Genetic Analyses Link Vitamin D Deficiency to Dementia Risk

In HealthDay News
by Healthday

In Mendelian randomization analyses, 25(OH)D associated with risk for dementia, but not stroke or neuroimaging outcomes

THURSDAY, July 7, 2022 (HealthDay News) — Low vitamin D status is associated with the risk for dementia and stroke, according to a study recently published in the American Journal of Clinical Nutrition.

Shreeya S. Navale, from the University of South Australia in Adelaide, and colleagues examined the association between 25-hydroxyvitamin D (25[OH]D) with neuroimaging outcomes (33,523 participants) and the risk for dementia and stroke (427,490 participants; 3,414 and 5,339 incident cases, respectively) using prospective data from the U.K. Biobank. Underlying causality for neuroimaging outcomes (23,901 participants) and dementia and stroke (294,514 participants; 2,399 and 3,760 cases, respectively) was assessed using nonlinear Mendelian randomization (MR) analyses.

The researchers identified nonlinear associations between 25(OH)D and total, gray matter, white matter, and hippocampal volumes, with lower volumes for low and high concentrations. An inverse association was seen for 25(OH)D with white matter hyperintensity volume. There were associations seen for vitamin D deficiency with an increased risk for dementia and stroke; the strongest associations were seen for 25(OH)D <25 nmol/L versus 50 to 75.9 nmol/L (adjusted hazard ratios, 1.79 and 1.40, respectively). The threshold effect of 25(OH)D on dementia was confirmed in nonlinear MR analyses, with the risk predicted to be 54 percent higher for participants at 25 versus 50 nmol/L. In MR analyses, no association was seen for 25(OH)D with neuroimaging outcomes or risk for stroke.

“Our study supports a role of vitamin D deficiency on brain health, notably for the risk of dementia,” the authors write.

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