Sex differences in US military personnel with insomnia, obstructive sleep apnea, or comorbid insomnia and obstructive sleep apnea

Study Objectives: The aim of this study was to evaluate sex-related differences in symptoms of sleep disorders, sleep-related impairment, psychiatric symptoms, traumatic brain injury, and polysomnographic variables in treatment-seeking military personnel diagnosed with insomnia, obstructive sleep apnea (OSA), or comorbid insomnia and OSA (COMISA). Methods: Participants were 372 military personnel (46.2% women, 53.8% men) with an average age of 37.7 (standard deviation = 7.46) years and median body mass index of 28.4 (5.50) kg/m². Based on clinical evaluation and video-polysomnography, participants were diagnosed with insomnia (n = 118), OSA (n = 118), or COMISA (n = 136). Insomnia severity, excessive daytime sleepiness, sleep quality, nightmare disorder, sleep impairment, fatigue, posttraumatic stress disorder, anxiety, depression symptoms, and traumatic brain injury were evaluated with validated self-report questionnaires. Descriptive statistics, parametric and nonparametric t-tests, and effect sizes were used to assess sex differences between men and women. Results: There were no significant differences between women and men with insomnia or OSA in sleep-related symptoms, impairment, or polysomnography-based apnea-hypopnea index. Military men with COMISA had a significantly greater apnea-hypopnea index as compared to military women with COMISA, but women had greater symptoms of nightmare disorder, posttraumatic stress disorder, and anxiety. Conclusions: In contrast to civilian studies, minimal differences were observed in self-reported sleep symptoms, impairment, and polysomnography metrics between men and women diagnosed with the most frequent sleep disorders in military personnel (ie, insomnia, OSA, or COMISA) except in those with COMISA. Military service may result in distinct sleep disorder phenotypes that differ negligibly by sex.