Differing urinary urea excretion among children with idiopathic hypercalciuria and/or hyperuricosuria.
OBJECTIVE
To estimate dietary protein intake in children with idiopathic hypercalciuria (HC) and/or hyperuricosuria (HU).


METHODS
We compared the 24-h urinary excretion of urea, as a reflection of protein intake, in four age- and sex-matched groups, each comprising 56 consecutive children: (1) HC, (2) HU, (3) HC+HU and (4) control.


RESULTS
Urinary urea excretion was significantly higher in HC, HU and HC+HU than in controls. HC and HU children had similar urea excretion. HC+HU children had urinary urea significantly higher than HC and HU, but urinary calcium similar to HC and urinary uric acid excretion similar to HU subjects. Urinary calcium was significantly (R(2)=0.21) correlated with urea excretion in HC children only, whereas urinary uric acid was significantly (R(2)=0.21) correlated with urinary urea in HU children only. No significant correlation between urinary urea and calcium or uric acid excretion was found in HC+HU patients although they had the highest urinary urea. A significant (p=0.004) interaction between urinary urea and sodium in increasing urinary calcium excretion resulted only in the HC group.


CONCLUSIONS
The association of dietary protein excess with HC and/or HU is conditioned by an individual (genetic?) predisposition and may be produced by different mechanisms.
Polito
Cesare
C
Department of Pediatrics, Second University of Naples, Via L.De Crecchio, 2, 80138 Naples, Italy. cesare.polito@golfonet.it
La Manna
Angela
A
Signoriello
Giuseppe
G
Lama
Giuliana
G
D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D004044:Dietary Proteins / Q000008:administration & dosage*; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D053565:Hypercalciuria / Q000235:genetics / Q000652:urine*; D008297:Male; D012044:Regression Analysis; D014508:Urea / Q000652:urine*; D014527:Uric Acid / Q000097:blood*
D004044:Dietary Proteins; D014527:Uric Acid; D014508:Urea