Employees who work shifts outside of a nine-to-five schedule are more likely to be overweight, experience sleep problems, and are also at higher risk of developing metabolic disorders, such as diabetes, scientists have found.
"Shiftwork employees are particularly vulnerable to experiencing sleep problems as their jobs require them to work night, flex, extended, or rotating shifts," said lead investigator Marjory Givens, an Associate Scientist with the University of Wisconsin School of Medicine and Public Health.
The investigators used cross-sectional data from the Survey of the Health of Wisconsin (SHOW) collected from 2008-2012.
In this analysis, 1,593 participants were assessed using measures from the physical examination to calculate body mass index and determine obesity or overweight status.
Type-2 diabetes (T2D) was assessed in 1,400 subjects using either self-report of physician-diagnosed T2D or glycated hemoglobin (HbA1c) equal to or greater than 6.5% as determined from a blood sample obtained at the physical examination.
Shiftworkers were significantly more likely than traditional schedule workers to be overweight (47.9% vs 34.7%). They also experienced more sleep problems such as insomnia (23.6% vs 16.3%), insufficient sleep (53.0% vs 42.9%), or excessive wake-time sleepiness (31.8% vs 24.4%).
Since shiftwork and sleep problems have both been implicated in poor metabolic health, the researchers wondered whether sleep problems may play a role in shiftworker health disparities.
Givens and her colleagues found that experiencing sleep problems was positively associated with being overweight/obese or diabetic.
Moreover, even though sleep problems did not fully explain the relation between shiftwork and overweight or diabetes, these association appear to be stronger among shiftworkers who were not able to obtain sufficient sleep (less than seven hours per day), suggesting that the adverse metabolic consequences of shiftwork could be partially alleviated by sufficient sleep.
"This study adds to a growing body of literature calling attention to the metabolic health burden commonly experienced by shiftworkers and suggests that obtaining sufficient sleep could lessen this burden," said Givens.
The study is published in the journal Sleep Health.