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(Stroke. 2009;40:2209.)
© 2009 American Heart Association, Inc.

Research Letters

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

Katherine Kasiman, MSc; John W. Eikelboom, FRCPA; Graeme J. Hankey, FRACP; Samantha P.-K. Lee, BSc (Hons); Joanna P.-Z. Lim, BSc (Hons); Jasinda H.-Q. Lee, BSc; Hui-Meng Chang, MRCP; Meng-Cheong Wong, FRCP Christopher P.L.-H. Chen, FRCP

From the Centre for Molecular Epidemiology (K.K.) and the Department of Pharmacology (J.H.-Q.L., C.P.L.-H.C.), Yong Loo Lin School of Medicine, National University of Singapore; the Department of Medicine (J.W.E.), McMaster University, Hamilton, Ontario, Canada; the Stroke Unit, Department of Neurology (G.J.H.), Royal Perth Hospital, Perth, Australia; the Department of Neurology (S.P.-K.L., J.P.-Z.L.), Singapore General Hospital; the Department of Neurology (H.-M.C.), National Neuroscience Institute, Singapore General Hospital Campus; and the Division of Medical Sciences (M.-C.W.), National Cancer Centre, Singapore.

Correspondence to Christopher P.L.-H. Chen, Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Clinical Research Centre, MD11 Level 5 #05-09, 10 Medical Drive, Singapore 117597. E-mail phccclh{at}nus.edu.sg

Background and Purpose— 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.

Methods— 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.

Results— 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±3.6µmol/L) despite ethnic differences in MTHFR genotype and baseline folic acid (FA) and vitamin B₁₂ (vitB₁₂) concentrations.

Conclusions— 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.

Key Words: stroke • homocysteine • ethnicity