Vitamin D and Type 2 Diabetes Mellitus

Diabetes is a major risk factor for various cardiovascular and renal diseases. The global prevalence of diabetes was 425 million adults in 2015, with an anticipated increase to 629 million by 2040. 

The main way to delay the development of type 2 diabetes is through lifestyle modifications, which can be difficult to maintain long-term. That is why new strategies are always being investigated to reduce the incidence of this condition.

Recently, a group of researchers evaluated the effect of vitamin D on the incidence of type 2 diabetes in people with impaired glucose tolerance in a population in Japan. The study was published in the British Medical Journal. 

Protective Effect in Some Patients

Vitamin D receptors are found in multiple cell types, including pancreatic β cells, which are the cells in charge of producing insulin, and active vitamin D is involved in insulin biosynthesis and secretion. 

Some studies have found an association between low serum levels of vitamin D and an increased incidence of type 2 diabetes. 

For the study, the team included a total of 1,256 participants, 571 women and 742 men that had a family history of type 2 diabetes. The mean age of the participants was 61 years. The patients had impaired glucose tolerance by using 75 g oral glucose tolerance and glycated hemoglobin levels. 

The participants were randomized to receive active vitamin D (eldecalcitol 0.75  μg per day) or a placebo for 3 years. The goal of the study was to evaluate the incidence of diabetes in the population and to also evaluate the regression to normoglycemia.

During the three-year follow-up period, 79 (12.5%) of 630 participants in the eldecalcitol group and 89 (14.2%) of 626 in the placebo group developed diabetes, which showed no significant difference between the groups. 

The team did find a significant decrease in the development of diabetes after the adjustment of confounding factors, especially in those with lower levels of basal insulin secretion, which suggests a potential beneficial effect of vitamin D on people with insufficient insulin secretion. 


Tetsuya Kawahara, et al. Effect of active vitamin D treatment on development of type 2 diabetes: DPVD randomised controlled trial in Japanese population. BMJ 2022; 377 doi: 

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