停供碘盐对不同水碘含量地区重点人群尿碘水平的影响

目的 观察停供碘盐后不同水含碘量地区重点人群尿碘水平的变化,为科学补碘提供依据.方法 在江苏省、内蒙古和山东省,分别选择水碘较高、而且变化范围较大睢宁县、土右旗和高青县作为调查地点,采用现场干预方法,对学龄儿童和育龄妇女采取停供碘盐的干预措施.以居民户水碘、学龄儿童和育龄妇女尿含碘量为调查内容,分别在干预前与干预后第1、2个月采集随意尿样进行尿含碘量测定,以尿含碘量为因变量进行相关回归分析.结果 调查对象的家庭生活饮用水水碘中位数为99.4μg/L,水碘范围为5.0～867.6 μg/L.干预前除水碘<30、30μg/L组外,学龄儿童和育龄妇女尿碘中位数均>300μg/L.水碘140μg/L组,在干预后第2个月,学龄儿童的尿碘中位数范围为188.5～308.2μg/L,较干预前(287.9～514.2μg/L)均明显下降(P均<0.01);育龄妇女的尿碘中位数范围为181.1～301.7μg/L.较干预前(299.9～632.2 μg/L)均明显下降(P均<0.01).水碘>150μg/L组,干预后第2个月,学龄儿童和育龄妇女尿碘中位数均>400μg/L,与干预前(484.5、401.9μg/L)比较,差异无统计学意义(X~2值分别为2.684、1.742,P均>0.05).干预后第2个月,学龄儿童、育龄妇女组尿碘中位数随水碘的升高而升高(r值分别为0.950、0.938,P均<0.05),水碘与尿碘回归方程均成立(F值分别为119.779、105.117,P均<0.01).根据回归方程,当尿碘中位数是200μg/L时,对应的水碘中位数是103.4 μg/L.结论 停供碘盐后2个月,学龄儿童、育龄妇女碘营养水平仍为正常;对于水碘均值>103.4μg/L,但≤150μg/L的地区,可以采取停供碘盐的措施;对于水碘>150μg/L的地区,除了停供碘盐外,还必须采取改水措施,有效降低水中的含碘量.

A field trial study on urinary iodine change of the target population with different iodine contents in drinking water after non-iodized salt intervention

Objective To evaluate urinary iodine change of the target population with different iodine contents in drinking water after non-iodized salt intervention so as to provide evidence for making strategies of scientific supply of iodized salt. Methods Three counties were chosen as investigation site by adopting purposive sampling method. The school children aged 8 - 13 years old and women aged of 18 - 49 years old in each selected family were used as investigation subjects. The families with different iodine contents in drinking water were chosen to substitute non-iodized salt for their current iodized salt for the 2 months through field trail study. Iodine content in the drinking water of each selected family was determined, and urine samples of the target population were collected for determination of iodine change respectively before and 1, 2 months after the intervention. Linear regression was used to analyze the factors that affected the urinary iodine concentration. Results The median of iodine in drinking water of families in the investigation site was 99.4 μg/L, and the scope was 5.0-867.6 μg/L. Before intervention, the medians of urinary iodine of school children and women were > 300 μg/L except the groups of iodine content in the drinking water less than 30 μg/L and 30 μg/L groups. Two months after the intervention, the scope of the median urinary iodine of school children was 188.5-308.3 μg/L, which was reduced obviously than that before intervention(287.9-514.2 μg/L) ; in women, it was also reduced obviously(181.1-301.7 μg/L) than that before intervention(299.9-632.2 μg/L), in the 140 μg/L groups of iodine content in the drinking water. Two months after the intervention in the group of iodine content in the drinking water above 150 μg/L, the medians of urinary iodine of school children and women were > 400 μg/L. The difference of average urine iodine level before and after was no statistical significance(X~2 = 2.684, 1.742, all P > 0.05). The urine iodine level of target population increased gradually with the elevation of water iodine level 2 months after the intervention (P < 0.05). Linear regression equation was obtained(r=0.950,0.938, all P < 0.01). When the median urinary iodine was 200 μg/L, the median iodine in drinking water was 103.4 μg/L. Conclusions The iodine nutrition level of school children and women are not deficient after stopping iodized salt supplement. Measures should be taken to stop the supply of iodized salt areas where the iodine content is more than 103.4 μg/L and less than or equal 150 μg/L in drinking water. It is necessary to take measures to improve water quality and to decrease iodine content in addition to stopping supply of iodized salt in areas where iodine content is more than 150 μg/L in dringking water.