Vitamin C Depletion and All-Cause Mortality in Renal Transplant Recipients

Nutrients. 2017 Jun 2;9(6):568. doi: 10.3390/nu9060568.

Abstract

Vitamin C may reduce inflammation and is inversely associated with mortality in the general population. We investigated the association of plasma vitamin C with all-cause mortality in renal transplant recipients (RTR); and whether this association would be mediated by inflammatory biomarkers. Vitamin C, high sensitive C-reactive protein (hs-CRP), soluble intercellular cell adhesion molecule 1 (sICAM-1), and soluble vascular cell adhesion molecule 1 (sVCAM-1) were measured in a cohort of 598 RTR. Cox regression analyses were used to analyze the association between vitamin C depletion (≤28 µmol/L; 22% of RTR) and mortality. Mediation analyses were performed according to Preacher and Hayes's procedure. At a median follow-up of 7.0 (6.2-7.5) years, 131 (21%) patients died. Vitamin C depletion was univariately associated with almost two-fold higher risk of mortality (Hazard ratio (HR) 1.95; 95% confidence interval (95%CI) 1.35-2.81, p < 0.001). This association remained independent of potential confounders (HR 1.74; 95%CI 1.18-2.57, p = 0.005). Hs-CRP, sICAM-1, sVCAM-1 and a composite score of inflammatory biomarkers mediated 16, 17, 15, and 32% of the association, respectively. Vitamin C depletion is frequent and independently associated with almost two-fold higher risk of mortality in RTR. It may be hypothesized that the beneficial effect of vitamin C at least partly occurs through decreasing inflammation.

Keywords: hs-CRP; inflammation; mortality; renal transplant; vitamin C.

MeSH terms

  • Adult
  • Ascorbic Acid / blood*
  • Ascorbic Acid Deficiency / complications*
  • Biomarkers / blood
  • Body Composition
  • Body Mass Index
  • C-Reactive Protein / metabolism
  • Creatinine / blood
  • Dietary Supplements
  • Endpoint Determination
  • Female
  • Follow-Up Studies
  • Humans
  • Inflammation / blood
  • Inflammation / complications
  • Intercellular Adhesion Molecule-1 / blood
  • Kidney / physiopathology
  • Kidney Diseases / blood
  • Kidney Diseases / mortality*
  • Kidney Diseases / surgery
  • Kidney Transplantation*
  • Male
  • Middle Aged
  • Mortality
  • Proportional Hazards Models
  • Prospective Studies
  • Proteinuria / blood
  • Proteinuria / diagnosis
  • Vascular Cell Adhesion Molecule-1 / blood

Substances

  • Biomarkers
  • Vascular Cell Adhesion Molecule-1
  • Intercellular Adhesion Molecule-1
  • C-Reactive Protein
  • Creatinine
  • Ascorbic Acid