The prevalence of obstructive sleep apnoea in an obese female population

Obstructive sleep apnoea (OSA) has been estimated to affect between 1 and 4% of the total population. OSA may be more frequent among women than studies based on subjects presenting for treatment would indicate. The aim of this study was to determine the prevalence of OSA in an obese female population (BMI > 30 kg/m2, age > 18 years) who presented to a hospital-based obesity clinic. The women were screened by an overnight ambulatory sleep study (MESAM) to detect OSA. Subjective sleep quality and sleep disturbance were assessed by a 19-item questionnaire, the Pittsburg sleep quality index (PSQI). From a population of 108 women, 29 were screened by MESAM. OSA was determined on the basis of respiratory disturbance index (RDI). The prevalence of OSA, defined as five or more respiratory disturbances per hour, was 37.9%. The mean age of the women was 43.6 +/- 2.57 years (mean +/- s.e.m.) and they had a mean BMI of 40.7 +/- 1.40 kg/m2. There was a significant positive correlation for RDI and BMI (r = 0.71; P < 0.001). Our findings indicate that over one third of women had OSA, yet they did not complain of symptoms even though the PSQI questionnaire indicated that they were poor sleepers. Non-specific symptomatology of OSA may be important diagnostically, particularly in women, and obese women should be considered at risk of OSA.