The relationship between job type and development of cerebral stroke in a large, longitudinal cohort study of workers in a railway company in Japan

Abstract

The aim of this study was to clarify the relationship between occupational factors and the development of cerebral stroke in a large cohort working at a railway company in Japan. A 10-year prospective cohort study was conducted in 32,441 male workers who received annual health check-ups at a Japanese railway company. Diagnosis of cerebral stroke was based on the results of the annual health check-ups and individual medical histories. Cerebral stroke included cerebral hemorrhage, cerebral infarction, and subarachnoid hemorrhage. The relationship between job type and the development of cerebral stroke was investigated using a proportional hazards regression with time-dependent covariates adjusted for age, body mass index, mean arterial pressure, family history of cerebral stroke, tobacco and alcohol consumption, and habitual exercise. A negative relationship between job type and the development of cerebral stroke was observed in train crew members, with a significantly lower hazard ratio (HR) seen in train drivers (HR 0.63, 95% confidence interval (CI), 0.42-0.95) and conductors (HR 0.41, 95% CI, 0.24-0.71) in comparison to clerical workers. Since the present results were adjusted for various behavioral and biological factors, they suggest that train crew work itself is associated with a decreased risk of cerebral stroke. These results suggest that further studies on the effect of driving on health may provide information useful for the future prevention of cerebral stroke.