title: The association of clinical findings and exposure profiles with melamine associated nephrolithiasis.
abstract: BACKGROUND
  Little is known about the exposure profiles of melamine in children. We evaluated the association of clinical findings, exposure patterns and biomarkers with nephrolithiasis in children with potential exposure to melamine.
  
  
  METHODS
  A case-control study was conducted in children aged 0-16 years with potential exposure to contaminated dairy products. Cases were defined as nephrolithiasis detected by renal ultrasonography. On the basis of different brands of contaminated dairy products consumed, subjects were classified into high exposure, low exposure and control groups with estimated melamine exposure levels of higher than 2.5 ppm, 0.05-2.5 ppm and lower than detection limits <0.05 ppm. We measured urine melamine for those with nephrolithiasis and age-matched and gender-matched controls within the subset of the study population.
  
  
  RESULTS
  The duration of consumption of contaminated products was longer in children with nephrolithiasis in the high exposure group than in controls (median (IQR) 12.0 (3.3-24.0) vs 6.0 (4.0-7.0) months; p = 0.048). High melamine exposure levels were significantly associated with nephrolithiasis (OR 61.04 (95% CI 12.73 to 292.84)). The risk was found to increase with estimate melamine exposure levels (p for trend <0.001). Two among 10 affected subjects with nephrolithiasis showed elevated urine melamine levels. In comparison, levels of all 20 controls were lower than the detection limit.
  
  
  CONCLUSIONS
  The risk of melamine-associated nephrolithiasis was related to duration of consumption of contaminated products and estimated melamine exposure levels. Though urine melamine was not a sensitive test, it might serve as an exposure biomarker in melamine-associated nephrolithiasis.
authors.affiliation: Department of Pediatrics,Taipei Hospital, Taipei, Taiwan.
authors.forename: I J
authors.initials: IJ
authors.lastname: Wang
authors.forename: Y N
authors.initials: YN
authors.lastname: Wu
authors.forename: W C
authors.initials: WC
authors.lastname: Wu
authors.forename: G
authors.initials: G
authors.lastname: Leonardi
authors.forename: Y J
authors.initials: YJ
authors.lastname: Sung
authors.forename: T J
authors.initials: TJ
authors.lastname: Lin
authors.forename: C L
authors.initials: CL
authors.lastname: Wang
authors.forename: C F
authors.initials: CF
authors.lastname: Kuo
authors.forename: K Y
authors.initials: KY
authors.lastname: Wu
authors.forename: W C
authors.initials: WC
authors.lastname: Cheng
authors.forename: C C
authors.initials: CC
authors.lastname: Chan
authors.forename: P C
authors.initials: PC
authors.lastname: Chen
authors.forename: S-L
authors.initials: SL
authors.lastname: Lin
mesh_terms: D000293:Adolescent; D015415:Biomarkers / Q000652:urine; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D002681:China; D003611:Dairy Products / Q000032:analysis*; D005260:Female; D005506:Food Contamination; D006801:Humans; D007223:Infant; D041943:Infant Formula; D007231:Infant, Newborn; D008297:Male; D053040:Nephrolithiasis / Q000139:chemically induced* / Q000000981:diagnostic imaging / Q000453:epidemiology; D012307:Risk Factors; D013624:Taiwan / Q000453:epidemiology; D013997:Time Factors; D014227:Triazines / Q000009:adverse effects / Q000652:urine*; D014463:Ultrasonography
chemical_list: D015415:Biomarkers; D014227:Triazines; C011907:melamine