[Analysis on the frequency of urinary iodine in a population-based intervention study].

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. CONCLUSION: 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.

[Study on the change of urinary iodine of different salt concentrations among the target population in an intervention trial].

OBJECTIVE: To analyze the change of urinary iodine in a cohort of intervention trial and to observe the role of different doses on salt iodization and related impact factors on nutritional condition of iodine. METHODS: Multistage cluster sampling was used to sample three townships in two counties for community intervention with different doses (15 ± 5, 25 ± 5, 35 ± 5) mg/kg. RESULTS: Compared to the (35 ± 5) mg/kg group, the urine iodine levels of three experimental townships were gradually declining in county B when time went on, and the (15 ± 5) mg/kg group showed an obvious results, at 6, 12, 18 and 24 months, with the urine iodine level as 180.00, 186.10, 150.04, 191.28 µg/L respectively, which were in accordance with the WHO standard and reached to appropriate range (187.96 µg/L) at the 18 month. The townships at county Y under intervention had declined slightly, but the urine iodine levels did not reach the WHO standard. The thyroid volume declined from 3.65 ml to 3.40 ml in two counties and the difference between them was statistically significant. CONCLUSION: To some extent, reducing the iodine concentration in salt, had a role of lowering the urine iodine level and reducing the strumous rate.