title: Higher 25-Hydroxyvitamin D Levels Are Associated With Lower Proteinuria in Kidney Transplant Recipients.
abstract: OBJECTIVE
  Proteinuria is associated with decreased graft and patient survival after kidney transplantation. Increasing evidence shows that vitamin D has antiproteinuric and renoprotective effects. The aim of our study was to assess the influence of 25-hydroxyvitamin D levels on proteinuria after kidney transplantation.
  
  
  METHODS
  Between May 1, 2012, and November 30, 2012, we tested 395 kidney transplant recipients for 25-hydroxyvitamin D levels during their regular visits to our transplant center together with routine blood sampling and proteinuria testing. Patients within 12 months of transplant, who had undergone parathyroidectomy, had unstable graft function, had concomitant intake of calcineurin inhibitors and mammalian target of rapamycin inhibitors were not included in the study. Subjects with advanced liver disease, or receiving vitamin D supplementation were also excluded. All laboratory, clinical, and therapeutic factors for proteinuria were taken into consideration. Statistical analyses included descriptive statistics and univariate and multivariate log-log regression with backward selection (SPSS version 22.0; SPSS Inc., Chicago, IL, USA), with significance at P < .05. Determination of total 25-hydroxyvitamin D levels was performed by a validated liquid chromatography-tandem mass spectrometry method.
  
  
  RESULTS
  Our study group included 230 patients (148 men, 82 women). Positive association was established between proteinuria and history of diabetes mellitus, rejection episode 12 months within testing for 25-hydroxyvitamin D levels, and use of mammalian target of rapamycin inhibitors (P < .05). Significant negative relations were detected for patient age, graft function, and 25-hydroxyvitamin D concentrations (P < .05).
  
  
  CONCLUSIONS
  Our study established that better vitamin D status is associated with lower proteinuria. However, further research is needed to clarify the possible renoprotective properties of vitamin D.
authors.affiliation: From the Department of Nephrology and Transplantation, and University Hospital "Alexandrovska," and the Medical University, Sofia, Bulgaria.
authors.forename: Jean J
authors.initials: JJ
authors.lastname: Filipov
authors.forename: Borelli K
authors.initials: BK
authors.lastname: Zlatkov
authors.forename: Emil P
authors.initials: EP
authors.lastname: Dimitrov
authors.forename: Dobrin A
authors.initials: DA
authors.lastname: Svinarov
mesh_terms: D000328:Adult; D051799:Delayed Graft Function; D048909:Diabetes Complications / Q000150:complications; D005260:Female; D006084:Graft Rejection; D006801:Humans; D007674:Kidney Diseases / Q000097:blood / Q000150:complications / Q000601:surgery* / Q000652:urine; D016030:Kidney Transplantation; D008297:Male; D008875:Middle Aged; D011507:Proteinuria; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D