title: Magnesium supplementation does not affect blood calcium level in treated hypoparathyroid patients.
abstract: BACKGROUND
  Magnesium is involved in the homeostasis of calcium metabolism, and magnesium deficiency may lead to clinically significant hypocalcemia. We have had two cases in our department in which treated hypoparathyroid patients with stable calcium levels developed hypercalcemia in conjunction with supplementary magnesium use. To our knowledge, there has been no prospective study looking at the effect of supplementary magnesium on calcium homeostasis in hypoparathyroid patients.
  
  
  OBJECTIVE
  The aim of this pilot study was to evaluate whether magnesium treatment affects plasma calcium levels in hypoparathyroid patients.
  
  
  METHODS
  We conducted a prospective, two-phase, uncontrolled treatment trial at a referral center of endocrine disorders.
  
  
  METHODS
  We enrolled treated (calcium + vitamin D analog) hypoparathyroid patients with normal plasma magnesium levels.
  
  
  METHODS
  Three weeks of treatment with oral magnesium (350 mg/d) were followed by 2 wk off treatment.
  
  
  METHODS
  We compared the plasma ionized calcium level after 3 wk of treatment to the pretreatment value. Plasma calcium, phosphate, magnesium, and creatinine levels were measured before treatment, after 3 wk on magnesium, and 2 wk after stopping magnesium treatment.
  
  
  RESULTS
  Ten patients completed the trial. Supplementary treatment with magnesium for 3 wk did not change calcium levels in these patients. Magnesium supplementation induced a small but statistically significant increase in the plasma magnesium level, but levels of phosphate and creatinine remained stable.
  
  
  CONCLUSIONS
  Magnesium supplementation did not influence plasma calcium levels in treated hypoparathyroid patients.
authors.affiliation: Department of Physiology, University of Tartu, 19 Ravila Street, 50411 Tartu, Estonia.
authors.forename: Maire
authors.initials: M
authors.lastname: Lubi
authors.forename: Kaia
authors.initials: K
authors.lastname: Tammiksaar
authors.forename: Svetlana
authors.initials: S
authors.lastname: Matjus
authors.forename: Eero
authors.initials: E
authors.lastname: Vasar
authors.forename: Vallo
authors.initials: V
authors.lastname: Volke
mesh_terms: D000328:Adult; D002118:Calcium / Q000097:blood*; D003404:Creatinine / Q000097:blood; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D007011:Hypoparathyroidism / Q000097:blood* / Q000188:drug therapy*; D008274:Magnesium / Q000097:blood / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D010710:Phosphates / Q000097:blood; D016896:Treatment Outcome
chemical_list: D010710:Phosphates; D003404:Creatinine; D008274:Magnesium; D002118:Calcium