasize the immediate need for targeted measures to alleviate the health and economic impacts of the growing OSA prevalence associated with rising temperatures,” he said.

The results highlight the urgency of limiting global warming to reduce the burden of warming-related increases in OSA prevalence, as well as the need for effective interventions to reduce the impact of high temperatures on OSA severity, said Lechat. The study findings also emphasize the importance of diagnosing and treating OSA in the community, as most of the burden stems from the high rate of undiagnosed and untreated patients, he added.

The findings were limited by several factors including the cross-sectional design. “Additionally, we had limited data from lower- and middle-income countries, so we plan to work towards collecting appropriate sleep and temperature data worldwide,” Lechat told Medscape Medical News.

“We would like to develop intervention studies to mitigate the effect of temperature on OSA, and we also would like to understand the physiological mechanisms that could explain the higher severity of OSA due to higher temperatures,” Lechat added.

Informing Management of Global OSA Burden

“High ambient temperatures have been linked to reduced sleep duration, increased sleep fragmentation, and poorer sleep quality; however, the effect of rising temperatures on obstructive sleep apnea has not been studied,” said Arianne K. Baldomero, MD, a pulmonologist and assistant professor of medicine at the University of Minnesota, Minneapolis, in an interview. “Investigating this relationship is important, as the global burden of OSA is already significant; with further temperature increases, we can expect this burden to grow even greater,” said Baldomero, who was not involved in the study.

The difference in the magnitude of associations between European countries and the United States or Australia, with Europeans experiencing a stronger link between rising temperatures and OSA, was interesting and somewhat surprising, and warrants further investigation, Baldomero told Medscape Medical News. In the meantime, clinicians and public health officials should be aware that higher ambient temperatures are associated with increased OSA, she added.

The current study highlights the importance of early diagnosis and effective management of OSA, especially during warmer periods, said Baldomero. “Ongoing research is needed on sleep disturbances associated with these warming temperature trends,” she said.

Limitations of the study included the reliance on under-mattress sensors that may not capture all OSA cases, Baldomero noted. “Further research should explore physiological mechanisms, differences in magnitude of associations by region, and test interventions to mitigate temperature effects on OSA,” she said.

This study was supported by Australia’s National Health and Medical Research Council. The researchers had no financial conflicts to disclose. Baldomero had no financial conflicts to disclose.