Elevated levels of plasma homocysteine are associated with 2- to 3-fold increased risk for atherosclerotic vascu- lar disease, including stroke.761 767 Carotid IMT and carotid artery stenosis are increased in people with elevated homo- In the Study of Health Assessment and Risk in Ethnic Groups (SHARE), a cross-sectional study of South Asian Chinese and white Canadians, plasma homocys- teine >11.7 mol/L, but not MTHFR C677T, was associated with increased carotid IMT.771 Several recent investigations found that the relationship between homocysteine levels and carotid IMT was eliminated after adjustment for other cardiovascular risk factors or renal function.772,773 One meta- analysis of epidemiological studies found a 19% (95% CI, 5 31) reduction in odds of stroke per 25% lower homo- cysteine concentration after adjustment for smoking, SBP, Another meta-analysis found that for each 5- mol/L increase in homocysteine, the odds of stroke increased by 59% (95% CI, 29 96), and for each 3- mol/L decrease in homocysteine, the odds of stroke decreased by A further line of evidence support- ing a causal role for homocysteine in a stroke is a meta-anal- ysis of 29 studies comparing the MTHFR C677T genotype between 4454 stroke patients and 7586 control subjects. This mendelian randomization approach found increased stroke in those with the TT genotype (OR for stroke, 1.26; 95% CI, 1.11 1.43) without significant between-study heterogeneity or evidence of publication bias.776 The B complex vitamins pyridoxine (B6 ), cobalamin (B12 ), and folic acid lower homocysteine levels. 