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Different Vitamin D Preparations & FGF23 in Humans

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00957879
Recruitment Status : Completed
First Posted : August 13, 2009
Last Update Posted : April 19, 2012
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Information provided by (Responsible Party):
Sherri-Ann M. Burnett-Bowie, Massachusetts General Hospital

Brief Summary:
Fibroblast growth factor 23 (FGF23) is a new hormone which controls phosphate and vitamin D levels in humans. Excess FGF23 is associated with an increased risk of death in patients with chronic kidney disease. In this study the investigators are investigating the effects of different forms of vitamin D on FGF23 levels in the blood in order to increase our understanding of how this important hormone works.

Condition or disease Intervention/treatment Phase
Vitamin D Deficiency Dietary Supplement: Ergocalciferol Dietary Supplement: Calcitriol Not Applicable

Detailed Description:

Fibroblast growth factor 23 (FGF23) is a novel hormone involved in phosphate and vitamin D physiology. X-linked hypophosphatemia (XLH), autosomal dominant hypophosphatemic rickets (ADHR), and tumor induced osteomalacia (TIO) are 3 rare diseases characterized by rickets/osteomalacia, fractures, and hypophosphatemia secondary to renal phosphate wasting and inappropriately low levels of activated vitamin D (calcitriol), which are caused by excess amounts of or mutated FGF23. FGF23 excess also occurs in renal failure, where elevated FGF23 levels predict increased mortality. Thus, abnormal FGF23 appears to be central to both rare and common diseases. While FGF23 appears to be regulated by vitamin D, dietary and serum phosphate, much is still unknown. The effects of different forms of vitamin D on FGF23 stimulation are not well characterized. Similarly, any racial differences in the regulation of FGF23 by vitamin D have not been investigated.

To address these knowledge deficits, we will randomize 52 vitamin D deficient (25OHD < or = 24 ng/mL by LC/MS) Caucasian and African-American men and women to treatment with either dietary vitamin D or activated vitamin D for 12 weeks. Our primary endpoint will be the change in FGF23 with dietary versus activated vitamin D.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 42 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Official Title: Effect of Different Vitamin D Preparations on Circulating FGF23 Levels in Vitamin D Deficient Caucasian and African-American Men and Women
Study Start Date : May 2009
Actual Primary Completion Date : September 2010
Actual Study Completion Date : March 2011

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Vitamin D

Arm Intervention/treatment
Active Comparator: ergocalciferol
Weekly ergocalciferol for 12 weeks
Dietary Supplement: Ergocalciferol
Ergocalciferol 50000 international units by mouth weekly for 12 weeks

Active Comparator: calcitriol
Daily calcitriol for 12 weeks
Dietary Supplement: Calcitriol
Calcitriol 0.5 mcg by mouth daily for 12 weeks

Primary Outcome Measures :
  1. Change in FGF23 levels [ Time Frame: 12 weeks ]

Secondary Outcome Measures :
  1. Change in serum phosphate [ Time Frame: 12 weeks ]
  2. Change in urinary phosphate [ Time Frame: 12 weeks ]
  3. Change in serum calcium [ Time Frame: 12 weeks ]

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 45 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Age 18 to 45 yrs
  • Serum 25OHD < 24 ng/mL by liquid chromatography/mass spectroscopy
  • At least 1 menses in the last 3 months (females) and normal serum testosterone (males)
  • African-American or Caucasian race

Exclusion Criteria:

  • Significant cardiac, hepatic, oncologic, or psychiatric disease
  • History of malabsorption, kidney stones, or recent alcohol excess/abuse
  • Use of medications known to affect serum phosphate levels including phosphate-binding antacids, sodium etidronate, calcitonin, excessive doses of vitamin D (> 1000 units per day), excessive doses of vitamin A (> 20,000 units/day), calcitriol, growth hormone, or anti-convulsants
  • Use of thiazide diuretics or cholestyramine
  • Serum calcium < 8 or > 11 mg/dL, creatinine > 1.5 mg/dL, or Hgb < 11 gm/dL
  • Serum glucose >140mg/dL
  • Liver function tests > 2 times the upper limit of normal
  • TSH < 0.1 or > 7 uU/mL
  • WBC < 2,000 or > 15,000/cmm
  • Platelet count < 100,000 or > 500,000/cum
  • Hormone replacement therapy (however, oral contraceptives are allowed) or testosterone use
  • Urine beta-hCG positive (females)
  • Serum phosphate > 4.6 mg/dL
  • Allergy to vitamin D

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00957879

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United States, Massachusetts
Massachusetts General Hospital
Boston, Massachusetts, United States, 02114
Sponsors and Collaborators
Massachusetts General Hospital
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
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Principal Investigator: Sherri-Ann M Burnett-Bowie, MD, MPH Massachusetts General Hospital
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Responsible Party: Sherri-Ann M. Burnett-Bowie, Assistant Professor of Medicine, Massachusetts General Hospital Identifier: NCT00957879    
Other Study ID Numbers: 2009P000567
K23DK073356 ( U.S. NIH Grant/Contract )
First Posted: August 13, 2009    Key Record Dates
Last Update Posted: April 19, 2012
Last Verified: April 2012
Keywords provided by Sherri-Ann M. Burnett-Bowie, Massachusetts General Hospital:
Vitamin D
Additional relevant MeSH terms:
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Vitamin D Deficiency
Deficiency Diseases
Nutrition Disorders
Vitamin D
Calcium-Regulating Hormones and Agents
Physiological Effects of Drugs
Calcium Channel Agonists
Membrane Transport Modulators
Molecular Mechanisms of Pharmacological Action
Vasoconstrictor Agents
Bone Density Conservation Agents