Obstructive sleep apnoea (OSA) affects females and males differently, and increases in prevalence with age. The aim of the present study was to characterise clinical, anthropometric and polygraphic sex differences in a large elderly OSA population. A total of 641 subjects aged 68 yrs were examined. Measurements of fat mass, using dual-energy X-ray absorptiometry (DEXA) and polygraphy, were obtained in all subjects. An apnoea/hypopnoea index (AHI) of >15 events·h⁻¹ identified the presence of OSA. OSA was diagnosed in 57% of the sample, 34% having a mild form and 23% having an AHI of >30 events·h⁻¹. Females with OSA exhibited a lower AHI, less severe hypoxaemia and greater peripheral fat mass, and frequently reported anxiety and depression. Comparison of females with and without OSA did not reveal significant differences in clinical, anthropometric and DEXA data. After adjustment for body mass index, hypertension, diabetes, smoking, anxiety and depression, logistic regression analysis revealed that the presence of hypertension was significantly associated with OSA risk in females (OR 1.52, p = 0.04). In a general community healthy population, the prevalence of undiagnosed OSA in females increases with age, with a risk similar to that in males. In females, the clinical spectrum, anthropometric data and fat distribution appear to be more sex-related than OSA-dependent. The occurrence of OSA contributes to hypertensive risk in elderly females.
Trial registration: ClinicalTrials.gov NCT00759304 NCT00766584.