Plasma fibrinogen and its correlates in Japanese and US population samples.

In a preliminary 1987 study, we reported that the plasma fibrinogen level was significantly higher in Caucasian American men than Japanese men. To confirm this finding, we used data from 1,020 Japanese men and women in a 1989-1991 Akita, Japan, population study and from > 15,000 men and women from the 1986-1989 Atherosclerosis Risk in Communities (ARIC) Study. To examine further the correlates of plasma fibrinogen level, subsamples of nonsmoking Akita Japanese (n = 150) and Minneapolis Caucasians (n = 150) were also studied separately in 1990. Compared with the Japanese in the Akita study, Caucasians and African Americans in ARIC had a 23-40 mg/dL higher age-adjusted fibrinogen level for men and a 25-67 mg/dL higher level for women. In the subsample, the mean plasma fibrinogen value was 288 mg/dL in Caucasian men and 248 mg/dL in Japanese men (test for difference: p < 0.001). Women showed a similar racial difference: 300 mg/dL in Caucasians and 257 mg/dL in Japanese (p < 0.001). There were weak but positi...