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Updated: May 14, 2026

A Semi-Automated and Reproducible Biological-Based Method to Quantify Calcium Deposition In Vitro
Published on: June 2, 2022
Calcium absorption response to cholecalciferol supplementation in hemodialysis
Laura A G Armas1, Mohsen Zena, Richard Lund
1Osteoporosis Research Center, Creighton University, Omaha, Nebraska 68131, USA. larmas@creighton.edu
Background And Objectives:
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.
Design, Setting, Participants, & Measurements:
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.
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