Plasma fibrinogen and coronary heart disease in elderly Japanese-American men

Clinical and epidemiological studies consistently indicate that elevations in plasma fibrinogen concentration are associated with the presence and development of coronary heart disease (CHD). These elevations are strongly correlated with smoking behavior and may play a significant role in mediating a relation of smoking to CHD. This cross-sectional survey of 3571 elderly Japanese-American men, aged 71 through 93 years, represents survivors of the Honolulu Heart Program cohort. Active smokers are almost twice as likely to be represented in the highest quintile of the fibrinogen distribution compared with the lowest quintile (9.8% versus 5.3%, respectively). The highest prevalence of CHD (34%) was noted in past and current smokers who were in the highest quintile of fibrinogen. The age-adjusted relative odds of prevalent CHD comparing the average fibrinogen levels in the first and fifth quintiles were 1.36 (95% confidence interval, 1.13 to 1.64). After adjustment for smoking status, blood pressure, total and HDL cholesterol, diabetes status, hematocrit, and white cell count, the association between fibrinogen and CHD was changed slightly and remained statistically significant (P<.05). These findings in an elderly cohort of Japanese-American men are consistent with previous studies among middle-aged adults demonstrating fibrinogen to be associated with indicators of clinical CHD and CHD risk factors. Because of the cross-sectional nature of this study, it is not possible to distinguish whether the observed relation of fibrinogen to prevalent CHD is causal or whether it represents a marker of active and progressive disease.