Large scale vitamin D study aims to explore diabetes link

The large-scale clinical trial is the first definitive study to investigate whether vitamin D supplementation can help delay or prevent type 2 diabetesin adults who have pre-diabetes and are at high risk for developing the condition.

The goal of the multiyear 'Vitamin D and Type 2 Diabetes' (D2d) study is to learn if vitamin D — specifically D3 (cholecalciferol) — will prevent or delay type 2 diabetes in adults aged 30 or older with pre-diabetes.

"This study aims to definitively answer the question: Can vitamin D reduce the risk of developing type 2 diabetes?"​ said Dr Myrlene Staten, D2d project officer at the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of NIH.

"It has been suggested as a remedy for a variety of conditions, including prevention of type 2 diabetes. But we need rigorous testing to determine if vitamin D will help prevent diabetes."​

"That's what D2d will do."​

Funded by the NIH, the study is taking place at about 20 study sites across the United States and will include around2,500 people.

The study​

D2d is the first study to directly examine if a daily dose of 4,000 International Units (IUs) of vitamin D — greater than a typical adult intake of 600-800 IUs a day, but within limits deemed appropriate for clinical research by the Institute of Medicine — helps keep people with pre-diabetes from getting type 2 diabetes.

The team are now recruiting volunteers to take part in D2d. Half of the participants will receive vitamin D, while the other half will receive a placebo. The study will be double-blinded, so neither participants nor the study's clinical staff will know who is receiving vitamin D and who is receiving placebo.

Participants will have check-ups for the study twice a year, and will receive regular health care through their own health care providers.

The study will continue until enough people have developed type 2 diabetes to be able to make a scientifically valid comparison between diabetes development in the two groups, likely about four years, said the research team.

Vitamin D hope​

Based on observations from earlier studies, researchers speculate that vitamin D could reduce the diabetes risk by 25%. The study will also examine if sex, age or race affect the potential of vitamin D to reduce diabetes risk.

"Past observational studies have suggested that higher levels of vitamin D may be beneficial in preventing type 2 diabetes, but until this large, randomised and controlled clinical trial is complete, we won't know if taking vitamin D supplements lowers the risk of diabetes,"​ explained Dr Anastassios Pittas - the study's principal investigator at Tufts Medical Center, USA.

"With D2d, we seek evidence for an affordable and accessible way to help prevent or delay type 2 diabetes,"​ added NIDDK director Dr Griffin P. Rodgers.