Rising temperatures linked to more severe sleep apnea worldwide

Sleep apnea will become more common and more severe due to global warming, leading to increased health and economic burdens across the globe, warn Flinders University sleep experts.

A new study, published in leading journal, Nature Communications, found that rising temperatures increase the severity of obstructive sleep apnea (OSA) and that under the most likely climate change scenarios, the societal burden of OSA is expected to double in most countries over the next 75 years.

Lead author and sleep expert, Dr. Bastien Lechat, from FHMRI Sleep Health says this is the first study of its kind to outline how global warming is expected to affect breathing during sleep and impact the world's health, wellbeing and economy.

"This study helps us to understand how environmental factors like climate might affect health by investigating whether ambient temperatures influence the severity of OSA," says Dr. Lechat.

Overall, we were surprised by the magnitude of the association between ambient temperature and OSA severity.

Higher temperatures were associated with a 45 per cent increased likelihood of a sleeper experiencing OSA on a given night.

Importantly, these findings varied by region, with people in European countries seeing higher rates of OSA when temperatures rise than those in Australia and the United States, perhaps due to different rates of air conditioning usage."

Dr. Bastien Lechat, FHMRI Sleep Health

Sleep apnea – a condition that disturbs breathing during sleep – affects almost 1 billion people globally and, if untreated or severe, increases the risk of dementia and Parkinson's disease, hypertension, cardiovascular disease, anxiety and depression, reduced quality of life, traffic accidents and all-cause mortality, previous research has found.

In Australia alone, the economic cost associated with poor sleep including sleep disorders like OSA has been estimated at $66 billion a year.

The study analysed sleep data from over 116,000 people globally using an FDA-cleared under-mattress sensor to estimate the severity of OSA.

For each user, the sensor recorded around 500 separate nights of data. The researchers then matched this sleep data with detailed 24-hour temperature information sourced from climate models.

They conducted health economics modeling using disability adjusted life years, a measure employed by the World Health Organization that captures the combined impact of illness, injury, and premature mortality, to quantify the wellbeing and societal burden due to increased prevalence of OSA from rising temperatures under several projected climate scenarios.

"Using our modelling, we can estimate how burdensome the increase in OSA prevalence due to rising temperature is to society in terms of wellbeing and economic loss," says Dr. Lechat.

"The increase in OSA prevalence in 2023 due to global warming was associated with a loss of approximately 800,000 healthy life years across the 29 countries studied.

"This number is similar to other medical conditions, such as bipolar disorder, Parkinson's disease or chronic kidney diseases."

Similarly, the estimated total economic cost associated was ~98 billion USD, including 68 billion USD from wellbeing loss and 30 billion USD from workplace productivity loss (missing work or being less productive at work).

"Our findings highlight that without greater policy action to slow global warming, OSA burden may double by 2100 due to rising temperatures."

Senior researcher on the paper, Professor Danny Eckert, says that while the study is one of the largest of its kind, it was skewed towards high socio-economics countries and individuals, likely to have access to more favourable sleeping environments and air conditioning.

"This may have biased our estimates and led to an under-estimation of the true health and economic cost," says Professor Eckert

In addition to providing further evidence of the major threat of climate change to human health and wellbeing, the study highlights the importance of developing effective interventions to diagnose and manage OSA.

"Higher rates of diagnosis and treatment will help us to manage and reduce the adverse health and productivity issues caused by climate related OSA," says Professor Eckert.

"Going forward, we want to design intervention studies that explore strategies to reduce the impact of ambient temperatures on sleep apnea severity as well as investigate the underlying physiological mechanisms that connect temperature fluctuations to OSA severity."