title: [Analysis on the frequency of urinary iodine in a population-based intervention study].
abstract: OBJECTIVE
  Through a two-year follow up program, this study was to analyze the urinary iodine frequency of a cohort in the intervention trial, concerning different doses of salt ionization, so as to explore the selection of appropriate concentration of salt ionization.
  
  
  METHODS
  A multistage cluster sampling method was used to select three townships in two countries for community intervention with different doses [(15±5) mg/kg, (25±5) mg/kg, (35±5) mg/kg] of salt ionization.
  
  
  RESULTS
  After intervention, the median of urinary iodine was reduced among the population. The urinary iodine frequencies of (15±5) mg/kg and (25±5) mg/kg among groups of children were mainly concentrated in 100-200 µg/L and 200-300 µg/L paragraphs in A county. While the 300 µg/L paragraph had an overall decline in B county, the 100 µg/L and 200 µg/L paragraph ratio increased but the trend seemed to be slow. The 100-300 µg/L paragraph of the four treatment groups took a larger proportion and kept smooth in a more ideal state. However, the control group still maintained at above 250 µg/L level.
  
  
  CONCLUSIONS
  The iodine supplementation should be gradually implemented in Chongqing. The doses of salt ionization should be reduced from the current (35±15) mg/kg to (25±5) mg/kg in the economically developed areas. At the same time, we need to continuously follow the changes of the condition.
authors.affiliation: Department of Epidemiology, School of Public Health and Management, Chongqing Medical University, Chongqing 400016, China.
authors.forename: Yin-yin
authors.initials: YY
authors.lastname: Song
authors.forename: Li-hong
authors.initials: LH
authors.lastname: Mu
authors.forename: Ge
authors.initials: G
authors.lastname: Li
authors.forename: Yu-lin
authors.initials: YL
authors.lastname: Wang
authors.forename: Bang-zhong
authors.initials: BZ
authors.lastname: Xiao
authors.forename: Xin-shu
authors.initials: XS
authors.lastname: Li
authors.forename: Yin
authors.initials: Y
authors.lastname: Lei
mesh_terms: D002648:Child; D005500:Follow-Up Studies; D006801:Humans; D007455:Iodine / Q000008:administration & dosage* / Q000652:urine*; D017673:Sodium Chloride, Dietary / Q000008:administration & dosage
chemical_list: D017673:Sodium Chloride, Dietary; C034024:iodized salt; D007455:Iodine