Interpretation of Guidelines to Iodine Supplementation for Chinese Residents / 中国实用内科杂志

The article makes an interpretation of the key contents in the Guidelines to Iodine Supplementation for Chinese Residents published this year. Iodine is a key component of the thyroid hormone. Sufficient iodine intake is crucial for thyroid hormone synthesis and brain development of offspring. Universal salt iodization is the most effective strategy to compensate the iodine deficiency in daily food. For pregnant women, daily iodine requirements increase. Patients with autoimmune thyroiditis need to maintain adequate iodine status while the goiter patients should be distinguished whether it is caused by iodine deficiency or iodine excess. Iodine deficiency not only increases the prevalence of thyroid nodules but also increases the pathological types of anaplastic thyroid cancer and follicular thyroid cancer.

Association between iron deficiency and prevalence of thyroid autoimmunity in pregnant and non-pregnant women of childbearing age: a cross-sectional study / 中华医学杂志(英文版)

Background@#Thyroid autoimmunity (TAI) is prevalent among women of reproductive age and associated with adverse pregnancy outcomes. This study aimed to investigate the association between iron nutritional status and the prevalence of TAI in women during the first trimester of pregnancy and in non-pregnant women of childbearing age.@*Methods@#Cross-sectional analysis of 7463 pregnant women during the first trimester of pregnancy and 2185 non-pregnant women of childbearing age nested within the sub-clinical hypothyroid in early pregnancy study, a prospective collection of pregnant and non-pregnant women’s data, was conducted in Liaoning province of China between 2012 and 2015. Serum thyrotropin, free thyroxine, thyroid peroxidase antibodies (TPOAbs), thyroglobulin antibodies (TgAbs), serum ferritin, and urinary iodine were measured. Iron deficiency (ID) was defined as serum ferritin <15 μg/L and iron overload (IO) was defined as ferritin >150 μg/L. TPOAb-positive was defined as >34 U/mL and TgAb-positive was defined as >115 U/mL. Multilevel logistic regression was conducted to examine the association between TAI and different iron nutritional status after adjusting for potential confounders.@*Results@#The prevalence of isolated TPOAb-positive was markedly higher in women with ID than those without ID, in both pregnant and non-pregnant women (6.28% vs. 3.23%, χ2 = 10.264, P = 0.002; 6.25% vs. 3.70%, χ2 = 3,791, P = 0.044; respectively). After adjusting for confounders and the cluster effect of hospitals, ID remained associated with TPOAb-positive in pregnant and non-pregnant women (odds ratio [OR]: 2.111, 95% confidence interval [CI]: 1.241–3.591, P = 0.006; and OR: 1.822, 95% CI: 1.011–3.282, P = 0.046, respectively).@*Conclusion@#ID was associated with a higher prevalence of isolated TPOAbs-positive, but not with isolated TgAb-positive, in both pregnant women during the first trimester of pregnancy and non-pregnant women of childbearing age, while IO was not associated with either isolated TPOAb-positive or isolated TgAb-positive.@*Clinical trial registration@#ChiCTR-TRC-13003805, http://www.chictr.org.cn/index.aspx.

Association between iron deficiency and prevalence of thyroid autoimmunity in pregnant and non-pregnant women of childbearing age: a cross-sectional study / 中华医学杂志(英文版)

BACKGROUND@#Thyroid autoimmunity (TAI) is prevalent among women of reproductive age and associated with adverse pregnancy outcomes. This study aimed to investigate the association between iron nutritional status and the prevalence of TAI in women during the first trimester of pregnancy and in non-pregnant women of childbearing age.@*METHODS@#Cross-sectional analysis of 7463 pregnant women during the first trimester of pregnancy and 2185 non-pregnant women of childbearing age nested within the sub-clinical hypothyroid in early pregnancy study, a prospective collection of pregnant and non-pregnant women's data, was conducted in Liaoning province of China between 2012 and 2015. Serum thyrotropin, free thyroxine, thyroid peroxidase antibodies (TPOAbs), thyroglobulin antibodies (TgAbs), serum ferritin, and urinary iodine were measured. Iron deficiency (ID) was defined as serum ferritin 150 μg/L. TPOAb-positive was defined as >34 U/mL and TgAb-positive was defined as >115 U/mL. Multilevel logistic regression was conducted to examine the association between TAI and different iron nutritional status after adjusting for potential confounders.@*RESULTS@#The prevalence of isolated TPOAb-positive was markedly higher in women with ID than those without ID, in both pregnant and non-pregnant women (6.28% vs. 3.23%, χ = 10.264, P = 0.002; 6.25% vs. 3.70%, χ = 3,791, P = 0.044; respectively). After adjusting for confounders and the cluster effect of hospitals, ID remained associated with TPOAb-positive in pregnant and non-pregnant women (odds ratio [OR]: 2.111, 95% confidence interval [CI]: 1.241-3.591, P = 0.006; and OR: 1.822, 95% CI: 1.011-3.282, P = 0.046, respectively).@*CONCLUSION@#ID was associated with a higher prevalence of isolated TPOAbs-positive, but not with isolated TgAb-positive, in both pregnant women during the first trimester of pregnancy and non-pregnant women of childbearing age, while IO was not associated with either isolated TPOAb-positive or isolated TgAb-positive.@*CLINICAL TRIAL REGISTRATION@#ChiCTR-TRC-13003805, http://www.chictr.org.cn/index.aspx.

Effects of Maternal Marginal Iodine Deficiency on Interactions between Cerebellar Bergmann Glia Cells and Purkinje Cells in Rat Offspring / 生物医学与环境科学（英文）

Iodine deficiency (ID) during early pregnancy has an adverse effect on children's psychomotor and motor function but the mechanism has not been clarified. Therefore, our aim was to study the effect of maternal marginal ID on cerebellar neurodevelopment and the underlying mechanism. After obtaining marginal ID rats, we examined interactions between Bergmann glia cells (BGs) and Purkinje cells (PCs) using immunofluorescence and expression of the glutamate transporter and receptor by western blot. Our results showed that marginal ID reduced the number of contacted points between BGs and PCs, and disturbed expression of the glutamate transporter and receptor. Our results support the hypothesis that marginal ID inhibits interactions of BGs-PCs, which may be involved in abnormal regulation of the glutamate transporter and receptor.

Initiating Characteristics of Early-onset Type 2 Diabetes Mellitus in Chinese Patients / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Type 2 diabetes mellitus (T2DM) has traditionally been considered to affect mainly the elderly; however, the age at diagnosis has gradually reduced in recent years. Although the incidence of young-onset T2DM is increasing, it is still not fully clear the onset characteristics and risk factors of early-onset T2DM. The aim of this study was to describe the initiating characteristics of early-onset T2DM in Chinese patients and evaluate the risk factors for diabetes mellitus.</p><p><b>METHODS</b>This cross-sectional controlled study was performed using a questionnaire survey method in outpatients of multiple centers in China. A total of 1545 patients with T2DM with an age at onset of <40 years were included, and the control group consisted of subjects aged <40 years with normal blood glucose level.</p><p><b>RESULTS</b>In patients with young-onset T2DM, the mean age and initial hemoglobin 1Ac at diagnosis were 32.96 ± 5.40 years and 9.59 ± 2.71%, respectively. Most of the patients were obese, followed irregular diet pattern and sedentary lifestyle, had life or work pressure, and had a family history of diabetes mellitus. Compared with subjects with normal blood glucose level, logistic regression analysis showed that waist-to-hip ratio (odds ratio [OR] 446.99, 95% confidence interval [CI] 42.37-4714.87), family history of diabetes mellitus (OR 23.46, CI 14.47-38.03), dyslipidemia (OR 2.65, CI 1.54-4.56), diastolic blood pressure (OR 1.02, CI 1.00-1.04), and body mass index (OR 0.95, CI 0.92-0.99) are independent factors for early-onset T2DM.</p><p><b>CONCLUSIONS</b>We observed that abdominal obesity, family history of diabetes mellitus, and medical history of hypertension and dyslipidemia are independent risk factors for early-onset T2DM. It is, therefore, necessary to apply early lifestyle intervention in young people with risk of diabetes mellitus.</p>

Efficacy and safety of avandamet or uptitrated metformin treatment in patients with type 2 diabetes inadequately controlled with metformin alone: a multicenter, randomized, controlled trial / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>At present, China has listed the compound tablet containing a fixed dose of rosiglitazone and metformin, Avandamet, which may improve patient compliance. The aim of this study was to evaluate the efficacy and safety of Avandamet or uptitrated metformin treatment in patients with type 2 diabetes inadequately controlled with metformin alone.</p><p><b>METHODS</b>This study was a 48-week, multicenter, randomized, open-labeled, active-controlled trial. Patients with inadequate glycaemic control (glycated hemoglobin [HbA1c] 7.5-9.5%) receiving a stable dose of metformin (≥1500 mg) were recruited from 21 centers in China (from 19 November, 2009 to 15 March, 2011). The primary objective was to compare the proportion of patients who reached the target of HbA1c ≤7% between Avandamet and metformin treatment.</p><p><b>RESULTS</b>At week 48, 83.33% of patients reached the target of HbA1c ≤7% in Avandamet treatment and 70.00% in uptitrated metformin treatment, with significantly difference between groups. The target of HbA1c ≤6.5% was reached in 66.03% of patients in Avandamet treatment and 46.88% in uptitrated metformin treatment. The target of fasting plasma glucose (FPG) ≤6.1 mmol/L was reached in 26.97% of patients in Avandamet treatment and 19.33% in uptitrated metformin treatment. The target of FPG ≤7.0 mmol/L was reached in 63.16% of patients in Avandamet treatment and 43.33% in uptitrated metformin treatment. Fasting insulin decreased 3.24 ± 0.98 μU/ml from baseline in Avandamet treatment and 0.72 ± 1.10 μU/ml in uptitrated metformin treatment. Overall adverse event (AE) rates and serious AE rates were similar between groups. Hypoglycaemia occurred rarely in both groups.</p><p><b>CONCLUSIONS</b>Compared with uptitrated metformin, Avandamet treatment provided significant improvements in key parameters of glycemic control and was generally well tolerated.</p><p><b>REGISTRATION NUMBER</b>ChiCTR-TRC-13003776.</p>

Effectiveness of different waist circumference cut-off values in predicting metabolic syndrome prevalence and risk factors in adults in China / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To study the effectiveness of waist circumference cut-off values in predicting the prevalence of metabolic syndrome (MetS) and risk factors in adults in China.</p><p><b>METHODS</b>A cross-sectional survey was condcuted in 14 provinces (autonomous region, municipality) in China. A total of 47,325 adults aged⋝20 years were selected by multistage stratified sampling, and questionnaire survey and physical and clinical examination were conducted among them. MetS was defined according to the International Diabetes Federation (IDF) criteria and modified IDF criteria.</p><p><b>RESULTS</b>The age-standardized prevalence of MetS was 24.2% (22.1% in men and 25.8% in women) and 19.5% (22.1% in men and 18.0% in women) according to the IDF criteria and modified IDF criteria respectively. The age-standardized prevalence of pre-MetS was 8.1% (8.6% in men and 7.8% in women) according to the modified IDF criteria. The prevalence of MetS was higher in urban residents than rural residents and in northern China residents than in southern China residents. The prevalence of central obesity was about 30% in both men and women according to the ethnicity-specific cut-off values of waist circumference for central obesity (90 cm for men and 85 cm for women). Multivariate regression analysis revealed no significant difference in risk factors between the two MetS definitions.</p><p><b>CONCLUSION</b>Using both the modified IDF criteria and ethnicity-specific cut-off values of waist circumference can provide more useful information about the prevalence of MetS in China. Conclusion Using both the modified IDF criteria and ethnicity-specific cut-off values of waist circumference can provide more useful information about the prevalence of MetS in China.</p>

Epidemiological study of the effects of smoking cigarette on thyroid gland / 中华流行病学杂志

<p><b>OBJECTIVE</b>To investigate the effect of cigarette smoking on thyroid gland volume, thyroid function and thyroid autoantibodies in the areas with different iodine intakes.</p><p><b>METHODS</b>A cross-sectional epidemiological study in Panshan (mild iodine-deficient area), Zhangwu (more than adequate iodine intake area) and Huanghua (iodine-excessive area) was conducted in 3761 subjects in 1999.80.2 % of them were followed up in 2004. Questionnaires, thyroid function, thyroid autoantibodies, urinary iodine concentration,and thyroid B ultrasound were performed.</p><p><b>RESULTS</b>The prevalence of goiter was higher in smokers than in non-smokers (15.1% vs. 11.5%, P< 0.05). The average thyroid volume was higher in smokers with phenomenon more obvious in Panshan and Huanghua areas. Data from logistic analysis showed that smoking cigarette was an independent risk factor of goiter. There was no difference in serum TSH and Tg level between smokers and non-smokers. The positive rate of TPOAb (>100 IU/ml) was higher in smokers than in non-smokers(10.8% vs. 9.0 % , P <0.05) and was especially obvious in Huanghua area. Smoking was a independent risk factor of increasing positive rate of TPOAb. During the prospective observation,it was found that the incidence of positive TPOAb(>,100 IU/ml) was 7.4% in the subjects that were from non-smokers turning to smokers and 2.9% in those whose smoking behavior did not change. Logistic analysis indicated that the shifting from non-smoking to smoking was independent risk factor for the increase on high incidence of positive TPOAb.</p><p><b>CONCLUSION</b>Smoking cigarette was a independent risk factor of goiter. Smoking was also a risk factor of increasing TPOAb positive rate. Shifting from not smoking to smoking was an independent risk factor of increasing high incidence of positive TPOAb.</p>

Expression of monocyte chemoattractant protein-1 in the pancreas of mice / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Type 1 diabetes has been recognized as an organ specific autoimmune disease owing to the immune destruction of pancreatic islet beta cells in genetically susceptible individuals. In both human and rodent models of type 1 diabetes, such as nonobese diabetic (NOD) mice, biobreeding rats, the disease has a distinct stage characterized by immune cells infiltrating in the pancreas (insulitis). The major populations of infiltrating cells are macrophages and T lymphocytes. Therefore, immune cell infiltration of pancreatic islets may be a crucial step in the pathogenesis of type 1 diabetes. Monocyte chemoattractant protein-1 can specifically attract monocytes in vivo. Interferon induced protein-10 has chemoattractant effects on the activated lymphocytes. In this study, we analysed the expression of monocyte chemoattractant protein-1 in the pancreas of mice and interferon inducible protein-10 mRNA in the pancreas of NOD mice, and discussed their possible role in the pathogenesis of type 1 diabetes.</p><p><b>METHODS</b>The immunohistochemical method and immunoelectronmicroscopy were used to evaluate the expression of monocyte chemoattractant protein-1 in the pancreas of NOD mice and BALB/c mice. RT-PCR was used to evaluate the expression of monocyte chemoattractant protein-1 and interferon inducible protein mRNA in NOD mice.</p><p><b>RESULTS</b>Monocyte chemoattractant protein-1 was positive in the pancreas of NOD mice, whereas negative in the pancreas of BALB/C mice. RT-PCR showed that monocyte chemoattractant protein-1 and interferon inducible protein-10 mRNA could be found in the pancreas of NOD mice. Immunoelectronmicroscopy demonstrated that monocyte chemoattractant protein-1 was produced by beta cells and stored in the cytoplasm of the cells.</p><p><b>CONCLUSIONS</b>Pancreatic islet beta cells produce monocyte chemoattractantprotein-1 in NOD mice. Monocyte chemoattractant protein-1 may play an important part in the pathogenesis of type 1 diabetes by attracting monocytes/macrophages to infiltrate pancreatic islets.</p>

Multivariate analysis of relationships between iodine biological exposure and subclinical thyroid dysfunctions / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To assess the relationships between iodine biological exposure and subclinical thyroid dysfunctions.</p><p><b>METHODS</b>The cross-sectional survey was performed to obtain the epidemiologic data of population in three communities with different iodine biological exposure: mild iodine deficiency [median urinary iodine concentration (MUI) of 50-99 microg/L], more than adequate iodine intake (MUI of 200-299 microg/L), and excessive iodine intake (MUI over 300 microg/L). Univariate and multivariate analysis (logistic regression analysis) were used to analyze the risk factors of subclinical hypothyroidism and subclinical hyperthyroidism.</p><p><b>RESULTS</b>Logistic regression analysis with sex and age controlled suggested that more than adequate iodine intake (OR = 3.172, P = 0.0004) and excessive iodine intake (OR = 6.391, P = 0.0001) increased the risk of subclinical hypothyroidism, while excessive iodine intake decreased the risk of subclinical hyperthyroidism (OR = 0.218, P = 0.0001). Logistic regression analysis including interaction of iodine intake and antibodies [thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TgAb)] suggested that excessive iodine intake was an independent risk factor of subclinical hypothyroidism (OR = 6.360, P = 0.0001), but independent protect factor of subclinical hyperthyroidism (OR = 0.193, P = 0.0001). More than adequate iodine intake and it's interaction with TgAb increased the risk of subclinical hypothyroidism independently, in addition, it decreased the risk of subclinical hyperthyroidism at the present of TPOAb.</p><p><b>CONCLUSION</b>Both excessive iodine intake and more than adequate iodine intake could increase risk of subclinical hypothyroidism, supplement of iodine should be controlled to ensure MUI within the safe range.</p>

Effect of different iodine intake on schoolchildren's thyroid diseases and intelligence in rural areas / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Reports are increasingly appearing on the side effects caused by excessive iodine intake. Our objective was to find out whether iodine excess would impair the thyroid function and intelligence of schoolchildren in rural areas of China.</p><p><b>METHODS</b>A comparative epidemiological study was made on thyroid function and intelligence of the schoolchildren in the areas of low, moderate or excessive intake of iodine. In the area of low intake of iodine (Panshan, Liaoning province, median urinary iodine (MUI) was 99 microg/L), of moderate intake of iodine (Zhangwu, Liaoning Province, MUI was 338 microg/L) and of excessive intake of iodine (Huanghua, Hebei Province, MUI was 631 microg/L). The numbers of schoolchildren from each area selected to take part in a Chinese version of Raven's Test were 190, 236 and 313, respectively, and then 116, 110 and 112 of them were tested for thyroid function, thyroid autoantibody (TAA) and urinary iodine (UI).</p><p><b>RESULTS</b>There were no significant differences in the incidences of overt hyperthyroidism, subclinical hyperthyroidism and overt hypothyroidism in Panshan, Zhangwu and Huanghua. But significant differences were found in the incidences of subclinical hypothyroidism (P = 0.001) in these three areas. The incidences of subclinical hypothyroidism in Huanghua and Zhangwu were 4.76 and 3.37 times higher than that in Panshan. TAA were negative in all the schoolchildren with subclinical hypothyroidism except for one. No significant difference was found among the rates of thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TGAb) in these three areas. Mean serum thyroglobulin (TG) value of Huanghua was markedly higher than those of the other two (P = 0.02). Mean serum TG value of Zhangwu was higher than that of Panshan but the difference was not significant. Mean IQ value of the schoolchildren in Huanghua was markedly higher than that for Zhangwu (P = 0.001). Mean IQ value of the schoolchildren in Panshan was lower than that of Huanghua and higher than that of Zhangwu but, again, the differences were not significant.</p><p><b>CONCLUSIONS</b>The increase of iodine intake may increase the risk for schoolchildren of subclinical hypothyroidism. In the area of iodine excess, most of the subclinical hypothyroidism cases are not of autoimmune origin. No obvious effect of excess iodine was found on mental development of schoolchildren.</p>

Determination of cut-off points of thyroid peroxidase antibody and thyroglobulin antibody and their clinical significance / 中华检验医学杂志

40 IU/ml were used as cut-off points.(4) TSH level was higher in subjects with positive thyroid autoantibodies than those without antibodies (P

Experimental investigation on iodine-induced autoimmune thyroiditis in NOD.H-2~(h4) mice / 中华内分泌代谢杂志

Objective To investigate the kinetic changes of inflammatory cell infiltration and thyroid autoantibodies in the development of iodine-induced autoimmune thyroiditis in NOD.H-2~(h4)mice.Methods Either 128 five-week-old NOD.H-2~(h4)mice or 128 Kunming mice were randomly divided into two groups,and received plain water or water containing 0.05% sodium iodide.At the time points of 1,2,4,8,12,16,and 24 week after receiving iodinated water,mice were anesthetized by diethyl ether and bled from eye socket vein,and their thyroid glands were collected.Indirect ELISA method was used to measure the levels of serum thyroglobulin autoantibodies (TgAb)and thyroid hormone.After being fixed with paraformaldehyde and embedded in paraffin,thyroid sections were stained with HE and used for morphometrieal analysis.Results In the iodine treated group of NOD.H-2~(h4) mice,autoimmune thyroiditis was observed as early as 1 week after they began receiving indinated water.The prevalence as well as the degree of autoimmune thyroiditis reached the maximum at 12 weeks and remained until 24 weeks.Serum TgAb level increased after 8 weeks of iodine ingestion in NOD.H-2~(h4) mice,then increased steadily throughout the 24 weeks of experiment.On the contrary,serum TgAb was not increased in the control group of Kunming mice.Conclusion Iodine may induce and exacerbate lymphocytic infiltration of the thyroid in genetically susceptible NOD.H-2~(h4) mice,and serum TgAb is just a marker of autoimmune thyroiditis.

Impact of iodine intake on thyroid diseases——A five-year prospective epidemiological study / 中华内分泌代谢杂志

Objective To evaluate the relationship between iodine intake level and the occurrence and development of thyroid diseases.Methods During the period of 1999-2004,a cross-sectional survey in 1999 and a 5-year follow-up survey were conducted in the 3 communities with different iodine intake levels in China:Panshan (mild deficiency),Zhangwu (more than adequate) and Huanghua (iodine excess).A total of 3 761 subjects were included in 1999 and 80.24% of them participated in the 5-year follow-up survey in 2004.The levels of serum thyroid hormones and thyroid autoantibodies were measured,and thyroid B ultrasound was performed.Results (1) The prevalence of overt hypothyroidism in 1999 in Zhangwu and Huanghua was 3.5 and 7.3 times,and that of subclinical hypothyroidism was 3.2 and 6.6 times as high as in Panshan,respectively.The 5-year cumulative incidence of subclinical hypothyroidism was 11.3 and 12.6 times as high as in Panshan,but no difference of incidence of overt hypothyroidism was found.(2) The prevalence of autoimmune thyroiditis (AIT) in 1999 in Zhangwu and Huanghua was 3.8 and 6.2 times,and the S-year cumulative incidence of AIT was 4.4 and 5.5 times as high as in Panshan.(3) During the 5-year follow-up period,the incidences of hypothyroidism in subjects with positive thyroid peroxidase antibody and euthyreidism in Zhangwu and Huanghua were 4.2 and 10.3 times as high as in Panshan.(4) No significant differences in both prevalence in 1999 and 5-year cumulative incidence of overt hyperthyroidism were found in the 3 communities.(5) The incidence of thyroid cancer was 19.37/100 000 per year in Huanghua,and all of the cases were papillary thyroid cancer,and no thyroid cancer was found in Zhangwu and Huanghua.Conclusion More than adequate or excessive dietary iodine intake may induce and promote the occurrence and development of hypothyroidism and AIT,therefore,median urinary iodine excretion (MUI)more than 200?g/L in the population appears not safe.The observation that a higher incidence of thyroid cancer occurred in the iodine excessive areas with MUI 600?g/L deserves further investigation.

Thyroid autoantibodies In a five-year follow-up survey of populations with different Iodine intakes / 中华内分泌代谢杂志

Objective To perform a follow-up survey about thyroid disorders in three rural communities with different iodine intakes in China,observe the incidences and natural outcomes of positive thyroid autoantibodies in euthyroid population,and also explore the influence of iodine intakes on these outcomes and autoantibodies.Methods In 1999,a cross-sectional study on thyroid disorders was performed in three rural communities of Pansan ( mild iodine deficient area),Zhangwu ( more than adequate iodine intake area) and Huanghua (excessive iodine intake area) in China.The 5-year follow-up study was performed in 2004.Both in 1999 and 2004,serum levels of TSH,thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TgAb) were measured with the same method.Iodine in urine and B ultrasound on thyroid were also examined.Results Among the euthyroid subjects with normal TSH level in 1999,an increased prevalence of positive TPOAb in Zhangwu and an increased prevalence of positive TgAb in Hnanghua were observed in 2004 (both P＜0.05 ).Most of euthyroid subjects with positive TPOAb or positive TgAb in 1999 remained positive thyroid antibodies in 2004. The percentage was even higher in those with high levels of antibodies.Thyroid dysfunction was more frequent in subjects with positive TPOAb and/or TgAh than in those without thyroid antibodies (14.44% vs 3.11%,P＜0.01).For those with positive antibodies in 1999,the incidence of hypothyroidism in 2004 was 1.32%,8.46% and 15.38% in Pansan,Zhangwu and Huanghua,respectively (P＜0.05).The 5-year cumulative incidences of positive TPOAb (≥50 U/ml) and TgAb (≥40 U/ml) were 2.81% and 3.82%,respectively.The incidence of positive TPOAb was the highest in Zhangwu ( 3.84% ).The incidence of positive TgAb was the highest in Huanghua (5.07%),significantly higher than those in other two areas (P＜0.05).Conclusion The incidence of thyroid dysfunction is higher in subjects with positive antibodies than that in those with negative antibodies.The high iodine intake is a risk factor of hypothyroidism in subjects with positive thyroid antibodies.Sustained excessive iodine intake increases the incidence of positive thyroid antibodies.

Incidences of hyperthyroidism in communities with different iodine intake levels:a five-year prospective and comparative epidemiological survey / 中华内分泌代谢杂志

Objective To analyze the relationship between different iodine intakes and epidemiological features of hyperthyroidism in 3 communities with different iodine intake levels,as well as to explore the risk factor for the pathogenesis of hyperthyroidism.Methods A cohort study was performed in 3 Chinese rural communities with long-term stable iodine nutrition status defined as mild deficient (Panshan),more than adequate (Zhangwu, previously mild iodine deficiency and salt iodization lasting 8 years until 2004) and excessive (Huanghua).A total of 3 761 (934 males,2 827 females) inhabitants aged above 13 participated in the original investigation in 1999 and 3 018(709 males,2 309 females) of them received identical examinations after 5 years.Results Median urinary iodine concentration of school-aged children was 87.61zg/L in Panshan,213.9?g/L in Zhangwu and 633.5?/L in Huanghua (P＜0.05) at fallowing up,and no statistic significance was found when comparing the corresponding data from original survey (83.5?g/L,242.9?g/L and 650.9?g/L).The accumulative incidence of hyperthyroidism was 13.6/1 000,9.4/1 000 and 8.1/1 000 (P＞0.05),being 16.4/1 000,11.2/1 000 and 9.1/1 000 (P＞0.05) in female,respectively in Panshan,Zhangwu and Huanghua.In original healthy subjects (without history of thyroid disease and overt thyroid dysfunction) merely with either positive thyroid peroxidase antibody (TPOAb＞50 IU/ml) or thyroglobulin antibody (TgAb＞40 IU/ml),the accumulative incidence of newly diagnosed hyperthyroidism was not significantly different among 3 communities in follow-up survey.TSH＜0.3 mIU/L,positive TPOAb or goiter in original healthy participants were associated with the occurrence of overt hyperthyroidism in 5 years [ Logistic Regression,OR = 5.7 (95% CI 2.1-15 ),OR = 3.8 (95% CI 1.7-8.7 ) and OR = 3.1 (95% CI 1.4-6.8) respectively].Conclusion Iodine supplementation in mild iodine deficient area does not increase the incidence of overt hyperthyroidism ultimately.Long-term excessive iodine intake does not affect the incidence and pattern of hyperthyroidism.TSH＜0.3 mIU/L,positive TPOAb and goiter in healthy individuals are the risk factors for hyperthyroidism.

A five-year follow-up study of hypothyroidism in areas with different iodine intakes / 中华内分泌代谢杂志

Objective To investigate epidemiologieal characteristics of hypothyroidism and factors influencing its outcome in the areas with different iodine intakes.Methods An epidemiologic follow-up study of thyroid diseases was performed in Panshan (iodine deficient),Zhangwu [mild iodine deficiency before universal salt iodination (USI) and more than adequate iodine intakes after USI ] and Huanghua ( iodine excessive) in China.A total of 3 761 subjects were investigated in 1999,and 3 018 (80.2% ) of them were followed up in 2004.FT_4,FT_3,TSH,thyroid autoantibodies and urinary iodine concentration were determined and thyroid B ultrasound was performed in all participants.Results Five-year cumulative incidence of overt hypothyroidism was 0.23%,0.47% and 0.35% in Panshan,Zhangwu and Huanghua,respectively.Twenty patients with autoimmune- induced overt hypothyroidism did not comply with the physician's orders to take thyroxine.Thyroid function spontaneously turned to normal in 55% of them,turned to subclinical hypothyroidism in 20% and maintained overt hypothyroidism in 25%.Five-year cumulative incidence of subclinical hypothyroidism in Zhangwu (2.60%) and Huanghua (2.89%) were significantly higher than that in Panshan(0.23% ) (both P＜0.01 ).One hundred patients with subclinical hypothyroidism were followed up,and 5% of them developed overt hypothyroidism,66% turned to euthyroidism and 29% maintained subclinical hypothyroidism.Raised serum TSH (＞6 mU/L) in the original survey ( OR = 3.4),positive thyroid autoantibodies in the follow-up study ( OR = 5.3 ) and more than adequate iodine supplementation in the mild iodine-deficient population ( OR = 8.0) were risk factors influencing outcome of subclinical hypothyroidism.Conclusion More than adequate iodine supplementation among a population in the mildly iodine-deficient area may increase the incidence of overt and subolinical hypothyroidism, and also influence outcome of subclinical hypothyroidism.