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Objective To understand the iodine nutritional status and thyroid function of different populations after 20 years of universal salt iodization in iodine deficiency area of Shanxi Province, and to provide data support for scientific iodine supplementation according to local conditions. Methods In 2014, six townships (Chengguan, Dadeng, Dengzhuang, Gucheng, Xiangling and Fencheng townships) in Xiangfen County, Linfen City, Shanxi Province, were selected as the place of investigation. Four hundred school-age children aged 6 - 12 years (school-age children), 400 child-bearing women aged 18 - 44 (child-bearing women), 400 pregnant women, 400 lactating women and their 0 - 6 months breast-feeding infants (breast-feeding infants), and 400 children aged 7 -24 months were selected by two-stage sampling method. Water samples of school-age children's domestic drinking water and salt samples for domestic consumption were collected, and the water iodine and salt iodine were detected by arsenic and cerium catalytic spectrophotometry ( recommended by the National Iodine Deficiency Disorders Reference Laboratory) and "General Test Method in Salt Industry-Determination of Iodine" (GB/T 13025.7-2012). Random urine samples of all subjects were collected, urine iodine was detected by "Method for Determination of Iodine in Urine by As3+-Ce4+ Catalytic Spectrophotometry" ( WS/T 107-2006 ) . Samples of filter paper dried blood spots (DBS) of school-age children, child-bearing women, pregnant women, lactating women and breast-feeding infants were collected, and serum total thyroxine (TT4) and thyroid stimulating hormone (TSH) levels were detected by time-resolved fluorescence immunoassay. Results A total of 290 water samples were collected, and the median of water iodine was 9.37μg/L. A total of 406 salt samples were collected, the median of salt iodine was 25.0 mg/kg, the coverage rate of iodized salt was 98.52％ (400/406), and the consumption rate of qualified iodized salt was 92.61％ (376/406). Urine samples of 389 school-age children, 379 child-bearing women, 363 pregnant women, 365 lactating women, 366 breast-feeding infants, and 366 children aged 7 - 24 months were collected, and the medians of urine iodine were 200.7, 175.0, 186.0, 113.2, 285.8 and 204.8 μg/L, respectively. Among them, school-age children, breast-feeding infants, and children aged 7-24 months were over the appropriate level, while the rest populations were at the iodine appropriate levels. Blood samples of 402 school-age children, 397 child-bearing women, 398 pregnant women, 390 lactating women, and 386 breast-feeding infants were collected, and the medians of TT4 were 127.2, 110.2, 141.7, 95.8 and 139.0 nmol/L, respectively; the medians of TSH were 1.2, 0.9, 0.8, 0.9 and 0.9 mU/L, respectively, and they were all within the reference ranges. The abnormal rates of TT4 (8.46％, 33/390) and TSH (7.95％, 31/390) in lactating women were higher than those in school-age children, child-bearing women, pregnant women and breast-feeding infants [TT4 abnormal rates were 0.25％(1/402), 1.26％ (5/397), 0.50％ (2/398), 1.04％ (4/386), respectively; TSH abnormal rates were 1.24％ (5/402), 1.51％ (6/397), 1.51％ (6/398) and 0.78％ (3/386), respectively, P < 0.05]. The rate of thyroid dysfunction in lactating women (7.95％, 31/390) was higher than those in the rest populations [1.24％ (5/402), 1.51％ (6/397), 1.51％ (6/398), 0.78％ (3/386), P < 0.05]. Conclusions The iodine intake of different populations in the survey area is generally sufficient, and the current salt iodine content standard can meet the iodine nutrition needs of different populations. Lactating women have a high rate of thyroid dysfunction. It is suggested to stick to the strategy of universal salt iodization to prevent iodine deficiency hazards in iodine deficiency areas, and further strengthen the monitoring of iodine nutrition and thyroid function of pregnant women and lactating women.
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Building on the results of a United Nations International Children's Emergency Fund (UNICEF)-Iodine Global Network (IGN) Technical Working Group Meeting,a new UNICEF "Guidelines for Monitoring of Salt Iodization Programmes and Assessment of Iodine Nutrition in the Population" has been formulated.This document aims to guide program managers to improve the effectiveness of national salt iodization programs.The main content of the guide is interpreted in this paper.
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@#Iodine deficiency is regarded as the single most common cause of preventable mental impairment in communities with suboptimal intake of iodine. Universal Salt Iodization is the most effective and sustainable intervention strategy for prevention, control and elimination of iodine deficiency. Urinary iodine concentration is the biochemical indicator for assessing the iodine status of a population. This study was prompted by reports showing evidence of cretinism in Karimui-Nomane district in Simbu province. The major objectives were therefore to assess the availability of adequately iodized salt in households, the per capita discretionary intake of salt per day and the iodine status of school children (age 6–12 years) in Karimui-Nomane, the district of concern, and Sina Sina Yonggomugl, a comparison district in Simbu province. Iodine level was assessed in salt samples collected from randomly selected households in both districts. The head of each household completed a questionnaire on knowledge, attitudes and practices related to salt iodization. Urinary iodine concentrations were measured in spot urine samples collected from randomly selected 6 to 12 years old children from selected primary schools in the two districts. 82.4% and 63.8% of salt samples from Karimui-Nomane and Sina Sina Yonggomugl respectively were adequately iodized above the national standard of 30ppm. The mean per capita discretionary intake of salt in households in Karimui-Nomane district was 4.62 ± 0.42 g/day, and in Sina Sina Yonggomugl district was 6.0 ± 2.61g/day. At measured levels of iodization (mean iodine content 34.7ppm and 32.7ppm respectively), this amount of salt would provide the recommended intake of iodine (150ug/day). However, for children in Karimui-Nomane the median UIC was 17.5μg/L and the interquartile range (IQR) was 15.0 – 43.0μg/L. and in Sina Sina Yonggomugl, the median UIC was 57.5μg/L and the IQR was 26.3–103.0μg/L, indicating severe and mild iodine deficiency respectively. These apparently conflicting findings may be explained by the fact that only 34% of households in Karimui-Nomane and 72% of households in Sina Sina Yonggomugl had salt on the day of the survey. The results indicate that iodine deficiency is a significant public health problem in Karimui-Nomane and Sina Sina Yonggomugl districts in Simbu province, potentially because of lack of access to salt, rather than inadequate implementation of salt iodization. Further studies are needed to quantify access to salt for communities in areas that are not easily accessible like Karimui-Nomane district in Papua New Guinea and, if inadequate salt access is confirmed, to develop alternative or complementary strategies to salt iodization
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Objective To investigate the constituent changes of hospitalized thyroid cancer patients in Changhai Hospital (Shanghai. China) during nearly 20 years of universal salt iodization (USD . so as to understand the relationship between iodine intake and thyroid carcinoma. Methods We analyzed the patients with thyroid diseases in Changhai Hospital over the past 20 years before and after the adaptation of USI, and the annual constituent ratios of thyroid carcinoma were calculated. The patients with thyroid diseases were divided into four groups according to the years they were treated: 1993-1997 (group A) , 1998-2002 (group B) , 2003-2007 (group C) , and 2008 2012 (group D). The constituent ratios of thyroid carcinoma were compared between different groups. Results After the adoption of universal salt iodization in 1994, the constituent ratio of thyroid carcinoma decreased from 11. 36%(25/220) in 1993 to 7. 59%(18/237) , and then the ratio gradually increased again, reaching 20. 76%(318/1 532) in 2012. The constituent ratios of thyroid carcinoma in group A, B, C and D were 8. 01%(112/ 1 398). 9. 61%(241/2 508), 11. 655%(501/4 299) and 16. 57%CI 101/6 645), respectively. The constituent ratios of thyroid cancer in A, B groups (initial salt iodization period) were not significantly different (P = 0. 095) j while those in C, D groups (after long-term salt iodization) were increased significantly compared with those in A, B groups(P<0. 001). Conclusion Short-term iodine supplementation may have a certain inhibitory effect against thyroid carcinoma. The detection rate of thyroid carcinoma is apparently increased 10 years after iodine supplementation; long-term iodine supplementation might be one of the reasons for the increase.
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<p><b>OBJECTIVE</b>To assess the effect of different levels of salt iodine content on thyroid volume (ThV) distribution using data from the 1999, 2011, and 2014 Chinese national iodine deficiency disorder (IDD) surveys.</p><p><b>METHODS</b>Probability proportion to size (PPS) sampling method was used to obtain a representative national sample of 34,547, 38,932, and 47,188 Chinese children aged 8-10 years in 1999, 2011, and 2014 Chinese national IDD surveys, respectively. The iodine content in household iodized salt and urinary iodine concentration were measured and thyroid ultrasound examination was performed. The data were analyzed by SAS software using histograms and box plots. The skewness and kurtosis were calculated for testing the normality of ThV.</p><p><b>RESULTS</b>The median iodine content in household iodized salt dropped from 42.30 mg/kg in 1999 to 25.00 mg/kg in 2014. The median urinary iodine concentration of children aged 8-10 years decreased from 306.0 μg/L in 1999 to 197.9 μg/L in 2014. The median and interquartile range (IQR) of ThV in 1999, 2011, and 2014 surveys were 3.44 mL and 1.50 mL, 2.60 mL and 1.37 mL, 2.63 mL and 1.25 mL, respectively. The skewness and kurtosis of ThV distribution in 1999, 2011, and 2014 surveys were 1.34 and 5.84, 0.98 and 3.54, 1.27 and 5.49, respectively.</p><p><b>CONCLUSION</b>With reduced salt iodization levels, the median urinary iodine concentration and median ThV of children decreased significantly, and the symmetry of the ThV distribution improved.</p>
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Child , Female , Humans , Male , China , Iodine , Nutritional Status , Sodium Chloride, Dietary , Thyroid Gland , Diagnostic Imaging , UltrasonographyABSTRACT
Iodine is an essential trace element,its physiological function is realized through thyroid hormone,both iodine deficiency and excess have influences on human health.After 20-year implementation of universal salt iodization in China,the iodine deficiency disorders have been controlled effectively,while the problem of iodine excess emerged.Because of different geographical environment,dietary habits and physiological status,some people did exposed to high level of iodine.In recent years,domestic and foreign scholars carried out series of researches aiming at disclose the effects of iodine excess on human health.The health problems induced by high iodine intaking are goiter,hyperthyroidism,hypothyroidism,autoimmune thyroiditis and thyroid cancer et al.Therefore,when preventing and treating iodine deficiency,iodine excess should also be avoided,so as to achieve the ideal goal of adjust measurements according to local conditions,classification guidance,and scientific iodine supplementation.
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Objective To explore the impact of iodine nutrition on pregnant women before and after adjusting the iodine content in iodine salt.Methods Twelve counties (areas,cities) in Hangzhou were divided into urban,suburban and rural areas before and after adjusting the iodine content of salt.One survey spot was selected in each district and one hundred pregnant women were selected;family salt and urinary samples of each pregnant woman were collected.The levels of salt and urinary iodine were measured by the methods of picric sodium thiosulfate titrimetric (GB 13025.7-2012) and spectrophotometer (WS/T 107-2006),respectively.Results One thousand two hundred and thirty-nine and one thousand two hundred and thirty-three household salt samples were collected before and after adjusting the iodine content in iodine salt.The median of salt iodine of pregnant women (23.30 mg/kg) before adjusting the iodine content in iodine salt was lower than that after adjusting the iodine content in iodine salt (30.09 mg/kg,x2 =-4.71,P ＜ 0.01).The iodine salt coverage rate and the consumption rate of qualified iodized salt after adjusting the iodine content in iodine salt [93.92％ (1 158/1 233),93.84％ (1 157/1 233)] were higher than those before adjusting the iodine content in iodine salt [91.85％ (1 138/1 239),91.37％ (1 132/1 239),x2 =4.01,5.51,all P ＜ 0.05].The iodine salt coverage rate and the consumption rate of qualified iodized salt in urban and suburb areas after adjusting the iodine content in iodine salt [99.42％ (510/513),100.00％ (203/203),97.86％ (5021513),100.00％ (203/203)] were higher than those before adjusting the iodine content in iodine salt [86.71％ (450/519),98.00％ (196/200),77.26％ (401/519),85.00％ (170/200)],but the iodine salt coverage rate and the consumption rate of qualified iodized salt in rural area before adjusting the iodine content in iodine salt [94.62％ (492/520),86.92％ (452/520)] were higher than those after adjusting the iodine content in iodine salt [85.69％(443/517),76.98％ (398/517),x2=64.22,2.32,100.02,32.90,23.31,17.33,all P ＜ 0.05].One thousand two hundred and thirty-four and one thousand two hundred and thirty-one household urine samples were collected before and after adjusting the iodine content in iodine salt.The median of urinary iodine (MUI,114.80 μg/L) of pregnant women after adjusting the iodine content in iodine salt was lower than that before adjusting the iodine content in iodine salt (168.60 μg/L,x2 =36.92,P ＜ 0.01).The MUIs of pregnant women in urban,suburban,and rural areas (171.30,170.20 and 162.40 μg/L) before adjusting the iodine content in iodine salt were higher than those after adjusting the iodine content in iodine salt (101.00,149.48 and 119.90 μg/L,x2 =-7.78,-2.63,-6.28,all P ＜ 0.01).The differences of urinary iodine between groups were statistically significant in urban,suburban and rural areas after adjusting the iodine content in iodine salt (x2 =32.86,P ＜ 0.01),the MUI of pregnant women in urban areas was lower than those in the suburban and rural areas (x2 =6.70,8.13,all P ＜ 0.05).Conclusions After adjusting the iodine content of salt in Hangzhou,the iodine-nutrition level of pregnant women is decreased.But the consumption rates of qualified iodized salt and the MUIs in urban,suburb,rural areas are different,so the coverage of iodized salt at household level needs to be enhanced and the health education should be highlighted.
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Following the reveal of borderline iodine sufficiency among the Sarawakians from the 2008 National Iodine Deficiency Disorders (IDDs) survey, a mandatory universal salt iodization (USI) was implemented in Sarawak thereafter. This study aimed to determine the current status of USI in Sarawak after a 3-year implementation of USI from 2008 to 2011. The IDD survey was conducted between Jun 2011 to July 2011 involving six districts in Sarawak (Sarikei, Mukah, Kapit, Sibu, Bintulu and Miri). The schools were selected via multistage proportionate-to-population size sampling technique and the children were randomly selected via systematic sampling. A total of 19 schools and 661 children were recruited into the survey. Thyroid size was determined by palpation and was and graded according to the classification of the World Health Organization (grade 0-2). The iodine excretion level in spot morning urine was measured using in-house microplate method. The urinary iodine concentration (UIC) values were compared by Kruskal-Wallis test and Chi-square tests were used to compare categorical variables. A total of 610 school children were participated in the study (92.3%). The TGR of grade 1 and 2 was found to be 0.3% (n = 2). Overall the median UIC level was 154.2 (IQR, 92.7 - 229.8) µg/L, with the highest median UIC been observed in Sarikei [178.0 (IQR, 117.6 - 308.9) µg/L], followed by Mukah [174.8 (IQR, 99.0 - 224.3) µg/L)], Miri [158.6 (IQR, 92.3 - 235.4) µg/L], Sibu [147.0 (IQR, 89.8 - 221.4) µg/L], Bintulu [142.3 (IQR, 52.8 - 245.1) µg/L] and Kapit [131.0 (IQR, 88.6 - 201.9) µg/L]. One in every ten child was of iodine deficient (UIC < 50µg/L) while a third of the child (32%) were of adequate level of UIC. The present findings indicate that the mandatory USI successfully improves the iodine level of children in Sarawak. However, regular and proper monitoring of the UIC level in the communities is needed to prevent excessive iodine intake.
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Iodine is a micronutrient essential for the production of thyroid hormones. Iodine deficiency is the most common cause of preventable mental impairment worldwide. Universal salt iodization (USI) has been introduced in many countries as a cost-effective and sustainable way to eliminate iodine deficiency disorders for more than 25 years. Currently, the relationship between USI and iodine excess has attracted more attention. Iodine excess can lead to hypothyroidism and autoimmune thyroiditis, especially for susceptible populations with recurring thyroid disease, the elderly, fetuses, and neonates. Nationwide USI was introduced in China in 1996. This review focused on the effects of iodine excess worldwide and particularly in China.
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Aged , Humans , Infant, Newborn , China , Fetus , Hypothyroidism , Iodine , Micronutrients , Thyroid Diseases , Thyroid Gland , Thyroid Hormones , Thyroiditis, AutoimmuneABSTRACT
Iodine Deficiency Disorders (IDD) Control Programme in Sudan adopted salt iodization as the long-term strategy in 1994. In 2000, it was found that less than 1% of households were using adequately-iodized salt. The objectives of this study were to: (i) study the coverage and variation of different geographical regions of Sudan regarding access to and use of iodized salt, (ii) explore the possible factors which influence the use of iodized salt, (iii) develop recommendations to help in the implementation of the Universal Salt Iodization (USI) strategy in Sudan. This paper is based on the Sudan Household Health Survey (SHHS) dataset. A total sample of 24,507 households was surveyed, and 18,786 cooking salt samples were tested for iodine levels with rapid salt-testing kits. Nationally, the percentage of households using adequately-iodized salt increased from less than 1% in 2000 to 14.4%, with wide variations between states. Access to iodized salt ranged from 96.9% in Central Equatoria to 0.4% in Gezira state. Population coverage with iodized salt in Sudan remains very low. The awareness and political support for USI programme is very weak. National legislation banning the sale of non-iodized salt does not exist. Utilization of the already-existing laws, like the National Standardization and Metrology Law (2008), to develop a compulsory national salt specification, will accelerate the USI in Sudan.
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Objective To assess the improvement of intelligence quotient through an Universal Salt Iodization Supply Program,among children.Methods 3518 and 1611 children were selected from primary schools in Linxia Hui Autonomous Prefecture of Gansu in 2006 and 2010respectively.Intelligence quotient (IQ) were measured by the revised Chinese Combined Raven Test C2 (CRT-C2).Results In 2006,the average IQ of children aged 8-10 was 85.1,including 16.7％ of them with IQ≤69.The average IQ was between 80-90 in different counties and cities,with significant differences (P＜0.05).The average IQs were 92.0,90.6 and 81.8 among 8,9 and 10 years old children respectively with 10 year old' s low than those 8 and 9 year olds (P＜0.05).The average IQs of boys and girls were 84.5 and 85.6,but with no significant difference (P ＞0.05).The average IQ of children aged 8-10 in 2010 was 97.2 and 12 points higher than in 2006 (P＜0.05),but 8 IQ points (P＜0.05) less than the average level 105 from the overall of Gansu province.4.7％ of the children having an IQ≤69.IQ of children from Linxia city and Yongjing county,were up to the theoretical level of 100,with an average IQ at around 95 in other counties.The average IQs between counties or cities showed significant differences.The IQ of 8,9 year olds and 10 year olds did not present significant difference (P＞0.05),but in boys (98.8) and in girls (95.9) the difference was significant (P＜0.05).Conclusion The average IQ was close to the theoretical level (100) with the gradual implementation of universal salt iodization program,showing that the iodized salt did play a key role on children's intelligence.However,the average IQ was still lower than the average level of the whole Gansu province in 2010.
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Objective To explore the iodine level in the environment and the iodine status among the general population as well as the prevalence of thyroid nodules in Hangzhou city.Relationship between the prevalence of thyroid nodules and the policy of universal salt iodization in Hangzhou was also analyzed.Methods Questionnaire,a 3- day weighed dietary record method,and 3 days' 24- hour dietary recall method were used to understand the iodine nutrition status and dietary intake of iodine among the general population in the city.Drinking water,edible salt and morning urine were collected to determine iodine content.All objects under survey underwent the thyroid B ultrasonic examination.Statistical analysis was done by SPSS 13.0 and SAS 9.1.Results (1)In total,12 620 effective questionnaires were available,with 221 water samples,12 730 urine samples,and 3593 salt samples collected.12 515 objects underwent B ultrasonic examination,and 1848received dietary investigation.(2)Water iodine level of Hangzhou was in the range of 0.20-5.99 μg/L,with the median level as 2.58 μg/L.(3) Average daily dietary intake of iodine for adult males in Hangzhou was 289.2 lμg/d.The contribution of iodine intake from iodized salt was 74.4％.(4) The median of Hangzhou residents' urinary iodine was 178.80 μg/L,with the urinary iodine levels at 100 μg/L-,200 μg/L-,＜100 μg/L,and ≥300 μg/L groups were 37.14％,23.11％,21.05％,and 18.69％ respectively.Urinary iodine of pregnant women was 141.0 tg/L.(5) Incidence of thyroid nodules in females(28.6％ ) was higher than that of males(20.1％ ).The detection rate increased with age (6.4％ at group 6-,10.9％ at 12-,12.0％ at 18-,24.4％ at 40-,and 38.8％ at 65-) ; with the highest in urban area (29.8％),followed by suburbs (23.3％) and in rural area it showed the least (20.3％).Urinary iodine level was found lower among the population who had been detected with thyroid nodules (160.36 μ g/L) than those among the undetected population (182.00 μg/L).Conclusion Hangzhou appeared to be an area where the environmental was iodine deficient.Iodized salt was the major source of iodine intake.The iodine status among the general population seemed to be safe and suitable,but the iodine level for pregnant women was not sufficient.There was still no evidence indicating that the universal salt iodization policy in Hangzhou was associated with the prevalence of thyroid nodules.
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Background & objectives: Universal salt iodization (USI) was implemented in all counties of China in 1995. This study was undertaken to assess the status of iodine deficiency disorders control and prevention after 10 years of implementation of USI in a severe iodine deficiency region in China. Methods: Thirty primary school were selected in Gansu province utilizing cluster sampling methodology for the years 1995 and 2005. In each selected school, 40 children aged 8-10 yr were randomly selected for thyroid and IQ examination, and urinary samples were collected from 12. On the spot casual urine samples and salt samples were collected from a subset of children included in the study. In 2005, casual urine samples were also collected from 50 pregnant and lactating women in each cluster. Effect of health education was studied by a combination method of giving questionnaires to and observing students and families. Results: The total goiter rates (TGR) were found to be 13.5 and 38.7 per cent in 2005 and 1995 respectively. The medians urinary iodine excretion levels of children were 191.8 and 119.9 μg/l in 2005 and 1995. The median urinary iodine excretion level of women was 161.9 μg/l. The mean intelligence quotient (IQ) was 96.9 in 2005 significantly more than that in 1997 (P<0.05). The health education pass rate of children and women were 21.1 and 51.1 per cent respectively. Interpretation & conclusion: After ten years of universal salt iodization (USI), iodine nutrition of people improved and the current iodine nutrition status of population was adequate. Decrease in TGR and increase in IQ showed that IDD control and prevention had made great progress through ten years USI, salt iodization played the key role in IDD control and prevention for sustained elimination of IDD, the programme of USI and other measures like health education should be persisted and enforced.
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Child , China/epidemiology , Dietary Supplements , Female , Goiter/diet therapy , Goiter/epidemiology , Goiter/prevention & control , Government Programs , Humans , Intelligence , Iodine/deficiency , Iodine/therapeutic use , Male , Population Surveillance , Pregnancy , Program Evaluation , Schools , Sodium Chloride, Dietary/therapeutic use , Thyroid Diseases/diet therapy , Thyroid Diseases/epidemiology , Thyroid Diseases/prevention & controlABSTRACT
A cross-sectional survey of 3589 adolescents was conducted in three cities from different typical geographical zones of Guangdong province. The median urinary iodine concentrations (MUI) of adolescents in Nanxiong, Guangzhou and Maoming were 286.6,204.1 and 166.0μ/L, respectively. The MUI of all these adolescents Was 231.7μg/L, which was slightly higher than the current World Health Organization recommendation.
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Objective To investigate and evaluate the detection and the variety of histology type constituent of the thyroid malignant tumor before and after universal salt iodization.Methods 1011 clinical pathological data of thyroid malignant tumor confirmed pathologically from 1961 to 2000 was retrospectively analyzed.The detection rate of thyroid malignant tumor,the constituent ratios of each histology type and the changes of age and sex distribution in main types of thyroid malignant tumor were determined.Results The total detection rate of thyroid malignant tumor after universal salt iodization (USI) (0.69%) were obviously increased compared with before universal salt iodization(0.46%,P40 years old) than before USI(≤40 years old).The incidence rates of thyroid malignant tumor in female patients were higher than male patients before and after USI.Conclusion The proportion and average age of thyroid malignant tumor increases after USI.The histological types of thyroid carcinoma have changes after USI:the proportion of PC increases obviously,the proportion of FC decreases accordingly.The average age of thyroid malignant tumor sufferers tends to increase and the peak ages of PC,FC and UC raise after USI.
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Objective To investigate the epidemiology of hyperthyroidism in three rural communities with different iodine intake after universal salt iodization (USI) since 1996 as well as the influence of USI on the incidence of hyperthyroidism. Methods Inhabitants in Panshan community did not take iodized salt whereas inhabitants in Zhangwu and Huanghua communities have taken iodized salt since 1996. The thyroid function, thyroid autoantibodies, urinary iodine concentration and thyroid B ultrasound were performed in 1103, 1584 and 1074 subjects respectively in the three communities and the number of hyperthyroidism patients between 1991 and 1999 was collected to calculate the yearly average incidence of hyperthyroidism. Results The median urinary iodine concentrations in Panshan, Zhangwu and Huanghua were 103 ?g/L, 375 ?g/L and 615 ?g/L, respectively (P0.05) andtheprevalenceofsubclinicalhyperthyroidism was 3.7%, 3.9% and 1.1%, respectively. Comparing the yearly average incidence of hyperthyroidism of 1996～1999 with that of 1991～1995, a significant increased incidence in Panshan, while a slight but insignificant elevated one in Zhangwu and a fixed one in Huanghua were found. Conclusion USI can not result in a raise of the prevalence of active hyperthyroidism as well as subclinical hyperthyroidism. The increase of iodine intake is not the only explanation for the raising of the incidence of hyperthyroidism.
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Objective To investigate the effect of universal salt iodization (USI) on the profile of in-patient thyroid diseases. Methods Informations on thyroid diseases were collected by retrospective approach in hospitalized patients. Results With USI for 1-4 years, the incidence of thyroid diseases in the total in-patient cases increased from 7.6‰ to 11.0‰, the female/male ratio increased from 3.6 to 4.1, patients aged