Gender, age and menopause effects on the prevalence and the characteristics of obstructive sleep apnea in obesity.

BACKGROUND: In the 1970s and 80s it was believed that obstructive sleep apnea (OSA) was primarily a disease of men. The present study was addressed to evaluate the effect of gender and menopause on the prevalence and the characteristics of OSA and on anthropometric, clinical, respiratory and polysomnographic data in a population of obese individuals. PATIENTS AND METHODS: A total of 230 obese subjects (BMI >/= 30 kg m-2), 148 women and 82 men, aged 16-75 years, were recruited and evaluated for general and anthropometric parameters, respiratory function, sleep-related symptoms and sleep disorders of breathing. RESULTS: Respiratory disturbance index (RDI) and the prevalence of OSA were lower in women than in men (P < 0.001 and P < 0.001, respectively). Among subjects < 55 years, neck circumference, percentage of predicted normal neck circumference (PPNC), waist-to-hip ratio (WHR), PaCO2, RDI and the prevalence of OSA were lower in female subjects (P = 0.05, P < 0.05, P < 0.001, P < 0.01 and P < 0.01, respectively). BMI, neck circumference, PPNC, WHR, RDI and the prevalence of OSA were higher in postmenopausal compared with premenopausal women (P < 0.01, P < 0.01, P < 0.01, P < 0.01 and P < 0.01, respectively). CONCLUSIONS: Our study demonstrates that (i) the male dominance regarding the prevalence and the severity of OSA disappears in men older than 55 years, and (ii) menopause seems to play a pivotal role in modulating both the presence and the degree of sleep disorder.