Sex-dependent impact of OSA on digital vascular function

Indexes of associations between OSA and impaired vascular function are mainly based on small, clinic-based studies of conduit artery function in men with severe sleep apnea. Larger population-based studies show no independent associations or associations in women only. Sex differences in OSA-related mortality may exist, and sex differences in vascular function in subjects with OSA need to be explored. We, therefore, assessed whether OSA is associated with digital vascular function in a large population-based sample and whether this association is influenced by sex.

From a population-based cohort of 30,000 subjects aged 30 to 65 years, we examined 479 subjects (mean age, 48 years; 43% women). Oversampling of subjects at high risk of OSA was performed. Sleep apnea was assessed by inhospital polysomnography. Endothelial function was assessed by digital peripheral arterial tonometry and was expressed as the reactive hyperemia index (RHI).

OSA was diagnosed in 266 subjects (55.5%). The RHI was significantly lower in subjects with severe OSA than in those without OSA (P = .002). In the multivariate model for RHI, a significant interaction between OSA and sex was found. In sex-specific multivariate linear regression models, adjusting for conventional cardiovascular risk factors, OSA was an independent predictor of a low RHI in women (P = .006) but not in men. The association between OSA and low RHI in women was independent of postmenopausal status.

In a large population-based sample of middle-aged subjects, OSA was independently associated with impaired digital vascular function in women only.