title: Effect of vitamin D repletion on urinary calcium excretion among kidney stone formers.
abstract: OBJECTIVE
  Despite the important role of vitamin D in maintaining bone health, many clinicians are reluctant to treat vitamin D deficiency in kidney stone formers because of the theoretical risk of increasing urinary calcium excretion. This study examined the effect of vitamin D repletion on urinary calcium excretion among stone formers.
  
  
  METHODS
  Participants (n=29) were recruited from urology clinics affiliated with New York Presbyterian Hospital. Enrollment criteria included a history of nephrolithiasis, urinary calcium excretion between 150 and 400 mg/d, and a serum 25-hydroxyvitamin D level <30 ng/ml. Participants were given oral ergocalciferol (50,000 IU/wk) for 8 weeks. Serum and 24-hour urine tests were repeated after 8 weeks.
  
  
  RESULTS
  Levels of 25-hydroxyvitamin D increased significantly after vitamin D repletion (17±6 and 35±10 ng/ml, P<0.001), but mean 24-hour urinary calcium excretion did not change (257±54 and 255±88 mg/d at baseline and follow-up, respectively, P=0.91). However, 11 participants had an increase in urinary calcium excretion ≥20 mg/d; these participants also had an increase in urine sodium excretion, likely reflecting dietary variability. No participant experienced adverse effects from vitamin D, including hypercalcemia.
  
  
  CONCLUSIONS
  Among stone formers with vitamin D deficiency, a limited course of vitamin D repletion does not seem to increase mean urinary calcium excretion, although a subset of individuals may have an increase. These data suggest that vitamin D therapy, if indicated, should not be withheld solely on the basis of stone disease, but 24-hour urinary calcium excretion should be monitored after repletion.
authors.affiliation: Department of Medicine, Columbia University, New York, New York, USA. DELEAF@partners.org
authors.forename: David E
authors.initials: DE
authors.lastname: Leaf
authors.forename: Ruslan
authors.initials: R
authors.lastname: Korets
authors.forename: Eric N
authors.initials: EN
authors.lastname: Taylor
authors.forename: Jie
authors.initials: J
authors.lastname: Tang
authors.forename: John R
authors.initials: JR
authors.lastname: Asplin
authors.forename: David S
authors.initials: DS
authors.lastname: Goldfarb
authors.forename: Mantu
authors.initials: M
authors.lastname: Gupta
authors.forename: Gary C
authors.initials: GC
authors.lastname: Curhan
mesh_terms: D000328:Adult; D002118:Calcium / Q000652:urine*; D004872:Ergocalciferols / Q000009:adverse effects / Q000494:pharmacology* / Q000627:therapeutic use; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000150:complications / Q000652:urine*; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010281:Parathyroid Hormone / Q000097:blood; D012964:Sodium / Q000652:urine; D018709:Statistics, Nonparametric; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000150:complications / Q000188:drug therapy*; D014815:Vitamins / Q000009:adverse effects / Q000494:pharmacology* / Q000627:therapeutic use
chemical_list: D004872:Ergocalciferols; D010281:Parathyroid Hormone; D014815:Vitamins; D014807:Vitamin D; D012964:Sodium; C104450:25-hydroxyvitamin D; D002118:Calcium