LeBlanc ES, et al. - Researchers described baseline characteristics of the Vitamin D and Type 2 Diabetes (D2d) study, the first large U.S. diabetes prevention clinical trial to apply current American Diabetes Association (ADA) criteria for prediabetes. They examined effects of oral daily 4,000 IU cholecalciferol (D₃) compared with placebo on incident diabetes in U.S. adults at risk for diabetes. A total of 2,423 participants (45% of whom were women and 33% nonwhite) were randomly allocated to to cholecalciferol or placebo. This multicenter, randomized, double-blind, placebo-controlled, primary prevention clinical trial indicated that black patients had the highest mean hemoglobin A_1c (HbA_1c) and lowest fasting plasma glucose (FPG) concentration vs white, Asian, and other races. Data reported that the D2d cohort had lower mean 2hPG concentration but similar HbA_1cand FPG concentrations.