title: Factors Associated With the Lower Prevalence of Nephrolithiasis in Children Compared With Adults.
abstract: OBJECTIVE
  To determine the reasons behind the lower prevalence of kidney stones in children by assessing urinary lithogenic parameters in healthy children, healthy adults, and 3 groups of stone-former patients.
  
  
  METHODS
  The study subjects included 75 healthy adults, 105 healthy children, 62 patients with previous calcium oxalate monohydrate papillary stones, 120 patients with previous calcium oxalate monohydrate unattached stones, and 248 patients with previous calcium oxalate dihydrate stones. Twenty-four-hour urine samples were collected, and the urinary lithogenic parameters were measured.
  
  
  RESULTS
  Calcium, magnesium, and phosphorous concentration differed significantly between healthy children and adults. Except citrate, all solute/creatinine ratios differed between healthy children and adults. However, these differences were much more important in the cases of calcium and magnesium. The calcium/creatinine ratio was 2-fold lower, whereas the magnesium/creatinine ratio was 2-fold higher, in healthy children than that in healthy adults (P <.001 each). The calcium/creatinine ratio was higher and the citrate/creatinine ratio lower in calcium oxalate dihydrate stone formers than that in healthy adults.
  
  
  CONCLUSIONS
  Ratios of calcium and magnesium to creatinine, as well as morphoanatomic factors and lifestyle habits, may explain the lower prevalence of nephrolithiasis in children than those in adults.
authors.affiliation: Laboratory of Renal Lithiasis Research, University Institute of Health Sciences Research (IUNICS-IdISPa), University of Balearic Islands, Palma de Mallorca, Spain. Electronic address: fgrases@uib.es.
authors.forename: Felix
authors.initials: F
authors.lastname: Grases
authors.affiliation: Laboratory of Renal Lithiasis Research, University Institute of Health Sciences Research (IUNICS-IdISPa), University of Balearic Islands, Palma de Mallorca, Spain.
authors.forename: Adrian
authors.initials: A
authors.lastname: Rodriguez
authors.affiliation: Laboratory of Renal Lithiasis Research, University Institute of Health Sciences Research (IUNICS-IdISPa), University of Balearic Islands, Palma de Mallorca, Spain.
authors.forename: Antonia
authors.initials: A
authors.lastname: Costa-Bauza
authors.affiliation: Laboratory of Renal Lithiasis Research, University Institute of Health Sciences Research (IUNICS-IdISPa), University of Balearic Islands, Palma de Mallorca, Spain.
authors.forename: Concepcion
authors.initials: C
authors.lastname: Saez-Torres
authors.affiliation: Laboratory of Renal Lithiasis Research, University Institute of Health Sciences Research (IUNICS-IdISPa), University of Balearic Islands, Palma de Mallorca, Spain; Department of Pediatric Nephrology, Son Espases University Hospital, Palma de Mallorca, Spain.
authors.forename: Dolores
authors.initials: D
authors.lastname: Rodrigo
authors.affiliation: Laboratory Department, Son Espases University Hospital, Palma de Mallorca, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Gómez
authors.affiliation: Laboratory of Renal Lithiasis Research, University Institute of Health Sciences Research (IUNICS-IdISPa), University of Balearic Islands, Palma de Mallorca, Spain; Department of Pediatric Nephrology, Son Espases University Hospital, Palma de Mallorca, Spain.
authors.forename: Concepcion
authors.initials: C
authors.lastname: Mir-Perello
authors.affiliation: Research Unit, Son Espases University Hospital, Palma de Mallorca, Spain.
authors.forename: Guiem
authors.initials: G
authors.lastname: Frontera
mesh_terms: D000328:Adult; D000367:Age Factors; D002129:Calcium Oxalate / Q000032:analysis; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D053040:Nephrolithiasis / Q000175:diagnosis / Q000453:epidemiology* / Q000652:urine; D015995:Prevalence; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D013030:Spain / Q000453:epidemiology; D019265:Spectroscopy, Near-Infrared
chemical_list: D002129:Calcium Oxalate