Trial that finds Vitamin D does not prevent type 2 diabetes in high risk adults

The results of the trial showed that supplements had no clinically meaningful effect in high-risk adults, but suggest there may be a benefit for people with insufficient insulin secretion, although this finding remains unclear.

Type 2 diabetes affects around 480 million people worldwide and is predicted to increase to 700 million by 2045. Another half a billion people have impaired glucose tolerance or pre-diabetes. Weight loss and exercise can lower the risk of progression to type 2 diabetes but are difficult to sustain, so new strategies are needed to tackle the problem.

To address this knowledge gap, researchers, therefore, set out to assess whether eldecalcitol could reduce the risk of developing type 2 diabetes among people with impaired glucose tolerance.

Participants of the trial were randomly assigned to receive either a standard daily dose ofeldecalcitol or placebo and were assessed for diabetes every three months over a three-year follow-up period.

During this period, the researchers found no meaningful differences between groups in those who developed diabetes (12.5% in the eldecalcitol group and 14% in the placebo group) or whose blood sugar levels returned to normal (23% in the eldecalcitol group and 20% in the placebo group).

They did, however, find a significant increase in both lower back and hip bone mineral densities among those taking eldecalcitol compared with placebo.

No significant difference in serious adverse events was seen between the two groups. 

As such, they say: "Although treatment with eldecalcitol did not significantly reduce the incidence of diabetes among people with pre-diabetes, the results suggested the potential for a beneficial effect of eldecalcitol on people with insufficient insulin secretion." And they call for further research to determine whether vitamin D is beneficial to people with pre-diabetes.

Until further data are available from high-quality randomized trials, she suggests healthcare professionals "should continue to discuss with patients the musculoskeletal health benefits of vitamin D and support them to achieve and maintain lifestyle changes that, although challenging to sustain, are known to decrease the development of type 2 diabetes.