In the largest study of its kind, researchers revealed that in older people, not getting enough vitamin D may double the risk of developing dementia and Alzheimer’s disease. The study was released August. 6, 2014, online issue of Neurology.
The study evaluated blood levels of vitamin D, which includes vitamin D from food, supplements and sun exposure. Dietary vitamin D is found in fatty fish such as salmon, tuna or mackerel and milk, eggs and cheese.
“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,” said study author David J. Llewellyn, PhD, of the University of Exeter Medical School in the United Kingdom.
The study evaluated 1,658 healthy people over the age of 65 without dementia and had their vitamin D blood levels tested. After an average of six years, 171 participants developed dementia and 102 had Alzheimer’s disease.
The results revealed people with low levels of vitamin D had a 53-percent increased risk of developing dementia and those who were severely deficient had a 125-percent increased risk compared to participants with normal levels of vitamin D.
Those with lower levels of vitamin D were nearly 70 percent more likely to develop Alzheimer’s disease and those who had severe deficiency were over 120 percent more likely to develop the disease.
The results remained the same after researchers adjusted for other factors that could affect risk of dementia, such as smoking, alcohol consumption and education.