Background Previous studies have indicated an increased incidence of myocar
dial 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 p
opulation. 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 driver
s and the reference groups except for the Stockholm area which showed a hig
her percentage of tobacco smokers as well as higher means for systolic and
diastolic blood pressures. The risk ratio compared with the reference sampl
es was significantly elevated in Stockholm but not in any of the other area
s.
Conclusions These somatic risk factors for myocardial infarction do not exp
lain the approximately 40% reported increase in myocardial infarction incid
ence among railway engine drivers. In the following study, psychosocial fac
tors will also be examined. (C) 2000 Lippincott Williams & Wilkins.