Examining Prevalence, Implications of Sleep Disorders in Women

Presented at the CHEST 2020 annual meeting, moderator Lauren Tobias, MD, assistant professor in the Section of Pulmonary, Critical Care, and Sleep Medicine at Yale School of Medicine, opened the session titled “Sleep Disorders in Women Across the Lifespan” by highlighting that as women transition across stages in their life, such as from childhood to adolescence and from reproductive years to perimenopause, there are changes in sleep architecture, time spent awake after sleep onset, and napping tendency. 

“There are significant alterations in the gonadal hormones, progesterone and estrogen, that might explain these changes in part, but social and behavioral factors are also likely important,” notes Tobias.

Although women were shown to achieve objectively better sleep through several parameters such as circadian timing, Tobias highlights these findings as a paradox that is accompanied by greater subjective reporting among women on sleep problems, including poor sleep quality, more problems falling asleep, waking up more often, and higher rates of daytime sleepiness.

Moreover, this higher burden of sleep issues may be understudied and undertreated, particularly for obstructive sleep apnea (OSA), as population studies show overall male predominance among OSA diagnoses as 2 to 1, with sleep centers showing a stark 8 to 1 ratio for men to women diagnosed with OSA.

“Although men are at higher risk for sleep apnea prior to menopause, this gender disparity disappears after menopause, when the ratio of men to women with OSA approach is 1 to 1,” said Tobias.

Speaking further on sex differences in the prevalence of sleep apnea, panelist Christine Won, MD, MS, director of the Women’s Sleep Health Program at Yale School of Medicine, highlighted that men are more likely to present with classic symptoms of sleep apnea, such as snoring and gasping, whearas women present with more atypical symptoms like difficulty falling asleep, night sweats, and morning headaches.

These differences additionally apply to risk factors by gender, in which Won explains how body mass index is among the most significant factors to assess for sleep apnea, but it has been shown to be more reflective for men than women. Conversely, android fat distribution and neck fat distribution was found to be more important in predicting OSA for women.

Delving into the clinical consequences of OSA based on gender, Won referenced conflicting findings among several clinical studies examining the risk of developing hypertension among men and women with the condition. Notably, some studies found no difference based on sex, some found significant risks among only men, and some found that the risk of developing hypertension was only significant among women with OSA and not men.

“So we asked ourselves, why do we get these conflicting findings? I want to bring up the possibility that it might be the way we categorize sleep apnea, how we define and capture disease, and likely that the way we're doing that, with this gross metric of the AHI [apnea-hypopnea index], we're often missing very important phenotypes of disease,” said Won.

Examining 2 patients who exhibit similar AHI scores, Won says that while they may be categorized with the same severe sleep apnea diagnosis, their clinical differences in breath duration and oxygen saturations point to possible differences in OSA phenotypes.

Seeking to explore whether there were different polysomnographic phenotypes in men and women with OSA, Won and colleagues conducted a recent study that assessed event desaturation and arousal criteria among a cohort from the Multi-Ethnic Study of Atherosclerosis. When comparing men during non-REM and REM sleep, Won says that their events were somewhat similar, as opposed to women, who exhibited far greater events during REM sleep and were more protected during non-REM sleep.

In concluding, Won notes that in women, diagnostic tools for sleep apnea are becoming more simplified and geared toward validating the AHI. This could prove troubling as home testing and mechanisms to diagnose women for OSA may neglect to consider factors such as REM sleep, signaling a potential gap in diagnosis for women.