Long-term effects of work-related factors on risk of psychiatric disorders among professional drivers have not been conclusive. A follow-up study was conducted to evaluate the individual and combined effects of stress and fatigue on drivers’ risk of developing psychiatric disorders.Methods
The Taiwan Bus Driver Cohort Study (TBDCS) recruited 1650 professional drivers from a large bus company in 2005. The subjects were interviewed in person and completed two scales of job stress- the Demand-Control-Support model (DC) and Effort-Reward Imbalance model (ERI), and one job fatigue model- Swedish Occupational Fatigue Inventory (SOFI). Psychiatric diseases were the outcomes of this study, including substance abuse, anxiety, mood, and sleep disorders. Cox proportional hazards model was used to estimate the hazard ratio (HR) for psychiatric disorders.Results
Between 2006 and 2012, 108 bus drivers were diagnosed as having psychiatric disorders. Neither DC nor ERI score was associated with psychiatric disorders risk. Drivers with high SOFI (>3.5) had an elevated risk for psychiatric disorders, adjusting for age, BMI, marriage status, education, drinking, smoking, exercise, sleeping pills, bus driving experience and shift work (HR: 2.02, 95% CI: 1.37 to 2.99; p=0.025). Among psychiatric disorders, those having anxiety or mood disorders were related to high SOFI in 2005.Conclusion
Among professional drivers, occupational fatigue as indicated by high SOFI might have predicted higher risk of psychiatric disorders, especially anxiety or mood disorders.