Daytime Sleepiness Relates to Snoring Independent of the Apnea-hypopnea Index in Women from the General Population

Objectives: The aim was to investigate the significance of snoring and sleep apnea on daytime symptoms in a population-based sample of women.

Method: From the general population, 400 women aged 20 to 70 years were randomly selected, with oversampling of habitually snoring women. The women were investigated using full-night polysomnography and a questionnaire. The apnea-hypopnea index (AHI) was calculated, and women who acknowledged snoring loudly and disturbingly often or very often were considered habitual snorers.

Results: Habitual snoring was independently related to excessive daytime sleepiness (odds ratio [OR], 2.28; 95% confidence interval [CI], 1.31 to 3.99), to falling asleep involuntarily during the day (OR, 2.11; 95% CI, 1.06 to 4.21), to waking up unrefreshed (OR, 2.14; 95% CI, 1.30 to 3.52), to daytime fatigue (OR, 2.77; 95% CI, 1.54 to 4.99), and to a dry mouth on awakening (OR, 2.00; 95% CI, 1.22 to 3.27) after adjustment for AHI, age, body mass index (BMI), smoking, total sleep time, percentage of slow-wave sleep, and percentage of rapid eye movement (REM) sleep. An AHI > or = 15/h was only related to a dry mouth on awakening after adjustment for snoring, age, BMI, smoking, total sleep time, percentage of slow-wave sleep, and percentage of REM sleep (OR, 2.24; 95% CI, 1.14 to 4.40). An AHI of 5 to 15/h was not related to any daytime symptom.

Conclusions: Excessive daytime sleepiness and daytime fatigue are related to habitual snoring independent of the apnea-hypopnea frequency, age, obesity, smoking, and sleep parameters in a population-based sample of women, but not to the AHI. This indicates that snoring is an independent cause of excess daytime sleepiness and not merely a proxy for sleep apnea.