Risk of coronary heart disease in middle-aged male bus and tram drivers compared to men in other occupations: a prospective study.

In the Gothenburg Primary Prevention Study the incidence of coronary heart disease (CHD) in 103 bus and tram drivers was compared with that of 6596 men in other occupation groups. The follow-up extended through a mean of 11.8 years. Bus and tram drivers had an incidence of CHD of 18.4% compared with 6.4% among the other men in the study; odds ratio (OR) 3.3 (95% confidence interval (CI) 2.0-5.5). The only other group with an increase in risk of similar magnitude were taxi drivers; OR 3.1 (1.6-6.2). No significant differences were noted as to smoking habits, serum cholesterol or blood pressure between bus and tram drivers and the other men. The bus and tram drivers tended to be more physically active during leisure time, but had a significantly higher body mass index than other men. In a multivariate logistic regression analysis with CHD as the dependent variable and age, serum cholesterol, blood pressure, smoking, body mass index, diabetes, marital state, family history of CHD, alcohol abuse, socioeconomic status, leisure time physical activity, physical activity at work, psychological stress and bus and tram driving as independent variables the OR for bus and tram driving was only slightly reduced to 3.0 (1.8-5.2). In this population, being a bus or tram driver was an independent predictor of CHD of considerable magnitude. The increased risk of taxi drivers was not significant in multivariate analysis.