Changes in folate, vitamin B₁₂ and homocysteine associated with incident dementia

Abstract

Objectives: Prospective findings have not been consistent for folate, vitamin B₁₂ and homocysteine concentrations as predictors of dementia. This study aimed to investigate both baseline concentrations of folate, vitamin B₁₂ and homocysteine and changes in these concentrations as predictors/correlates of incident dementia.

Methods: Of 625 elderly patients without dementia at baseline, 518 (83%) were followed over a 2.4 year period and were clinically assessed for incident dementia and Alzheimer’s disease (AD). Serum concentrations of folate, vitamin B₁₂ and homocysteine were measured at the baseline and follow-up assessments. Covariates included age, sex, education, disability, depression, alcohol consumption, physical activity, vascular risk factors, serum creatinine concentration, vitamin intake and weight change.

Results: Only baseline lower folate concentrations predicted incident dementia. The onset of dementia was significantly associated with an exaggerated decline in folate, a weaker increase in vitamin B₁₂ concentrations and an exaggerated increase in homocysteine concentrations over the follow-up period. These associations were reduced following adjustment for weight change over the same period.

Conclusions: Incident dementia is more strongly associated with changes in folate, vitamin B₁₂ and homocysteine than with previous concentrations. These changes may be linked to other somatic manifestations of early dementia, such as weight loss.