title: The specific relationship between vitamin D deficiency and diabetic nephropathy among patients with advanced chronic kidney disease: a cross-sectional study in Gran Canaria, Spain.
abstract: OBJECTIVE
  Vitamin D deficiency is highly prevalent in subjects with advanced chronic kidney disease (CKD), but diabetes, the most common cause of CKD, has also been linked to low levels of serum 25-hydroxyvitamin D [25(OH)D]. We compare vitamin D status between subjects with type 2 diabetes-related advanced CKD and subjects with either advanced CKD without diabetes or type 2 diabetes without advanced CKD.
  
  
  METHODS
  Subjects were patients with advanced CKD (estimated glomerular filtration rate (eGFR) < 30 mL/min/1.73 m2) from February 2011 to November 2013 (113 with diabetes-related CKD and 80 without diabetes) and 61 patients with long-lasting type 2 diabetes without advanced CKD, simultaneously enrolled from our center. Participants fulfilled a survey questionnaire and underwent physical examination, blood samples, and 24-h urine collection. Kidney disease was assessed using eGFR and 24-h urinary protein excretion. Serum 25(OH)D was measured by chemiluminescence immunoassay.
  
  
  RESULTS
  The prevalence of vitamin D deficiency (25(OH)D < 20 ng/mL) was 70.8% in subjects with diabetes-related CKD, 38.8% in subjects with non-diabetic CKD and 41% in subjects with diabetes without advanced CKD. Adjusted means (95% confidence interval (CI)) of 25(OH)D in participants with diabetes-related CKD, in nondiabetic participants with CKD, and in participants with diabetes without advanced CKD were, respectively, 17.5 (14.2 - 20.7), 23.6 (19.4 - 27.8), and 23.5 (16.8 - 30.3) ng/mL (p = 0.023).
  
  
  CONCLUSIONS
  Low vitamin D status is characteristically associated with advanced diabetic nephropathy. This relationship is not entirely attributable to the individual effects of CKD or long-lasting diabetes.
authors.affiliation: Section of Endocrinology and Nutrition, Service of Nephrology, Service of Clinical Biochemistry, Hospital Universitario Insular, and Department of Special Didactics and Department of Medical and Surgical Sciences, University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain.
authors.forename: Rosa M
authors.initials: RM
authors.lastname: Sánchez-Hernández
authors.forename: César
authors.initials: C
authors.lastname: García-Cantón
authors.forename: Dionisio L
authors.initials: DL
authors.lastname: Lorenzo
authors.forename: Virginia
authors.initials: V
authors.lastname: Quevedo
authors.forename: Elvira
authors.initials: E
authors.lastname: Bosch
authors.forename: Laura
authors.initials: L
authors.lastname: López-Ríos
authors.forename: Marta
authors.initials: M
authors.lastname: Riaño
authors.forename: Mauro
authors.initials: M
authors.lastname: Boronat
mesh_terms: D000368:Aged; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000150:complications*; D003928:Diabetic Nephropathies / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D051436:Renal Insufficiency, Chronic / Q000097:blood*; D013030:Spain; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000453:epidemiology*
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D