Sex-Related Differences in Sleep-Related PSG Parameters and Daytime Complaints in a Clinical Population

BACKGROUND: Recent research suggested that perception of sleep impairments might present sex-related effects (ie, women appear to be more prone to report fatigue rather than sleepiness). The latter has been evidenced in sleep-related breathing disorders (SRBD). Differently, it has been suggested that sleep-related movement disorders may also be associated to fatigue rather than to sleepiness. Whether sex-related differences would be similar irrespective of diagnosis remains unclear. METHODS: During a one-year period, systematic clinical evaluation, by means of structured symptom scales, was performed for a cohort of 921 consecutive patients attending an academic sleep center for polysomnography. The Brugmann Fatigue Scale (BFS), an instrument designed for the assessment of rest propensity was used among other scales (ie, Epworth Sleepiness Scale, ESS). According to inclusion and exclusion criteria, 420 men and 376 women were finally included in the study and retained for data analysis. RESULTS: While men and women presented with similar age, BMI, total sleep time and sleep efficiency, men presented with higher levels of respiratory events and more periodic limb movements. Irrespective of diagnosis, women presented with significantly higher levels of sleep-associated complaints on all scales. Comparative stratifications of daytime symptoms, per diagnostic groups (SRBD, Movement Disorders (SRMD) and Insomnia), revealed significant main effects for diagnosis alongside with main effects of biological sex. Associations between common markers of disease severity for SRBD or SRMD and sleep or rest propensity, respectively, only showed significant correlation between periodic limb movements and rest propensity. The strength of association was similarly significant for both sexes. CONCLUSION: While men displayed more objective impairment on polysomnography (PSG) and lower symptom levels, the opposite was true in women. However, both men and women present with statistically significant associations between SRMD severity (PLMS index) and physical fatigue.