Urinary calcium excretion in healthy school children.
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.
Alconcher
L F
LF
Pediatric Nephrology Unit, Penna Hospital, Bahia Blanca, Buenos Aires, Argentina.
Castro
C
C
Quintana
D
D
Abt
N
N
Moran
L
L
Gonzalez
L
L
Cella
M
M
Torelli
M
M
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
D003404:Creatinine; D002118:Calcium