Vitamin D Levels in Brain Linked to Decreased Risk of Dementia-Related Cognitive Decline
High levels of vitamin D in the brain may be associated with a decreased risk of demential-related cognitive decline in community-dwelling older adults, according to the results of a recent study.
Prior studies have resulted in mixed findings on the relationship between vitamin D intake and cognitive impairment. The authors of this study aimed to further examine this relationship by focusing on 25(OH)D3 levels, the main circulating form of vitamin D in the brain, as well as other various markers of vitamin D status in the brain and the impact that 25(OH)D concentrations may have on post-mortem neuropathology.
The study included 290 participants of the Rush Memory and Aging Project (MAP) longitudinal study. Of the total participants, 270 had plasma total 25(OH)D3, free 25(OH)D, and vitamin D binding protein measured across the mid-temporal cortex, mid-frontal cortex, cerebellum, and anterior watershed white matter brain regions.
The results indicated that higher concentrations of 25(OH)D3 were associated with a 25% to 33% lower risk of dementia or mild cognitive impairment at the last clinic visit before death (p ≤ .031). Higher concentrations of 25(OH)D3 were associated with better ante-mortem cognitive function scores and better semantic and working memory across all measured regions. Higher concentrations in the anterior watershed white brain matter region were also associated with a slower rate of cognitive decline and better episodic memory and perceptual speed.
No associations were observed between neuropathological outcomes and concentration of 25(OH)D in the brain. All other measures of vitamin D included here were not associated with cognitive function or decline.
However, the researchers note that limitations of this study exist due to the observational design and limited inclusion of racial/ethnic groups other than White, non-Hispanic individuals.
Despite these limitations, the researchers concluded: “Higher brain 25(OH)D3 concentrations were associated with better cognitive function prior to death. Additional research is needed to clarify the specific mechanisms underlying this potentially protective relationship.”
Shea MK, Barger k, Dawson-Hughes B, et al. Brain vitamin D forms, cognitive decline, and neuropathy in community-dwelling older adults. Alzheimers Dement. Published online December 7, 2022. doi:10.1002/alz.12836
Correction: A previous version of this article incorrectly stated that vitamin D levels in the brain were linked to increased dementia-related cognitive decline. The article has been updated. We apologize for the error.