Conversion from mild cognitive impairment to dementia: influence of folic acid and vitamin B12 use in the VITA cohort.

OBJECTIVE

Increased serum homocysteine and low folate levels are associated with a higher rate of conversion to dementia. This study examined the influence of vitamin B12/folic acid intake on the conversion from mild cognitive impairment (MCI) to dementia.

PARTICIPANTS

A community dwelling cohort of older adults (N=81) from the Vienna Transdanube aging study with MCI.

DESIGN

Prospective study with a retrospective evaluation of vitamin intake.

MEASUREMENTS: Laboratory measurements, brain magnetic resonance imaging, and cognitive functioning were assessed at baseline and at five-year follow-up.

RESULTS

The self-reported combined use of folic acid and vitamin B12 for more than one year was associated with a lower conversion rate to dementia. Serum levels of homocysteine and vitamin B12 as measured at baseline or at five years were not associated with conversion. Higher folate levels at baseline in females predicted a lower conversion rate to dementia. The assessment of brain morphological parameters by magnetic resonance imaging revealed higher serum folate at baseline, predicting lower medial temporal lobe atrophy and higher levels of homocysteine at baseline, predicting moderate/severe global brain atrophy at five years. Users of vitamin B12 or folate, independent of time and pattern of use, had lower grades of periventricular hyperintensities and lower grades of deep white matter lesions as compared to non-users.

CONCLUSIONS

These results from a middle European study support observations on the protective ability of folate in MCI patients with respect to conversion to dementia; they also point to a participation of homocysteine metabolism on processes associated with brain atrophy.