Fibrinogen, coronary heart disease and mortality from all causes in smokers and nonsmokers. The Study of Men Born in 1933

Objective. To analyse the relation between fibrinogen concentration and incidence of coronary heart disease and mortality from all causes. A secondary aim was to investigate whether the effect of fibrinogen, as in previous cross-sectional analyses from this population, was restricted to nonsmokers. Design. Prospective population study. Setting. City of Goteborg, Sweden. Subjects. A total of 664 men from a population sample of 1016 men aged 50 in 1983, without prior myocardial infarction. Main outcome measures. Development of coronary heart disease (myocardial infarction, coronary death or, in men with angina, revascularization, or scintigraphic evidence of coronary disease) and death from all causes, in relation to fibrinogen concentration and smoking status at baseline, during 9 years' follow-up. Results. Rates of coronary heart disease during follow-up in the lowest, middle and highest third of the fibrinogen distribution were 4.6, 6.4 and 10.3%, respectively, but this did not remain significant after controlling for smoking and other risk factors (adjusted odds ratio [OR] for the highest, compared to the lowest third 1.5 [0.7-3.4]). Percentages of men who died from any cause were 3.2, 5.9 and 10.7 in the lowest, middle and highest thirds of fibrinogen, respectively. After adjustment for smoking and other risk factors, this difference remained significant (relative risk 2.6 [1.2-5.9]). In men who were smokers at baseline, fibrinogen was not significantly related to coronary heart disease or mortality. Men who did not smoke in the lowest, middle, and highest third of the fibrinogen distribution had rates of coronary heart disease of 1.8, 3.6 and 10.3%, respectively, and of deaths from all causes of 1.8, 2.9 and 8.4%, respectively. The adjusted OR remained significant at 5.4 (1.4-20.0) for coronary heart disease, as did the adjusted relative risk for mortality at 3.8 (1.01-14.4). Conclusion. Plasma fibrinogen is an independent predictor of premature death, and also of coronary heart disease, in middle-aged men and in non-smokers. A high fibrinogen concentration, particularly in a nonsmoker, deserves attention.