(May 2001)

The best known risk factors for coronary heart disease are high blood cholesterol concentration, elevated blood pressure, smoking, and low blood levels of high-density lipoprotein cholesterol (HDL, so-called good cholesterol). In recent years, two others have been shown to be important - the blood concentration of the amino acid homocysteine and the blood clotting substance, fibrinogen. A new study from Japan in the American Journal of Epidemiology in September 2000 provides additional evidence about fibrinogen.

The authors studied almost 12,000 men and women who had blood fibrinogen levels determined and were followed for an average of almost five years. During that period, there were 21 heart attacks and 20 additional cases of coronary heart disease. Those who developed heart attacks or coronary heart disease had substantially higher fibrinogen levels at baseline, several years before the onset of the coronary heart disease and heart attacks.

The authors concluded "plasma fibrinogen is useful to predict the risk of coronary heart disease among urban Japanese".

Commentary: This is an interesting study with one major drawback, namely that there were only 41 cases of coronary heart disease in the study group of almost 12,000 persons. Still, all the results were statistically quite significant. Furthermore, the study is supported by 13 other studies reported from the United States, Great Britain, Europe, and Japan.

The evidence is really pretty good that high fibrinogen levels in the blood are a significant risk factor for coronary heart disease and heart attacks. Elevated fibrinogen levels are probably not as important as the big risk factors - high cholesterol, high blood pressure, smoking, low blood concentrations of HDL. Besides, there is nothing you can do about a high fibrinogen level; in contrast, you can do a lot about the four major risk factors listed above.

At present, Healthful Life does not recommend obtaining either a screening fibrinogen level or regular fibrinogen levels. We do recommend regular measurements of cholesterol, blood pressure, and HDL, and we recommend regular exercise, a prudent diet that includes plenty of vegetables and fruits, and being sure you get adequate folic acid either in the diet or in supplements (folic acid helps to keep homocysteine concentrations from getting too high).

Sato, S., et al. Plasma fibrinogen and coronary heart disease in urban Japanese. American Journal of Epidemiology. Vol 152. Pgs 420-423. 2000.