不同盐碘含量的儿童和孕妇碘营养状况及甲状腺功能调查

Effects of different concentrations of iodized salt on iodine nutrition and thyroid function of children and pregnant women

目的评价盐碘含量调整前、后儿童和孕妇碘营养状况和甲状腺功能的变化,探讨适宜盐碘含量标准。方法2012和2014年分别在山东和甘肃省,采用整群抽样方法,以碘盐覆盖率> 95%、水碘< 10 μg/L、水氟≤1 mg/L的地点为调查地区。在盐碘含量调整前(2012年)、后(2014年),每个地区调查儿童和孕妇两类人群,采集居民家庭盐样、水样和尿样,分别检测盐碘、水碘、水氟和尿碘含量;B超法检测儿童甲状腺容积并计算甲状腺肿大率(甲肿率);同时采集儿童和孕妇血样,检测血清促甲状腺激素(TSH)和甲状腺球蛋白(Tg)。结果盐碘含量调整前,山东和甘肃省儿童尿碘中位数分别为291.4、329.1 μg/L,处于碘超适宜和碘过量水平;孕妇尿碘中位数分别为220.5、274.7 μg/L,处于碘适宜和碘超适宜水平。盐碘含量调整后,山东和甘肃省儿童尿碘中位数分别为199.8、178.2 μg/L,孕妇尿碘中位数分别为178.6、159.2 μg/L,均处于碘适宜水平。山东省儿童甲肿率由调整前的7.95%(7/88)下降到调整后的5.88%(7/119),甘肃省儿童甲肿率由2.06%(2/97)升至5.77%(6/104),但调整前、后比较差异无统计学意义(χ^2 = 0.34、1.81,P均> 0.05)。盐碘含量调整前、后,山东和甘肃省儿童、孕妇TSH水平比较差异无统计学意义(Z =- 1.08、- 0.83,- 1.30、- 0.80,P均> 0.05)。盐碘含量调整后,山东省儿童和孕妇Tg水平较调整前明显降低(Z =- 10.78、- 7.04,P均< 0.01);甘肃省孕妇Tg水平均较调整前升高(Z =- 2.78,P < 0.01)。结论盐碘含量调整后,山东省儿童和孕妇碘营养状况和甲状腺功能指标趋向合理,而甘肃省各项指标有向缺碘方向发展的趋势,因此需加强监测,及时调整盐碘含量。

Objective To assess iodine nutrition and thyroid function in children and pregnant women before and after iodized salt concentration decline, and investigate the appropriate concentration of iodized salt. Methods Cluster sampling was carried out, study areas in Shandong and Gansu provinces were selected according to the coverage rate of iodized salt which was more than 95% and the levels of iodine and fluoride in drinking water which were less than or equal to 10 μg/L and 1 mg/L, respectively in 2012 and 2014. Before (2012) and after (2014) iodized salt concentration decline: children and pregnant women were selected;salt, drinking water and urinary samples were collected;the iodine content of salt, the iodine and fluoride content of drinking water, and urinary iodine were tested. B ultrasound was used to examine the thyroid volume and the total goiter rate (TGR) was calculated in children. The blood sample was collected to test thyrotropin (TSH) and thyroglobulin (Tg) in the 2 groups of subjects. Results Before iodized salt concentration decline, the children median urinary iodine (MUI) concentrations of Shandong and Gansu provinces were 291.4 and 321.9 μg/L, which at the over appropriate and overdose levels, respectively. MUI of Shandong and Gansu provinces were 220.5 and 274.7 μg/L in pregnant women, which were at adequate and over appropriate levels. After iodized salt concentration decline, MUI of Shandong and Gansu provinces were 199.8 and 178.2 μg/L in children, and were 178.6 and 159.2 μg/L in pregnant women, which were all at adequate levels. Children's TGR declined from 7.95%(7/88) to 5.88%(7/119) in Shandong Province, children's TGR rose to 5.77%(6/104) from 2.06%(2/97) in Gansu Province, there was no statistical differences (χ^2 = 0.34, 1.81, P > 0.05). Before and after iodized salt concentration decline, there were no differences statistically in TSH levels of children and pregnant women in Shandong and Gansu provinces (Z =- 1.08,- 0.83,- 1.30,- 0.80, P > 0.05). After iodized salt concentration decline, the Tg levels were significantly lower than that before intervention in children and pregnant women in Shandong Province (Z =- 10.78,- 7.04, P < 0.01);the Tg level was increased than that before intervention in pregnant women group in Gansu Province (Z =- 2.78, P < 0.01). Conclusion After iodized salt concentration declined, iodine nutrition and thyroid function status of Shandong Province are reasonable, but the indicators of Gansu Province have a trend of iodine deficiency, monitoring needs to be strengthened, and iodized salt content needs to be adjusted in time.