In the most robust study of its kind to date, researchers found a very strong link between low vitamin D levels and a greater risk of dementia. For the study researchers measured the blood vitamin D levels in 1,658 people over the age of 65 and then followed their cognitive function over the next 5.6 years. At the beginning of the study, all of the study subjects had normal cognitive function. At the end of the study, 171 subjects had developed dementia and 102 had developed Alzheimer’s disease. Those with low levels of vitamin D at the beginning of the study were 53% more likely to get dementia, while those who were the most deficient exhibited a whopping 125% higher risk. For Alzheimer’s disease there were very strong links too. Those with lower levels had a 70% higher risk and those most deficient had a 125% higher risk.

The researchers noted that while they anticipated a significant link, the association between low vitamin D and the subsequent development of dementia was twice as strong as they anticipated. (Neurology, online, DOI: 10.1212/WNL.0000000000000755)