December 3, 2012. The October, 2012 issue of the Journals of Gerontology Series A: Biological Sciences and Medical Sciencespublished the outcome of a study conducted by Yelena Slinin, MD, MS, of Minneapolis’ Veterans Administration Medical Center which uncovered a protective effect for higher vitamin D levels against the development of cognitive decline in women.
The study included 6,257 women enrolled in the Study of Osteoporotic Fractures. Serum 25-hydroxyvitamin D was measured upon enrollment and tests of cognitive function were administered at the beginning of the study and at follow-up after four years. Women with low vitamin D levels of less than 10 nanograms per milliliter (ng/mL) had a 60 percent greater risk of cognitive impairment at the beginning of the study and a 58 percent greater risk of becoming cognitively impaired over follow-up in comparison with those whose levels were at least 30 ng/mL.
In another study published in the November, 2012 issue of the same journal, Cedric Annweiler, MD, PhD, of Angers University Hospital in France and his associates report an association between reduced vitamin D intake and a greater risk of developing Alzheimer’s disease. The study included 498 older women enrolled in the EPIDemiology of OSteoporosis Toulouse cohort study. Dietary questionnaires administered at the beginning of the study were analyzed for the intake of vitamin D from food sources. Over a seven year period, 70 participants developed Alzheimer’s disease. In comparison with those who did not develop dementia or developed other types of dementia, women who developed Alzheimer’s disease consumed less vitamin D. When participants were grouped according to vitamin D intake, those in the top one-fifth were found to have a 77 percent lower risk of Alzheimer’s compared to the lowest fifth.
These studies, and others, reinforce the importance of vitamin D in the maintenance of cognitive health over the course of a lifetime.