Plasma fibrinogen: a new factor of the metabolic syndrome. A population-based study

To evaluate whether hyperfibrinogenemia represents a component of the metabolic syndrome.

A cross-sectional study was conducted on the relation between fibrinogen and the metabolic syndrome in a working population of 1,252 nondiabetic men, aged 35-64 years, randomly selected among all men participating in a health screening. We measured anthropometric characteristics, blood pressure, fasting plasma fibrinogen, cholesterol (total, LDL, and HDL), triglycerides, glucose, and insulin. Individuals with two or more metabolic abnormalities (defined as being in the highest quartile of the distribution of diastolic blood pressure, plasma glucose, or triglycerides or being in the lowest quartile of HDL cholesterol) were considered to have the metabolic syndrome.

Age-adjusted fibrinogen levels correlated significantly with BMI, waist-to-hip ratio, systolic and diastolic blood pressure, plasma total cholesterol, LDL cholesterol, triglycerides, insulin, and HDL cholesterol (inversely). Subjects with the metabolic syndrome had significantly higher plasma fibrinogen levels than those without (285.1 +/- 1.9 vs. 300.2 +/- 3.0 mg/dl, mean +/- SE, P = 0.0001). Plasma fibrinogen concentrations and the prevalence of hyperfibrinogenemia (defined as > or = 350 mg/dl) increased progressively from 279 to 307 mg/dl (P = 0.0001) and from 9 to 22% (P = 0.0024), respectively, across categories with an increasing number of metabolic disorders characterizing the syndrome (only one, any two, three or more). In multivariate analyses, both plasma insulin and the metabolic syndrome were significantly and independently associated with plasma fibrinogen.

The finding suggests that hyperfibrinogenemia may be considered a component of the metabolic syndrome. This may also explain the increased cardiovascular risk associated with hyperinsulinemia/insulin resistance.