Can Vitamin D Supplementation Prevent Diabetes?

Low levels of vitamin D have been shown to be associated with increased risk of diabetes, but whether the relationship is causal is still uncertain.

In an attempt to better define this relationship, researchers conducted a mendelian randomization analysis of nucleotide polymorphisms (SNPs) found within genes related to 25-(OH)D—a marker associated with vitamin D status—synthesis and metabolism in nearly 100,000 participants.
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Researchers assessed each SNP for an association with vitamin D levels, risk of type 2 diabetes, and concentrations of fasting glucose, insulin, and HbA1c. They compared their results against a meta-analysis of observational studies on the relationship between the vitamin and diabetes.

They found no causal connection between vitamin D levels and the risk of developing type 2 diabetes. 

“The association between 25-(OH)D concentration and type 2 diabetes is unlikely to be causal,” researchers concluded.

“Efforts to increase 25-(OH)D concentrations might not reduce the risk of type 2 diabetes as would be expected on the basis of observational evidence. These findings warrant further investigations to identify causal factors that might increase 25-(OH)D concentration and also reduce the risk of type 2 diabetes.”

The complete study is published in the October issue of Lancet Diabetes and Endocrinology.

-Michelle Canales

Reference:

Condezo-Hoyos L, Mohanty IP, Noratto GD. Association between circulating 25-hydroxyvitamin D and incident type 2 diabetes: a mendelian randomization study. Lancet Diabetes Endocrinol. 2014 October [epub ahead of print] doi: 10.1016/S2213-8587(14)70184-6.