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Metabolic syndrome (MetS) is considered very important because of the increased risk for cardiovascular diseases. Identifying modifiable factors may help prevent MetS. We aimed to investigate the relationship between iodine intake as a dietary factor and MetS in euthyroid adult in an iodine-replete area. A total of 4,277 adult aged ≥19 years from the Korea National Health and Nutrition Examination Survey VI (2013-2015) with urinary iodine concentration (UIC) results and normal thyroid function were included. Participants were grouped according to their iodine nutrition status based on the WHO recommendations and modifications: insufficient (<100 μg/L), adequate (100-299 μg/L), and excessive (≥300 μg/L) iodine intake. We estimated the odds ratios (ORs) for MetS according to the UIC groups using logistic regression models. Of the study participants, 27.2% men and 23.9% women had MetS. Men with excessive iodine intake had a significantly lower risk of elevated triglycerides [OR 0.733, 95% confidence interval (CI) 0.603-0.890, p = 0.010], as compared to those with adequate iodine intake. Women with insufficient iodine intake had a significantly greater risk of elevated blood glucose (OR 1.519, 95% CI 1.011-2.282, p = 0.044), as compared to those with adequate iodine intake. In women, insufficient iodine intake was a significant risk factor for MetS compared to adequate iodine intake, even after adjusting for confounding variables including age, smoking, alcohol consumption, walking activity, serum thyroid-stimulating hormone, free thyroxine, and anti-thyroid peroxidase antibody (OR 1.544, 95% CI 1.031-2.311, p = 0.035). There was no association between iodine intake and risk of MetS in men. In conclusion, insufficient iodine intake was associated with an increased risk of MetS only in euthyroid adult women. Our data support that sex differences may influence the relationship between iodine intake as a dietary pattern and MetS.

Background: Nowadays, the Republic of Belarus belongs to the countries with sufficient iodine supply, which made it possible to reduce the incidence of non-toxic goiter and congenital hypothyroidism. However, even a slight change in iodine consumption influences the pattern of thyroid diseases. In addition to iodine deficiency, other environmental conditions, as well as genetic factors, play a significant role in the etiology of thyroid diseases., Aim: To analyze the dynamics of the main epidemiological indicators of benign thyroid diseases from 2009 to 2019 in the adult population of the Republic of Belarus, using the data of official state statistics., Materials and Methods: The indicators of the incidence and prevalence of benign thyroid diseases were studied on the basis of state statistics for 2009-2019. To analyze the dynamics of the studied indicators, regression analysis was used with the construction of linear and polynomial models., Results: A decrease in the incidence and prevalence of diffuse euthyroid goiter and an increase in the incidence and prevalence of nodular euthyroid goiter, thyroiditis, acquired hypothyroidism, Graves' disease, as well as the incidence of nodular toxic goiter were revealed., Conclusion: Obtained data indicate, that there is an increase in the prevalence of most of the studied thyroid diseases, despite the adequate iodine supply. The above justifies the need for further study of the causes of the identified trends, as well as the necessity of developing new methods of diagnosis and treatment of thyroid diseases.

Background: The incidence rates of thyroid tumors and nodular goiter show an upward trend worldwide. There are limited reports on the risk of perchlorate and iodine on thyroid tumors, but evidence from population studies is scarce, and their impact on thyroid function is still uncertain. Therefore, the objective of this study was to investigate the association of perchlorate and iodine with the risk of nodular goiter (NG), papillary thyroid microcarcinoma (PTMC), and papillary thyroid carcinoma (PTC) and to assess the correlation between perchlorate and iodine with thyroid function indicators., Methods: A case-control population consisting of 184 pairs of thyroid tumors and nodular goiter matched by gender and age (±2 years) was recruited in this study. Serum and urine samples were collected from each participant. Thyroid function indicators in serum were tested by automatic chemical immunofluorescence, and perchlorate and iodine levels in urine were determined by ultra-high performance liquid chromatography tandem-mass spectrometry and inductively coupled plasma-mass spectrometry, respectively. Conditional logistic regressions and multiple linear regressions were used to analyze the associations., Results: Urinary perchlorate concentration was significantly higher in total cases, NG and PTC than in the corresponding controls (P < 0.05). Perchlorate was positively associated with PTC (OR = 1.058, 95% CI: 1.009, 1.110) in a non-linear dose-response relationship, but there was no association between perchlorate and NG or PTMC. Iodine was not associated with the risk of thyroid tumors and NG and did not correlate with the thyroid function indicators. Furthermore, perchlorate showed a positive correlation with thyroid stimulating hormone (TSH) at iodine adequate levels (P < 0.05), and a negative correlation with free triiodothyronine (FT3) and a positive correlation with thyroglobulin antibody (TgAb) at iodine more than adequate or excess levels (P < 0.05)., Conclusions: Perchlorate can increase the risk of PTC in a non-linear dose-response relationship and disturb the thyroid hormone homeostasis and thyroid autoantibody levels., (© 2021. The Author(s).)

More than one tenth of the world population is to some degree affected by goitre and most of these harbour nodules. The large differences in thyroid disease prevalence between populations may be caused by genetic and environmental factors. Among the latter, iodine deficiency seems by far to be the most important risk factor. Thus, nodular goitre is a condition predominantly seen in iodine deficient areas of the world. In the present review, we evaluated in detail autopsy and ultrasound studies of the thyroid gland. In autopsy studies, large thyroid volumes and high frequencies of goitres have been reported in countries affected by iodine deficiency. Many cross-sectional studies using thyroid ultrasound investigations have been performed world-wide and reported high thyroid volumes and goitre prevalences, and to some extent also high prevalences of thyroid nodules in iodine-deficient countries. Most of these goitres were classified as nodular goitres. On the other hand, few studies have shown that abundant iodine intake may lead to development of diffuse goitres, but world-wide this has been a minor problem compared with development of nodular goitres. In the past century we have observed a trend towards smaller thyroid glands, and hopefully less than 10% of the world population will experience goitre within a few decades., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Iodine is essential for the synthesis of thyroid hormones. Iodine deficiency can affect human health in different ways, and is commonly referred to as iodine deficiency disorders (IDD). These range from defective development of the central nervous system during the fetal-neonatal life, to goitre in the adult. Only a few countries were completely iodine sufficient before 1990. Since then, a major effort has been made to introduce salt iodization to ensure sufficient intake of iodine in deficient areas. Iodine prophylaxis has been shown to exert a pivotal role in abating goitre and other iodine-deficiency disorders, and has also been shown to modulate the pattern of thyroid diseases. An increased frequency of thyroid autoimmunity and of hypothyroidism has been observed after introducing iodization programmes. Nevertheless, available evidence clearly confirms that the benefits of correcting iodine deficiency, consisting mainly of reducing nodular goitre and non-autoimmune hyperthyroidism, far outweigh the risks of iodine supplementation., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

The paper deals with etiopathogenetic and clinical peculiarities, and also therapeutic methods during the pathological processes in the thyroid system in the childhood. The most common of these processes is the diffuse nontoxic goiter, which results in abnormality of metabolic processes regulation in the child's growing organism and often signals to the beginning of many thyropathies.

Purpose: To explore whether there are regional differences in iodine status and in prevalence of thyroid diseases in the two main regions of Belgium., Methods: A national survey of iodine status among children was performed in 1998. The raw data of this survey were reanalyzed to explore regional differences. The total number of thyroidectomies, carried out for multinodular goiter or solitary nodules, was obtained from the Minimal Clinical Summary hospital discharge database. Percentage of people with thyroid diseases going to the general practitioner or the specialist was assessed by means of data about the number of adults using anti-thyroid medications. Food consumption patterns were explored using national food consumption data., Results: In Flanders, median urinary iodine concentration (UIC) was higher than in Wallonia, 84 μg/L (n = 1,316) and 78 μg/L (n = 1,268), respectively (p < 0.001). There were no differences in goiter prevalence and thyroid volume between the regions among children. Data from the food consumption survey showed a significant higher consumption of seafood in Flanders compared to Wallonia. Further, it was observed that the number of thyroidectomies, carried out for MNG or solitary nodules, and the use of anti-thyroid medication were significantly higher in Wallonia than in Flanders., Conclusion: Iodine status in children was found slightly different in both regions of the country. This finding is in agreement with a higher incidence of thyroidectomies and more extensive use of anti-thyroid medications in the adult population in the region with the lowest iodine excretion.

Background: Obesity and insulin resistance predispose individuals to the development of both metabolic syndrome and non-toxic nodular thyroid diseases., Aim: The aim of this observational, cross-sectional study is to evaluate the relationship between metabolic syndrome and multinodular nontoxic goiter in an inpatient population from a geographic area with moderate iodine deficiency., Subjects and Methods: We examined 1422 Caucasian euthyroid inpatients. Thyroid volume was determined by ultrasound of the neck. A fine-needle aspiration biopsy was performed to evaluate single thyroid nodules and dominant nodules ≥15 mm in euthyroid multinodular goiter. The diagnosis of metabolic syndrome was made according to the criteria of the American Heart Association/ National Heart, Lung, and Blood Institute., Results: Of the sample, 277 patients had clinical evidence of multinodular nontoxic goiter, 461 met the criteria for the diagnosis of metabolic syndrome, and 132 were found to have both conditions. After adjusting for age, gender, body mass index, nicotinism, parity, alcohol intake, thyroid function, and metabolic syndrome- related pharmacological treatment, metabolic syndrome was found to be an independent risk factor for the occurrence of multinodular non-toxic goiter. The relationship between metabolic syndrome and multi nodular non-toxic goiter was apparent in both men and women., Conclusions: In this study of euthyroid inpatients, we demonstrate that metabolic syndrome is an independent risk factor for the occurrence of multinodular non-toxic goiter in a geographic area with moderate iodine deficiency. We propose that patients meeting the criteria for metabolic syndrome should be screened for the presence of multinodular non-toxic goiter.

Background: Nontoxic nodular goiter (NTNG) is common in endemic goiter regions. Thyroxine (T4) is often used to treat NTNG. There is little information regarding T4 treatment in regions that have recently become iodine sufficient. We studied the effect of T4 treatment on thyroid function tests in southwestern Greece (SWG), a recently iodine-sufficient area., Methods: We studied 827 residents of SWG (group A) to determine goiter prevalence, thyroid function, and urinary iodine concentration (UIC). Group B: 385 consecutive patients with thyroid dysfunction. Of these, 89 had NTNG and followed for 10 years on T4 treatment, and 296 had hyperthyroidism. Group C: 29 patients with NTNG, treated with triiodothyronine (T3) 50 mug/day and followed for 6 months. Measurements included serum T4 and 24-hour radioactive iodine uptake (RAIU) before and at the end of T3 administration., Results: The median UIC in group A was 114 microg/L. In group B (89 patients), the incidence of newly diagnosed hyperthyroidism was 5-7% per year with a cumulative percentage of 33% at the 10th year. The initial thyrotropin (TSH) was lower (0.78 +/- 0.51 mIU/L) in those who developed thyrotoxicosis compared to those who remained euthyroid (1.17 +/- 0.74 mIU/L) (p < 0.05). In 296 thyrotoxic patients, the incidence of autoimmune hyperthyroidism and toxic multi-nodular goiter (TMNG) was similar. In group C, 10/29 patients remained euthyroid and the 24-hour RAIU decreased by 49% during T3 treatment. Similarly, serum T4 decreased by 49%. In the remaining patients who developed hyperthyroidism, 24-hour RAIU and T4 were decreased by 19% and 22%, respectively., Conclusions: In SWG, a recently iodine-sufficient region, the risk of developing hyperthyroidism in patients with NTNG after administration of 100-150 microg T4 is relatively high in those whose serum TSH before T4 treatment is in the lower normal range. Therefore, T4 treatment should be avoided in these patients.

Objective: The association between iodine status and the prevalence of goiter and thyroid nodules has been well established but the extent to which different iodine intake levels influence the incidence of goiter and thyroid nodules is unclear. The aim of the study was to determine the incidence of goiter and thyroid nodules in 3 regions with different iodine intake levels: mildly deficient, more than adequate, and excessive., Design, Patients and Measurements: Of the 3385 unselected subjects enrolled in 1999 in Panshan, Zhangwu, and Huanghua where median urinary iodine excretion (UIE) was 83.5 microg/l, 242.9 microg/l, and 650.9 microg/l, respectively, 2708 (80.0%) participated in the follow-up study in 2004. The examinations of thyroid ultrasonography, thyroid function, thyroid autoantibodies and UIE were performed at baseline and follow-up., Results: The cumulative incidence of diffuse goiter was 7.1%, 4.4%, and 6.9%, respectively, higher in Panshan and Huanghua than in Zhangwu (p=0.013 and p=0.015) and that of nodular goiter was 5.0%, 2.4%, and 0.8%, respectively, declining with increasing iodine intake levels (p<0.001). Mild iodine deficiency, chronic iodine excess as well as positive thyroid autoantibodies were associated with the occurrence of goiter [Logistic regression: odds ratio (OR)=1.83 (95% confidence interval (CI) 1.26-2.65), OR=1.46 (95% CI 1.01-2.11) and OR=1.68 (95% CI 1.14-2.48), respectively]. The cumulative incidence of single nodule was 4.0%, 5.7%, and 5.6%, respectively and that of multiple nodules was 0.4%, 1.2%, and 1.0%, respectively., Conclusions: The relationship between iodine and the risk for the occurrence of diffuse goiter shows a U-shaped curve. Nodular goiters are more prevalent in iodine-deficient areas.

Background: The catchment area of the patients under study was the sub-Himalayan plains, which are recognized as iodine-deficient areas., Methods: A retrospective analysis of 1576 surgically treated patients with thyroid disorders is presented. The indications for surgery were hyperthyroidism or cytologically diagnosed malignancy and large size, pressure symptoms, cosmesis, suspicious cytologic findings for malignancy, and clinical suspicion of malignancy in clinically benign euthyroid goiters., Results: Histologically, 83 of 703 solitary thyroid nodules, 36 of 329 clinically benign euthyroid multinodular goiters, and four of 181 Graves' disease were cancers. Of all follicular cell cancers in this study, 132 were papillary, 83 were follicular, and 38 were anaplastic and squamous cell cancers. The different histologic types exhibited an aggressive clinical behavior, with advanced lesions with cervical lymph node involvement and distant metastases frequently seen at presentation. Locoregional recurrence occurred frequently even after radical surgical ablation, and overall mortality caused by the disease was high., Conclusions: Even well-differentiated cancers pursued a virulent clinical course with high mortality, despite routine radical surgical and radionuclide ablation., (2005 Wiley Periodicals, Inc.)

The aim of the study carried out in 1989-90 and 1998-99 was to define the iodine deficiency state and goiter prevalence in adult population of Cracow. The analysis included data obtained from 230 individuals (143 females and 87 males). The mean age was 36 +/- 15 years. The thyroid size and morphology was determined by ultrasound method using Aloka unit equipped with 7.5 MHz linear transducer. The concentration of iodine in casual morning urine sample was measured using Sandell-Kolthoff's method. The 10- year observation revealed an insignificant decrease in prevalence of goiter from 26.2% to 21.8%. We observed statistically significant (p = 0.001) decrease in the parenchymal goiter prevalence from 22.7% to 11.7 in the same period of time. The significant increase in incidence of nodular goiter was found (6.5% vs 20.8%, p < 0.001). In all groups investigated through 1989-99, there was an increase in medians of ioduria over the 10-year period. The level of urinary iodine excretion was not essential element for risk of nodular goitre. Thus, the results indicate the beneficial effect of iodine prophylaxis which reflects in decrease of prevalence of parenchymal goiter. No clear effect of iodine prophylaxis was noticed regarding rise in nodular goiter incidence.

An optimal supply of iodine--150-200 microg/day--has not yet been secured in all regions and in all phases of life. The appreciable diminishment in thyroid gland mass in children and adolescents is, however, indicative of an improvement in this situation. In elderly persons, however, prophylactic measures do not result in struma or nodule regression. Nodules are found in some 40% of women and 28% of men older than 45. Medical treatment of nodular goiter is aimed at achieving a reduction in size or preservation of the status quo. Depending on the size of the goiter, iodine-deficiency goiter is treated with iodine or a combination of iodine and levothyroxine. In view of the pathogenesis and the marginal alimentary lack that still persists, there are no adequate arguments for L-thyroxine monotherapy of uncomplicated iodine-deficiency goiter.

The Hospital de Clínicas organized a free program of goiter detection by palpation. This campaign was aimed at the population of the metropolitan area of Greater Buenos Aires (11 million inhabitants), with the prerequisite that each participant should be quite unaware whether he/she was a carrier of any thyroid disease. Attendees were split into two groups, i.e., Random and Induced. The former consisted of 542 individuals who came to consultation due to mere curiosity, while the latter involved 500 subjects, comprising consanguineous family members of patients with thyroid disorders and also individuals who suffered from other ailments. Ages ranged from 2 to 85 years. In the Random Group, goiter prevalence of 8.7% was observed, while in the Induced Group it climbed to 14.4%. Since both groups were mostly made up of women (87.2%), a correction based on the masculinity index was applied to members of the Random Group. Thus, the total observed prevalence of goiter was 6%, diffuse goiters corresponding to 3.5% and nodular ones to 2.5%. The frequency of nodules increased with age, 90.5% occurring in those over 40 years. In the Induced Group, goiter prevalence among relatives of patients with thyroid disorders proved to be 13.1%, rising to 17.8% in those who suffered from other complaints. The epidemic data presented herein are the first arising from a screening survey carried out in a large iodine-sufficient population of the southernmost tip of the American continent. These results are useful to build up the world map of goiter prevalence in non-endemic areas.

Iodine deficiency is widely known to be the main cause of nodular goiter (NG). In iodine deficient areas subclinical and overt hyperthyroidism is the major cause of morbidity and it is mainly due to toxic NG rather than Graves' disease. Toxic NG, including toxic multinodular goiter and toxic thyroid adenoma is usually encountered in subjects with long-standing NG, in whom thyrotoxicosis is usually preceded by a long phase of euthyroidism and then subclinical hyperthyroidsm (abnormally low TSH with normal circulating thyroid hormones). Epidemiological studies indicate that, compared to Graves' disease, the incidence and prevalence of non-autoimmune hyperthyroidism due to toxic adenoma and toxic multinodular goiter differ in different regions of the world, being much more frequent in areas of iodine deficiency. Recently, mutations of the TSH receptor (TSHr) gene causing permanent activation of the thyroid follicular cell adenylate-cyclase, have been shown to be the most probable cause of the hyperfunction and growth of toxic adenoma. In this review we will focus our attention on the role of external factors (i.e. iodine deficiency) with respect to individual factors (i.e. genetic mutations) in the pathogenesis of toxic NG.

Despite the observation that parity may increase the risk of thyroid carcinoma, very few studies have investigated the possible repercussion of parity on thyroid benign pathology. Recently, parity has been identified as one of the factors contributing to a larger thyroid size in healthy females. The aim of this work was to investigate a possible role for parity on the prevalence of multinodular goiter in iodine deficient areas. For this purpose, the reproductive histories of 2 cohorts of women, normal (Group I, 235 cases) and non-toxic multinodular goiter (NTMNG) affected (Group II, 274 cases) were compared. All subjects were euthyroid and had no previous history of thyroid function abnormalities. The number of full-term previous pregnancies (2.55+/-0.11 vs 1.77+/-0.10) and age (47.7+/-0.76 vs 42.3+/-0.83 yr) were found significantly higher (p<0.001) in multinodular goiter (MNG) patients than controls. Parity and age were found to be directly correlated (p<0.001), nevertheless the partial correlation coefficients demonstrated an independent and statistically significant difference for both variables between normal and NTMNG. Therefore, the independent effects of parity and age were further investigated. The effect of age on NTMNG prevalence seems to be weaker, in fact significant differences (p<0.001) for age between patients and controls were detected only when the effect of parity was absent (nulliparous), while with increasing gestations the effect of age disappeared. Our results indicate that age plays a minor role compared to parity which can therefore be considered as a stronger risk factor. In conclusion, the present study shows that, at least in iodine deficient regions, non-toxic multinodular goiter women show a statistically significant higher parity rate than healthy controls. Age may play a certain role but only when additional stronger risk factors are absent.

Thyroid nodules were assessed by ultrasound in 3 621 presumably healthy free-living French subjects participating in the SU.VI.MAX cohort (2 160 females aged 35-60 years and 1 461 males aged 45-60 years). Urinary iodine was measured in all participants in random morning urine samples. Nodular thyroid structures ranging from 3 mm to 57 mm in diameter were found in 14.5% of the population, without significant differences between regions in the different age and sex groups. Single nodules and multiple lesions were found in, respectively, 9.7% and 3.1% of the subjects. In females, nodules increased from 12.9% to 19.2% between 35-45 years and 45-60 years, respectively (p<0.001). Thyroid nodularity was more frequent among women aged 45-60 years than among men of those ages (19.2% vs. 11.0%, p=0.001). Descriptive data provided by ultrasound differentiated the nodules into solid (43.4%), cystic (38.4%), and mixed solid-cystic (18.2%). Most solid thyroid nodules, 76.1%, were hypoechoic, while 16.6% were iso-, and 7.3% were hyperechoic. The median of iodine concentrations (n=3 276) was 8.0 microgram/100 ml, with 19.4% of the samples being<5 microgram/100 ml. Median iodine concentrations displayed wide regional variations, with values significantly higher in residents of western regions than among those living in the eastern areas (p<0.001), independently of age and sex. No relationship was found between prevalence of nodular thyroid structure and the state of borderline iodine status observed in France.

Objective: To study the annual incidence of thyroid diseases before and after the increase of iodized salt intake., Method: A total of 26,010 persons were examined from mid August to the end of December in 1999., Results: 1. Three hundred and ten patients of thyroid diseases were identified from 1990 to July 1999. One hundred and eighty-three patients were diagnosed after iodine supplementation. 2. The constitution of thyroid diseases had changed significantly regarding the increase of hyperthyroidism, simple goiter and thyroid nodule. 3. Fifty-five patients with hyperthyroidism including 39 patients (70.91%) receiving iodine supplementation were diagnosed. The average annual incidence of hyperthyroidism after iodine supplementation was 36.87 per 100,000, a three-time increase as compared with that before iodine supplementation. The incidence of hyperthyroidism began to show a significant rise in 1996. The year with highest annual incidence was 1997, remaining at high level after supplying iodized salt. Since then the annual relative risk for hyperthyroidism had been increasing., Conclusion: The number of patients with thyroid diseases showed a significant increase after mass iodine supplement. At the same time, the spectrum of thyroid diseases had also changed. Iodized salt intake and the incidence of hyperthyroidism showed a significant correlation. However, the typical model of the change of disease patterns incidence needs further study.

Recent studies have raised doubts about the efficacy of the postoperative use of levothyroxine (LT4) suppressive doses in patients who underwent thyroid surgery for multinodular goiter. The purpose of this retrospective study was to examine the efficacy of different doses of LT4 in preventing postsurgical recurrences of simple multinodular goiter and to identify a marker that could be useful in discriminating patients with a higher risk of developing recurrence. Two hundred thirty-two patients (57 male, 175 female) operated for nontoxic multinodular goiter were divided into two groups: (I) patients with normal postsurgery thyrotropin (TSH) levels (0.25 to 4.5 mU/L) and (II) patients with elevated postsurgery TSH levels (>4.5 mU/L). All patients were subjected to replacement (1.3 microg LT4/kg/day) or suppressive (1.7 microg LT4/kg/day) doses of LT4, and they were followed for a median period of 6 years (range 2 to 12). No statistical difference was found for sex, age, and postsurgery serum TSH between patients submitted to suppressive and replacement therapy. The ultrasound (US) detection of new postsurgery nodules of at least 0.5 cm maximum diameter was considered a recurrence of disease and was found in 10% of the cases studied. Patients with normal postsurgery serum TSH showed a high recurrence rate (30.4%) when submitted to lower daily doses of LT4. In patients with elevated postsurgery serum TSH, the rate of nodular goiter recurrence did not vary with different types of LT4 therapy. In conclusion, our results suggest that the postsurgical serum TSH is useful for prediction of nodular goiter recurrence, as it reflects the amount of residual functioning thyroid tissue in the cervical area. It may also be indicative of patients who might benefit from LT4 suppressive therapy.

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.

In 1980 the iodide content of salt was increased in Switzerland from 7.5 to 15 mg/kg. This raised the mean urinary iodine excretion from 90 (indicating mild iodine deficiency) to 150 micrograms/g creatinine. We examined whether this public health measure was followed by a change of the incidence of hyperthyroidism in a defined catchment area of 109,000 persons. Except for a 27% rise in the first year of the new salt, the total incidence of hyperthyroidism declined steadily to reach 44% of the control level in 1988/89. This was due to a decrease mostly of toxic nodular goitre (minus 73%), less so of Graves' disease (minus 33%). We conclude that correction of mild iodine deficiency has beneficial effects on the incidence of hyperthyroidism, contrary to what is seen initially after correction of severe deficiency.

We evaluated the prevalence of antithyroid peroxidase antibodies (anti-TP0 Ab) in 402 patients with thyroid disease and 30 healthy controls by a commercial radioimmunoassay (RIA) and compared the results with the passive hemagglutination (HA) method. The patients in the study had autoimmune thyroid disorders (AITD) such as Graves' disease and Hashimoto's disease or had nonautoimmune thyroid diseases (NAITD) such as thyroid cancer, congenital goiter, endemic goiter, and nodular goiter. Subjects were recruited from a population with a mild iodine deficiency (Sao Paulo, Brazil). The effect of specific therapy (for either thyrotoxicosis or chronic thyroiditis) on the circulating anti-TPO levels was also investigated. Positive anti-TPO Ab was detected in 89.9% of the patients with AITD as compared with a prevalence of positive tests of only 4.8% in patients with NAITD. Positive microsomal antibody (M Ab) was found in 68.4% of the patients with AITD and in 6.4% of the patients with NAITD. A positive and significant correlation was obtained between M Ab and anti-TPO Ab. A positive anti-TPO test with negative anti-M was found in 14.1% of the patients with AITD but in only 4.3% of the patients with NAITD and normal controls. These results suggest that anti-TPO Ab by RIA is more sensitive and specific than M Ab by HA. In patients with AITD, anti-TPO Ab levels usually decreased after treatment, suggesting that this parameter could be used in the follow-up of these thyroid disorders.

After 30 years of iodine prophylaxis the incidence of goiter in the Valea Jiului area was reassessed. A number of 7,892 pupils aged 7-16 years were examined, of whom goiter was found in 32%. Before iodine prophylaxis started the incidence was 91.8%. The present survey shows that the small-sized goiters markedly prevail over middle-sized ones, while large-sized goiters became extinct. The diffuse to nodular goiter ratio changed by the disappearance of the nodular forms. The neurologic and psychic complications in goiter-bearing children disappeared. Attempts to correlate taste sensitivity to thiocarbamide with goiter failed. Examination of the digito-palmar dermatoglyphics showed a greater incidence of the higher atd angle, with transition forms of sulcus palmaris.