title: Relationship between vitamin D status, parathyroid hormone levels and bone mineral density in patients with chronic kidney disease stages 3 and 4.
abstract: OBJECTIVE
  Low vitamin D status is associated with secondary hyperparathyroidism and increased bone turnover in the general population and can aggravate the hyperparathyroidism of chronic kidney disease (CKD) patients. It is also correlated to low bone mineral density (BMD), but this correlation is less clear in CKD patients. Aims of our study were to investigate these associations in CKD stages 3 and 4 patients, and to identify significant predictors of BMD in this population.
  
  
  METHODS
  Serum 25-hydroxyvitamin D (25OHD) levels, BMD at the femur and radius, and bone mineral metabolism parameters were measured in 89 CKD stages 3 and 4 patients. Vitamin D status was defined according to the NKF/KDOQI guidelines.
  
  
  RESULTS
  Mean 25OHD levels were 53.8+/-32.1 nmol/L and correlated to the severity of proteinuria. Thirty-five patients (39%) had vitamin D insufficiency, 29 (33%) had vitamin D deficiency and five (6%) had severe deficiency. Of the 89 patients, two had osteoporosis and 31 had osteopenia either at femur or radius. Independent predictors for the total femur BMD were the intact parathyroid hormone (iPTH) levels and the body mass index (BMI). For the total radius BMD, independent predictor was only the BMI. Serum 25OHD levels were not directly associated with BMD, but they were independent predictors of iPTH.
  
  
  CONCLUSIONS
  Vitamin D insufficiency and deficiency are very common in CKD stages 3 and 4 population and may indirectly affect, via effects on iPTH, the BMD of these patients.
authors.affiliation: Nottingham Renal and Transplant Unit, Nottingham University Hospitals, Nottingham, UK. stavroulopoulos@yahoo.co.uk
authors.forename: Aristeidis
authors.initials: A
authors.lastname: Stavroulopoulos
authors.forename: Christine J
authors.initials: CJ
authors.lastname: Porter
authors.forename: Simon D
authors.initials: SD
authors.lastname: Roe
authors.forename: David J
authors.initials: DJ
authors.lastname: Hosking
authors.forename: Michael J D
authors.initials: MJ
authors.lastname: Cassidy
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015519:Bone Density / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D006934:Hypercalcemia / Q000453:epidemiology / Q000209:etiology* / Q000378:metabolism; D015994:Incidence; D007676:Kidney Failure, Chronic / Q000150:complications / Q000175:diagnosis / Q000378:metabolism*; D008163:Luminescent Measurements; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000453:epidemiology / Q000209:etiology* / Q000378:metabolism; D010281:Parathyroid Hormone / Q000097:blood*; D011379:Prognosis; D012720:Severity of Illness Index; D006113:United Kingdom / Q000453:epidemiology; D014807:Vitamin D / Q000097:blood*; D014808:Vitamin D Deficiency / Q000453:epidemiology / Q000209:etiology* / Q000378:metabolism
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D