Background and purpose: Elevated fibrinogen levels are suggested to increase the risk of myocardial infarction and stroke. Carriers of the A allele of the fibrinogen -455G/A polymorphism have increased plasma fibrinogen levels. We studied the association of this polymorphism with stroke subtype in the Stroke Aging Memory (SAM) cohort.
Methods: The SAM cohort comprises 486 consecutive patients 55 to 85 years of age who, 3 months after ischemic stroke, completed a detailed stroke assessment. Stroke subtypes were examined with MRI. -455G/A genotype was determined by polymerase chain reaction. MRI and genotype data were available for the 299 patients who constitute the present study population.
Results: Genotype distributions were 64.9% (GG), 31.8% (GA), and 3.3% (AA). In a logistic regression model with age, sex, hypertension, diabetes, hypercholesterolemia, hypertriglyceridemia, myocardial infarction, arrhythmia, atrial fibrillation, peripheral arterial disease, and smoking as possible confounders, there was a significant association between A+ genotype and >or=3 lacunar infarcts (odds ratio [OR], 2.57; 95% CI, 1.23 to 5.36; P=0.01). Hypertensive patients carrying the A allele had increased risk (OR, 4.24; 95% CI, 1.29 to 13.99; P=0.02) for >or=3 lacunar infarcts. A similar increase in risk was observed among smokers with the A+ genotype (OR, 2.67; 95% CI, 0.92 to 7.77; P=0.07).
Conclusions: Stroke patients carrying the A allele of the Bbeta-fibrinogen -455G/A polymorphism frequently presented with multiple lacunar infarcts. This association was stronger among hypertensives and smokers. These associations suggest that the A allele may predispose to atherothrombotic events in cerebrovascular circulation.