Many Women May Go Undiagnosed with Obstructive Sleep Apnea

The findings of a new study, published in the journal Sleep, show that women tend to experience obstructive sleep apnea (OSA) during dream sleep, and many are going undiagnosed with the condition.

“Over the years, I’ve felt strongly that sleep apnea may be an exemplar of a chronic disease that may manifest differently in men and women, from how it presents to its underlying physiology, with implications for how it should be treated,” said senior author Susan Redline, MD, MPH, a senior physician in the Division of Sleep and Circadian Disorders in the Departments of Medicine and Neurology at the Brigham in a press release. “Here, we begin to drill down to understand how sleep apnea may differ and how common scoring approaches may underestimate sleep apnea in women.”

In this study, researchers assessed data on 2,057 participants (average age, 68) in the Multi-Ethnic Study of Atherosclerosis (MESA) between 2010 and 2013. They gauged a wide range of parameters, including brain activity and body movement, and compared a range of summary measures of sleep apnea severity based on the apnea-hyponea index (AHI), which is the number of breathing pauses per hour of sleep. An AHI score greater than 15 indicates moderate to severe sleep apnea and is associated with increased risk of developing hypertension and potentially dying. They calculated the AHI in several ways, some of which were more sensitive to capturing changes in breathing patterns during REM sleep and non-REM sleep.

According to the results of the study, during non-REM sleep, twice as many men as women had an AHI score greater than 15. However, during REM sleep, the prevalence was the same in men and women. Among the study population, almost 60% of men and women met diagnostic criteria for moderately severe sleep apnea.

Moreover, the researchers noted that there is evidence linking sleep apnea during REM sleep and adverse cardiovascular outcomes. Also, they found that the physiological mechanisms that influence sleep apnea differ, as women have a had lower loop gain (lower sensitivity to changes in ventilation), less airway collapsibility, and lower arousal threshold (more easily wake up after an apnea) in non-REM sleep. The researchers note that these specific aspects of sleep apnea may serve as targets for new treatments for sleep apnea.

“We are more and more appreciating that sleep apnea is a heterogeneous disease,” said corresponding author Christine Won, MD, MSc, the director of the Women’s Sleep Health program at Yale School of Medicine. “It’s important to understand how it affects men and women differently. Understanding sex-specific mechanisms allows us to target therapy and is expected to lead to better outcomes.”