Vitamin B12 supplementation did not improve cognition but reduced delirium in demented patients with vitamin B12 deficiency

To examine the effects of vitamin B12 supplementation on the cognitive function, delirium, and neuropsychiatric symptoms of mild to moderate dementia patients with vitamin B12 deficiency. Thirty consecutive mild to moderate dementia cases aged over 60 years with low serum B12 (<200 pmol/l) were given vitamin B12 supplementation for 40 weeks. The Mattis Dementia Rating Scale (MDRS), Category Verbal Fluency Test (CVFT), Delirium Rating Scale (DRS), Mini-Mental State Examination (MMSE), and the Neuropsychiatric Inventory (NPI) were performed at baseline, and after 6, 16, and 40 weeks. No significant changes in cognitive function and behavioral symptoms were detected between baseline and 40 weeks. DRS scores decreased significantly at 6 and 40 weeks (median change of −1 at both follow-ups, p = 0.006 and 0.04, respectively). Cognitive function of mild to moderately demented older people with vitamin B12 deficiency did not significantly change with vitamin B12 supplementation over a 10-month period. The supplementation reduced delirium associated with dementia.