title: Association of urinary calcium excretion with serum calcium and vitamin D levels.
abstract: OBJECTIVE
  Population-based data on urinary calcium excretion are scarce. The association of serum calcium and circulating levels of vitamin D [25(OH)D2 or D3] with urinary calcium excretion in men and women from a population-based study was explored.
  
  
  METHODS
  Multivariable linear regression was used to explore factors associated with square root-transformed 24-hour urinary calcium excretion (milligrams per 24 hours) taken as the dependent variable with a focus on month-specific vitamin D tertiles and serum calcium in the Swiss Survey on Salt Study.
  
  
  RESULTS
  In total, 624 men and 669 women were studied with mean ages of 49.2 and 47.0 years, respectively (age range=15-95 years). Mean urinary calcium excretion was higher in men than in women (183.05 versus 144.60 mg/24 h; P<0.001). In adjusted models, the association (95% confidence interval) of square root urinary calcium excretion with protein-corrected serum calcium was 1.78 (95% confidence interval, 1.21 to 2.34) mg/24 h per milligram per deciliter in women and 0.59 (95% confidence interval, -0.11 to 1.29) mg/24 h per milligram per deciliter in men. Men in the third 25(OH)D3 tertile had higher square root urinary calcium excretion than men in the first tertile (0.99; 95% confidence interval, 0.36 to 1.63 mg/24 h per nanogram per milliliter), and the corresponding association was 0.32 (95% confidence interval, -0.22 to 0.85) mg/24 h per nanogram per milliliter in women. These sex differences were more marked under conditions of high urinary sodium or urea excretions.
  
  
  CONCLUSIONS
  There was a positive association of serum calcium with urinary calcium excretion in women but not men. Vitamin 25(OH)D3 was associated with urinary calcium excretion in men but not women. These results suggest important sex differences in the hormonal and dietary control of urinary calcium excretion.
authors.affiliation: Due to the number of contributing authors, the affiliations are provided in the Supplemental Material.
authors.forename: Anita
authors.initials: A
authors.lastname: Rathod
authors.affiliation: Due to the number of contributing authors, the affiliations are provided in the Supplemental Material.
authors.forename: Olivier
authors.initials: O
authors.lastname: Bonny
authors.affiliation: Due to the number of contributing authors, the affiliations are provided in the Supplemental Material.
authors.forename: Idris
authors.initials: I
authors.lastname: Guessous
authors.affiliation: Due to the number of contributing authors, the affiliations are provided in the Supplemental Material.
authors.forename: Paolo M
authors.initials: PM
authors.lastname: Suter
authors.affiliation: Due to the number of contributing authors, the affiliations are provided in the Supplemental Material.
authors.forename: David
authors.initials: D
authors.lastname: Conen
authors.affiliation: Due to the number of contributing authors, the affiliations are provided in the Supplemental Material.
authors.forename: Paul
authors.initials: P
authors.lastname: Erne
authors.affiliation: Due to the number of contributing authors, the affiliations are provided in the Supplemental Material.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Binet
authors.affiliation: Due to the number of contributing authors, the affiliations are provided in the Supplemental Material.
authors.forename: Luca
authors.initials: L
authors.lastname: Gabutti
authors.affiliation: Due to the number of contributing authors, the affiliations are provided in the Supplemental Material.
authors.forename: Augusto
authors.initials: A
authors.lastname: Gallino
authors.affiliation: Due to the number of contributing authors, the affiliations are provided in the Supplemental Material.
authors.forename: Franco
authors.initials: F
authors.lastname: Muggli
authors.affiliation: Due to the number of contributing authors, the affiliations are provided in the Supplemental Material.
authors.forename: Daniel
authors.initials: D
authors.lastname: Hayoz
authors.affiliation: Due to the number of contributing authors, the affiliations are provided in the Supplemental Material.
authors.forename: Antoinette
authors.initials: A
authors.lastname: Péchère-Bertschi
authors.affiliation: Due to the number of contributing authors, the affiliations are provided in the Supplemental Material.
authors.forename: Fred
authors.initials: F
authors.lastname: Paccaud
authors.affiliation: Due to the number of contributing authors, the affiliations are provided in the Supplemental Material. Michel.Burnier@chuv.ch Murielle.Bochud@chuv.ch.
authors.forename: Michel
authors.initials: M
authors.lastname: Burnier
authors.affiliation: Due to the number of contributing authors, the affiliations are provided in the Supplemental Material. Michel.Burnier@chuv.ch Murielle.Bochud@chuv.ch.
authors.forename: Murielle
authors.initials: M
authors.lastname: Bochud
mesh_terms: D015652:25-Hydroxyvitamin D 2 / Q000097:blood*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002118:Calcium / Q000097:blood* / Q000652:urine*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012737:Sex Factors; D013557:Switzerland; D055815:Young Adult
chemical_list: D015652:25-Hydroxyvitamin D 2; D002118:Calcium
keywords: population-based; serum calcium; sex; urinary calcium excretion; vitamin D