Thyroid autoimmunity is associated with higher urinary iodine concentrations in an iodine-deficient area of Northwestern Greece.

Northwestern Greece was identified in the 1960s for its high prevalence of endemic goiter and iodine deficiency. Although iodized salt has been commercially available since then, a recent epidemiological survey of 3916 schoolchildren found that low-grade goiter is still prevalent in endemic proportions (21%). The aim of this study was to further assess the cause of goiter and the severity of iodine deficiency in children from this endemic area of Greece. Of the 800 children with clinically detectable goiter, 97 children (60 girls and 37 boys, 8-15 years) were recruited for determination of urinary iodine excretion, as well as assessment of thyroid volume and function and detection of antithyroid antibodies. The median urinary iodine concentration was 8.4 microg/dL, indicative of a mild iodine deficiency. Thyroid function was normal in all but 11 children who had subclinical hypothyroidism. Sixteen children (16.5%), including all those with subclinical hypothyroidism, were positive for antithyroid antibodies. Their median urinary iodine concentration (20.6 microg/dL) was higher compared to children who were negative for antibodies (7.4 microg/dL; p<0.001). The mean thyroid volume by ultrasonography (12.2+/-4.1 mL) was above the upper limit of normal for this age group. Thyroid volume was inversely related to the urinary iodine content in the children with negative antithyroid antibodies. Iodine deficiency is still prevalent in northwestern Greece although of mild severity and constitutes the primary cause of goiter among schoolchildren. However, it appears that autoimmune thyroiditis is emerging as a frequent cause of goiter in those children with sufficient iodine intake.     

Natural course of autoimmune thyroiditis after elimination of iodine deficiency in northwestern Greece.

We have previously reported the elimination of iodine deficiency and increasing prevalence of autoimmune thyroiditis (AIT) among schoolchildren in northwestern Greece. This study followed up 29 children (12-18 years old) with AIT for 5 years to track its course in the postiodination era. At diagnosis, thyroid peroxidase autoantibodies (TPOAbs) were positive in 25 children (86%) and became positive in all children during follow-up. Thyroglobulin autoantibodies (TgAbs) were positive in 17 children at diagnosis (59%) and became positive in 3 more children (69%). Both antibody types increased by the end of the observation period (p < 0.005). Regarding thyroid function, 7 children (24%) at diagnosis had subclinical hypothyroidism that persisted and 4 more children developed subclinical hypothyroidism during the study period (38%). Only 5 of these children (45%) had positive TgAbs. There was an increase in thyrotropin (TSH) so that at the end of the study all children had TSH greater than 2.5 mU/L but none developed overt hypothyroidism. Thyroid hypoechogenicity that increased over time was seen in all children, especially in those with subclinical hypothyroidism. In conclusion, both antibody types increased in frequency and level, but TPOAbs were the predominant autoimmunity marker predictive of impending thyroid failure in children with AIT, as was thyroid hypoechogenicity on ultrasound.     

Familial aggregation of autoimmune thyroiditis in first-degree relatives of patients with juvenile autoimmune thyroid disease.

Several studies have shown aggregation of autoimmune thyroiditis in families by estimation of thyroid antibodies. However, the prevalence by concurrent estimation with fine-needle aspiration cytology (FNAC) and thyroid antibodies has not been previously reported. We therefore studied 222 first-degree relatives (group 1) of 71 index cases diagnosed as lymphocytic thyroiditis on FNAC and 81 family members (group 2) of 23 goitrous children diagnosed as colloid goiter on FNAC for comparison. Successful FNAC conducted in 122 group 1 subjects revealed lymphocytic thyroiditis in 51 (42%), whereas lymphocytic thyroiditis was diagnosed in only 5 goitrous subjects (13%) in group 2. Among group 1 subjects with FNAC-proven lymphocytic thyroiditis, antithyroid peroxidase (TPO) antibodies were found in 35 (67%), while in anti-TPO antibody positive goitrous relatives of group 1, lymphocytic thyroiditis was found in 36 (78%). Eight new cases of overt hypothyroidism and 45 new cases of subclinical hypothyroidism were diagnosed among group 1 subjects. Our study suggests: (1). familial clustering of autoimmune thyroiditis; (2). if only FNAC or thyroid antibodies is used for diagnosis of autoimmune thyroiditis in children, 22%-33% of cases are likely to be missed; and (3). serum thyrotropin (TSH) should be offered to all first-degree relatives of patients with juvenile autoimmune thyroiditis.     

The Sardinian Autoimmunity Study: 3. Studies on circulating antithyroid antibodies in Sardinian schoolchildren: relationship to goiter prevalence and thyroid function.

The relationship among iodine intake, goiter prevalence, and thyroid autoimmunity remains controversial. In the present article, we report the prevalence of antithyroid antibodies (ATA) in relation to iodine intake, frequency of goiter, and thyroid function in a large group of Sardinian schoolchildren living in areas with borderline iodine sufficiency, or mild to moderate iodine deficiency. A total of 8,040 schoolchildren (4,194 males, 3,846 females, ages 6-15 years) from 29 communities were examined between 1986-1994. Thyroid size was assessed by palpation, according to the Pan American Health Organization (PAHO) criteria. In all cases antimicrosomal (MAb) or antithyroid peroxidase antibodies (TPOAb) and thyrotropin (TSH) were assayed. Urinary iodine was determined in a subgroup of 820 children. ATA was detected in 235 (2.92%) sera (88 males, 2.12%; 147 females, 3.82%; chi2 = 20.41, p < 0.0001). ATA prevalence ranged between 0.0%-7.3% in the 29 communities without any geographical correlation with goiter prevalence and urinary iodine excretion. However, ATA was more frequently detected in goitrous children, especially in females. The presence of ATA was not age-dependent in males, whereas a significant increase of ATA was observed in females older than 11 years of age. Seventy-seven (0.96%) children showed borderline to slightly increased serum TSH (>5.2-32 mU/L). Increased serum TSH concentration was more frequently found in children with ATA, especially at higher titers. In summary, our study in Sardinian schoolchildren indicates: (1) ATA display geographical heterogeneity, which seems to be unrelated to goiter prevalence and/or to iodine supply; (2) ATA are more frequently detected in females older than 11 years of age, suggesting that puberty has a role in determining the predominance in females of thyroid autoimmunity; (3) although most goitrous children are ATA-negative, the prevalence of ATA is increased in children with enlarged glands; (4) ATA is associated with an increased prevalence of subclinical hypothyroidism.     

轻度碘缺乏城市食盐加碘后甲状腺疾病流行病学调查研究

 目的 评价轻度碘缺乏城市贵阳食盐加碘25年后的碘营养状态及各种甲状腺疾病的患病情况。
方法 采用分层整群抽样方法,抽取贵阳市云岩区宅吉社区20岁及以上居民1509人,测定其血清促甲状腺素（TSH）、游离T₃、游离T₄、甲状腺过氧化物酶抗体（TPOAb）、甲状腺球蛋白抗体（TgAb）水平、尿碘水平及甲状腺B超检查;同时抽取8~10岁学龄儿童80名,测定其尿碘水平。
结果 8~10岁儿童尿碘中位数为228.7 μg/L。成人临床甲状腺功能减退症（甲减）、亚临床甲减、临床甲状腺功能亢进症（甲亢）及亚临床甲亢的患病率分别为1.79%、14.12%、1.52%及1.06%,亚临床甲减的患病率显著高于临床甲减（P < 0.05）;TPOAb及TgAb的阳性率分别为14.38%及 13.59%,自身免疫性甲状腺炎的患病率为4.44%。甲状腺肿大患病率为1.06%,其中,弥漫性甲状腺肿（0.86%）较结节性甲状腺肿（0.20%）多见（P < 0.05）。
结论 食盐加碘25年后,贵阳市处于碘超足量状态,成人临床甲减、亚临床甲减、甲状腺自身抗体阳性及自身免疫性甲状腺炎的患病率均较高。     

The spectrum of thyroid disorders in an iodine-deficient community: the Pescopagano survey

We carefully assessed thyroid status and goiter by ultrasound in 1411 subjects virtually representing the entire resident population of Pescopagano, an iodine-deficient village of Southern Italy. Median urinary iodine excretion was 55 microg/L. The prevalence of goiter was 16.0% in children and 59.8% in adults. Thyroid nodularity was 0.5% in children and progressively increased with age to 28.5% in the 56- to 65-yr-old group. The prevalence of present or past hyperthyroidism was 2.9%, including 9 cases with toxic diffuse goiter and 20 with toxic nodular goiter. Functional autonomy was rare in children, progressively increased with age up to 15.4% in the elderly, and was related to nodular goiter. The prevalences of overt and subclinical hypothyroidism in the adults were 0.2% and 3.8%, respectively. Serum autoantibodies to thyroglobulin and thyroperoxidase were detected in 12.6% of the entire population. The prevalence of diffuse autoimmune thyroiditis was 3.5%, being very low in children. Thyroid cancer was found in only 1 case. In conclusion, in the present survey of an iodine-deficient community, a progressive increase with age of goiter prevalence, thyroid nodularity, and functional autonomy was observed. Hyperthyroidism was twice as high as that reported in iodine-sufficient areas, mainly due to an increased frequency of toxic nodular goiter. Although low titer serum thyroid antibodies were relatively frequent, the prevalences of both overt and subclinical autoimmune hypothyroidism were not different from those observed in iodine-sufficient areas.     

Thyroid function, autoimmune thyroiditis and coeliac disease in juvenile idiopathic arthritis

OBJECTIVES: Autoimmune diseases have been associated with some organ non-specific rheumatological disorders such as rheumatoid arthritis and systemic lupus erythematosus; however, few studies have been performed in an extensive cohort of children with juvenile idiopathic arthritis (JIA). Our objective was to evaluate the thyroid function and the prevalence of antithyroid antibodies, autoimmune thyroiditis and coeliac disease in children with JIA. METHODS: One hundred and fifty-one children (120 female, 31 male, median age 8.3 yr, range 2.4-16.9 yr) with JIA were evaluated. All patients underwent thyroid function tests (u-TSH, free T(4) and free T(3)), antithyroglobulin (TgA) and antiperoxidase (TPOA) antibodies, antigliadin, anti-endomysium and antitransglutaminase antibodies. All patients with raised thyroid stimulating hormone levels, low thyroid hormone levels or positive TPOA and/or TgA values had a thyroid high-resolution sonography examination. Coeliac disease was confirmed by jejunal biopsy if the specific antibodies profile was positive. One hundred and fifty-eight age- and sex-matched Caucasian children from the same geographical area acted as controls. RESULTS: Fourteen (9.3%) patients showed subclinical hypothyroidism, 17 (11.9%) patients showed autoimmune thyroiditis with nine patients also showing a non-homogeneous thyroid parenchyma at ultrasound evaluation. Coeliac disease was demonstrated in 10 (6.6%) patients. Compared with controls, JIA patients had higher prevalence of subclinical hypothyroidism (P < 0.01), autoimmune thyroiditis (P < 0.0001) and coeliac disease (P < 0.005). CONCLUSIONS: JIA children have an increased prevalence of autoimmune thyroiditis, subclinical hypothyroidism and coeliac disease. These data seem to suggest careful monitoring of thyroid function, thyroid autoantibodies and coeliac disease in JIA children.     

Hashimoto's thyroiditis: countrywide screening of goitrous healthy young girls in postiodization phase in India

Countrywide salt iodization, to prevent nutritional iodine deficiency, has been achieved in India recently. The current study was planned to evaluate the prevalence of goiter and thyroid autoimmunity and assess thyroid functional status in a cohort of 6283 healthy schoolgirls from different parts of the country in the postiodization phase. Goitrous girls (n = 1810; 28% of subjects) were investigated for serum T4 and TSH, antithyroid microsomal antibody (TMA) and antithyroglobulin antibody (TGA), urinary iodine excretion, and cytomorphology by fine-needle aspiration cytology (FNAC). FNAC carried out successfully in 764 goitrous girls revealed juvenile autoimmune thyroiditis (JAT) in 58 (7.5%), which included Hashimoto's thyroiditis in 43 (5.6%) and focal lymphocytic thyroiditis in 15 (1.9%). TMA and TGA estimated in 722 goitrous girls detected significantly positive titers of TMA (> or =1:1600) and TGA (> or =1:160) in 52 (7.2%) and 4 (0.55%) girls, respectively. Only 29 (67.4%) girls with Hashimoto's thyroiditis were TMA positive. In patients with FNAC-proven JAT, overt clinical and biochemical hypothyroidism was seen in three (6.5%) and subclinical hypothyroidism in seven (15%). Subclinical hyperthyroidism was detected in 5.1% cases of JAT, and none had overt hyperthyroidism. No definite correlation was seen between urinary iodine excretion and thyroid autoimmunity.     

Introduction of iodized salt to severely iodine-deficient children does not provoke thyroid autoimmunity: a one-year prospective trial in northern Morocco.

To determine if introduction of iodized salt induces thyroid autoimmunity in goitrous children, we conducted a prospective trial in iodine-deficient Moroccan schoolchildren (n = 323). Local salt was iodized at 25 microg iodine per gram of salt and distributed to households. Before introduction of iodized salt and at 10, 20, 40, and 52 weeks, we measured antithyroid peroxidase antibodies (TPO-Ab), antithyroglobulin antibodies (Tg-Ab), urinary iodine (UI), and thyroid hormones, and examined the thyroid using ultrasound. At baseline, median UI was 17 microg/L and the prevalence of goiter and hypothyroidism was 72% and 18%, respectively. Provision of iodized salt maintained median UI at 150-200 microg/L for the year (p < 0.0001). There was a significant increase in mean total thyroxine (T(4)) and a significant reduction in the prevalence of hypothyroidism (p < 0.001). There was a transient increase in the prevalence of detectable antibodies after introduction of iodized salt (p < 0.0001) with levels returning to baseline at 1 year. Only congruent with 1% of children had elevated TPO-Ab and none had elevated Tg-Ab over the course of the study, and no child with elevated TPO-Ab had abnormal thyrotropin (TSH) or T(4) concentrations. None developed clinical or ultrasonographic evidence of thyroid autoimmune disease and/or iodine-induced hypothyroidism or hyperthyroidism. Rapid introduction of iodized salt does not provoke significant thyroid autoimmunity in severely iodine-deficient children followed for 1 year.     

Thyroid volume and urinary iodine excretion in the schoolchild population of a Northwestern Italian sub-Alp metropolitan area

Iodine deficiency is recognised as a major preventable public-health worldwide problem. The aim of this study is to assess local reference values for thyroid volume, and give a snapshot of the epidemiology of goiter and iodine nutritional status of the Turin schoolchild population. Sonographic thyroid volume and median urinary iodine excretion were obtained in 1067 schoolchildren aged 11-15 yr resident in Turin for more than 5 yr to assess both goiter prevalence and iodine intake. All the subjects were asked to fill in a questionnaire about their life habits. Anamnestic and anthropometric data, thyroid volume by both bimanual palpation and ultrasonography were assessed, and spot urinary iodine samples were collected. The results show that the median urinary iodine concentration is 113.1 microg/l and the prevalence of goiter <5%, indicating this area as iodine-sufficient. Nevertheless, 40.5% of the schoolchild population has urinary iodine levels lower than the cut-off level recommended as iodine-sufficiency. Interestingly, the high relative prevalence of ultrasound features of autoimmune thyroid disease suggests autoimmune-thyroiditis as a frequent thyroid disease in Turin schoolchildren. As no active programs of salt, milk or water iodisation have ever been carried out, a silent iodine prophylaxis has probably occurred in the city. Despite a sufficient median urinary iodine excretion, a focused program of iodine prophylaxis should be developed due to the presence of a large rate of iodine-deficient population.     

The prevalence of anti-thyroid peroxidase antibodies and autoimmune thyroiditis in children and adolescents in an iodine replete area

BACKGROUND: The iodine supply of the population in Berlin has normalized during the last 5 Years. Therefore autoimmune thyroiditis has become the most important differential diagnosis in children and adolescents with goiter. OBJECTIVE: The aim of the present study was to define the prevalence of anti-thyroid peroxidase (TPO) antibodies and autoimmune thyroiditis in children and adolescents with a normalized iodine intake. DESIGN: To enable the measurement of antibodies to thyroid peroxidase (anti-TPO-Ab) in a large cohort, a method to determine anti-TPO-Ab in dried filter paper blood spots was established. In co-operation with pediatricians the antibody prevalence was assessed and data regarding thyroid size, echostructure and the medical history concerning iodine intake and familial thyroid diseases were collected. METHODS: 660 children and adolescents participated in the study; urinary iodine, TSH and TPO-Ab were measured and an ultrasound of the thyroid gland was performed. RESULTS: The sensitivity of the newly established filter paper assay was 91.8% and specificity was 100%. The results confirmed the improved iodine supply, with a median urinary iodine concentration of 139 microg iodine/g creatinine. The prevalence of anti-TPO-Ab was 3.4% with a female to male ratio of 2.7:1. CONCLUSION: The prevalence of anti-TPO-Ab is lower or equal to data reported from other iodine sufficient areas. Data from a moderate iodine deficiency in schoolchildren range from 0.0 to 7.3%. Using the new filter paper method field studies can be implemented to monitor the effect of changes in iodine nutrition on thyroid autoimmunity. Furthermore, this study on the prevalence of anti-TPO-Ab in a cohort of healthy children and adolescents in an iodine replete area can serve as reference data for future investigations and for the comparison with other groups of patients with increased risks for thyroid autoimmunity.     

Natural course of autoimmune thyroiditis in Thai children

Forty-seven pediatric patients with autoimmune thyroiditis were followed for an average of 5.18+/-2.89 years. The diagnosis was based on a firm goiter and a positive test for antithyroid antibodies. Initially, 23 patients had euthyroidism, 11 overt hypothyroidism, 6 compensated hypothyroidism and 7 with low TSH. All patients had clinical euthyroidism, except two who had overt hypothyroidism. The thyroid function tests, the size of the thyroid gland and the thyroid antibodies were regularly evaluated. After the follow-up, 26 patients had untreated euthyroidism, 12 with overt hypothyroidism received eltroxin for maintenance of euthyroidism, while 4 had compensated hypothyroidism and 5 low TSH levels. All had clinical euthyroid. The thyroid size was reduced in 12 patients (26%) while 4 (9%) had normal-sized gland. The goiter size in 35 patients (74%) remained unchanged. The antithyroglobulin and antimicrosomal antibody titers fluctuated higher in patients with overt hypothyroidism. Eltroxin was given only to those having overt hypothyroidism with diminished goiter size in 8 patients (73%).     

Role of autoimmune and familial factors in goiter prevalence. Studies performed in a moderately endemic area

The goitrogenic role of autoimmune phenomena in endemic goiter is still uncertain. Scanty and discrepant results have been reported in different areas of the world. This prompted us to evaluate the prevalence of circulating thyroid antibodies in an area of North-Western Tuscany during a survey for endemic goiter. The survey was carried out according to the P.A.H.O. criteria in a stable community. In all schoolchildren (n = 142, age range 7-15 yr) and in most of their parents (n = 159), thyroid size was evaluated and urine was collected for iodine determination. Blood was drawn for determination of circulating thyroid microsomal (MAb) and thyroglobulin antibodies (TgAb), TT3, TT4 and TSH. Prevalence of goiter in schoolchildren was 77.9% and 94.8% in their parents. Mean (+/- SD) urinary iodine excretion was 55.0 +/- 2.1 micrograms/24 h. The overall frequency of TgAb and MAb in the adult population was 14.4%, statistically higher than that of control subjects matched for sex and age. The frequency in schoolchildren was 4.3%. The presence of goiter in children was unrelated to the presence of thyroid antibodies in parents, whether goitrous or nongoitrous. A higher prevalence of goiter was found in children with goitrous parents as compared to children with nongoitrous parents (p less than 0.005). In conclusion, the frequency of thyroid autoantibodies in the adult population of the endemic area studied was increased, but showed no relation with the presence of goiter. The prevalence of goiter in children was associated with the presence of goiter but not of thyroid autoantibodies in parents. These data suggest that autoimmune phenomena are of limited importance in the development of endemic goiter.     

Chronic thyroiditis and mitral valve prolapse

Mitral valve prolapse is more prevalent in patients with autoimmune diffuse toxic goiter, suggesting a possible etiologic association. The prevalence of mitral valve prolapse was determined in 75 patients with chronic lymphocytic thyroiditis, another autoimmune thyroid disorder, and in 50 healthy control subjects. Mitral valve prolapse was found in 31 of 75 (41%) patients with chronic lymphocytic thyroiditis and in 4 of 50 (8%) controls (odds ratio, 8.10; 95% confidence interval, 2.64 to 24.83; p less than 0.0005). The age-race adjusted odds ratio was 9.26 (95% confidence interval, 2.83 to 30.26; p less than 0.0005). No correlation between the prevalence of mitral valve prolapse and the presence of hypothyroidism, serum antithyroid antibodies, or the duration of chronic lymphocytic thyroiditis was found. The prevalence of mitral valve prolapse is substantially increased in patients with the autoimmune thyroid disorders.     

The predominant form of non-toxic goiter in Greece is now autoimmune thyroiditis.

Endemic non-toxic goiter (NTG) in Greece has been attributed primarily to iodine deficiency. Thirty years ago about 60% of the prepubertal boys and girls examined in endemic goiter regions presented with NTG and among them thyroid autoimmunity was rarely detected. Although iodine supplementation has corrected this deficiency during the past 30 years, new cases of NTG still appear. To evaluate the prevalence and type of NTG and the effect of iodine supplementation on them in Greece at present, we performed two cross-sectional clinical studies and a retrospective pathology one: (i) thyroid gland volume and urinary iodine excretion (UIE) were assessed in a representative sample of 1213 schoolchildren from previously endemic and non-endemic regions; (ii) serum thyroxine, tri-iodothyronine, TSH, thyroid autoantibodies (AAB) (anti-thyroid peroxidase and anti-thyroglobulin antibodies) and UIE (in 60 patients) were measured in 300 consecutive patients with NTG from Athens and Heraklion; and (iii) we compared the prevalence of autoimmunity among fine needle aspiration smears of benign thyroid pathologies performed by the same pathologist between 1985 and 1986 (975 cases) and between 1994 and 1995 (2702 cases). We found that 12. 5% of the schoolchildren examined in regions with a previous history of endemic goiter had NTG, whereas this percentage was only 1.7% in areas without such a history. In Athens (61.6%) and Heraklion (58. 5%) a substantial number of NTG patients were AAB positive and biochemically hypothyroid. UIE in Athens did not differ between patients with autoimmune goiter (ATG) and simple goiter. The prevalence of autoimmune stigmata in pathology smears has increased from 5.94% (years 1985-1986) to 13.91% (years 1994-1995) (P<0.05). We conclude that: (i) the persistence of endemic goiter in regional foci despite iodine deficiency correction suggests a possible role for a naturally occurring goitrogen; (ii) ATG is the predominant form of NTG in Greece nowadays; and (iii) the five-fold decrease in the prevalence of NTG during the past 30 years followed by the increase of ATG may support the relative character of the latter.     

Prevalence of thyroid dysfunction in elderly subjects from the general population in an iodine deficiency area.

The prevalence of thyroid disorders was investigated in 466 (403 female, 63 male) subjects over the age of 60 years (79.2 +/- 7.5 years; mean +/- SD) from the general population in an area of iodine deficiency. In addition to thyroid hormone assays, thyroid antibodies and urinary iodine excretion were determined. In cases with thyroid dysfunction, ultrasound investigations were performed. Twenty-two of the 466 subjects (4.7%) showed hyper- or hypothyroidism; 7 subjects were hyperthyroid (1.5%), 5 had primary hypothyroidism (1.1%), and 10 showed "subclinical" hypothyroidism (2.2%). The latter constellation is defined as an elevation of thyrotropin (TSH) with normal values for thyroxine and triiodothyronine. Most subjects with hyperthyroidism had a goiter by palpation (6/7); thyroid volume by ultrasound (median) was 26.2 mL with an inhomogeneous echo pattern in 6 of the 7 subjects. In 4 cases, a rise in urinary iodine excretion was documented; none had TSH-receptor antibodies. Most subjects with overt or subclinical hypothyroidism had a homogeneous or low-echogenic pattern by ultrasound; thyroid volume (median) was 12.9 mL and 12.7 mL, respectively. By palpation, 8 of the 15 subjects had no goiter. In general, these persons had no rise in urinary iodine excretion (11/13), but most showed an elevation of antibodies against the microsomal antigen and/or thyroglobulin (11/15).(ABSTRACT TRUNCATED AT 250 WORDS)     

碘致甲状腺功能减退症的流行病学对比研究

目的：研究不同碘摄入量人群的临床甲减和亚临床甲减患病率,方法：选择盘山,彰武和黄骅3个农村社区（分别为低碘,适碘和高碘地区（）,在入户问卷调查的基础上行采样调查,共问卷调查16287人,采样3761人,所有采样对象接受体格检查,,测定血清TSH,甲状腺过氧化的酶抗体（TPOAb),甲状腺球蛋白抗体（TGAb)和甲状腺球蛋白（TG）,测定尿碘浓度及进行甲状腺B超检查,TSH异常者测定FT4,FT3和TSH受体抗体（TRAb)。结果：盘山,彰武和黄骅社区成人尿碘水平分别为103．1ug/L,374.8ug/L和614.6ug/L,盘山,彰武和黄骅社区临床甲减患病率分别为0．27％,0．95％和2．05％, 临临床甲减的患病率分别为0．91％,2．90％,和5．96％,引起临床甲减的主要原因是自身免疫性甲状腺炎,亚临床甲减中三分之一患者甲状腺自身抗体阳性,结论：横断面的流行病学对比研究证实碘摄入量增加有可能导致甲状腺功能减退症患病率增加。     

Etiologic discussion and clinical relevance of thyroid ultrasonography in subclinical hypothyroidism. A retrospective study in 1845 patients

Background

Acquired subclinical hypothyroidism in adulthood is mainly due to autoimmune thyroiditis. In the absence of a goiter or a palpable firm thyroid, measurement of thyroid antibodies can improve the diagnosis. Whether thyroid antibodies are detected or not, what might be the clinical relevance of ultrasonography in this setting?

Methods

We studied 1845 cases of subclinical hypothyroidism in adults recruited for symptoms indicative of hypothyroidism or thyroid pathology. All patients were screened for thyroid antibodies and underwent an ultrasonographic thyroid examination.

Localisation

Multicentric retrospective study.

Results

Chronic autoimmune thyroiditis was confirmed in 70% of patients. Thyroid antibodies were undetectable in 30% of patients. In all patients, thyroid ultrasound facilitated measurement of the thyroid volume and detection of non-palpable nodules and therefore allowed biopsy. In patients negative for thyroid antibodies, ultrasonography suggested autoimmune thyroiditis in 31% of cases. Ultrasonography did not contribute to diagnosis in a large number of patients without nodules and in case of normal echostructure. The strategy of thyroid hormone replacement therapy was not influenced by ultrasonographic data. Thyroid biopsies detected smears suspected to be cancerous in 10 patients (4%). Cancer was confirmed in nine patients after surgery. Ultrasonography displayed suspicious aspects in six patients.

Conclusion

In subclinical hypothyroidism, thyroid ultrasonography is not required for the diagnosis of autoimmune thyroiditis but is useful for patients with abnormal thyroid palpation and allows detection of non-palpable thyroid nodules. For patients that were negative for thyroid antibodies, thyroid ultrasonography can improve diagnosis for some patients, allowing detection of autoimmune thyroiditis.     

High prevalence of thyroid dysfunction and autoimmune thyroiditis in adolescents after elimination of iodine deficiency in the Eastern Black Sea Region of Turkey.

In the present study we evaluated the effects of iodine intake on the prevalence of thyroid dysfunction, autoimmunity, and goiter in two regions with different iodine status after two years of iodization in Turkey. In total 1733 adolescent subjects were enrolled into the study (993 from an iodine-sufficient area--the Eastern Black Sea Region (group 1) and 740 from an iodine-deficient area--Middle Anatolia (group 2)). We measured free thyroxine (FT(4)), thyrotropin (TSH), antithyroid peroxidase antibodies (Anti-TPO), antithyroglobulin antibodies (Anti-Tg), and urinary iodine (UI), and examined the thyroid gland by ultrasound. Median urinary iodine excretion was found to be significantly different in group 1 and group 2 (139 micro/l vs 61micro/l, p < 0.001). Hyperthyroidism was more frequent in group 1 (3.6% vs 0.7%; p < 0.001), but the hypothyroidism rate was similar between groups (1.8% vs 1.4 %; p>0.05). The percentage of anti-Tg positive subjects was found to be 17.6% in group 1 and 6.4% in group 2; that of anti-TPO positive subjects was 4.3% in group 1 and 1.5% in group 2. The prevalence of antithyroid antibody (anti-Tg and/or anti-TPO) positivity was significantly higher in group 1 than in group 2 (18.52% vs 6.62%; p < 0.001). Thyroid volumes of the hyperthyroid subjects in both groups were significantly higher than hypo- and euthyroid subjects. In conclusion, iodine supplementation in Turkey has resulted in the elimination of iodine deficiency in the Eastern Black Sea Region, and this has been accompanied by an increase in the prevalence of autoimmune thyroiditis and thyroid dysfunction.     

Thyroid function and amiodarone. Consequences on dysthyroidism testing

Amiodarone induces a decrease in serum T3 whereas T4 and rT3 increase. An increase of the thyroid iodine content (TIC) is observed in all patients at the exception of those who develop hypothyroidism under treatment. Actually, no method are available to predict an induced thyroid toxicosis (ITT) and there is no reason to perform systematically thyroid function tests except if past of the patient or clinical or morphological thyroid examinations suggest thyroid abnormality. In case of suspicion of ITT it is necessary to perform T4, T3 determinations and a TRH test. TIC measurement can be useful in order to eliminate a subacute or silent thyroiditis. Hypothyroidism is generally observed in patients with autoimmune thyroiditis. Antithyroid antibodies and TSH determinations after some months of treatment can detect subclinical hypothyroidism which is due to a high susceptibility to iodide.