Somatic risk factors for myocardial infarction among Swedish railway engine drivers.

Background: Previous studies have indicated an increased incidence of myocardial infarction among railway engine drivers.

Objective: To analyse whether somatic risk factors for myocardial infarction among male drivers in different geographical areas in Sweden differed from that in general population samples drawn from the same geographical areas.

Design: A cross-sectional study comparing drivers and men from the general population.

Methods: Engine railway drivers aged 25-59 years (n = 2318) were compared with randomly selected men (n = 3016) with respect to their serum cholesterol, systolic and diastolic blood pressures and smoking habits.

Results: The levels of the risk factors did not differ between engine drivers and the reference groups except for the Stockholm area which showed a higher percentage of tobacco smokers as well as higher means for systolic and diastolic blood pressures. The risk ratio compared with the reference samples was significantly elevated in Stockholm but not in any of the other areas.

Conclusions: These somatic risk factors for myocardial infarction do not explain the approximately 40% reported increase in myocardial infarction incidence among railway engine drivers. In the following study, psychosocial factors will also be examined.