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Objective: To reveal the relationship between iodine nutrition and the change of spectrum on thyroid diseases through comparing the different iodine environments pre- and post- the universal salt iodization(USI)campaign., Methods: To compare the urinary iodine concentration between 1000 normal people and 5998 patients with thyroid disease who had undergone surgical operations, from 4 major cities, including iodine deficient and rich areas of Guangxi Zhuang Autonomous Region., Results: After USI was put into practice, the urinary iodine concentration of patients with thyroid appeared higher than those of normal people(324.3 µg/L vs. 238.5 µg/L, P < 0.05). The urinary iodine concentrations of nodular goiter,Graves disease, toxic nodular goiter, thyroid papillary carcinoma and Hashimoto's thyroiditis were higher than those before the USI was taken(263.8 µg/L vs. 69.75 µg/L, 289.7 µg/L vs. 228.3 µg/L, 346.8 µg/L vs. 268.4 µg/L, 350.3 µg/L vs. 316.2 µg/L and 378.5 µg/L vs. 305.8 µg/L). The proportions of toxic nodular goiter, thyroid papillary carcinoma and Hashimoto's thyroiditis appeared as 7.59% vs. 4.80%, 5.85% vs. 4.02% and 3.88% vs. 2.46%, all higher than those before the implementation of USI, except the nodular goiter which showed a reduction (63.56% vs. 69.75%)., Conclusion: The spectrum of thyroid diseases appeared an obvious change in Guangxi within the last 10-year implementation of USI. However, the excessive intake of iodine might serve as a risk factor for toxic nodular goiter, thyroid papillary carcinoma and Hashimoto's thyroiditis.

Objective: To evaluate the iodine nutrition level of population in Zhejiang province and to analyze the relevant influencing factors from 2009 to 2011., Methods: From October 2009 to October 2011, a total of 19 517 subjects were recruited in this cross sectional survey, by multistage stratified cluster random sampling method. The subjects were all living over three years in Zhejiang province. The basic information and life styles were interviewed by questionnaires; and the samples of drinking water, edible salt and urines were separately collected from the subjects to test the content of iodine. In total, 16 228 subjects answered the questionnaire, and 265 samples of drinking water, 7811 samples of edible salt and 19 517 samples of urine were collected. Then, we analyzed the distribution of iodine in water, edible salt and urine samples, as well as the relevance., Results: The median (25% - 75% percentile) of water iodine was 2.42 (1.17 - 6.28) µg/L in drinking water among Zhejiang residents; while separately 2.79 (1.60 - 6.87) µg/L in city and 2.04 (1.03 - 5.29) µg/L in country side (Z = 2.07, P < 0.05). The figures turned out to be 2.17 (1.22 - 5.73) µg/L, 2.77 (1.88 - 6.87) µg/L, and 1.40 (0.77 - 5.65) µg/L, respectively, in coastal areas, coastal periphery areas and inland areas (χ(2) = 11.16, P < 0.05). The median (25% - 75% percentile) of salt iodine was 28.80 (22.93 - 32.40) mg/kg; while separately 29.00 (24.50 - 32.60) mg/kg and 28.50 (13.90 - 32.29) mg/kg in city and country side (Z = 6.32, P < 0.05). The figures turned out to be 25.19 (0.00 - 30.20) mg/kg, 29.00 (26.60 - 31.70) mg/kg and 32.40 (28.94 - 36.30) mg/kg, respectively, in coastal areas, coastal periphery areas and inland areas (χ(2) = 1581.62, P < 0.05). The coverage rate of iodized salt was 79.54% (6213/7811) in all province. The urinary iodine median was 160.74(97.20 - 247.00) µg/L, while the urinary iodine median in pregnant women was 137.99 (82.40 - 215.30) µg/L, lower than the recommended optimal levels, which was 150 - 249 µg/L. The figures turned out to be 153.45(92.00 - 237.50) µg/L in city and 168.00 (102.18 - 257.00) µg/L in country side (Z = -9.25, P < 0.05); while in coastal, coastal periphery place and inland areas, the median were separately 156.00 (94.29 - 242.80) µg/L, 150.14 (94.70 - 227.00) µg/L and 187.70 (109.00 - 276.80) µg/L (χ(2) = 194.12, P < 0.05). The analysis of relevance between urine iodine, water iodine and iodized salt showed that the urine iodine would increase as long as the iodized salt increased; and the difference had statistical significance (χ(2) = 440.88, P < 0.01). And there were no relevance between urine iodine level and the water iodine level (χ(2)cmh = 0.57, P = 0.45). The analysis of the influencing factors showed that education background (χ(2) = 14.17, P < 0.05), different styles of career (χ(2) = 16.15, P < 0.01) and diet habits (χ(2) = 108.63, P < 0.01) could influence the level of urine iodine., Conclusion: Iodine was deficient in Zhejiang province. The nutrition level of iodine was fine in Zhejiang in 2009, however, the coverage rate of iodine was commonly low in coastal areas, especially the pregnant women suffered from iodine deficiency. In our study, the factors influencing the urine iodine level included iodized salt, age, education background and diet habits.

To verify the existence and reveal the epidemiological characteristics of endemic iodide-induced goiter in Jiangsu Old Yellow River flooded plain, 12 spots were selected in this survey. The results showed that the total goiter rate of 22.18% by palpation and 12.83% by B-ultrasound which surpassed the 5%-cutpoint-recommended jointly by WHO/UNICEF/ICCIDD. The urinary iodine median was 962 micrograms/L in 607 samples. The average 24 hours I31iodine-emissivity ratio was 4.6 +/- 0.3% with most of the serum TSH, T4, T3 within normal ranges. Of 1049 water samples in 65 towns, 771 had iodine content over 300 micrograms/L with water iodine concentration over 300 micrograms/L in 52 towns. These findings suggested that goiter in this plain had been endemic which related to excessive iodine in shallow well water. Heavy load of iodine over general population was noticed.

Dun Hua is a district where endemic goiter has been prevalent. Residents commenced to eat iodined salt ten years ago. We studied 469 people in this district and discovered that the incidence of endemic goiter had somehow come down but still kept 10.4%. However, the incidence of thyroid cancer went up to 1.9% with the incidence of thyroiditis 0.85%. Pathological characteristic of endemic goiter frequently appeared adenoniatoid feature with some atypical hyperplasia follicles which facilitates the cancerization in the fibrigenic part. Reasons accounted for the endemic goiter occurrance might not only relate to the insufficient intake of iodined salt but also to the increase of iodine excretion from the body. The increase of iodine excretion may be related to the factors as varieties of subsidiary food and vegetables as well as personal habitualness on food and drinks.

Intelligence in children without iodine supplement during their fetal and infant periods, and in those born three to four years after the implementation of stable supply of iodized salt in the areas with endemic cretinism and goiter was tested with Standord-Binet method. Results indicated there existed a lot of mental retarded children in the iodine-deficiency areas, with most of them born before the implementation of iodine supplement. In order to study the changes of intelligence development in children probably induced by stable supply with iodine, the tested children living in the areas with endemic cretinism were followed-up for two years, and no improvement in children's intelligence could been seen. It suggested that impairment to children's intelligence development caused by iodine deficiency during their fetal and infant periods was irreversible.

An investigation on children's intelligence and the metabolism of iodine and fluorine in high iodine and fluorine regions was carried out. The results were as follows. In high iodine and high fluorine areas, the thyroid enlargement prevalence rate among inhabitants and that among children were 3.8% and 29.8%, respectively. The dental fluorosis prevalence rate among inhabitants and that among children was 35.48% and 72.9%, respectively. The pupils' average intelligence quotient (IQ) was 76.67 +/- 7.75, slightly lower than the control point, but that of low intelligent pupils was 16.7%. The urinary iodine and urinary fluoride were 816.25 +/- 1.80 micrograms/L and 2.08 +/- 1.03 mg/L, respectively, markedly higher than the control point. The thyroid iodine-131 (131I) uptake rate was markedly lower than the control point. The values at 3 h and 24 h were 9.36 +/- 1.55% and 9.26 +/- 4.63%, respectively. The serum TSH was obviously higher than the control point. These results indicate that high iodine and high fluorine exert severe damage to human body.