Association of vitamin B12 mediated hyperhomocysteinemia and methylenetetrafolate reductase (C677T) gene polymorphism with cognitive impairment: A population based study from North India.

The present study attempts to understand the association of homocysteine, vitamin B12, folate, and MTHFR C677T gene polymorphism with cognitive impairment (CI) among 808 individuals of either sex (aged 30-70 years) from a largely vegetarian, mendelian population of North India. Biochemical and genetic analyses were done using standard protocols. Results indicate that 34.3% of the subjects had mild CI, 28.7% moderate CI and 0.2% were having severe CI. Hyperhomocysteinemia was found to be a significant risk factor for moderate/severe CI. Both CT genotype and T allele of MTHFR C677T gene polymorphism were found to pose significant decreased risk for CI.