“Vitamin D deficiency is associated with a substantially increased risk of all-cause dementia and Alzheimer disease,” concluded a team of mainly US researchers in a study published in Neurology. The researchers examined vitamin D levels in 1,658 elderly adults who participated in the US population–based Cardiovascular Health Study between 1992–1993 and 1999, in which 171 people ultimately developed some form of dementia. Adults with a moderate vitamin D deficiency had a 53 percent higher risk of dementia, and for those with severe deficiences the risk was 125 percent higher. The rates were comparable for vitamin D deficiencies and the development of Alzheimer’s specifically.
According to the Washington Post, researcher David J. Llewellyn said the team expected to find a link between vitamin D deficiency and dementia, but the strong correlation between the two was surprising. “We thought it was important for bone health. But there’s this recent revelation that it might be playing an important role throughout the body,” Llewellyn said, adding that vitamin D may act as a buffer regulating calcium levels in brain cells.
“Our findings support the hypothesis that vitamin D may be neuroprotective and that ‘sufficiency’ in the context of dementia risk may be in the region of 50 nmol/L,” wrote the researchers. “This information is likely to prove useful in improving the design and reducing the cost of randomized controlled trials investigating whether vitamin D supplements can be used to delay or prevent the onset of dementia and AD in older adults.”
Researchers say Vitamin D deficiency raises Alzheimer’s risk (The Washington Post, August 6, 2014)
Vitamin D and the risk of dementia and Alzheimer disease (Littlejohns, Thomas J. et al. Published online before print August 6, 2014, doi: 10.1212/WNL.0000000000000755 Neurology 10.1212/WNL.0000000000000755)