TIME Research

Low Vitamin D Increases Risk for Dementia and Alzheimer’s, Study Says

Senior woman covering face with her hands
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Research shows a correlation, not a causal link, with the ailments

Elderly people with a moderate-to-severe Vitamin D deficiency are significantly more likely to develop dementia and Alzheimer’s disease, according to a study published this week, confirming a link that was much stronger than what the researchers had anticipated.

An international team of researchers spent six years looking at 1,658 Americans, aged 65 or older, who at the start of the study had not suffered from dementia, cardiovascular disease or a stroke—and who could walk without assistance. The team found that adults who were moderately deficient in Vitamin D were 53% more likely to develop a form of dementia; those with a severe deficiency were 125% more likely to be stricken with the disease.

The researchers emphasized that the study, partially funded by the Alzheimer’s Association and published online in Neurology, shows a correlation between Vitamin D deficiency and dementia but does not establish a causal link.

“Clinical trials are now needed to establish whether eating foods such as oily fish or taking Vitamin D supplements can delay or even prevent the onset of Alzheimer’s disease and dementia,” the study’s leader, Dr. David Llewellyn of the University of Exeter Medical School, said in a statement. “We need to be cautious at this early stage and our latest results do not demonstrate that low Vitamin D levels cause dementia. That said, our findings are very encouraging, and even if a small number of people could benefit, this would have enormous public health implications given the devastating and costly nature of dementia.”

More than 44 million people around the world suffer from dementia, the researchers note, and that figure could triple by 2050 as the global population quickly ages.

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