title: Urinary calcium excretion in postmenopausal African American women.
abstract: OBJECTIVE
  The objective of this study was to develop a reference range for urine calcium excretion (both 24-hour and fasting) for African American women compared to White women. In addition, the variables that determine urine calcium excretion were identified.
  
  
  METHODS
  Data were analyzed for baseline studies of healthy postmenopausal volunteers who participated in seven separate studies conducted at one site.
  
  
  METHODS
  Some studies included fasting urine Ca/Cr and others 24-hour urine calcium excretion. 24-hour urine calcium was considered with and without correction for urinary creatinine excretion. Calcium was measured initially by atomic absorption spectrophotometry and more recently by an automated method (ADVIA 2400 Chemistry System).
  
  
  RESULTS
  Participants were considered healthy based on history and physical and routine laboratory studies. Those screened who had a history of nephrolithiasis were excluded. A reference range for 24-hour urine calcium and fasting urine calcium/ creatinine was developed. Reference intervals of 11 - 197 mg/24-hour urine calcium excretion and of 0.007 - 0.222 of fasting Ca/Cr were found for African American women compared to 21 - 221 mg/24 hours and 0.019 - 0.264 in White women, respectively. Urine creatinine excretion was higher in African Americans consistent with their higher muscle mass.
  
  
  CONCLUSIONS
  Urine calcium excretion is lower in postmenopausal African American than White women. The reference range developed should be considered in the diagnosis of hypocalciuric states and may also be useful in the diagnosis of hypercalciuria.
authors.forename: John F
authors.initials: JF
authors.lastname: Aloia
authors.forename: Albert
authors.initials: A
authors.lastname: Shieh
authors.forename: Mageda
authors.initials: M
authors.lastname: Mikhail
authors.forename: Shahidul
authors.initials: S
authors.lastname: Islam
mesh_terms: D001741:Black or African American / Q000706:statistics & numerical data*; D000368:Aged; D002118:Calcium / Q000652:urine*; D003404:Creatinine / Q000652:urine; D005260:Female; D006801:Humans; D053565:Hypercalciuria; D008875:Middle Aged; D017698:Postmenopause / Q000652:urine*; D012016:Reference Values; D014481:United States / Q000453:epidemiology
chemical_list: D003404:Creatinine; D002118:Calcium