Plasma fibrinogen concentrations and risk of stroke and its subtypes among Japanese men and women.

BACKGROUND AND PURPOSE We aimed to examine the impact of fibrinogen concentrations on the incidence of stroke. METHODS We examined the association between fibrinogen and risk of total stroke and stroke subtypes in an 11-year prospective study of 4608 men and 7589 women aged 40 to 79 years with no history of stroke and/or coronary heart disease. The analysis was repeated, stratified by smoking status, to examine whether the association between fibrinogen and stroke was modified by smoking. RESULTS There were 317 incident total strokes comprising 103 hemorrhagic strokes (70 intraparenchymal hemorrhages [22.1% of strokes], 33 subarachnoid hemorrhages [10.4%]), 206 ischemic strokes (65.0%), and 8 strokes of undetermined type (2.5%). The multivariable hazard ratio (95% CI) for the highest versus lowest fibrinogen quartiles after adjustment for age, sex, area, and known cardiovascular risk factors was 2.5 (1.3 to 5.0), P<0.01, for hemorrhagic stroke and 3.2 (1.4 to 7.4), P<0.01, for intraparenchymal hemorrhage. There was no positive association of fibrinogen with risk of ischemic stroke or subarachnoid hemorrhage. Among never-smokers, the multivariable hazard ratio (95% CI) for the highest versus lowest fibrinogen quartiles was 3.5 (1.3 to 9.3), P=0.01, for hemorrhagic stroke and 4.4 (1.3 to 15.2), P=0.02, for intraparenchymal hemorrhage. CONCLUSIONS High plasma fibrinogen concentration can be a predictor for risk of intraparenchymal hemorrhage.