Blood homocysteine and vitamin B levels are not associated with cognitive skills in healthy normally ageing subjects.

Increased plasma total homocysteine (tHcy) levels are a known risk factor for vascular disease and have been reported in association with cognitive impairment of old age. Alternatively, however, increased tHcy levels may simply be an indicator of B vitamin deficiency. We evaluated the relationship between plasma tHcy levels, serum vitamin B12 and folate levels, and the scores at a battery of neuropsychological tests in 54 healthy cognitively normal subjects aged 65 years and over. Hyperhomocysteinemia prevalence (plasma tHcy>15 micromol/L) was about 24%. In univariate analysis, vitamin B12 levels were associated with both verbal memory and visuo-spatial skills, whereas no association was found between psychometric test scores and folate levels or tHcy levels. However, none of the univariate associations of neuropsychological test scores and serum B12 vitamin levels was confirmed when adjusting for age, education and other confounding variables. In conclusion, although a relationship between homocysteine, B vitamins and poor cognitive skills in the elderly is plausible, this study does not suggests that such relationship is biologically important.