Ethnicity Does Not Affect the Homocysteine-Lowering Effect of B-Vitamin Therapy in Singaporean Stroke Patients

Increased total homocysteine (tHcy) is a risk factor for stroke. This study examines whether the efficacy of B-vitamins in reducing tHcy is modified by ethnicity in a Singaporean ischemic stroke population. 505 patients (419 Chinese, 41 Malays and 45 Indians) with ischemic stroke were randomized to receive placebo or B-vitamins. Fasting blood samples collected at baseline and 1 year were assayed for tHcy. MTHFR polymorphisms were genotyped. Ethnicity did not independently determine tHcy at baseline. The magnitude of tHcy reduction by B-vitamin treatment was consistent across ethnic groups (Chinese -3.8+/-4.5, Malay -4.9+/-4.2, and Indian -3.3+/-3.6 micromol/L) despite ethnic differences in MTHFR genotype and baseline folic acid (FA) and vitamin B(12) (vitB(12)) concentrations. Ethnicity does not appear to affect the tHcy-lowering effect of B-vitamins, despite differences in dietary intake and prevalence of MTHFR polymorphisms. This suggests that the effect of B-vitamins in lowering tHcy is generalizable across Asian populations. However, due to relatively small numbers of non-Chinese studied, confirmation in other populations is required.