Mental function declines faster in seniors with low vitamin D status, according to a study from Rutgers University in New Jersey. Mental function and vitamin D status were compared in a group of 382 seniors, with an average age of 75-years-old. The researchers defined four blood levels of vitamin D: 1) deficiency was less than 12 nanograms per milliliter (ng/ml), 2) insufficient as 12 to less than 20 ng/ml, 3) adequate was 20 to less than 50 ng/ml, and 4) high was 50 ng/ml and higher. Most people in the study had low vitamin D levels; 26% were deficient and 35% were insufficient. At the start of the study 17.5% of the seniors had dementia, almost 33% had some problems with thinking and memory (mild cognitive impairment), and 49.5% were mentally normal. Results showed that vitamin D was lowest in those seniors with dementia. Over the course of the following eight years, memory, thinking, and problem-solving declined the most in those seniors who had been vitamin D deficient and insufficient at the start of the study. The researchers conclude that, “vitamin D levels should be checked at least once in people 55 and older, and should be a part of any evaluation of mental impairment.” Especially, they add, “…since there is a good chance that most people over 75 in the United States are vitamin D deficient.”
In Perspective: This is not the first study to note a link between poor vitamin D status and cognitive decline in seniors. For example, a study from the University of Padova in Italy found that vitamin D status predicted future risk for dementia in both men and women.
Miller J, Harvey D, Beckett L, et al: Vitamin D status and rates of cognitive decline in a multiethnic cohort of older adults. Journal of the American Medical Association – Neurology 2015;September 14th.
Toffanello E, Coin A, Perissinotto E, et al: Vitamin D deficiency predicts cognitive decline in men and women. Neurology 2014;83:2292-2298.