Clues for Occupational Health Surveillance and Epidemiological Research on Night Shift Work from a Scoping Review on Sleep Disruption

Background: Sleep deprivation is a frequent outcome of nightshift work, a probable human carcinogen. However, social, cultural, and technological changes have contributed to spread sleep deprivation also among the general population. We reviewed the literature on sleep disorders in adults associated with lifestyle, environmental, and workplace conditions unrelated to shift work aiming to: 1. identify sleep depriving factors during the pre-placement medical examination of night shift workers; and 2. recognize potential sources of confounding and bias in epidemiological studies of shift workers. Methods: We searched public repositories of publications in English or with an informative English abstract up to January 2024. We used standard tools to assess the quality of the selected studies. Results: Overall, we identified 134 papers. Our review confirms that poor sleep quality and sleep deprivation are highly prevalent and result from multiple non-occupational factors as well as occupational factors other than shift work. Physical activity, coffee and alcohol intake, eating habits, lifestyle, and work-related stress were most frequently investigated (67/134 publications). There is sufficient evidence that aging, female sex, family responsibilities, caffeine intake, smoking, poor mental and physical health, and work-related stress can impair sleep quality and reduce sleep duration. Contradictory findings and the possibility of reverse causation due to the predominance of cross-sectional studies prevent drawing conclusions regarding other potential risk factors. Conclusions: Non-occupational causes of sleep disorders shall be assessed during the pre-placement examination as well as when monitoring the health status of night shift workers or evaluating shift work-related health outcomes.