Shift work sleep disorder: prevalence and consequences beyond that of symptomatic day workers

Abstract

Study objectives: Although there are considerable data demonstrating the impact of shift work on sleep and alertness, little research has examined the prevalence and consequences of shift work sleep disorder in comparison to the difficulties with insomnia and excessive sleepiness experienced by day workers. The present study was designed to determine the relative prevalence and negative consequences associated with shift work sleep disorder in a representative sample drawn from the working population of metropolitan Detroit.

Design: Random-digit dialing techniques were used to assess individuals regarding their current work schedules and a variety of sleep- and non-sleep-related outcomes.

Setting: Detroit tricounty population.

Participants: A total of 2,570 individuals aged 18 to 65 years from a representative community-based sample including 360 people working rotating shifts, 174 people working nights, and 2036 working days.

Measurements and results: Using standardized techniques, individuals were assessed for the presence of insomnia and excessive sleepiness, based on DSM-IV and ICSD criteria. Those individuals with either insomnia or excessive sleepiness and who were currently working rotating or night schedules were classified as having shift work sleep disorder. Occupational, behavioral, and health-related outcomes were also measured. Individuals who met criteria for shift work sleep disorder had significantly higher rates of ulcers (odds ratio = 4.18, 95% confidence interval = 2.00-8.72), sleepiness-related accidents, absenteeism, depression, and missed family and social activities more frequently compared to those shift workers who did not meet criteria (P < .05). Importantly, in most cases, the morbidity associated with shift work sleep disorder was significantly greater than that experienced by day workers with identical symptoms.

Conclusion: These findings suggest that individuals with shift work sleep disorder are at risk for significant behavioral and health-related morbidity associated with their sleep-wake symptomatology. Further, it suggests that the prevalence of shift work sleep disorder is approximately 10% of the night and rotating shift work population.