Daytime sleepiness: An epidemiological study of young adults

Objectives. Although excessive daytime sleepiness is associated with increased risks for accidents, decreased productivity, and interpersonal difficulties, information on its epidemiology is scarce. This paper examines correlates of and suspected risk factors for daytime sleepiness from a longitudinal epidemiological study of young adults. Methods. The sample consisted of 1007 randomly selected young adults from a large health maintenance organization in southeast Michigan. Data were gathered in personal interviews conducted with 97% of the sample 5.5 years after baseline. Information on sleep characteristics in the last 2 weeks, including daytime sleepiness, nocturnal sleep onset, snoring, and hours of sleep, was collected on a self-administered instrument. Psychiatric disorders were measured by the National Institute of Mental Health's Diagnostic Interview Schedule. Results. The average length of nocturnal sleep on weekdays was 6.7 hours. Daytime sleepiness was inversely related to hours of sleep and positively related to the ease of falling asleep at night; it varied significantly by employment and marital status. Snoring was associated with increased daytime sleepiness, as was recent major depression. Conclusions. Factors that might increase daytime sleepiness among young adults include social factors (being single and being employed full time) and pathological conditions (frequent snoring and major depression).