title: Extremely high prevalence of hypercalciuria in children living in the Aral Sea region.
abstract: The Aral Sea region is a natural area seriously polluted by human activities. In addition to the increased prevalence of diverse chronic diseases in children, the risk of developing urolithiasis is reported to be high in this region. This study was undertaken to clarify the prevalence of hypercalciuria in children of the Aral Sea region. A group of 205 children living in Kazalinsk, close to the Aral Sea, and a group of 187 children living in Zhanakorgan, far from the Aral Sea, were screened for hypercalciuria. Urinary sodium excretion (sodium per creatinine, uNa/Cr) in addition to calcium excretion (calcium per creatinine, uCa/Cr) was also calculated for each subject. Mean uCa/Cr (mmol/mmol) and uNa/Cr (mmol/mmol) excretions were significantly higher in Kazalinsk than in Zhanakorgan (uCa/Cr: 0.75 +/- 0.74 and 0.33 +/- 0.30; uNa/Cr: 3.54 +/- 2.27 and 2.89 +/- 1.69, respectively, mean +/- SD, p < 0.01). Hypercalciuria regarded as an uCa/Cr of more than 0.703 was observed in 79 out of 205 Kazalinsk children (38.6%) while this was seen in only 24 out of 187 Zhanakorgan children (12.8%). Linear regression analysis revealed a direct positive correlation between urinary calcium and sodium excretion (p < 0.01) in Kazalinsk children.
  
  
  CONCLUSIONS
  The prevalence of hypercalciuria in children around the Aral Sea region is extremely high. This may be associated with excessive intake of calcium and sodium, or due to impaired renal tubular function caused by toxic chemicals. Therefore, hypercalciuria that may lead to urolithiasis should be taken into account when considering the health problems of this area.
authors.affiliation: Department of Pediatrics, Juntendo University School of Medicine, Tokyo, Japan. kkaneko@med.juntendo.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Kaneko
authors.forename: M
authors.initials: M
authors.lastname: Chiba
authors.forename: M
authors.initials: M
authors.lastname: Hashizume
authors.forename: O
authors.initials: O
authors.lastname: Kunii
authors.forename: S
authors.initials: S
authors.lastname: Sasaki
authors.forename: T
authors.initials: T
authors.lastname: Shimoda
authors.forename: Y
authors.initials: Y
authors.lastname: Yamashiro
authors.forename: D
authors.initials: D
authors.lastname: Dauletbaev
authors.forename: W
authors.initials: W
authors.lastname: Caypil
authors.forename: Z
authors.initials: Z
authors.lastname: Mazhitova
mesh_terms: D001209:Asia, Central; D002118:Calcium / Q000652:urine*; D002128:Calcium Metabolism Disorders / Q000503:physiopathology / Q000652:urine*; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D015995:Prevalence
chemical_list: D002118:Calcium