Low vitamin D levels `linked to cognitive decline in oldies`

Last Updated: Tuesday, July 13, 2010 - 00:00

London: Make sure that you daily eat contains adequate vitamin D as you age, for a new study claims that lack of it can lead to cognitive decline in older adults.

Researchers have found that older people with low levels of vitamin D appear more likely to experience declines in thinking, learning and memory, the `Archives of Internal
Medicine` reported.

According to them, vitamin D may help prevent the degeneration of brain tissue by having a role in formation of nervous tissue, maintaining levels of calcium in the body, or
clearing of beta-amyloid, the substance that forms the brain plaques and tangles associated with Alzheimer`s disease.

The researchers at University of Exeter, led by David J Llewellyn, assessed blood levels of vitamin D in 858 adults who were age 65 or older when the study began in 1998. All the participants completed interviews and medical examinations and provided blood samples.

At the beginning of the study and again after three and six years, they repeated three tests of cognitive function one assessing overall cognition, one focusing on attention and one that places greater emphasis on executive function, or the ability to plan, organise and prioritise.

The participants who were severely deficient in vitamin D (having blood levels of 25-hydroxyvitamin D of less than 25 nanomoles per liter) were 60 per cent more likely to
have substantial cognitive decline in general over the six- year period and 31 per cent more likely to experience declines on the test measuring executive function than those with sufficient vitamin D levels.

"The association remained significant after adjustment for a wide range of potential confounders and when analyses were restricted to elderly subjects who were non-demented at baseline," the researchers said.

"If future prospective studies and randomised controlled trials confirm vitamin D deficiency is causally related to cognitive decline, then this will open up important
new possibilities for treatment and prevention," they added.

Bureau Report




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