Variables associated with fibrinogen in a population-based study: Interaction between smoking and age on fibrinogen concentration

The aim of the study was to assess the association between fibrinogen and other cardiovascular risk factors. A cross-sectional population-based study in Gerona (Spain) was designed, 1544 subjects (747 men, 797 women) participated. Anthropometric measurements, blood pressure and blood samples were obtained. Fibrinogen was measured by a coagulometric method. Smoking habits, alcohol consumption and physical activity practice were recorded by questionnaires. Fibrinogen was directly related to age, body mass index (BMI) and female gender and inversely to alcohol and moderate–heavy physical activity practice. Fibrinogen was also higher in men and young women who smoked. In the multivariate analysis, age (regression coefficient (RC): 1.33; standard error (SE): 0.13; unit = 1 year), female gender (RC: 12.24; SE: 3.56) and BMI (RC: 1.83; SE: 0.39; unit = 1 kg/m2) were directly associated with fibrinogen, whereas alcohol (RC: −0.04; SE: 0.01; unit = 1 g/d) was inversely associated. A statistically significant interaction between smoking and age was observed. Age was the strongest variable associated with fibrinogen and modifies the association between smoking and fibrinogen; the magnitude of this association increases with age.