Homocysteine and cognitive performance in healthy elderly subjects

Hyperhomocysteinemia is a risk factor for dementia but only scanty data exist about its relationship to specific cognitive abilities during normal aging. We recruited 62 healthy and cognitively normal subjects of age 65-91 years from the Conselice Study of brain aging. The following neuropsychological tests were applied (i) The mental deterioration battery (MDB) consisting of 7 parts: the Rey's 15 words immediate and delayed recall, word fluency, sentence construction, Raven's progressive matrices '47, immediate visual memory, freehand copying of drawings and copying drawings with landmarks. (ii) The Prose memory test. (iii) The Corsi block-tapping task. (iv) The mini mental state examination (MMSE) scores. We measured plasma total homocysteine (tHcy), serum folate, vitamin B-12, and plasma vitamin B-6. Multivariate-adjusted linear regression analysis showed statistically significant negative association of plasma tHcy with scores at MMSE (b= -0.012, p < 0.001) and word fluency (b = -0.009, p = 0.021). A non-significant trend towards a negative association was also found for sentence construction (b = -0.006, p = 0.076). One can conclude that in healthy elderly subjects, increased plasma tHcy is correlated to poorer performance at a specific measure of language abilities being compromised in both vascular and Alzheimer's dementia. The study suggests that plasma tHcy could be an early marker of cognitive impairment.