Sex differences in the associations of obstructive sleep apnoea with epidemiological factors

Despite the well-known male predominance in the prevalence of obstructive sleep apnoea (OSA), sex differences in the associations between OSA and a comprehensive range of epidemiological factors remain less clear. We examined the prevalence of self-reported OSA in 143326 females (age 48-93 years) from the Nurses' Health Study (NHS) and NHS-II and 22896 males from the Health Professionals Follow-up Study (age 65-101 years) in 2012-2013. Multivariable logistic regression was used to estimate the sex-specific prevalence odds ratios (pOR) and 95% confidence intervals of OSA by demographic, anthropometric, lifestyle and comorbidity factors. The overall prevalence of self-reported OSA was 6.4% in females and 13.8% in males. After mutual adjustment, the associations of OSA with physical inactivity, hypertension and daytime sleepiness were stronger in females, whereas the associations with waist circumference and witnessed apnoea were stronger in males (p-heterogeneity <0.01). There were qualitative sex differences in the associations with age (pOR per 5-year increment in females 0.95, 95% CI 0.94-0.96, and males 1.04, 1.01-1.08; p-heterogeneity <0.0001) and marital status (pOR for married versus other in females 0.85, 95% CI 0.81-0.89, and males 1.11, 0.99-1.25; p-heterogeneity <0.0001). Substantial sex differences exist in the associations with various factors, suggesting sex-specific mechanisms in OSA.