Relations between homocysteine, folate and vitamin B12 in vascular dementia and in Alzheimer disease

The aim of this study was to evaluate the relationship between homocysteine (Hcy), folate and vitamin B12 levels in vascular dementia (VaD) and Alzheimer Disease (AD) to elucidate if they had similar pathogenesis due to cerebrovascular injury. Plasma Hcy and serum folate, vitamin B12 levels were studied 67 VaD, 51 AD and 40 healthy control subjects. Vascular risk factors in these groups were also considered. The changes in the levels of Hcy, folate and vitamin B12 were found to be not related with vascular risk factors. In VaD, Hcy level was higher ( p < 0.001), folate and vitamin B12 levels were lower ( p < 0.05 for folate, p < 0.001 for vitamin B12) than those in AD. Hcy level was negatively correlated with folate and vitamin B12 ( p < 0.05) in VaD but in AD. Hcy/folate and Hcy/vitamin B12 ratios were the highest in VaD. The increase of Hcy in AD were seemed to be not related to cerebrovascular injury. It is possibly related to biochemical damages as result of oxidative stress.