EFFECT OF VITAMIN B12 ON COGNITION

Abstract

The effect of serum vitamin B12 on cognitive decline is controversial. From the database of Alzheimer’s Disease Neuroimaging Initiative, 274 subjects with baseline diagnosis of normal cognition (NC), 604 patients with MCI, and 199 patients with dementia were identified. Serum vitamin B12 and CSF Alzheimer’s disease (AD) biomarkers were checked at the baseline evaluation, and subjects were categorized into higher, middle, and lower tertile group according to the baseline vitamin B12 level. Cognitive function was evaluated with Mini-Mental Status Examination (MMSE). The effects of serum vitamin B12 on longitudinal cognitive decline was evaluated with linear mixed effect model controlling for possible confounders. Demographic features and baseline CSF biomarkers were comparable between the three vitamin B12 tertile groups. In NC and MCI, baseline MMSE score was higher in the higher tertile group compared to the middle and the lower tertile groups. Linear mixed effect models showed that the higher tertile group showed faster MMSE decline compared to the middle and the lower tertile groups in patients with baseline diagnosis of MCI. This effect of vitamin B12 was more prominent in male patients compared to female patients. There was no significant effect of vitamin B12 on longitudinal cognitive decline in subjects with baseline NC and dementia diagnosis. Higher vitamin B12 level is associated with higher baseline MMSE score and faster cognitive decline in MCI patients. Higher vitamin B12 level could be a cognitive reserve factor in MCI patients.