Apolipoprotein E genetic polymorphism and stroke subtypes in a Bangladeshi hospital-based study

Abstract

The association between apolipoprotein E (apoE) genetic polymorphism and stroke has not been concordant in different racial populations. We investigated the association between apoE genotypes and stroke subtypes by a case-control study in Bangladesh for the first time among south Asian countries. First-ever-stroke patients (n=227; cerebral infarction, n=147, cerebral hemorrhage, n=80) and 190 controls were recruited from a hospital in Dhaka, Bangladesh. The diagnosis of stroke was based on CT and clinical findings. Cerebral infarction was classified anatomically into cortical and penetrating region. Infarction in the cortical region was further categorized etiologically into thrombosis and embolism. Cerebral hemorrhage was considered as a whole in all analyses. ApoE genotypes were determined by restriction fragment length polymorphism. In the multivariate conditional logistic regression analysis adjusted for potential confounders both the ε 3/ ε 4 genotype and ε 4 carrier conferred an approximately 3-fold increased risk for cerebral thrombosis in the cortical artery region (OR 3.5, 95% CI 1.2 to 10.4 and OR 3.1, 95% CI 1.1 to 9.0, respectively) compared with ε3/ε3 genotype. However, when the analysis was restricted to the elderly (>60 years), ε 2 carrier was associated with a risk of hemorrhagic stroke (OR 19.2, 95% C11.3 to 295.2). Our study suggested that both apoE ε3/ε4 genotype and ε4 carriers were risk factors for cerebral thrombosis in cortical artery region, whereas ε 2 carrier was a risk factor for hemorrhaqic stroke in the elderly.