A randomised controlled trial evaluating the impact of targeted vitamin D supplementation on endothelial function in type 2 diabetes mellitus: The DIMENSION trial. (May 2016)

• Record Type: Journal Article
• Authors: Dalan, Rinkoo; Liew, Huiling; Assam, Pryseley Nkouibert; Chan, Edwin SY; Siddiqui, Fahad Javaid; Tan, Alvin WK; Chew, Daniel EK; Boehm, Bernhard O; Leow, Melvin KS
• Is Part Of: Diabetes & vascular disease research. Volume 13:Number 3(2016:May)
• Page Start: 192
• Page End: 200
• Publication Date: 2016-05
• Subjects: Vitamin D -- endothelial function -- cholecalciferol -- type 2 diabetes; Diabetic angiopathies -- Periodicals; 616.462005
• DOI: 10.1177/1479164115621667
• Languages: English
• ISSNs: 1479-1641

Abstract

We sought to determine if vitamin D supplementation, to target 25(OH)D concentrations of 30–40 ng/mL, improves endothelial function in Singapore's multi-ethnic type 2 diabetes mellitus population. We randomised 64 type 2 diabetes mellitus patients with hypovitaminosis D to cholecalciferol 4000 International Unit/matching placebo [baseline 25(OH)D < 20 ng/mL] or cholecalciferol 2000 International Unit/matching placebo [baseline 25(OH)D: 20–30 ng/mL] daily for 16 weeks with a down titration at 8 weeks if 25(OH)D > 30 ng/mL. Endothelial function was assessed by peripheral tonometry (reactive hyperaemia index–endothelial peripheral arterial tonometry) and vascular biomarkers: E-selectin, von-Willebrand factor and high-sensitivity C-reactive protein. We compared the change from baseline parameters in the two groups using Student's t -test or Kruskal–Wallis test. A log-normal multivariate regression analysis was used to adjust for relevant baseline variables. The median reactive hyperaemia index in the vitamin D group increased from 0.65 (interquartile range: 0.42) to 0.73 (interquartile range: 0.36), whereas it decreased from 0.73 (interquartile range: 0.65) to 0.65 (interquartile range: 0.38) ( p = 0.02) in the placebo group. After adjustment for baseline variables, the change was not statistically significant for reactive hyperaemia index ( p = 0.07) and for other vascular biomarkers ( p > 0.05). Targeted vitamin D supplementation for 16 weeks resulted in a small but non-significant improvement in endothelial function in a type 2 diabetes mellitus cohort.