Fuse Yozen, Igari Tomoyuki, Yamada Chieri, Sakano Shoji, Ito Harumichi, Umenai Takusei, Irie Minoru
Department of Neonatology, Toho University School of Medicine, The University of Tokyo, Japan.
Clin Endocrinol (Oxf). 2003 Sep;59(3):298-306. doi: 10.1046/j.1365-2265.2003.01840.x.
Although endemic goiter had been recognized in most parts of the country, there are few available data on iodine-deficiency disorders (IDDs) in Mongolia. This study aimed to characterize the current status of iodine deficiency in Ulaan Baatar, Mongolia's capital city.
Cross-sectional, observational study designed and performed according to the surveillance methods for IDD prevalence recommended by WHO/UNICEF/ICCIDD.
A total of 505 schoolchildren aged 9-14 years (237 girls and 268 boys) and 138 mothers and their neonatal infants were selected to clinical and biochemical examination of the thyroid in 1996 and 1999.
The anthropometric measurements, thyroid volume determined by ultrasound, blood TSH and FT4 concentrations, urinary iodine concentration and iodine content of salt consumed in households.
Median thyroid volumes based on age were generally higher than those in iodine-sufficient areas and comparative to those reported in mild iodine-deficiency areas. Application of the updated WHO/ICCIDD reference values in iodine-replete European schoolchildren to the Mongolian children aged 10-12 years resulted in a goiter prevalence of 43.3%. The median value of urinary iodine concentration was 152.5 micro g/l (1.20 micro mol/l) and 40.3% of children excreted iodine below 100 micro g/l. Iodized salt (> 40 ppm) was consumed in 63.1% of households and in the children using noniodized salt their urinary iodine concentration was lower than those using ionized salt. In postpartum women, median thyroid volume and urinary iodine concentration were 11.3 ml and 107 micro g/l (0.84 micro mol/l), respectively, and 46% of women excreted less than 100 micro g/l (0.79 micro mol/l) of iodine. Of their neonates, 17.8% had elevated blood TSH levels (> 5 mU/l). In a 1999 survey, the goiter prevalence and ratio of low iodine excretion in schoolchildren decreased to 29.8% and 31.3%, respectively, while median urinary iodine concentration remain unchanged (160 micro g/l; 1.26 micro mol/l).
The present study clearly indicates the presence of mild iodine deficiency in Mongolia. Enlarged thyroid gland and normal iodine excretion observed in schoolchildren living in Ulaan Baatar may result from the residual effects of iodine deficiency previously and presumably still exist in the city. Slight reduction in the rate of children with enlarged thyroid and low urinary iodine excretion after the onset of national iodinization programme suggests incomplete normalization of thyroid volume in children and that the correction of iodine deficiency is now in progress in Ulaan Baatar. Further nationwide surveys together with monitoring the progress of the national programme eliminating IDD are required in suburban areas surrounding the city and also in rural areas.
尽管该国大部分地区都已认识到地方性甲状腺肿，但蒙古关于碘缺乏病（IDD）的可用数据很少。本研究旨在描述蒙古国首都乌兰巴托碘缺乏的现状。
根据世界卫生组织/联合国儿童基金会/国际控制碘缺乏病理事会推荐的碘缺乏病患病率监测方法设计并开展的横断面观察性研究。
1996年和1999年共选取了505名9至14岁的学童（237名女孩和268名男孩）以及138名母亲及其新生儿进行甲状腺的临床和生化检查。
人体测量指标、通过超声测定的甲状腺体积、血液促甲状腺激素（TSH）和游离甲状腺素（FT4）浓度、尿碘浓度以及家庭食用盐的碘含量。
按年龄划分的甲状腺体积中位数总体上高于碘充足地区，与轻度碘缺乏地区报告的数值相当。将欧洲碘充足学童更新后的世界卫生组织/国际控制碘缺乏病理事会参考值应用于10至12岁的蒙古儿童，甲状腺肿患病率为43.3%。尿碘浓度中位数为152.5微克/升（1.20微摩尔/升），40.3%的儿童碘排泄量低于100微克/升。63.1%的家庭食用加碘盐（>40 ppm），食用非加碘盐的儿童尿碘浓度低于食用加碘盐的儿童。产后妇女的甲状腺体积中位数和尿碘浓度分别为11.3毫升和107微克/升（0.84微摩尔/升），46%的妇女碘排泄量低于100微克/升（0.79微摩尔/升）。其新生儿中，17.8%的婴儿血TSH水平升高（>5 mU/l）。在1999年的一项调查中，学童的甲状腺肿患病率和低碘排泄率分别降至29.8%和31.3%，而尿碘浓度中位数保持不变（160微克/升；1.26微摩尔/升）。
本研究清楚地表明蒙古存在轻度碘缺乏。居住在乌兰巴托的学童甲状腺肿大且碘排泄正常，可能是先前碘缺乏的残留影响，且推测该市仍然存在这种影响。国家碘盐普及计划实施后，甲状腺肿大儿童和尿碘排泄低的儿童比例略有下降，这表明儿童甲状腺体积尚未完全恢复正常，乌兰巴托的碘缺乏纠正工作正在进行中。需要在该市周边郊区以及农村地区开展进一步的全国性调查，并监测国家消除碘缺乏病计划的进展情况。
