Plasma fibrinogen in women: relationships with oral contraception, the menopause and hormone replacement therapy

Researchers analyzed 1987-1988 data on 4837 women aged 25-64 living in Scotland to determine the effects of oral contraceptive (OC) use menopause and hormone replacement therapy on plasma fibrinogen levels. Current smokers had higher plasma fibrinogen levels than did ex-smokers who in turn had higher levels than never smoker (2.51 g/1 2.33 g/l and 2.28 g/l respectively). When they standardized for age women with a history of OC use premenopausal women and women on hormone replacement therapy had lower plasma fibrinogen levels than did never users postmenopausal women and women not on hormone replacement therapy (2.34 vs. 2.39 g/l p < .001; 2.26 vs. 2.44 g/l p < .001; 2.03 vs. 2.38 g/l p < .005 respectively). The multivariate analysis indicated that menopausal status and hormone replacement therapy independently affected fibrinogen levels but together they accounted for less than 1% of the variation of fibrinogen levels. OC use did not have an independent effect. Menopausal status and hormone replacement therapy together with the other common risk factors (e.g. smoking age total cholesterol HDL/cholesterol and body mass index) explained just 9.9% of the total variation in plasma fibrinogen level. Selection of healthier women to whom physicians administered hormone replacement therapy may explain hormone replacement therapys protective effect. These findings verified a postmenopausal increase in fibrinogen level which may contribute to an increased risk of coronary heart disease.