Vitamin D does not prevent type 2 diabetes in high-risk adul
Based on study of 1,256 Japanese adults with impaired glucose tolerance recruited from three hospitals in Japan between June 2013 and August 2019. Their average age was 61 (range 30-78) years, 46% were women, and 59% had a family history of type 2 diabetes. Participants were randomly assigned to receive either a standard daily dose of eldecalcitol (630 participants) or placebo (626 participants) 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). However, after adjusting for 11 potentially influential factors, including age, sex, blood pressure, body mass index, and family history of diabetes, the results suggested that eldecalcitol might prevent type 2 diabetes in pre-diabetic patients with insufficient insulin secretion.

The results show that supplements had no clinically meaningful effect in high risk adults, but suggest there may be a benefit for people with insufficient insulin secretion.