title: Vitamin D affects survival independently of vascular calcification in chronic kidney disease.
abstract: OBJECTIVE
  Cardiovascular disease is the main cause of mortality in chronic kidney disease (CKD) patients. Vitamin D might have beneficial effects on vascular health. The aim of this study was to determine the prevalence of vitamin D deficiency (25-hydroxyvitamin D [25D] <or= 15 ng/ml) and insufficiency (25D levels between 16 and 30 ng/ml) in a cohort of patients at different CKD stages and the relationships between vitamin D serum levels, vascular calcification and stiffness, and the mortality risk.
  
  
  METHODS
  One hundred forty CKD patients (85 men, mean age 67 +/- 12 yr; CKD stages 2 [8%], 3 [26%], 4 [26%], 5 [7%], and 5D [(33%]) were allocated for a prospective study. Serum levels of 25D and 1,25-dihydroxyvitamin D, aortic calcification score, and pulse wave velocity (PWV) were evaluated.
  
  
  RESULTS
  There was a high prevalence of vitamin D deficiency (42%) and insufficiency (34%). Patients with 25D <or= 16.7 ng/ml (median) had a significantly lower survival rate than patients with 25D >16.7 ng/ml (mean follow-up, 605 +/- 217 d; range, 10 to 889; P = 0.05). Multivariate adjustments (included age, gender, diabetes, arterial pressure, CKD stage, phosphate, albumin, hemoglobin, aortic calcification score and PWV) confirmed 25D level as an independent predictor of all-cause mortality.
  
  
  CONCLUSIONS
  Vitamin D deficiency and insufficiency were highly prevalent in this CKD cohort. Low 25D levels affected mortality independently of vascular calcification and stiffness, suggesting that 25D may influence survival in CKD patients via additional pathways that need to be further explored.
authors.affiliation: Institut National de la Santé et de la Recherche Medicale, Equipe Région INSERM 12 (Equipe d'Accueil 4292), Amiens, France.
authors.forename: Daniela Veit
authors.initials: DV
authors.lastname: Barreto
authors.forename: Fellype Carvalho
authors.initials: FC
authors.lastname: Barreto
authors.forename: Sophie
authors.initials: S
authors.lastname: Liabeuf
authors.forename: Mohammed
authors.initials: M
authors.lastname: Temmar
authors.forename: Francis
authors.initials: F
authors.lastname: Boitte
authors.forename: Gabriel
authors.initials: G
authors.lastname: Choukroun
authors.forename: Albert
authors.initials: A
authors.lastname: Fournier
authors.forename: Ziad A
authors.initials: ZA
authors.lastname: Massy
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002114:Calcinosis / Q000378:metabolism / Q000401:mortality*; D002117:Calcitriol / Q000097:blood; D002318:Cardiovascular Diseases / Q000378:metabolism / Q000401:mortality*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D016016:Proportional Hazards Models; D051436:Renal Insufficiency, Chronic / Q000378:metabolism / Q000401:mortality*; D012307:Risk Factors; D016019:Survival Analysis; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000378:metabolism / Q000401:mortality*
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D; D002117:Calcitriol