A study by the University of Exeter Medical School, published in the Neurology journal, found that low levels of vitamin D substantially increased risk of dementia and Alzheimer’s disease in older people.
The research team investigated research participants who took part in a Cardiovascular Health Study and consisted of 1,658 adults aged 65 and older who did not exhibit any dementia, cardiovascular disease or stroke signs at the start of the study. The patients were followed for six years and it was found that adults who exhibited a moderate deficiency in Vitamin D had a 53 % increased risk of developing dementia. The risk increased to 125% for those patients who showed a severe deficiency of Vitamin D.
Similar results were recorded for Alzheimer’s disease, with the moderately deficient group 69 % more likely to develop this type of dementia, jumping to a 122 % increased risk for those severely deficient. A threshold level of vitamin D levels above 50 nmol/L are most strongly associated with good brain health.
Dr Llewellyn said: “We expected to find an association between low Vitamin D levels and the risk of dementia and Alzheimer’s disease, but the results were surprising — we actually found that the association was twice as strong as we anticipated. “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. 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.”
Thomas J. Littlejohns, William E. Henley, Iain A. Lang, Cedric Annweiler, Olivier Beauchet, Paulo H.m. Chaves, Linda Fried, Bryan R. Kestenbaum, Lewis H. Kuller, Kenneth M. Langa, Oscar L. Lopez, Katarina Kos, Maya Soni, and David J. Llewellyn. Vitamin D and the risk of dementia and Alzheimer disease. Neurology, August 2014 DOI: 10.1212/WNL.0000000000000755