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Calculated free and bioavailable vitamin D metabolite concentrations in vitamin D-deficient hip fracture patients after supplementation with cholecalciferol and ergocalciferol.
Bone. 2013 Oct; 56(2):271-5.BONE

Abstract

We previously showed that oral cholecalciferol and ergocalciferol have comparable effects in decreasing circulating parathyroid hormone (PTH), despite a greater increase in total serum 25-hydroxyvitamin D (25OHD) concentration with cholecalciferol supplementation. However, the effects of cholecalciferol and ergocalciferol on total serum 1,25-dihydroxyvitamin D (1,25(OH)2D), vitamin D-binding protein (DBP), free 25OHD and free 1,25(OH)2D concentrations have not been previously studied. We randomized 95 hip fracture patients (aged 83±8 years) with vitamin D deficiency (serum 25OHD <50 nmol/L) to oral supplementation with either cholecalciferol 1000 IU/day (n=47) or ergocalciferol 1000 IU/day (n=48) for three months. All were given matching placebos of the alternative treatment to maintain blinding. We measured serum 25OHD (high-pressure liquid chromatography), 1,25(OH)2D (Diasorin radioimmunoassay), DBP (immunonephelometry), ionized calcium (Bayer 800 ion-selective electrode) and albumin (bromocresol green) concentrations before and after treatment. We calculated free and bioavailable concentrations of the vitamin D metabolites using albumin and DBP, and calculated free vitamin D metabolite indices as the ratios between the molar concentrations of the vitamin D metabolites and DBP. Seventy participants (74%) completed the study with paired samples for analysis. Total serum 1,25(OH)2D did not change significantly with either treatment (p>0.05, post-treatment vs baseline). Both treatments were associated with comparable increases in DBP (cholecalciferol: +18%, ergocalciferol: +16%, p=0.32 between groups), albumin (cholecalciferol: +31%, ergocalciferol: +21%, p=0.29 between groups) and calculated free 25OHD (cholecalciferol: +46%, ergocalciferol: +36%, p=0.08), with comparable decreases in free 1,25(OH)2D (cholecalciferol: -17%, ergocalciferol: -19%, p=0.32 between groups). In the treatment-adherent subgroup the increase in ionized calcium was marginally greater with cholecalciferol compared with ergocalciferol (cholecalciferol: +8%, ergocalciferol: +5%, p=0.03 between groups). There were no significant differences between the treatments in their effects on the calculated bioavailable concentrations or free indices of the vitamin D metabolites (p>0.05 between groups). In vitamin D-deficient hip fracture patients, oral supplementation with cholecalciferol and ergocalciferol had no effect on total serum 1,25(OH)2D, and comparable effects on DBP and free vitamin D metabolite concentrations. This is despite cholecalciferol having greater effects than ergocalciferol in increasing total 25OHD, and in increasing ionized calcium in treatment-adherent subjects. These findings may explain why cholecalciferol and ergocalciferol supplementation result in similar magnitudes of PTH reduction, but implicate potential differences in other vitamin D metabolites, such as 24,25(OH)2D, that could explain their different effects on ionized calcium.

Authors+Show Affiliations

Department of Core Clinical Pathology and Biochemistry, Royal Perth Hospital, Perth, Western Australia, Australia. Paul.Glendenning@health.wa.gov.auNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Randomized Controlled Trial
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

23792937

Citation

Glendenning, Paul, et al. "Calculated Free and Bioavailable Vitamin D Metabolite Concentrations in Vitamin D-deficient Hip Fracture Patients After Supplementation With Cholecalciferol and Ergocalciferol." Bone, vol. 56, no. 2, 2013, pp. 271-5.
Glendenning P, Chew GT, Inderjeeth CA, et al. Calculated free and bioavailable vitamin D metabolite concentrations in vitamin D-deficient hip fracture patients after supplementation with cholecalciferol and ergocalciferol. Bone. 2013;56(2):271-5.
Glendenning, P., Chew, G. T., Inderjeeth, C. A., Taranto, M., & Fraser, W. D. (2013). Calculated free and bioavailable vitamin D metabolite concentrations in vitamin D-deficient hip fracture patients after supplementation with cholecalciferol and ergocalciferol. Bone, 56(2), 271-5. https://doi.org/10.1016/j.bone.2013.06.012
Glendenning P, et al. Calculated Free and Bioavailable Vitamin D Metabolite Concentrations in Vitamin D-deficient Hip Fracture Patients After Supplementation With Cholecalciferol and Ergocalciferol. Bone. 2013;56(2):271-5. PubMed PMID: 23792937.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Calculated free and bioavailable vitamin D metabolite concentrations in vitamin D-deficient hip fracture patients after supplementation with cholecalciferol and ergocalciferol. AU - Glendenning,Paul, AU - Chew,Gerard T, AU - Inderjeeth,Charles A, AU - Taranto,Mario, AU - Fraser,William D, Y1 - 2013/06/20/ PY - 2013/01/31/received PY - 2013/05/22/revised PY - 2013/06/08/accepted PY - 2013/6/25/entrez PY - 2013/6/25/pubmed PY - 2014/3/22/medline KW - Calculated free vitamin D concentrations KW - Cholecalciferol KW - Ergocalciferol KW - Hip fracture KW - Vitamin D-binding protein SP - 271 EP - 5 JF - Bone JO - Bone VL - 56 IS - 2 N2 - We previously showed that oral cholecalciferol and ergocalciferol have comparable effects in decreasing circulating parathyroid hormone (PTH), despite a greater increase in total serum 25-hydroxyvitamin D (25OHD) concentration with cholecalciferol supplementation. However, the effects of cholecalciferol and ergocalciferol on total serum 1,25-dihydroxyvitamin D (1,25(OH)2D), vitamin D-binding protein (DBP), free 25OHD and free 1,25(OH)2D concentrations have not been previously studied. We randomized 95 hip fracture patients (aged 83±8 years) with vitamin D deficiency (serum 25OHD <50 nmol/L) to oral supplementation with either cholecalciferol 1000 IU/day (n=47) or ergocalciferol 1000 IU/day (n=48) for three months. All were given matching placebos of the alternative treatment to maintain blinding. We measured serum 25OHD (high-pressure liquid chromatography), 1,25(OH)2D (Diasorin radioimmunoassay), DBP (immunonephelometry), ionized calcium (Bayer 800 ion-selective electrode) and albumin (bromocresol green) concentrations before and after treatment. We calculated free and bioavailable concentrations of the vitamin D metabolites using albumin and DBP, and calculated free vitamin D metabolite indices as the ratios between the molar concentrations of the vitamin D metabolites and DBP. Seventy participants (74%) completed the study with paired samples for analysis. Total serum 1,25(OH)2D did not change significantly with either treatment (p>0.05, post-treatment vs baseline). Both treatments were associated with comparable increases in DBP (cholecalciferol: +18%, ergocalciferol: +16%, p=0.32 between groups), albumin (cholecalciferol: +31%, ergocalciferol: +21%, p=0.29 between groups) and calculated free 25OHD (cholecalciferol: +46%, ergocalciferol: +36%, p=0.08), with comparable decreases in free 1,25(OH)2D (cholecalciferol: -17%, ergocalciferol: -19%, p=0.32 between groups). In the treatment-adherent subgroup the increase in ionized calcium was marginally greater with cholecalciferol compared with ergocalciferol (cholecalciferol: +8%, ergocalciferol: +5%, p=0.03 between groups). There were no significant differences between the treatments in their effects on the calculated bioavailable concentrations or free indices of the vitamin D metabolites (p>0.05 between groups). In vitamin D-deficient hip fracture patients, oral supplementation with cholecalciferol and ergocalciferol had no effect on total serum 1,25(OH)2D, and comparable effects on DBP and free vitamin D metabolite concentrations. This is despite cholecalciferol having greater effects than ergocalciferol in increasing total 25OHD, and in increasing ionized calcium in treatment-adherent subjects. These findings may explain why cholecalciferol and ergocalciferol supplementation result in similar magnitudes of PTH reduction, but implicate potential differences in other vitamin D metabolites, such as 24,25(OH)2D, that could explain their different effects on ionized calcium. SN - 1873-2763 UR - https://www.unboundmedicine.com/medline/citation/23792937/Calculated_free_and_bioavailable_vitamin_D_metabolite_concentrations_in_vitamin_D_deficient_hip_fracture_patients_after_supplementation_with_cholecalciferol_and_ergocalciferol_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S8756-3282(13)00230-5 DB - PRIME DP - Unbound Medicine ER -