Vitamin D supplementation may lower dementia incidence by 40 %.

The findings are published in Alzheimer's and Dementia: Diagnosis, Assessment and Disease Monitoring.

There is a relationship between Vitamin D deficiency and dementia, but the data regarding the role of vitamin D supplementation is scarce.

Researchers explored the associations between vitamin D supplementation and incident dementia in 12,388 dementia-free persons (National Alzheimer's Coordinating Center).

The study summary includes the following:

• There were D+ and D- groups.
• In the D+ group, there was exposure to vitamin D and included 4637 participants aged 71 years, constituting 70.5 % females. The participants of this group were more educated.
• In D- group, there was no exposure or supplementation before the onset of dementia, with 7751 participants and 46.9 % females.
• Vitamin D exposure was related to more prolonged dementia-free survival.
• Exposure to vitamin D was associated with a lower incidence of dementia when compared to without exposure, with a hazard ratio of 0.60
• Vitamin D supplementation was associated with 40% lower dementia incidence versus no exposure.

They concluded, "Vitamin D exposure was associated with lower dementia incidence across all strata of sex, cognitive diagnosis, and APOE ε4 status; the rates were lower in females versus males, NC (normal cognition) versus MCI ( mild cognitive impairment), and APOE ε4 non-carriers versus carriers."

They added that, Alternatively, APOE ε4 is the most substantial genetic risk factor for Alzheimer's disease (AD) and vitamin D supplementation cannot overcome the risk.

Vitamin D can prevent dementia and be used as additional support for those at risk. Future studies are required for more investigations related to this.

Further reading:

Vitamin D supplementation and incident dementia: Effects of sex, APOE, and baseline cognitive status. https://alz-journals.onlinelibrary.wiley.com/doi/10.1002/dad2.12404