Obstructive sleep apnea (OSA) is far more common in men, for reasons not completely understood. As many as 40% of all OSA patients may be non-obese (Body mass index [BMI] < 30). Gender differences influence polysomnographic (PSG) features of OSA. Males with OSA tend to have more apneas and supine events, and females tend to have more rapid eye movement (REM) related sleep apnea. To our knowledge, this association has not been previously well-studied in a non-obese cohort of OSA patients. The purpose of our study was to retrospectively evaluate the influence of gender on PSG findings in non-obese patients with OSA.
Patients referred to our sleep lab for evaluation of OSA were included in the study. We recorded and tabulated all routine PSG parameters including detailed analysis of phase-specific events. Patients with a diagnosis of OSA (Respiratory Disturbance Index > 10) and who underwent a subsequent full-night continuous positive airway pressure (CPAP) titration study were included in the study.
22 women and 37 men were included. Age, BMI and overall apnea hypopnea index (AHI) were comparable in both groups. Sleep efficiency, and sleep architecture including time spent in supine sleep, in REM and slow wave sleep were similar between genders. Mean apnea index as well as supine AHI were not different between men and women. Difference between total AHI and REM AHI was greater in females. (See table).
Differences in PSG variables in OSA between women and men may be modulated by the influence of obesity. When examined in a non-obese cohort, men do not tend to have more apneas and more supine events than women. However, the phasic predilection for REM-related sleep apnea in women seems to be not modulated by the effect of obesity.
Differences in PSG variables between genders seem to be modulated by the presence or absence of obesity –this finding may have implications for factors that govern or modulate gender variance in upper airway collapsibility.
Amarbir Mattewal, No Financial Disclosure Information; No Product/Research Disclosure Information