[Prevalence of sleep disorders in an employed Swiss population: results of a questionnaire survey]

Abstract

Background: The aim of the study was to demonstrate the variety of sleep disorders occurring in a working population in Switzerland and to estimate the prevalence of the main sleep disorders in this Swiss cohort. We also intended to demonstrate that with just a few systematic questions a straightforward diagnostic workup is possible in general practice.

Methods: A questionnaire was sent to all 1473 clerks of the Berne main post office. The questions allowed a choice between "yes" or "no", or often (= +3), occasionally (= +2), rarely (= +) and never (= 0). Daytime sleepiness was assessed by the Epworth Sleepiness Scale.

Results: 668 questionnaires (45%) were available for analysis. Daytime sleepiness, assessed by an Epworth score > or = 10, was found in 13% of the respondents. Short sleep (< 7 h sleep) was reported in 47%, and long sleep (> 9 h sleep) in 5% of this population. Specific questions clearly suggested obstructive sleep apnoea in 6%, restless-legs syndrome in 4%, disorders of initiating and maintaining sleep in 19% and narcolepsy in 0.5% of respondents.

Conclusion: Chronic sleep insufficiency and sleep complaints appear to be frequent in this relatively young Swiss working population. The questionnaire-based estimated prevalence of the main sleep disorders is comparable to previously published international data.