title: Vitamin D deficiency and endothelial dysfunction in non-dialysis chronic kidney disease patients.
abstract: BACKGROUND
  Cardiovascular (CV) events are common in patients with chronic kidney disease (CKD) but inadequately explained by traditional risk factors. Vitamin D deficiency is highly prevalent in CKD and has been proposed to be a non-traditional risk factor, but its relationship with vascular function is unknown.
  
  
  RESULTS
  The aim of this study was to investigate the relationship between vitamin D levels and endothelial function in non-diabetes patients with mild to moderate CKD. Endothelial function was measured non-invasively using brachial artery flow mediated dilation (FMD). 25 hydroxy vitamin D levels were measured using electrochemiluminescence immunoassay. In 50 CKD patients (age 56±11 years, BMI 25±4kg/m(2), 46% females, 14% smokers, 86% hypertensives, 52% with dyslipidaemia) the mean vitamin D level was 53±33nmol/L (21±13ng/L). The mean FMD was 3.8±2.4%. Decreasing 25 hydroxy vitamin D levels were associated with decreasing FMD [r=0.44, p=0.001]. In multivariate analysis the association remained independent after adjustment with traditional risk factors (adjusted beta 0.451; t=3.46; p<0.002). Patients with low vitamin D (≤37.5nmol/L) demonstrated low FMD compared to patients with vitamin D values >37.5nmol/L (4.4±2.5% vs. 2.5±1.6%; p=0.007); however the traditional risk factors were similar between the two groups.
  
  
  CONCLUSIONS
  This is the first demonstration of an association of vitamin D deficiency with abnormal vascular endothelial function in non-dialysis CKD patients. Further studies with intervention and exploration of the mechanism are needed to establish a cause effect relationship.
authors.affiliation: Renal and Transplantation Unit, St Georges Healthcare NHS Trust and Cardiovascular Sciences Research Centre, St Georges, University of London, Blackshaw Road, Tooting, London SW17 0QT, UK.
authors.forename: Nihil
authors.initials: N
authors.lastname: Chitalia
authors.forename: Alejandro
authors.initials: A
authors.lastname: Recio-Mayoral
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Kaski
authors.forename: Debasish
authors.initials: D
authors.lastname: Banerjee
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002318:Cardiovascular Diseases / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology*; D016009:Chi-Square Distribution; D002908:Chronic Disease; D004730:Endothelium, Vascular / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007118:Immunoassay; D007674:Kidney Diseases / Q000150:complications / Q000503:physiopathology*; D008131:London; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D018570:Risk Assessment; D012307:Risk Factors; D014463:Ultrasonography; D014664:Vasodilation; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000150:complications / Q000503:physiopathology*
chemical_list: D015415:Biomarkers; D014807:Vitamin D; C104450:25-hydroxyvitamin D