FRI593 Ergocalciferol And Pancreatic β-Cell Function In New-onset Type 1 Diabetes: A Randomized Controlled Trial

Disclosure: B.U. Nwosu: None. S. Parajuli: None. R. Sharma: None. B.A. Barton: None. A.F. Lee: None. Background: The impact of high-dose vitamin D (ergocalciferol) on pancreatic β-cell function in youth with newly diagnosed type 1 diabetes (T1D) is unclear. Objective: To determine the effect of ergocalciferol on residual pancreatic β-cell function (RBCF) in youth with newly diagnosed T1D. Hypothesis: Ergocalciferol supplementation increases RBCF and prolongs the partial clinical remission (PR) phase of T1D. Design, Setting, and Participants: This 12-month randomized, double-blind, placebo-controlled trial of youth aged 10-21 years with newly diagnosed T1D of <3mo was conducted at a single center in the US between October 19, 2017 through April 20, 2021. Interventions: Participants were randomized 1:1 to once weekly dose of 50,000 IU of ergocalciferol for 2 months, and then once every 2 weeks for 10 months, versus placebo. Main outcomes and measures: The primary outcome was the percentage change from baseline in the area under the curve (AUC) of stimulated C-peptide over 12 months. Results: Thirty-six subjects were randomized to either the ergocalciferol arm: n=18, mean age 13.3±SD2.8 years, with 10 male and 8 female subjects; or to the placebo arm: n=18, mean age 14.3±2.9 years, with 14 male and 4 female subjects. Ergocalciferol significantly reduced the temporal trends in both the A1c (p=0.04) and the insulin-dose adjusted A1c (IDAA1c) (p=0.02), and the overall group means for IDAA1c versus placebo (p=0.02). A random intercept model, adjusted for age, sex, and race, showed that the percentage change in AUC C-peptide from baseline through the 12-month study period declined in both arms of the study. Specifically, by 28.4 ± 6.2 (p<.0001) in the ergocalciferol arm and by 41.5 ± 5.9 (p<.0001) in the placebo arm, with the decline in the ergocalciferol arm being significantly slower than that in the placebo arm, p=0.029 for the difference in the slopes of the trends between the two arms. There were no adverse events. Conclusion: High-dose ergocalciferol significantly slowed the rate of decline in C-peptide compared to placebo in children and adolescents with T1D. Presentation: Friday, June 16, 2023