Risk factors for myocardial infarction among Swedish railway engine drivers during 10 years follow-up

BACKGROUND: Railway engine drivers have had an increased risk of myocardial infarction which could be due to reported low decision latitude and low social support but not to elevated somatic risk factors. OBJECTIVE: To study somatic and psychosocial risk factors for myocardial infarction among railway engine drivers prospectively. DESIGN: A prospective study of 2318 drivers followed for 10 years. METHODS: Risk factors were surveyed in conjunction with periodic health checks at 15 different centres but with common methodology and commonly used questionnaires. Questionnaire and register information on myocardial infarction during follow-up was recorded. RESULTS: Within this group of engine drivers, age, family history of myocardial infarction, systolic blood pressure and low body height were independent predictors of myocardial infarction, but diabetes, elevated serum cholesterol and smoking were not. Neither were a longer time in the occupation or work-related psychosocial factors. The drivers were all at the lower end of the decision authority and latitude scale and had low social support. With this limited span, it may be difficult to detect these variables as risk factors within this group. CONCLUSIONS: Several well-known, somatic risk factors for myocardial infarction were documented in this study, whereas psychosocial working conditions, which were common to all the drivers, were not significantly related to outcome.