title: Urinary oxalate to creatinine ratios in healthy Turkish schoolchildren.
abstract: OBJECTIVE
  we aimed to establish reference values for urinary oxalate to creatinine ratios in healthy children aged 6-15 years and to investigate the relationship between their nutritional habits and oxalate excretion.
  
  
  METHODS
  Random urine specimens from 953 healthy children aged 6-15 years were obtained and analyzed for oxalate and creatinine. Additionally, a 24-h dietary recall form was prepared and given to them. The ingredient composition of the diet was calculated. The children were divided into three groups according to age: Group I (69 years, n = 353), Group II (10-12 years, n = 335), and Group III (13-15 years, n = 265).
  
  
  RESULTS
  The 95th percentile of the oxalate to creatinine ratio for subjects aged 6-9, 10-12, and 13-15 years were 0.048, 0.042, and 0.042 mg/mg, respectively. The oxalate to creatinine ratio was significantly higher in Group 1 than in Group 2 and Group 3. Urinary oxalate excretion was positively correlated with increased protein intake and negatively correlated with age. A significant positive correlation was determined between urinary oxalate excretion and the proline, serine, protein, and glycine content of diet. Dietary proline intake showed a positive correlation with the urine oxalate to creatinine ratio and was found to be an independent predictor for urinary oxalate.
  
  
  CONCLUSIONS
  These data lend support to the idea that every country should have its own normal reference values to determine the underlying metabolic risk factor for kidney stone disease since regional variation in the dietary intake of proteins and other nutrients can affect normal urinary excretion of oxalate.
authors.affiliation: a Department of Pediatric Nephrology , Erciyes University, Faculty of Medicine , Kayseri , Turkey.
authors.forename: Ismail
authors.initials: I
authors.lastname: Dursun
authors.affiliation: b Department of Pediatrics , Erciyes University, Faculty of Medicine , Kayseri , Turkey.
authors.forename: İlknur
authors.initials: İ
authors.lastname: Çelik
authors.affiliation: a Department of Pediatric Nephrology , Erciyes University, Faculty of Medicine , Kayseri , Turkey.
authors.forename: Hakan M
authors.initials: HM
authors.lastname: Poyrazoglu
authors.affiliation: c Department of Biochemistry , Erciyes University, Faculty of Medicine , Kayseri , Turkey.
authors.forename: Kader
authors.initials: K
authors.lastname: Köse
authors.affiliation: c Department of Biochemistry , Erciyes University, Faculty of Medicine , Kayseri , Turkey.
authors.forename: Esen
authors.initials: E
authors.lastname: Tanrıkulu
authors.affiliation: d Department of Nutrition and Dietetics , Erciyes University, Atatürk Health School , Kayseri , Turkey.
authors.forename: Habibe
authors.initials: H
authors.lastname: Sahin
authors.affiliation: a Department of Pediatric Nephrology , Erciyes University, Faculty of Medicine , Kayseri , Turkey.
authors.forename: Kenan
authors.initials: K
authors.lastname: Yılmaz
authors.affiliation: e Department of Biostatistics , Erciyes University, Faculty of Medicine , Kayseri , Turkey.
authors.forename: Ahmet
authors.initials: A
authors.lastname: Öztürk
authors.affiliation: a Department of Pediatric Nephrology , Erciyes University, Faculty of Medicine , Kayseri , Turkey.
authors.forename: Sibel
authors.initials: S
authors.lastname: Yel
authors.affiliation: a Department of Pediatric Nephrology , Erciyes University, Faculty of Medicine , Kayseri , Turkey.
authors.forename: Zübeyde
authors.initials: Z
authors.lastname: Gündüz
authors.affiliation: a Department of Pediatric Nephrology , Erciyes University, Faculty of Medicine , Kayseri , Turkey.
authors.forename: Ruhan
authors.initials: R
authors.lastname: Düşünsel
mesh_terms: D000293:Adolescent; D002648:Child; D003404:Creatinine / Q000652:urine*; D004032:Diet; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D010070:Oxalates / Q000652:urine*; D012016:Reference Values; D012044:Regression Analysis; D012307:Risk Factors; D014421:Turkey
chemical_list: D010070:Oxalates; D003404:Creatinine
keywords: Turkish children; Urine oxalate; diet; hyperoxaluria; reference value