Higher vitamin B12 from mid- to late life is related to slower rates of cognitive decline.

INTRODUCTION

Evidence is needed to evaluate whether low vitamin B12 from mid- to late life, either alone or in the presence of elevated folate, is associated with cognitive decline.

METHODS

Participants from the Framingham Heart Study without baseline dementia who had ≥ 2 measures of a three-component vitamin B12 indicator (3cB12) and neuropsychological factor scores were included (n = 1994; mean age: 60 years). Adjusted linear mixed effects models estimated annual changes in each factor score between 3cB12 quartiles. Interaction by folate status was also evaluated.

RESULTS

Participants in the highest 3cB12 quartile had slower declines in memory, executive function, and language compared to the lowest quartile (memory: β = 0.0071, 95% confidence interval [CI] = 0.003-0.01; executive function: β = 0.0056, 95% CI = 0.0009-0.01; and language: β = 0.0090, 95% CI = 0.004-0.01). Findings were largely robust by folate status (elevated: ≥ 20 ng/mL; non-elevated: 6-19 ng/mL).

DISCUSSION: Improving B12 status in dementia-free older adults may help mitigate cognitive decline into later life.

HIGHLIGHTS: Higher vitamin B12 status is associated with slower annual cognitive decline. Higher B12 was linked with 0.05 to 0.09 standard deviation less cognitive decline over 10 years. B12 and memory findings are robust for elevated, not non-elevated, folate status.