Sex Differences in Sleep Disorders

Abstract

Sex and gender differences in sleep and circadian rhythms are observed across the lifespan and impact evaluation and treatment of sleep disorders. Insomnia is more common in women than men, and has links to sex-specific reproductive hormones in males and females. Although behavioral treatments for insomnia work equally well regardless of gender, certain pharmacologic treatments require different dosing based on sex. There are gender disparities in the diagnosis of sleep disorders. For example, narcolepsy has a nearly equal prevalence between men and women, but women experience symptoms for nearly 2 years longer than men before diagnosis. Obstructive sleep apnea affects more men than women, but the majority of women with sleep apnea go undiagnosed. Variation in presenting symptoms between men and women and differences in how sleep apnea testing detects disease features that differ by sex contribute to this disparity. Sex differences in restless legs syndrome emerge after childbirth in women, likely related to higher rates of iron deficiency in parous women. Data on sex differences in parasomnias are inconsistent and likely are related more to differences in treatment-seeking and disease recognition than substantial sex differences in the disorders per se. Circadian cycle lengths tend to be longer in men than in women, and women demonstrate earlier peaks in alertness during the day and sleepiness at night, as well as a larger amplitude of circadian variation in sleepiness and performance, resulting in more nighttime impairment in women. Sex and gender differences are present both in healthy sleep and circadian rhythms and in the presentation of sleep disorders, underscoring the need to account for sex and gender in sleep medicine and sleep research.