For the study, the researchers performed polysomnography on 400 randomly selected women, aged 20 to 70 years.
The apnea-hypopnea index (AHI) was calculated, and women who acknowledged snoring loudly and either disturbingly often or very often were considered habitual snorers.
The researchers found that habitual snoring was independently related to excessive daytime sleepiness, falling asleep involuntarily during the day, waking up unrefreshed, daytime fatigue, and dry mouth on awakening, even after adjusting for AHI, age, BMI, smoking, total sleep time, percentage of slow-wave sleep, and percentage of rapid eye movement sleep.
Researchers, therefore, concluded that snoring is an independent cause of excessive daytime sleepiness and not merely a proxy for sleep apnea.
This study is published in the November issue of the journal Chest.