Assessment of OSA
All individuals with clinical suspicion underwent overnight polysomnography (PSG). They were asked if they had a specific set of symptoms indicating OSA: witnessed snoring; observed to have apneas; non-restful sleep; daytime sleepiness. Diagnosis of OSA was defined by standard criteria.9
The Epworth Sleepiness Scale (ESS) questionnaire, which is widely used for assessing daytime sleepiness, was also finished by the patients on the same visit. Demographic data including gender, age, BMI, AHI, minimum oxygen saturation and oxygen saturation <90% were also obtained.