title: Urinary calcium excretion in healthy school children.
abstract: Two hundred and twenty Argentinian primary school children (122 boys, 98 girls, aged 6-13 years) were studied to establish reference values of 24-h urinary calcium excretion (UCa) and calcium/creatinine ratio (Ca/Cr) in 24-h urine collections and in first-morning urine samples. Mean UCa excretion was 2.05 +/- 1.40 mg/kg per day and the 95th percentile was 4.74 mg/kg per day. UCa excretion was higher in boys than girls (2.33 +/- 1.47 and 1.70 +/- 1.24 mg/kg per day respectively, P < 0.001). Statistically significant differences were found between the 6- to 9-year and the 10- to 13-year age groups (2.37 +/- 1.49 vs. 1.73 +/- 1.25 mg/kg per day, P < 0.001). Mean Ca/Cr ratios in 24-h collections and in first-morning urine samples were 0.129 +/- 0.086 and 0.105 +/- 0.079 for the group overall (P < 0.001). The Ca/Cr ratio in the first-morning urine sample correlated poorly with the 24-h calcium excretion, suggesting that the Ca/Cr ratio in first-morning urine samples cannot replace the 24-h measurement.
authors.affiliation: Pediatric Nephrology Unit, Penna Hospital, Bahia Blanca, Buenos Aires, Argentina.
authors.forename: L F
authors.initials: LF
authors.lastname: Alconcher
authors.forename: C
authors.initials: C
authors.lastname: Castro
authors.forename: D
authors.initials: D
authors.lastname: Quintana
authors.forename: N
authors.initials: N
authors.lastname: Abt
authors.forename: L
authors.initials: L
authors.lastname: Moran
authors.forename: L
authors.initials: L
authors.lastname: Gonzalez
authors.forename: M
authors.initials: M
authors.lastname: Cella
authors.forename: M
authors.initials: M
authors.lastname: Torelli
mesh_terms: D000293:Adolescent; D000375:Aging / Q000652:urine; D001118:Argentina; D002118:Calcium / Q000652:urine*; D002648:Child; D003404:Creatinine / Q000652:urine; D005260:Female; D006801:Humans; D008297:Male; D012016:Reference Values
chemical_list: D003404:Creatinine; D002118:Calcium