No Effect of High-Dose Vitamin D Supplementation on Glycemic Status or Cardiovascular Risk Factors in Subjects With Prediabetes - Sollid, S T; Hutchinson, M Y; Fuskevag, O M; Figenschau, Y; Joakimsen, R M; Schirmer, H; Njolstad, I; Svartberg, J; Kamycheva, E; Jorde, R (Diabetes Care, 2014)