Aging: Vitamin D Levels Tied to Dementia Risk, By NICHOLAS BAKALAR, Published: February 23, 2009, New York Times, http://www.nytimes.com/2009/02/24/health/research/24aging.html?scp=4&sq=vitamin+d&st=nyt. "Low blood levels of vitamin D may be associated with an increased risk for dementia, a British study has found. Scientists measured blood levels of the vitamin in a representative sample of 1,766 people over 65 and assessed their mental functioning with a widely used questionnaire. About 12 percent were cognitively impaired, and the lower their vitamin D level, the more likely they were to be in that group. Compared with those in the highest one-quarter for serum vitamin D, those in the lowest were 2.3 times as likely to be impaired, even after statistically adjusting for age, sex, education and ethnicity. Men showed the effect more strongly than women. “The cause of dementia is not vitamin D deficiency,” said David Llewellyn, a research associate at Cambridge University and the study’s lead author. “It’s a very complicated disease. But while further research is needed, vitamin D supplementation is cheap, safe and convenient, and may therefore play an important role in prevention.” According to background information in the study, which appears online in The Journal of Geriatric Psychology and Neurology, vitamin D receptors are present in a variety of cells, including neurons and the glial cells associated with them. That suggests that the vitamin may play a role in brain development and the protection of neurons."