不同剂量食盐加碘干预试验中人群尿碘的变化规律

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

目的分析不同剂量食盐加碘干预后人群尿碘水平的变化规律及其影响因素。方法采用多级整群随机抽样方法，抽取2个县（B县和Y县）中各3个乡镇居民研究对象，分别进行不同食盐加碘浓度（15±5、25±5、35±5）mg／kg的社区干预，观察干预后各人群的尿碘变化规律。结果B县3个实验乡镇的尿碘水平随着干预时间逐渐下降，且以（15±5）mg／kg组下降较为明显，在6、12、18、24个月时分别为180．00、186．10、150．04、191．28gg／L，符合WHO标准；（25±5）mg／kg组下降幅度次之，并在干预18个月时（187．96ug／L）达到WHO标准；（35±5）mg／kg变动不大。Y县实验乡镇干预后尿碘略有下降，但均未达到WHO标准。两县甲状腺容积总体上由干预前3．65ml降至干预后的3．40ml，干预前后差异有统计学意义（x2=54．29，P〈0．0001）。结论降低碘盐浓度可在一定程度降低尿碘水平，减少甲状腺肿大率。

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 ug/L respectively, which were in accordance with the WHO standard and reached to appropriate range （187.96ug/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.