Vitamin D and Cognitive Decline
Low vitamin D levels have been correlated with cardiovascular disease, various autoimmune diseases, diabetes, cancer, falls, fractures, and depression.
Is vitamin D deficiency in elders also a risk factor for dementia and Alzheimer disease? We know that vitamin D plays a critical role in the proper functioning of nerves and helps to reduce inflammation. Thus, a role for vitamin D in the development of cognitive impairment and Alzheimer Disease (AD) is plausible.
To examine this association, researchers studied 1658 ambulatory adults (mean baseline age, 74) who were free from dementia, cardiovascular disease, and stroke who participated in the U.S. population-based Cardiovascular Health Study. Vitamin D deficiency was defined as 25 to 50 nmol/L and severe deficiency as <25 nmol/L.
Low vitamin D levels were most often associated with female sex, black race, obesity, and fewer minutes walking for physical activity. Low levels were also associated with greater alcohol consumption and current smoking
During a mean follow-up of 5.6 years, 171 participants developed all-cause dementia, including 102 with AD. The risks for both all-cause dementia and AD were significantly higher in participants who were either vitamin D-deficient (53% and 69% higher risks, respectively) or severely deficient (125% and 122% higher risks, respectively). Vitamin D deficiency was also associated with a greater decline in global cognitive function over 4 years of follow-up.
These results confirm that vitamin D deficiency is associated with substantially increased risks for all-cause dementia and AD. These results raise important new possibilities for treatment and prevention of these dementias including good nutrition and Vitamin D supplementation when blood levels are shown to be deficient.
- Littlejohns TJ et al. Vitamin D and the risk of dementia and Alzheimer disease. Neurology 2014 Sep 2;
- Wilson, VK et al Relationship Between Vitamin D and Cognitive Function in Older Adults: The Health, Aging, and Body Composition Study JAGS 62:636-641, 2014