title: A survey of urolithiasis in young children fed infant formula contaminated with melamine in two townships of Gansu, China.
abstract: OBJECTIVE
  To determine the prevalence of urolithiasis in young children fed infant formula (IF) contaminated with melamine, and the association between IF consumption and urolithiasis.
  
  
  METHODS
  A total of 2 733 children < or = 3 years of age on September 1, 2008 in two townships of Gansu Province, China were studied. Cases of urolithiasis were diagnosed by ultrasonography. Milk product consumption was determined by their caregivers. Remaining IF samples were tested for melamine and cyanuric acid.
  
  
  RESULTS
  Of 2 733 eligible children in the two townships, 2 186 (80%) were enrolled in our study. Overall, 16.6% (362) of 2 186 children had urolithiasis. The prevalence was 24.6% in children exclusively fed Sanlu brand IF, 9.7% in those fed other IF, and 8.5% in those fed exclusively on other milk products. For children exclusively breast-fed, no urolithiasis was found (P < 0.05). The prevalence of urolithiasis was 11.4% in children fed 400 g of Sanlu IF, rising to 37.5% in children fed over 25 600 g. Of 48 Sanlu IF samples, 91.7% contained melamine (median = 1 800 ppm; range = 45-4 700) and 66.7% contained cyanuric acid (median = 1.2 ppm; range = 0.4-6.3). Melamine was also detected in 22.2% of 36 other brand IF (median = 27.5 ppm, range = 4-50).
  
  
  CONCLUSIONS
  Urolithiasis was associated with melamine-contaminated IF. Although one product caused most morbidity, other milk products may have also contributed to the outbreak.
authors.affiliation: Chinese Center for Disease Control and Prevention, Beijing 100050, China.
authors.forename: Guo Qing
authors.initials: GQ
authors.lastname: Shi
authors.forename: Zi Jun
authors.initials: ZJ
authors.lastname: Wang
authors.forename: Zi Jian
authors.initials: ZJ
authors.lastname: Feng
authors.forename: Yong Jun
authors.initials: YJ
authors.lastname: Gao
authors.forename: Jian
authors.initials: J
authors.lastname: Di Liu
authors.forename: Tao
authors.initials: T
authors.lastname: Shen
authors.forename: Ming
authors.initials: M
authors.lastname: Li
authors.forename: Jin
authors.initials: J
authors.lastname: Yang
authors.forename: Hai Bing
authors.initials: HB
authors.lastname: Xu
authors.forename: Xiao Hong
authors.initials: XH
authors.lastname: Jiang
authors.forename: Zhao Nan
authors.initials: ZN
authors.lastname: Wang
authors.forename: Mei
authors.initials: M
authors.lastname: Cai
authors.forename: Yu Min
authors.initials: YM
authors.lastname: Wang
authors.forename: Ye Fan
authors.initials: YF
authors.lastname: Zhu
authors.forename: Hui Hui
authors.initials: HH
authors.lastname: Liu
authors.forename: Rui
authors.initials: R
authors.lastname: Wang
authors.forename: Wei Yi
authors.initials: WY
authors.lastname: Xiong
authors.forename: Zhu Tian
authors.initials: ZT
authors.lastname: Wang
authors.forename: Wei Zhong
authors.initials: WZ
authors.lastname: Yang
authors.forename: Pei Sen
authors.initials: PS
authors.lastname: Hou
authors.forename: Guang
authors.initials: G
authors.lastname: Zeng
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
mesh_terms: D002675:Child, Preschool; D003625:Data Collection; D005506:Food Contamination; D006801:Humans; D007225:Infant Food / Q000032:analysis*; D014227:Triazines / Q000633:toxicity*; D052878:Urolithiasis / Q000139:chemically induced*
chemical_list: D014227:Triazines; C011907:melamine