Homocysteine, folate and cognition in a large community-based sample of elderly people--the 3C Dijon Study.

BACKGROUND

Hyperhomocysteinemia is associated with an increased risk of cognitive impairment in the elderly. Recent studies suggest that folate level may also influence the course of cognitive decline.

OBJECTIVE

We performed the cross-sectional analysis of the relationship between homocysteine and folate levels and cognitive performances in a population-based study including 3,914 subjects aged 65 years and older.

METHOD: Subjects had an evaluation of their cognitive level using five neuropsychological tests. A Cognitive Summary Score was computed as the sum of each of the 5 cognitive tests score standardized. Relations of folate and homocysteine levels with cognition were first studied separately in a covariance analysis. Stratified analyses were also performed because of interaction between folate and homocysteine in relation to cognition.

RESULTS

Subjects in the higher quartile of homocysteine (high homocysteine group) and subjects in the lower quartile of folate (low folate group) had consistently lower cognitive performances in all tests. When stratified on folate level, high homocysteinemia was associated with lower cognitive performances only in subjects with a low folate level.

CONCLUSION

In this large population-based sample of elderly people, the association between high homocysteinemia and decreased cognition was only seen in participants with low folate levels.