Background: Plasma fibrinogen may be an independent risk factor for cardiovascular disease. Cigarette smoking is a well-recognized determinant of plasma fibrinogen however it remains unclear how fibrinogen levels relate to the degree and duration of smoking, or to time since smoking cessation.
Methods: In a population-based study of 11 059 men and women aged 45-74 years, we examined the cross-sectional relationship between plasma fibrinogen and cigarette smoking habit.
Results: Mean fibrinogen concentrations were higher in current smokers compared to non-current smokers (men: 3.13+/-0.77 versus 2.80+/-0.71 g/l, P<0.0001; women: 3.03+/-0.72 versus 2.95+/-0.71 g/l, P=0.01), independent of age, body mass index and hormone replacement therapy in women In men, fibrinogen concentrations declined with years since stopping smoking but remained higher than in life-long non-smokers for 15 years. No relationship between fibrinogen and duration of smoking cessation was observed in women. On multivariate analysis, age, body mass index, use of hormone-replacement therapy, smoking status and pack-years of smoking were independent predictors of plasma fibrinogen.
Conclusions: Plasma fibrinogen is strongly associated with cigarette smoking with a dose-response relationship with total pack-years of smoking. In men who stop smoking plasma fibrinogen may remain elevated for several years after cessation.