Inverse relationship between physical activity and plasma fibrinogen in postmenopausal women

The relationship between habitual physical activity and plasma level of fibrinogen was investigated in a cohort of 180 postmenopausal women, aged 60-69 years. Plasma fibrinogen was determined from prediluted plasma by adding an appropriate amount of thrombin to the sample. The time until fibrin formation occurred was measured. Physical activity during the month and year preceding the examination was assessed using self-administered questionnaires. There was a statistically significant inverse relationship between physical activity and fibrinogen (beta = -0.20; P = 0.005). For further analyses of the association between physical activity and fibrinogen the subjects were classified into three categories according to their weekly physical activity frequency: 0 to 1, 2 to 3, and 4 or more during the preceding month. The mean (S.D. [95% CI]) levels of fibrinogen from lowest to highest categories were: 3.49 (1.10 [2.99, 3.99]), 3.31 (1.52 [2.82, 3.81]), and 3.20 (2.26 [2.73, 3.67]) g/l, respectively, when age, body mass index (BMI), smoking, alcohol intake, LDL-cholesterol and estrogen use were allowed for (P = 0.021). BMI was directly associated with fibrinogen (beta = 0.30; P < 0.001), especially in the physically least active women. Smoking was directly (beta = 0.19; P = 0.006) and estrogen use inversely (beta = -0.15; P = 0.037) related to plasma fibrinogen level. The present data suggest that in postmenopausal women a low level of physical activity is associated with a high level of plasma fibrinogen.