Our team has published extensively in an effort to uncover a link between vitamin D and diabetes. We have published original manuscripts (original trials, ancillary analyses of completed trials, observational studies, systematic reviews), book chapters and editorials.
Post-randomization biases may influence the estimate of efficacy of supplemental vitamin D in diabetes prevention trials. In the Vitamin D and Type 2 Diabetes (D2d) study, to overcome this challenge, we calculated intra-trial vitamin D exposure as the cumulative rolling mean of annual serum 25(OH)D measurements. Among participants at risk for diabetes treated with vitamin D, those who maintained intra-trial blood 25(OH)D levels of 40-49 ng/mL (100–124 nmol/L) had a 52% lower risk of developing diabetes compared to those who maintained a level of 20-29 ng/mL (50–74 nmol/L). Those who maintained blood 25(OH)D levels equal to or greater than 50 ng/mL (125 nmol/L) had a 71%, lower risk of developing diabetes. We concluded that daily vitamin D supplementation to maintain a blood 25(OH)D level greater than 40 ng/mL (100 nmol/L) is a promising approach to reducing the risk of diabetes in adults with prediabetes.