Vitamin D supplementation has the potential to be a viable dementia prevention strategy, especially when initiated early, new research suggests.

In a large prospective cohort study, people who took vitamin D were 40% less likely to develop dementia than peers who did not take vitamin D. The effects of vitamin D were most pronounced in women, those with normal cognitive function, and apolipoprotein E (APOE) ε4 noncarriers.

“We know that vitamin D has some effects in the brain that could have implications for reducing dementia; however, so far, research has yielded conflicting results,” lead researcher Zahinoor Ismail, MD, with the Hotchkiss Brain Institute, University of Calgary, said in a news release.

“Our findings give key insights into groups who might be specifically targeted for vitamin D supplementation. Overall, we found evidence to suggest that earlier supplementation might be particularly beneficial before the onset of cognitive decline,” said Ismail.

The study was published online March 1 in Alzheimer’s and Dementia: Diagnosis, Assessment and Disease Monitoring.

Promising, but Preliminary

The findings are based on 12,388 adult participants (mean age, 71 years) in the US National Alzheimer’s Coordinating Center database who had normal cognition or mild cognitive impairment (MCI) at the outset. A total of 4637 (37%) took vitamin D supplements, and 7751 did not.

Tho