A case-control study of sleep-related factors and occupational injuries at an Italian teaching hospital

Background: Sleep disorders have been associated with increased risk of occupational injuries in various settings. Purpose: We investigated the associations between sleep, daytime sleepiness, and chronotype (preference for morning or evening activities) and the risk of occupational injuries in an Italian teaching hospital. Methods: A case-control study of employees of the University Hospital of Udine, Italy, was conducted on 200 employees reporting occupational injuries and 183 controls. Information was collected on usual sleep quantity and quality. Sleepiness was assessed with the Epworth Sleepiness Scale. Chronotype was assessed with the Horne–Ostberg morningness–eveningness questionnaire. The association of sleep-related exposures with the risk of injury was assessed with multivariate unconditional logistic regression, adjusting for potentially confounding individual characteristics. Results: Among sleep-related variables, the number of reported sleep disturbances was positively related with occupational injuries, whereas daytime sleepiness was inversely associated with injuries. Cases had shorter usual sleep hours than controls, although the difference was not statistically significant. No association was found between usual sleep hours and injuries. Chronotype was not significantly associated with injury, although we observed a decreasing trend in risk of injury from morning to evening chronotypes. Conclusions: Self-reported sleep disturbance was positively associated with increased risk of occupational injury in an Italian hospital. However, contrary to expectation, daytime sleepiness was inversely related to injuries.