现场干预试验中人群尿碘频数的分析

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

目的分析不同剂量食盐加碘干预后队列人群的尿碘频数，探索较为适宜且安全的碘盐浓度。方法2007-2010年采用多级整群随机抽样方法抽取观察对象，以抽样A、B县的各3个乡镇为单位进行不同食盐加碘浓度[（15±5）、（25±5）、（35±5）mg／kg]的社区干预，随访观察分析干预后队列人群的尿碘频数变化。结果下调浓度后，2县4个试验乡镇人群尿碘中位数随着干预时间逐步降低。A县（15±5）mg／kg和（25±5）mg／kg组儿童尿碘频数主要集中在100-200μg／L和200-300μg／L。B县儿童尿碘频数〉300μg／L总体有所下降，100-μg/L和200-μg/L比例升高，但趋势较为缓慢。4个试验组尿碘频数100-300μg／L的比例较大且保持平稳，始终处于一个较理想的状态；对照组仍以〉250μg／L为主。结论建议在重庆市逐步实施分类补碘，在经济较发达地区可将食盐碘浓度从现行的（35±15）mg／kg下调至（25±5）mg／kg，并继续随访其变化。

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 iodization, so as to explore the selection of appropriate concentration of salt iodization. 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 iodization. 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 200-300μg/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 250μg/L level. Conclusion The iodine supplementation should be gradually implemented in Chongqing. The doses of salt iodization 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.