Summary
Although obesity is associated with increased cardiovascular risk, the mechanism has
not been fully explained. Since thrombosis is a critical component of cardiovascular
disease, we examined the relationship between obesity and hemostatic factors. We studied
3230 subjects (55% females, mean age 54 years) without a history of cardiovascular
disease in cycle 5 of the Framingham Offspring Study. Obesity was assessed by body
mass index and waist-to-hip ratio. Fasting blood samples were obtained for fibrinogen,
plasminogen activator inhibitor (PAI-1) antigen, tissue plasminogen activator (tPA)
antigen, factor VII antigen, von Willebrand factor (VWF), and plasma viscosity. Body
mass index was directly associated with fibrinogen, factor VII, PAI-1 and tPA antigen
in both men and women (p<0.001) and with VWF and viscosity in women. Similar associations
were present between waist-to-hip ratio and the hemostatic factors. With minor exceptions
for VWF and viscosity, all associations persisted after controlling for age, smoking,
total and HDL cholesterol, triglycerides, glucose level, blood pressure, and use of
antihypertensive medication. The association between increased body mass index and
waist-to-hip ratio and prothrombotic factors and impaired fibrinolysis suggests that
obesity is a risk factor whose effect is mediated in part by a prothrombotic state.
Keywords
Obesity - thrombosis - cardiovascular disease