Plasma fibrinogen and its correlates in elderly Japanese men living in Japan and Hawaii.

Plasma fibrinogen levels were determined using comparable methods for 329 Japanese men in Hiroshima Japan, and 3571 Japanese-American men in Honolulu Hawaii, aged 71-93 years. The age-adjusted mean fibrinogen level in Japanese-American men (307 mg/dl) was significantly higher (p<0.0001) than in native Japanese men (270 mg/dl). In multiple linear regression models, the fibrinogen level was associated significantly and positively with white blood cell count (WBC) and total cholesterol, and inversely with HDL cholesterol and hematocrit in both study samples. The strongest association with fibrinogen was shown for WBC, and this association was not mediated through cigarette smoking. The observed difference in fibrinogen levels could not be fully explained by WBC, total and HDL cholesterol, triglyceride, hematocrit, body mass index, and diabetes. Some unmeasured environmental or lifestyle variables such as diet and physical activity may be partly responsible for the observed difference in fibrinogen levels between native Japanese men and Japanese-American men in Hawaii.