Effects of vitamin D and calcium supplementation on pancreatic β cell function, insulin sensitivity, and glycemia in adults at high risk of diabetes: the Calcium and Vitamin D for Diabetes Mellitus (CaDDM) randomized controlled trial

摘要: Background: A suboptimal vitamin D and calcium status has been associated with higher risk of type 2 diabetes in observational studies, but evidence from trials is lacking. Objective: We determined whether supplementation, or without calcium, improved glucose homeostasis adults at high diabetes. Design: Ninety-two were randomly assigned a 2-by-2 factorial-design, double-masked, placebo-controlled trial to receive either cholecalciferol (2000 IU once daily) carbonate (400 mg twice for 16 wk. The primary outcome was the change pancreatic β cell function as measured by disposition index after an intravenous-glucose-tolerance test. Other outcomes acute insulin response, sensitivity, measures glycemia. Results: Participants had mean age 57 y, body mass (BMI; kg/m2) 32, glycated hemoglobin (Hb A1c) 5.9%. There no significant × interaction on any outcomes. increased group decreased no–vitamin (adjusted ± SE: 300 130 compared −126 127, respectively; P = 0.011), which explained improvement secretion (62 39 −36 37 mU · L−1 min, 0.046). Hb A1c less, nonsignificantly, than (0.06 0.03% 0.14 0.03%, 0.081). difference calcium. Conclusion: In diabetes, short-term supplementation marginal effect attenuating rise A1c. This registered clinicaltrials.gov NCT00436475.