Low Vitamin D increases risk of cognitive impairment

The aim of this study was to examine the association between vitamin D status as measured by 25-hydroxyvitamin D (25(OH)D) levels and the presence of cognitive impairment in a large population- based sample of elderly adults, living independently and in institutions who were 65 years of age or older. [1]

A total of 1766 individuals participated (708 men and 1058 women) who were evaluated for cognitive status and had valid serum 25(OH)D data. Cognitive impairment was quantified by a mental test score.

The risk of cognitive impairment increased as the vitamin D status decreased. The ranges of the four 25(OH)D quartiles were 8-30, 31-44, 45-65 and 66-170 nmol/L (to get ng/mL, divide by 2.5).

Compared to the highest quartile, the increased risk of cognitive impairment was 10%, 40% and 130% for decreasing quartiles, respectively. These results were adjusted for age, gender, education, ethnicity, season of testing, and additional risk factors for cognitive impairment.

This study underscores the importance of having a high vitamin D status.According to the vitamin D experts, a good level to aim for is to be above 125 nmol/L (50 mg/dL).

According to the newsletter of the Vitamin D Council, it is important to be aware that sometimes the wrong vitamin D test is ordered. It is for 1,25- dihydroxyvitamin D and does not directly indicate the 25(OH)D levels.

Readers are encouraged to ask for copies of the lab reports and check the test and the units and judge for themselves if they are deficient.

Source:
1. "Vitamin D and Cognitive Impairment" 4 Feb 2009, D.J. Llewellyn, Journal of Geriatric Psychiatry and Neurology

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