title: Calcium absorption response to cholecalciferol supplementation in hemodialysis.
abstract: OBJECTIVE
  Recent understanding of extrarenal production of calcitriol has led to the use of more vitamin D supplementation in CKD populations. This paper reports the effect of cholecalciferol supplementation on calcium absorption.
  
  
  METHODS
  Paired calcium absorption tests were done before and after 12-13 weeks of 20,000 IU weekly cholecalciferol supplementation in 30 participants with stage 5 CKD on hemodialysis. The study was conducted from April to December of 2011. Calcium absorption was tested with a standardized meal containing 300 mg calcium carbonate intrinsically labeled with (45)Ca; 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D were measured.
  
  
  RESULTS
  25-Hydroxyvitamin D rose from 14.2 ng/ml (11.5-18.5) at baseline to 49.3 ng/ml (42.3-58.1) at the end of the study (P<0.001). 1,25-Dihydroxyvitamin D rose from 15.1 (10.5-18.8) pg/ml at baseline to 20.5 (17.0-24.7) pg/ml at the end of the study (P<0.001). The median baseline calcium absorption was 12% (7%-17%) and 12% (7%-16%) at the end of study.
  
  
  CONCLUSIONS
  Patients with stage 5 CKD on hemodialysis had very low calcium absorption values at baseline, and cholecalciferol supplementation that raised 25(OH)D levels to 50 ng/ml had no effect on calcium absorption.
authors: Osteoporosis Research Center, Creighton University, Omaha, Nebraska 68131, USA. larmas@creighton.edu
authors: Laura A G
authors: LA
authors: Armas
authors: Mohsen
authors: M
authors: Zena
authors: Richard
authors: R
authors: Lund
authors: Robert P
authors: RP
authors: Heaney
mesh_terms: D000368:Aged; D002119:Calcium Carbonate / Q000008:administration & dosage / Q000097:blood*; D002136:Calcium, Dietary / Q000097:blood*; D002762:Cholecalciferol / Q000097:blood / Q000627:therapeutic use*; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D007408:Intestinal Absorption / Q000187:drug effects*; D008297:Male; D008875:Middle Aged; D009329:Nebraska; D006435:Renal Dialysis; D051436:Renal Insufficiency, Chronic / Q000097:blood / Q000175:diagnosis / Q000628:therapy*; D013997:Time Factors; D016896:Treatment Outcome; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D014815:Vitamins / Q000097:blood / Q000627:therapeutic use*
chemical_list: D002136:Calcium, Dietary; D014815:Vitamins; D014807:Vitamin D; D002762:Cholecalciferol; C097949:1,25-dihydroxyvitamin D; C104450:25-hydroxyvitamin D; D002119:Calcium Carbonate