Sleep problems are a strong predictor of stress-related metabolic changes in police officers. A prospective study

Objective: Sleep is an essential physiological function for well-being and health. Previous studies have shown that workers chronically exposed to occupational stress have an increased risk of metabolic syndrome (MetS). The purpose of this study was to verify whether sleep problems are MetS predictors, and to clarify the relationship between stress and sleep. Method: In a previously published longitudinal study we demonstrated that in the absence of other risk factors, continuous exposure to occupational stress was significantly associated with the risk of developing MetS at follow-up. In this study we also processed data concerning sleep quantity and quality and evaluated whether sleep problems alter the relationship between stress and MetS. Results: Sleep problems were significantly related to incident cases of MetS. The average number of hours of sleep had a protective effect. The adjusted OR (corrected for demographic variables, excessive daytime sleepiness and job stress) was 0.457 (CI95% = 0.255-0.818). However, MetS was more strongly related to quality of sleep than quantity of sleep: if insomnia symptoms (difficulty sleeping, sleep interruptions, and early awakenings) were added to the multivariate hierarchical logistic model, the hours of sleep were no longer significant, and insomnia symptoms showed a highly significant aOR (8.347; CI95%= 3.042-22.906) with MetS. We observed a bidirectional longitudinal relationship between job stress and sleep problems. Work-related stress was a significant predictor of insomnia symptoms, short sleep duration, sleep dissatisfaction, and sleepiness. Police officers with sleep problems at baseline had significantly higher odds of reporting job strain at follow-up compared to the reference group. Conclusion: Sleep problems play a mediating role in the relationship between occupational stress and MetS. Sleep symptoms are a powerful indicator of MetS. MetS prevention must include not only the control of stress factors and an increase in the resilience of workers, but above all correct sleep hygiene.