Study objectives: To study the prevalence, risk factors, and gender differences in symptoms related to obstructive sleep apnea. A secondary objective was to study gender differences in relation to referral to a sleep clinic for sleep investigations.
Design and setting: A questionnaire study in a representative sample of the general population. A second cohort included patients referred for sleep apnea investigation between 1991 and 2000 in the same geographic region.
Participants: A representative sample of 5,424 subjects aged 20 to 69 years living in northern Sweden. Responses were obtained from 4,648 subjects (85.7%).
Results: Of the male respondents, 17.9% stated that snoring was a problem or said that they had relatives who were concerned about witnessed sleep apnea, and of the female respondents, 7.4%. The prevalence of snoring and witnessed apneas increased with age. In men, there was a peak prevalence rate at 55 to 59 years of age, while the corresponding figure in women the peak prevalence rate was at 60 to 64 years of age. Having snoring as a problem and relatives who were concerned about witnessed sleep apnea were independently associated with male gender, age, and current smoking. Snoring as a problem also was associated with higher education. Women who snored reported significantly more daytime sleepiness than did men who snored. The estimated number of subjects aged 20 to 69 years who had snoring as a problem or had relatives who were concerned about witnessed sleep apnea in the population was 21,160. During the previous decade, 3,955 subjects had been referred to sleep laboratories, so < 20% of the estimated number of symptomatic subjects in the population had been referred during this 10-year period. The referral rate ratio for men/women after correction for population and prevalence of symptoms was 1.25:1 (p = 0.012).
Conclusion: Experiencing snoring as a problem or having relatives who are concerned about witnessed sleep apnea are common findings in the population. However, during the last decade, only about 20% of the subjects with snoring as a problem or with relatives who are concerned about witnessed sleep apnea were referred to sleep laboratories. Women were significantly underrepresented in sleep laboratory referrals, even though women who snored experienced more subjective daytime sleepiness than men.