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.

Psychosocial risk factors for myocardial infarction among Swedish railway engine drivers [corrected].

BACKGROUND: Several earlier investigations have found an increased incidence of myocardial infarction among male drivers and, not least, among railway engine drivers. In a previous study we found that increased serum cholesterol, blood pressure or tobacco smoking did not explain this increased risk. OBJECTIVE: To investigate psychosocial factors and primarily work-related factors among male engine drivers. DESIGN: Engine drivers were compared with random population samples in a cross-sectional study. METHOD: Two thousand three hundred and eighteen engine drivers aged 25-59 years were compared with 331 randomly selected men who were mainly from the Göteborg MONICA population study. Job demands and job decision latitude as well as social support were the main factors compared. RESULTS: Job demands were reported as being significantly lower by both younger and older engine drivers compared to their referents (P = 0.002 and P = 0.0001, respectively). Decision latitude was reported as being lower by both younger and older engine drivers than among controls (P = 0.0001 for both groups). Engine drivers experienced deficient support from their superiors compared to the referents (P = 0.0001 for younger as well as older engine drivers). Low decision latitude was associated with significantly higher diastolic blood pressure (r = -0.11 and P = 0.0001), but otherwise there were no significant relationships between psychosocial work characteristics and somatic risk factors. CONCLUSIONS: The combination of low decision latitude and low social support seems to be a key factor in the increased risk of myocardial infarction among railway engine drivers. They generally undertake shift work which may be an additional risk factor for myocardial infarction.

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.