title: Role of 1,25-dihydroxy vitamin D3 and parathyroid hormone in urinary calcium excretion in calcium stone formers.
abstract: OBJECTIVE
  To find out the possible role of 1,25(OH)₂ vitamin D₃ [1,25(OH)₂D₃] and parathyroid hormone (PTH) as intrinsic factors in urinary calcium stone formers (SFs), we investigated their relationship with serum and urinary biochemical parameters.
  
  
  METHODS
  A total of 326 calcium SFs (male: 204, female: 122) were enrolled and underwent outpatient metabolic evaluations including 1,25(OH)₂D₃ and PTH as well as serum and 24-hour urinary biochemical parameters. As control, 163 age- and sex-matched (2:1) individuals (non-SFs) who have never urinary stone episode were included.
  
  
  RESULTS
  1,25(OH)₂D₃ level was positively correlated with urinary calcium excretion (r=0.347, p<0.001). The hypercalciuric group and recurrent SFs had higher serum 1,25(OH)₂D₃ levels than the normocalciuric group (p<0.001) and first SFs (p=0.050). In the adjusted multiple linear regression analysis, serum 1,25(OH)₂D₃ level (β=0.259, p<0.001) and serum PTH level (β=-0.160, p<0.001) were significantly correlated with urinary calcium excretion. The patients in highest tertile of 1,25(OH)₂D₃ had a more than 3.1 fold risk of hypercalciuria than those in the lowest tertile (odds ratio=3.14, 95% confidence interval: 1.431-6.888, p=0.004). No correlation was observed between PTH and 1,25(OH)₂D₃ (R=0.005, p=0.929) in calcium SFs, while a negative correlation was found in controls (R=-0.269, p=0.001).
  
  
  CONCLUSIONS
  1,25(OH)₂D₃ was closely correlated with urinary calcium excretion, and high 1,25(OH)₂D₃ levels were detected in the hypercalciuric group and in recurrent SFs. However, 1,25(OH)₂D₃ was not correlated with PTH in calcium SFs. These findings suggest that 1,25(OH)₂D₃ might be important intrinsic factor for altered calcium regulation in SFs.
authors.affiliation: Department of Urology, College of Medicine, Chungbuk National University, Cheongju, Korea. ; Department of Urology, Graduate School of Medicine, Yonsei University, Seoul, Korea.
authors.forename: Won Tae
authors.initials: WT
authors.lastname: Kim
authors.affiliation: Department of Urology, College of Medicine, Chungbuk National University, Cheongju, Korea.
authors.forename: Yong-June
authors.initials: YJ
authors.lastname: Kim
authors.affiliation: Department of Urology, College of Medicine, Chungbuk National University, Cheongju, Korea.
authors.forename: Seok Joong
authors.initials: SJ
authors.lastname: Yun
authors.affiliation: Department of Laboratory Medicine, College of Medicine, Chungbuk National University, Cheongju, Korea.
authors.forename: Kyung-Sub
authors.initials: KS
authors.lastname: Shin
authors.affiliation: Department of Urology, Graduate School of Medicine, Yonsei University, Seoul, Korea.
authors.forename: Young Deuk
authors.initials: YD
authors.lastname: Choi
authors.affiliation: Department of Urology, College of Medicine, Chungbuk National University, Cheongju, Korea. lscuro@chungbuk.ac.kr.
authors.forename: Sang Cheol
authors.initials: SC
authors.lastname: Lee
authors.affiliation: Department of Urology, College of Medicine, Chungbuk National University, Cheongju, Korea.
authors.forename: Wun-Jae
authors.initials: WJ
authors.lastname: Kim
mesh_terms: D000328:Adult; D002118:Calcium / Q000378:metabolism / Q000652:urine*; D005260:Female; D006801:Humans; D007669:Kidney Calculi; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D010281:Parathyroid Hormone / Q000097:blood / Q000502:physiology* / Q000652:urine; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood / Q000502:physiology / Q000652:urine
chemical_list: D010281:Parathyroid Hormone; C118756:dihydroxy-vitamin D3; D014807:Vitamin D; D002118:Calcium
keywords: 1,25-dihydroxy-vitamin D₃; calcium; parathyroid hormone; urolithiasis