Background: The aim of this study was to compare plasma fibrinogen levels in hypertensive and normotensive men. Possible confounding factors, such as age, cholesterol levels, body-mass index and smoking habits were also to be considered.
Methods: We studied 708 men with essential hypertension (according to the World Health Organization's criteria) and 944 with normal blood pressures, all of whom had similar lifestyles; the overall age range was 18-60 years. The clinical evaluation included measurements of blood pressure, heart rate, body weight and height as well as a medical examination and personal habits history. After an overnight fast, blood samples were taken in order to measure fibrinogen and total-cholesterol levels.
Results: The mean fibrinogen level did not differ between the groups, although the distribution of the levels was different and was J-shaped in the hypertensive group. Plasma fibrinogen levels increased significantly with age in both groups. A significant positive correlation was found between fibrinogen and total-cholesterol levels, but not between fibrinogen and body-mass index or systolic or diastolic blood pressures. Cigarette smokers had significantly higher fibrinogen levels than non-smokers, irrespective of their blood pressure status; ex-smokers had intermediate values, suggesting a direct but reversible effect of tobacco. In cigarette smokers, fibrinogen levels increased with the number of cigarettes smoked, which is indicative of a dose-response relationship.
Conclusion: This study confirms the strong association between fibrinogen levels and smoking and the weaker association with age and total-cholesterol levels. Mean fibrinogen level was not significantly related to blood pressure, although the distribution of fibrinogen levels appeared to be J-shaped in hypertensive men.