Cognitive and behavioral correlates of low vitamin B12 levels in elderly patients with progressive dementia

Vitamin B-12 deficiency is common in elderly persons, yet its role in dementia and psychiatric illness is unclear. The authors examined the relationship between vitamin B-12 serum levels and cognitive and neuropsychiatric symptoms in dementia. Community-dwelling elderly subjects (N = 643) meeting NINCDS-ADRDA criteria for probable or possible Alzheimer disease (AD) underwent comprehensive neuropsychiatric evaluation and measurement of vitamin B-12 serum levels. Thirty-seven subjects (5.7%) had low B-12 serum levels (200 pcg/ml or less). Subjects with low B-12 levels were significantly older and bad significantly lower scores on the Mini-Mental State Exam and higher scores on the Blessed Dementia Scale, but nota different pattern of cognitive or behavior disturbances compared with the normal-B-12 subjects. In AD, the prevalence of low vitamin B-12 serum levels is consistent with that found in community-dwelling elderly persons in general but is associated with greater overall cognitive impairment.