Diet and Epithelial Cancer of the Thyroid Gland

Enhanced secretion of thyroid stimulating hormone (TSH) has been linked with increased risk of thyroid carcinoma. Diet can increase TSH secretion in various ways: 1) low iodine intake, 2) high goitrogen intake, especially in subjects living in iodine-deficiency areas and 3) direct stimulation of anterior pituitary gland. Excessive iodine intake, however, has also been shown to increase risk of goitre and, perhaps, also thyroid carcinoma. Epidemiological evidence on the role of diet in the etiology of thyroid carcinoma is reviewed here. Ad hoc studies in affluent countries are few and often conflicting. A case-control study conducted in the North of Italy suggests that perhaps dietary aspects other than iodine or goitrogens (i.e. fresh fruit and vegetables and animal fat) may be involved.

Socio-demographic characters, distribution and transformation of iodine in soil, plant and wheat grains at District Diamer, Gilgit-Baltistan, Pakistan

Iodine deficiency in soils and plants is a common problem in the hilly areas and has still been ignored. The aim of the current study is to investigate associated health issues, socio-economic characteristics and people's perception regarding iodine deficiency. Furthermore, a follow-up study was conducted to determine iodine and nutrients concentration in soil and crops at District Diamer, Gilgit-Baltistan, Pakistan. A descriptive and empirical analysis was examined. Most importantly, male was significantly observed as more affected for iodine deficiency than female, as contrary to the literature, socio-economic factors such as households' income and awareness (education) are reported as negative and significant contributor to reduce the iodine deficiency among the people irrespective of the gender. Majority of people (84%) heard about the iodine, but about 51.6% people argue that iodine has no effect on the human body and 56% of the respondents do not know why iodine is necessary for human. It was found that 11.5% of the community was affected from the IDD and majority of them were females. Wheat crops were the principal crop since it supplies 75% of calorific energy in an average Pakistani diet. The concentrations of iodine in soil samples range from 4.21 to 5.45 mg kg^-1. The concentration of iodine in wheat crop plant sampled were considerably varied as Boner > Gais > Goher Abad with 1.12, 0.91 and 0.81 mg kg^-1. respectively. Likewise, grain iodine concentration was varied as Gais > Boner > Goher Abad with 0.126, 0.102 and 0.078 mg kg^-1, respectively. This study exposed that community using the cereal crops could face iodine deficiency in their diet which can cause endemic goiter among the population and control the iodine deficiency by empowering the rural community to raise the income level and providing the awareness to the people.

[From Geomorphological Research in the Canton of Aargau to European Military Pathologies. Entangling Anthropological Discourses of Crisis through the Army, 1860-1900]

Military statistics and medical research were closely related over the 19th century. The army not only made use of these new forms of knowledge, but also provided an important institutional setting through the military medicine, which was of crucial importance to medical research in the 19th century. Besides that, Swiss military also played a crucial role in new geographical and geological research, resulting in a series of new mapping projects. This article looks on the ways, in which military context gained influence on scientific research practices in the second half of the 19th century, by analyzing the case of Heinrich Bircher's work on military recruiting statistics and the endemic goiter. New mapping projects and statistical practices were linked, transforming big parts of the country into pathological spaces. Coming from this point, the article discusses in how far the military context lead to politicizing medical discourses and, furthermore, linked them to discourses of an anthropological crisis, common in many European countries.

Bioavailability of iodine in the UK-Peak District environment and its human bioaccessibility: an assessment of the causes of historical goitre in this area

Iodine is an essential micronutrient for human health. Its deficiency causes a number of functional and developmental abnormalities such as goitre. The limestone region of Derbyshire, UK was goitre-endemic until it declined from the 1930s and the reason for this has escaped a conclusive explanation. The present study investigates the cause(s) of goitre in the UK-Peak District area through an assessment of iodine in terms of its environmental mobility, bioavailability, uptake into the food chain and human bioaccessibility. The goitre-endemic limestone area is compared with the background millstone grit area of the UK-Peak District. The findings of this study show that 'total' environmental iodine is not linked to goitre in the limestone area, but the governing factors include iodine mobility, bioavailability and bioaccessibility. Compared with the millstone grit area, higher soil pH and calcium content of the limestone area restrict iodine mobility in this area, also soil organic carbon in the limestone area is influential in binding the iodine to the soil. Higher calcium content in the limestone area is an important factor in terms of strongly fixing the iodine to the soil. Higher iodine bioaccessibility in the millstone grit than the limestone area suggests that its oral bioaccessibility is restricted in the limestone area. Iodine taken up by plant roots is transported freely into the aerial plant parts in the millstone grit area unlike the limestone area, thus providing higher iodine into the human food chain in the millstone grit area through grazing animals unlike the goitre-prevalent limestone area.

Residual goiter in Semirom; iodine status and thiocyanate overload do not play a role

This study was performed to investigate the role of thiocyanate overload in the etiology of endemic goiter in schoolchildren of Semirom, Iran. A total of 1828 schoolchildren were selected by multi-stage random sampling. Urinary iodine concentration (UIC) and urinary thiocyanate (USCN) were measured in a group of these children. The median UIC was 18.5 microg/dl. The mean +/- SD of USCN in goitrous and nongoitrous subjects did not differ significantly (0.75 +/- 0.78 mg/dl vs. 0.63 +/- 0.40 mg/dl; p = 0.30). Finally, we concluded that neither iodine deficiency nor thiocyanate overload contributed to the high prevalence of goiter in Semirom. The role of other goitrogenic factors should be investigated in this region.

Insulin-like growth factor-1 and zinc status of goitrous primary-school children in Arak, Islamic Republic of Iran

Despite a successful national salt iodinization programme, endemic goitre still persists in Iranian children. In a cross-sectional study in Arak the prevalence of goitre was 5.2% in a sample of 6520 primary-school children. Subsamples of 193 children with goitre and 151 healthy children were assessed for urinary iodine excretion, thyroid hormone profile, insulin-like growth factor-1 (ICF-1) and serum zinc. The mean urinary iodine levels of goitrous children and healthy children were 17.4 microg/dL and 15.3 microg/dL respectively, suggesting that iodine consumption was adequate. No significant differences were found between goitrous and healthy schoolchildren in mean levels of urinary iodine, serum IGF-1 or serum zinc. Other factors need be evaluated to, explain the residual prevalence of goitre.

The role of thyroid autoantibodies in the etiology of endemic goiter in schoolchildren of Isfahan, Iran

BACKGROUND

Eleven years after the initiation of universal salt iodization program in Iran, the prevalence of goiter is still high in some areas.

AIM

To investigate the role of thyroid autoimmunity in the etiology of residual goiter in schoolchildren of Isfahan, Iran.

MATERIAL AND METHODS

In a cross-sectional study, 2331 schoolchildren were selected by multi-stage random cluster sampling. Thyroid size was estimated in each child by inspection and palpation. Urinary iodine concentration (UIC), serum anti-thyroperoxidase antibody (anti-TPO Ab), and anti-thyroglobulin antibody (Anti-Tg Ab) were measured.

RESULTS

Overall, 32.9% of children had goiter. The median UIC was 1955.5 microg/dl. There was significant difference in prevalence of positive anti-TPO Ab in goitrous (grade 2) and non-goitrous children (9.7 vs 3.7%, p= 0.02). Goitrous children had higher prevalence of positive anti-Tg Ab than non-goitrous ones (15.1 vs 3.1%, p<0.001).

CONCLUSIONS

According to the present study, goiter is still a public health problem in this region. This study suggests that thyroid autoimmunity is among the contributors of goiter persistence after elimination of iodine deficiency in Isfahan.

Endemic goitre in the Darfur region (Sudan). Epidemiology and aetiology

In the Darfur region of Sudan, 85.5% of 7134 subjects examined, mainly school children, had goitre and in 23.9% the goitre was large (stage II or III). The prevalence of goitre was high in prepubertal children of both sexes and in adult females. There was a higher frequency of large goitre in the rural than in the urban areas (40.9 and 11.4%, respectively). In Port Sudan on the Red Sea Coast the goitre rate was 13.5% among 7697 schoolchildren, but here visible goitre was extremely rare. Of the subjects from Darfur, 54.5% excreted less than 50 micrograms of iodine/g creatinine, while all except one subject in Port Sudan excreted more than that. The median urinary excretion of iodine was 45.3 micrograms/g in subjects from Darfur and 171.2 in those from Port Sudan, the mean value being significantly lower in the former than in the latter (p less than 0.001). The iodine content of all water samples was very low, and the contents of calcium and fluoride were not high. Other goitrogenic factors could not be excluded. However, iodine deficiency is the major cause of goitre in the Darfur region and a prophylactic programme is urgently needed.

Dietary supplies of iodine & thiocyanate in the aetiology of endemic goitre in Imphal East district of Manipur, north east India

BACKGROUND & OBJECTIVE

The present investigation was undertaken to study the iodine nutritional status of school children of Imphal east district in Manipur where endemic goitre persists during post-salt iodization phase along with the investigation of the factors responsible for the occurrence of goitre endemicity.

METHODS

A total of 1,286 children (6-12 yr) were clinically examined for goitre from study areas of Imphal east district. A total of 160 urine samples were collected and analyzed to measure urinary iodine and thiocyanate levels. Iodine content was measured in 140 salt samples and 16 drinking water samples.

RESULTS

Overall goitre prevalence was about 30 per cent (grade 1-24.7%; grade 2-5.3%) and median urinary iodine level was 17.25 microg/dl. The mean urinary thiocyanate level was 1.073 +/- 0.39 mg/dl. Iodine/thiocyanate ratio (microg/mg) was in the ranges from 15.65 to 22.34. The mean iodine content in drinking water samples was 2.92 +/- 1.75 microg/l and 97.8 per cent of edible salts had iodine level above 15 ppm at the consumption point.

INTERPRETATION & CONCLUSION

Our findings showed that in spite of no biochemical iodine deficiency, iodine deficiency disorders (IDD) is a serious public health problem in Imphal east district of Manipur. The consumption pattern of certain plant foods containing thiocyanate (or its precursors) was relatively high that interfere with thyroid hormone synthesis resulting in the excretion of more iodine. Thus, the existing dietary supplies of thiocyanate in relation to iodine may be a possible aetiological factor for the persistence of endemic goitre in the study region during post salt iodization period.

Iodine: deficiency and therapeutic considerations

Iodine deficiency is generally recognized as the most commonly preventable cause of mental retardation and the most common cause of endocrinopathy (goiter and primary hypothyroidism). Iodine deficiency becomes particularly critical in pregnancy due to the consequences for neurological damage during fetal development as well as during lactation. The safety of therapeutic doses of iodine above the established safe upper limit of 1 mg is evident in the lack of toxicity in the Japanese population that consumes 25 times the median intake of iodine consumption in the United States. Japan's population suffers no demonstrable increased incidence of autoimmune thyroiditis or hypothyroidism. Studies using 3.0- to 6.0-mg doses to effectively treat fibrocystic breast disease may reveal an important role for iodine in maintaining normal breast tissue architecture and function. Iodine may also have important antioxidant functions in breast tissue and other tissues that concentrate iodine via the sodium iodide symporter.

Role of exposure analysis in solving the mystery of Balkan endemic nephropathy

We evaluated the role of exposure analysis in assessing whether ochratoxin A or aristolochic acid are the agents responsible for causing Balkan endemic nephropathy. We constructed a framework for exposure analysis using the lessons learned from the study of endemic goiter within the context of an accepted general model. We used this framework to develop an exposure analysis model for Balkan endemic nephropathy, evaluated previous findings from the literature on ochratoxin A and aristolochic acid in the context of this model, discussed the strength of evidence for each, and proposed approaches to address critical outstanding questions. The pathway for exposure to ochratoxin A is well defined and there is evidence that humans have ingested ochratoxin A. Factors causing differential exposure to ochratoxin A and how ochratoxin A is implicated in Balkan endemic nephropathy are not defined. Although there is evidence of human exposure to aristolochic acid and that its effects are consistent with Balkan endemic nephropathy, a pathway for exposure to aristolochic acid has been suggested but not demonstrated. Factors causing differential exposure to aristolochic acid are not known. Exposure analysis results suggest that neither ochratoxin A nor aristolochic acid can be firmly linked to Balkan endemic nephropathy. However, this approach suggests future research directions that could provide critical evidence on exposure, which when linked with findings from the health sciences, may be able to demonstrate the cause of this disease and provide a basis for effective public health intervention strategies. One of the key unknowns for both agents is how differential exposure can occur.

Medical geology in tropical countries with special reference to Sri Lanka

Sri Lanka provides an ideal opportunity for the study of the effect of geology on human health. The vast majority of the people of Sri Lanka still live in rural areas within areas termed geochemical provinces. Very broadly, one could say that a geochemical province has characteristic chemical composition in soil, water stream sediments and rocks, enabling their delineation from others. The chemical composition is presumed to be have an impact on the health of the inhabitants of the particular geochemical province, particularly because of the fact that their food and water are obtained mostly from the terrain itself. This leads to the concept of "diseases of geochemical origin". Among these are dental fluorosis, iodine deficiency disorders (IDDs) and selenium-based diseases. The Dry Zone of Sri Lanka has several areas rich in groundwater fluoride, the ingestion of which leads to dental fluorosis. Iodine deficiency diseases are more common in the Wet Zone, though their aetiologies are more complicated. Interestingly, it has also been observed that significant proportions of the female population of Sri Lanka are selenium-deficient, which could well be related to the geological environment. Chronic renal failure (CRF) has been observed in some areas of the Dry Zone of Sri Lanka, where there is a relationship of CRF with the mineral content of drinking water. This subject matter falls under the auspices of Medical Geology, a scientific discipline still in its infancy, and much more concerted studies are needed to attract the attention of medical research.

Goiter and other iodine deficiency disorders: A systematic review of epidemiological studies to deconstruct the complex web

A systematic review of the available literature on goiter and other iodine deficiency disorders (IDDs) was carried out with the aim of analyzing available evidence and providing inputs to the policy makers and program formulators regarding the entire issue. The findings point to major issues such as the following: methodological issues in epidemiology of goiter and other iodine deficiency disorders (IDDs); lacunae in causal linkages; inadequate attention to multicausality; flawed assessment of the impact of intervention, i.e., iodized salt; and harmful effects of iodine not given due cognizance. Most of the research to date has been unidirectional and does not provide comprehensive data on all aspects of IDDs. To further compound the issue, many independent researchers, on finding something different from the existing dominant paradigm (iodized salt as panacea for goiter) have tended to ignore these in their final conclusions and recommendations. Thus, evidence from this systematic review demonstrates enough basis to start a debate on the entire issue, recognizing opposing research findings while continuing with the present strategy. This imposes specific problems and necessitates area-specific solutions instead of a universal solution, which apart from being less effective may be harmful in the long run.

The role of iodine in the evolution of thyroid disease in Greece: from endemic goiter to thyroid autoimmunity

The thyroid gland is dependent on dietary iodine for the production of thyroid hormones, normal iodine requirement being about 150-200 microg/day. Long-term deficiency in iodine intake is associated with the development of goiter. When the prevalence of goiter in a population rises above 5-10%, the problem is considered endemic. Greece is a country with a recent history of moderate iodine deficiency, endemic goiter being prevalent in the 1960s in inhabitants of mountainous regions. Despite recognition of the problem, an iodine prophylaxis program was never officially implemented. Instead, "silent iodine prophylaxis" took place during the 1980s and 1990s with Greece's improvement in socioeconomic conditions. This resulted in the elimination of iodine deficiency and a parallel decrease in the prevalence of goiter among schoolchildren in formerly iodine deficient areas. However, the transition from iodine deficiency to iodine sufficiency or excess was followed by the emergence of autoimmune thyroiditis, especially among young girls, indicating that exposure to excess iodine may trigger thyroid autoimmunity. Thus, the modification of an environmental factor, ie dietary iodine, over the last 40 years in Greece has been associated with changes in the phenotypic expression of thyroid disease from endemic goiter to goiter associated with autoimmune thyroiditis.

Low serum selenium concentration as a possible factor for persistent goiter in Iranian school children

Selenium deficiency can have adverse effect on thyroid metabolism and response to iodine supplementation. The aim of this study was to determine relationship between prevalence of goiter, thyroid hormone profile, urinary iodine and serum selenium concentrations in Iranian schoolchildren. In a cross- sectional study, 1188 schoolchildren in the age group of 8-13 years were evaluated for goiter prevalence. Urine and serum samples were collected from 500 children and assayed for urinary iodine concentration, thyroid hormone profile and serum selenium concentration. The overall goiter prevalence was 39.6% and the median urinary iodine excretion, indicated to an adequate iodine intake. The mean serum selenium concentration was 119.1 +/- 31 mug/l with significant difference between boys and girls (108.4 +/- 26.2 mug/l vs 127.7 +/- 32.1 mug/l). An increase in free T4 concentration was observed in those with a lower selenium level and there was a significant relationship between the presence or absence of goiter and serum selenium concentration. Selenium supplementation may be an advisable measure to optimize thyroid hormone metabolism and decrease the prevalence of goiter in schoolchildren with low serum selenium concentration.

Predictive factors for recurrent non-toxic goitre in an endemic region

Aims: We aimed to determine the risk factors for recurrence and to assess the complication rate associated with surgery for benign, recurrent goitre.

Methods: We studied 125 consecutive patients with recurrent goitre who underwent re-operative thyroid surgery (group one). Patients in the control group were randomly selected from those undergoing their first procedure during the same period (group two). Age, initial surgery, presence of multinodular goitre, presence of carcinoma in the resected thyroid tissue, interval between initial operation and re-operation, and complications were analysed and compared for the two groups.

Results: The mean age (± standard deviation) was found to be significantly greater in group one compared with group two. The mean age at the time of primary thyroid operation was found to be significantly less in group one compared with group two. The interval between the initial and the re-operative procedures was a mean of 15.8±eight years. Initial surgery was conservative. Papillary thyroid carcinoma was found in 14/125 (11 per cent) of group one patients. The incidence of complications was found to be significantly higher in group one compared with group two.

Conclusion: The incidence of recurrent goitre has been directly related to conservative thyroid surgery and to the retention of large amounts of remnant tissue. To avoid recurrent goitre and possible re-operative complications, total or near-total thyroidectomy should be performed in all patients with bilateral, multinodular goitre, especially in endemic regions.

[Hair trace elements in patients with goiter]

The investigation determined whether there was a relationship of thyroid diseases with the geology of the place of residence and its associated spectrum of trace elements (iron, chromium, selenium, manganese, cobalt, copper, nickel, arsenic, and zinc). The geologo-geomorphological factors of the habitat, such as geological formations (mineral composition, structure, the degree of rock metamorphism), tectonics, the history of geological development, relief, paleorelief, were found to be of considerable importance in the formation of the human trace element status. Both deficiency and excess of trace elements was shown to be of pathogenetic value in the development of thyroid diseases. Residence in the area wherein carbonate rocks are predominant contributes to an increase in incidence of thyroid diseases.

[Iodine prophylaxis in children population on the Wielkopolska Region area from year 1992 to 2005]

INTRODUCTION

The aim of the study was to evaluate of efficiency of iodine prophylaxis based on obligatory model of salt iodization.

MATERIAL AND METHODS

The study included 1444 children from the rural and urban area, with the proportional sex and age (8-12 years) distribution--432 children in 1992 (before salt iodization), 558 children in 2000 and 454 children in 2005 (during salt iodization from 1996).

RESULTS

The prevalence of goiter detected in children population in 1992 was 40% (recount by current criteria), in 2005 was reduced to 6% (p < 0.01). Parallel, median of urinary iodine concentration increased from 44 microg/l in 1992 to 107 microg/l (p < 0.01) in 2005. The increase of incidence of autoimmunological thyroid diseases is observed, especially chronic thyroiditis.

CONCLUSIONS

The study proves high efficiency of iodine prophylaxis in Wielkopolska Region, but it is still the area with mild iodine deficiency.

[Current views on the etiopathogenesis of goiter in children]

The most frequent cause of goiter in children is a deficit of iodine, leading to endemia of goiter in the regions with insufficient supplementation of this element. Goiter occurs also in the course of autoimmunological diseases of the thyroid gland (Hashimoto disease, Graves' disease), genetically-related disorders of thyroid hormones, biosynthesis/impaired biosynthesis of thyroid hormones. According to the theory of goiter pathogenesis, excessive enlargement of the thyroid gland is due to adaptation of follicle cells of the gland aiming at neutralizing the impaired synthesis of the thyroid hormones caused by various intrathyroid, environmental and genetic factors/agents. The mechanisms stimulating thyrocytes to hyperplasia or hypertrophy are very complex and still unknown in spite of having identified many physiological and pathogenetic factors connected with goiter.

Risk factors for goiter in primary school girls in Qom city of Iran

OBJECTIVE

Goiter is endemic in Iran. The iodine deficiency disorders program was begun a few years ago in Iran, and the coverage of iodized salt is sufficient now. But, in a periodic yearly medical examination of primary school girls in Qom, the prevalence of goiter was above 30% in 2002. This survey was designed to study the risk factors of goiter in those students.

DESIGN

The study was a randomized (multistage, proportional simple random sampling) case-control study.

SUBJECTS AND INTERVENTIONS

We selected and performed thyroid examinations in 1050 girl students in primary schools in Qom city of Iran in 2002. We found 284 cases: girls in primary schools had goiter in accordance with the clinical exam of World Health Organization classification. Among students who did not present with goiter in the clinical exam, we randomly selected 288 students as the control group. We used a questionnaire to evaluate them for the risk factors of goiter.

RESULTS

The mean+/-s.d. ages of cases and controls were 8.7+/-1.3 and 8.9+/-1.3 years, respectively. There is no significant difference between the two groups regarding history of soya, kale, turnip, fish, daily iodized salt usage, education and job of mothers, monthly family income, nationality, immigration and residential situation. By using multinomial logistic regression, we found that storage of iodized salt in open containers, odds ratio (OR): 2.201 (1.412-3.428); P-value <0.0001, medium socioeconomic situation (SES) of family, OR: 2.099 (1.029-4.282), P-value=0.041, district 2 of Qom city, OR: 2.880 (1.376-6.027), P-value=0.005, and district 3 of Qom city, OR: 2.051(1.032-4.078), P-value=0.041, were the major risk factors for goiter in this population.

CONCLUSIONS

In this study, the main risk factors for goiter were storage of iodized salt in open containers, medium SES and also living in specific districts of Qom city. As the coverage of iodinized salt is over 95% in Iran, we advise the education of the family about storage of iodized salt in closed containers. We also recommend the study of the other risk factors of goiter in the different geographical areas of Iran, because of differences in the SES and nutritional habits.

SPONSORSHIP

This study was supported by issuing permission letters for our activities: (not funding support) Qom Health Network and Medical Services, Qom Medical University, Qom Primary School Education Office, Fathemieh Medical University.

Risk Factors for Goiter in a Previously Iodine-Deficient Region

OBJECTIVE

Little information exists from formerly iodine-deficient areas regarding gender-specific risk factors for goiter and their synergisms. The aim of the present study was to investigate such gender-specific risk factors and their interactions in a large population-based sample.

METHODS AND RESULTS

The Study of Health in Pomerania (SHIP) comprised 4310 randomly selected participants, aged 20 - 79 years. SHIP was performed in a previously iodine-deficient region. Data from 3915 participants with no known thyroid disorders were analyzed. Goiter was determined by thyroid ultrasound. Sociodemographic characteristics, smoking and alcohol drinking habits, marital status, education level, urine thiocyanate concentrations, and specifically in women, parity and previous or current use of oral contraceptives and hormone replacement therapy, were considered as candidate risk factors for multivariable statistical tests. Only two variables, an advanced age and current smoking, were independently associated with an increased risk for goiter in both genders. Analyses further revealed specific risk factor profiles for goiter which were different among men, pre- and postmenopausal women.

CONCLUSION

We conclude that besides previous iodine deficiency, other risk factors for goiter exist which differ between gender. Among the avoidable risk factors, current smoking was strongly associated with the risk of goiter in men and women. These findings should influence activities which are intended to prevent thyroid disease.

Prevalence of iodine deficiency disorders among schoolchildren in three blocks of Bardhaman District and Bardhaman Municipal area of West Bengal, India: a comparative study

Urinary iodine levels in children (6-12 years) living in three rural blocks and in the municipal urban area of Bardhaman District, West Bengal, were analyzed to compare the status of recent iodine nutrition in the rural and urban population of the district. Goiter, indicating previous iodine status, was simultaneously estimated. Iodine levels in salt samples, that provide insight into the usage of iodized salt, were estimated. Data indicated that 56.6% of urban children and 51.1% of rural children were biochemically iodine repleted and had urinary iodine excretion (UIE) levels > or = 10microg/dl. Urban children (29.4%) and rural children (37.1%) were found to have goiter. Eighty percent and 50% of the rural and urban salt samples, respectively, were found to have iodine levels below 10 ppm; with significant urban-rural differences. The results indicate that iodine repletion in the surveyed area needs continuous surveillance of the proper distribution and use of iodized salt.

Chronic iodine overload and apoptosis in cold nodules from endemic multinodular goiters

As apoptosis and necrosis are known to exist during experimental goiter development and involution, we studied them in ten Tunisian multinodular endemic goiters, five of them having received a chronic excess of iodine during six months. Apoptotic thyrocyte nuclei have been counted on hematoxylin-eosin stained semi-thin sections. Using immunoperoxidase on paraffin sections, bcl-2 and bax immunoreactivities have been evidenced, and CD34 positive microvessels counted; ultra-thin sections have also been observed. After six months of iodine overload, apoptotic thyrocytes were ten times more numerous; CD34 positive endothelial cells were diminished by one half bcl-2 immunoreactivity disappeared in thyrocytes and a bax one appeared in thyroid follicular and endothelial cells. Presence of numerous apoptotic follicular and endothelial cells was confirmed using electron microscopy. Chronic iodine excess induces apoptosis and necrosis of thyroid follicular and endothelial cells, leading to thyroglobulin accumulation in connective tissue.

Goitre and environmental iodine deficiency in the UK--Derbyshire: a review

Endemic goitre was prevalent in the population of Derbyshire in the UK for many centuries until it declined from the 1930s. A contemporary medical survey showed that endemicity of goitre was particularly higher in the Carboniferous limestone areas of the Derbyshire-Peak District. Unlike classical goitrous areas of the world, where the distribution of goitre has been found to be related to the iodine content in the environment, there is no such relationship reported for the Derbyshire-Peak District area. The present study reviews the presence of endemic goitre in this area with reference to iodine in different environmental media using past and present data. In comparison with the world average values, the iodine contents in the soil and sediment in the Peak District are not deficient, but compared to England, Wales and Scotland averages, these levels are low. As no information on the mobility and bioavailability of iodine of this area is available, a cautious approach is necessary before any assumption is made on the aetiology of endemic goitre. The study also discusses some hypotheses relating to the possible cause of endemic goitre in the limestone areas. Further research needs are suggested depending on the land use and geochemistry of the Peak District to determine the underlying causes of the former endemic goitre in this area.

Experiences in the prevention, control and elimination of iodine deficiency disorders: a regional perspective

Before 1987, iodine deficiency was not considered an issue of major importance in the countries of the Eastern Mediterranean Region (EMR). Progress began with a systematic national study of goitre and other iodine deficiency disorders (IDD) in the Islamic Republic of Iran in 1983. Following a major review of the prevalence of IDD in member states, Guidelines for national programmes for the control of iodine deficiency disorders in the EMR were published by the World Health Organization (WHO) in 1988. This paper discusses progress towards elimination of iodine deficiency by reviewing the status of IDD in the countries of EMR and programmes for prevention and control of IDD with particular reference to the Islamic Republic of Iran, the first country to be declared IDD-free by WHO.

Goitrogenic content of Indian cyanogenic plant foods & their in vitro anti-thyroidal activity

BACKGROUND & OBJECTIVES

Consumption of cyanogenic foods has been considered as one of the etiological factors in certain instances for the persistence of endemic goitre. The present study was undertaken to study the cyanogenic glucosides, glucosinolates and thiocyanate content in edible portion of certain selected plant foods of Indian origin. Further in vitro anti-thyroidal activity using raw, boiled and cooked extracts of these plants with and without excess iodide was also studied.

METHODS

Cyanogenic plant foods generally vegetables were collected from different areas of West Bengal and Tripura. Cassava was obtained from Meghalaya and Kerala and their cyanogenic glucosides, glucosinolates and thiocyanate were estimated. Thyroid peroxidase activity (TPO) of human thyroid was assayed from microsomal fraction following I3- from iodide. The anti-TPO activities of the plants were assayed after adding raw, boiled and cooked extracts in the assay medium with and without extra iodide. Relative antithyroidal potency of the plant extracts was also evaluated in terms of the concentration (IC50) necessary to produce 50 per cent inhibition of TPO activity. PTU equivalence of the plant foods was also determined.

RESULTS

Cabbage and cauliflower were rich in glucosinolates, bamboo shoot and cassava were rich in cyanogenic glucosides, mustard, turnip and radish were relatively rich in thiocyanate however all the constituents were present in each plant. Boiled extracts showed maximum inhibition of TPO activity followed by cooked and raw extracts. Excess iodide was found relatively effective for raw extract but less effective for boiled and cooked extracts in reversing anti-TPO activity. Inhibition constant (IC50) was found highest with bamboo shoot and least with cabbage.

INTERPRETATION & CONCLUSION

Raw, boiled and cooked extracts of the plants showed anti-thyroidal activity in vitro. Excess iodide reversed the anti-TPO activity to same extent but could not neutralise it.

[Diagnosis and treatment of benign goiter]

Although the German population is now appreciably better supplied with iodine, this is still not adequate in all regions and in all situations, e.g. during pregnancy and breast feeding. As a result, more than 20 million Germans have an iodine-deficiency goiter that requires treatment. Investigation of a goiter is effected with sonography and the determination of serum TSH. If the results indicate euthyroid diffuse goiter, medical treatment should be initiated. In recent years, the combination of thyroid hormone and iodine has proved particularly effective. In contrast to monotherapy with levothyroxine goiter recurrence after discontinuation of treatment is less common, and the combination is usually tolerated better.

[Effect of three years obligatory iodine prophylaxis on the incidence of goiter in school children fron the seaside region of Poland]

In 1993 a mild iodine deficiency in the seaside region of Poland was revealed. In 1997 a mandatory iodine prophylaxis was introduced. The aim of the study was to determine the prevalence of goiter in schoolchildren aged 12-15 years from the seaside area after 3 years of obligatory iodine prophylaxis. The study comprised 628 children (291 boys and 337 girls). Thyroid size was estimated by palpation and by ultrasonography. Analysis of iodine excretion (Uroiod-Test Merck) was performed in 147 children. The goiter was found in 9% of children by palpation. The mean thyroid volume in 12 years old group was 9.3 +/- 5.1 ml, in 13 years old group 10.6 +/- 4.2 ml, 14 years old group 11.7 +/- 3.9 ml, 15 years 13.8 +/- 4.3 ml. The thyroid volume in girls was larger than that in boys. Thyroid volume above 97th percentile was assessed by ultrasound in 16% children (all of them from rural area). No goiter was found by palpation or ultrasound in children living in Gdańsk Thyroid volume is closely correlated with iodine excretion, age and height. Urinary iodine excretion above 100 micrograms/l was stated in 68% children.

CONCLUSIONS

Model of obligatory iodised salt prophylaxis is highly effective and is able to increase urinary iodine excretion and decrease of goiter prevalence. Ultrasound is especially recommended for the evaluation of thyroid volume in children from previously mild iodine deficiency areas.

[Prevention of endemic goiter in areas jointly exposed to natural and industrial chemical factors]

The present paper deals with the sanitary evaluation of goiter endemia and with a rationale for principles in its prevention in areas exposed to natural and industrial chemical factors (in case of the Perm Region). The findings suggest that the elevated levels of some toxic metals and organic compounds in the body and zinc deficiency are strumogenic factors that maintain and aggravate the severity of goiter endemia in the presence of iodine deficiency. Comprehensive programs for prevention and correction of goiter endemia should be worked out differentially, by taking into account a combined influence of natural and industrial chemical factors on the population.

Urinary iodine concentration during pregnancy in an area of unstable dietary iodine intake in Switzerland

We prospectively investigated urinary iodine concentration (UIC) in pregnant women and in female, non-pregnant controls in the canton of Berne, Switzerland, in 1992. Mean UIC of pregnant women [205 +/- 151 microg iodine/g creatinine (microg l/g Cr); no. = 153] steadily decreased from the first (236 +/- 180 microg l/g Cr; no. = 31) to the third trimester (183 +/- 111 microg l/g Cr, p < 0.0001; no. = 66) and differed significantly from that of the control group (91 +/- 37 microg l/g Cr, p < 0.0001; no. = 119). UIC increased 2.6-fold from levels indicating mild iodine deficiency in controls to the first trimester, demonstrating that high UIC during early gestation does not necessarily reflect a sufficient iodine supply to the overall population. Pregnancy is accompanied by important alterations in the regulation of thyroid function and iodine metabolism. Increased renal iodine clearance during pregnancy may explain increased UIC during early gestation, whereas increased thyroidal iodine clearance as well as the iodine shift from the maternal circulation to the growing fetal-placental unit, which both tend to lower the circulating serum levels of inorganic iodide, probably are the causes of the continuous decrease of UIC over the course of pregnancy. Mean UIC in our control group, as well as in one parallel and several consecutive investigations in the same region in the 1990s, was found to be below the actually recommended threshold, indicating a new tendency towards mild to moderate iodine deficiency. As salt is the main source of dietary iodine in Switzerland, its iodine concentration was therefore increased nationwide in 1998 for the fourth time, following increases in 1922, 1965 and 1980.

Chernobyl and iodine deficiency in the Russian Federation: an environmental disaster leading to a public health opportunity

The Chernobyl nuclear disaster of April 26, 1986, triggered a chain of devastating events that later included an unexpected increase in childhood thyroid cancer and evidence of iodine deficiency (ID) in Russia. For the Russian people the Chernobyl event had profound psychological impacts, provoking anxiety about nuclear technology and mistrust of governmental control efforts. Frequently in public health a crisis is required to create the political will to manage longstanding problems, and public health officials must rapidly mobilize to take advantage of the opportunity. In this case, ID, previously not seen as a problem in Russia, was recognized to be potentially serious, and the Russian Federation, assisted by the catalytic bi-national effort of the U.S.-Russian Joint Commission on Economic and Technological Cooperation (Gore-Chernomyrdin Commission (GCC)) established a model salt iodization policy, developed a planning process, and implemented a program to prevent ID through a systematic approach that included the people, government, and private groups using open communication, dissemination of the findings, and action plans. By 1999, political will had been mobilized and over 20% of the nation's salt was being iodized, up from about 1% in 1996. Universal iodization of salt was not a specific objective of the GCC; however, the increasing availability of iodized salt is leading to the elimination of ID, which is now a political goal in Russia. The full realization of this goal will require more time for education, marketing, and possibly legislative action.

[Supply of iodine during pregnancy--an inventory in Berlin, Germany]

BACKGROUND

Iodised salt was introduced in Germany in the early 1980s. A nation-wide study in 1996 showed that iodine levels among the population had improved since the introduction of the supplementation. The study did not separately investigate the iodine status of pregnant women. In our prospective study, we used three parameters to assess the iodine levels among pregnant women.

PATIENTS AND METHODS

Between October 1999 and February 2000, we asked 109 German-speaking patients seeking prenatal care in our clinic to participate. Following informed consent, we measured goiter volume by ultrasound and collected venous blood (serum) and urine samples. We asked patients about any history of thyroid gland illnesses and about iodine supplementation which is generally given to pregnant patients in Germany. The blood and urine samples were stored at -18 degrees C until measurement. We used the iodine-creatinine-ratio to measure ioduria. Iodine was measured using the Cer-Arsenite-method (Dade-Behring). The thyroglobulin concentration in serum was measured using RIA.

RESULTS

The mean iodine-creatinine ratio was 181 +/- 109 microg/g, 20.4 % of the patients had a ratio between 50 and 100 microg/g which is defined as iodine deficiency I degrees (WHO). 8.7 % of the patients had thyreoglobulin levels above the cut-off value of 50 ng/ml. 12.6 % of the patients had a goiter (volume > 18 ml). 58 % of the patients were taking iodine supplements. These patients had significantly higher iodine-creatinine ratio levels (204 microg/g vs. 148 microg/g, P = 0.007) and lower serum thyroglobulin levels (38.4 vs. 34.1 pmol/l, P = 0.06) than non-supplemented patients.

CONCLUSIONS

The prevalence of goiter reflects an extended period of iodine deficiency. Using laboratory methods, up to 20.4 % of pregnant women were identified as having an iodine deficiency which indicates the need for a general iodine supplementation during pregnancy.

Thyroid dysfunction in eastern Nepal

Nepal lies in an area of endemic iodine deficiency. Thyroid dysfunction, along with a higher than average prevalence of goiter, is a major public health problem among the local population. The present study was undertaken to investigate the prevalence of thyroid dysfunction among the hill and terai (low land) castes of eastern Nepal that attended the thyroid clinic at the BP Koirala Institute of Health Sciences (BPKIHS), Dharan. A total of 599 cases were studied during a single year. The distribution of hyperthyroid and hypothyroidism was 13.68% and 17.19% respectively. The majority of the thyroid dysfunction was seen in the 21-40 year age group. The prevalence of hypothyroidism was slightly higher among terai castes (17.66%) when compared with hill castes (15.17%). There was a similar distribution of thyroid dysfunction among the male and female populations of the goitrous subjects (n=157), most were euthyroid (58.59%); hyperthyroidism affected (27.38%). Since, it was a hospital-based study, the prevalence of thyroid dysfunction may not be applicable to the general population. Extensive field-based countrywide epidemiological studies are necessary to provide data about thyroid dysfunction in the community.

Iodine deficiency in Europe and its consequences: an update

This paper updates the information on the prevalence of the disorders induced by iodine deficiency (IDD) in Europe. Thirty-two European countries were still affected by mild to severe iodine deficiency in the late 1990s. The most severely affected countries were in Eastern Europe, including Central Asia, but Western Europe was also still affected. National surveys recently conducted in 11 of these countries show that, with the exception of the Netherlands, none has yet reached a state of iodine sufficiency, though very significant improvement in the situation has been evidenced in many of them, e.g. Poland, Bulgaria and Macedonia. The consequences of persisting iodine deficiency are goitre, hyperavidity of the thyroid for iodide (which increases the risk of thyroid irradiation in the event of a nuclear accident) and subclinical hypothyroidism during pregnancy and early infant (with a concomitant risk of minor brain damage and irreversible impairment of the neuropsychointellectual development of offspring). Access to iodised salt at the household level in European countries affected by IDD increased from 5%-10% in 1990 to 28% in 1999. This constitutes encouraging progress. However, in terms of access of iodine-deficient countries to iodised salt, Europe remains the worst region in the world, as shown by the fact that the mean figure worldwide in 1999 was 68%. In Latin America it even reached 90%. Salt iodisation has to be further implemented in Europe. Until that goal is achieved, iodine supplementation in those groups most sensitive to the effects of iodine deficiency (pregnant and lactating women and young infants) will have to be considered in the most severely affected areas.

[Role of some environmental factors in the development of endemic goiter (a review)]

The review presents possible causes of endemic goiter since only iodine deficiency fails to explain such a great spread of this disease. Etiological factors of endemic goiter, such as the imbalance of trace elements, the use of contaminated drinking water, the toxic action of chemicals, exposure to ionizing radiation, genetic factors, are discussed. Prevalence rates of endemic goiter in Russia and other countries of the world are presented. The causes of a significant increase in the incidence of this disease are discussed.

[Iodine deficiency and other potential goitrogens in the persistence of endemic goiter in Mexico]

OBJECTIVE

To measure the frequency of goiter and the presence of potential goitrogens in a sample of school-age children and pregnant women.

METHODS

Cross-sectional study in a purposive sample in three regions, one with known high prevalence of goiter (Huejutla), one with unknown prevalence (Ixmiquilpan) and one with no expected deficiency (Pachuca). Children were sampled from schools and pregnant women from rural reference hospitals. Goiter was evaluated by manual exam and ultrasound.

RESULTS

Goiter prevalence in 673 children between 6 and 14 years old was 8% in Pachuca, 9% in Ixmiquilpan, and 14% in Huejutla. In 300 pregnant women, goiter prevalence was 19% in Pachuca, 20% in Ixmiquilpan, and 52% in Huejutla. In 936 interviews on salt consumption, 98% of families consumed table salt, but only 50% of the samples were adequately iodized. Twenty-four percent of families obtained water from wells contaminated with arsenicum and mercury in Pachuca and Ixmiquilpan, and with colibacilli in Ixmiquilpan.

CONCLUSIONS

Even at the end of the millenium, endemic goiter is still a public health problem in this sample of school-age children and pregnant women. Despite consumption of iodized salt, ingestions of goitrogens may be contributing to the persistence of this problem.

Thyroid cancer and thyroiditis in Salta, Argentina: a 40-yr study in relation to iodine prophylaxis

The natural history of thyroid cancer and thyroiditis in relation to iodine prophylaxis in the region of Salta, Argentina, where goiter is common was investigated over a time span of 40 yr. For analysis of thyroid cancer, the specimens were divided into two periods. The first 15 yr (59 cases), including 5 yr before prophylaxis, was compared with the second 25 yr (182 cases), a period well after salt iodination. Papillary carcinomas formed the largest group of tumors in both periods, with a significant increase in their proportion in the second period (44 vs 60%, chi(2): p < 0.05), while the percentage of follicular and undifferentiated carcinomas decreased and medullary carcinoma remained about the same. The ratio of papillary to follicular carcinoma rose from 1.7:1 in the first period to 3.1:1 in the second. Four thyroid lymphomas of non-Hodgkin's B-cell type occurred in the second period in females over age 50. A severe lymphoid thyroiditis was present in the two cases with assessable background thyroid tissue. The frequency of moderate to severe lymphoid infiltrate in females rose from 2 of 12 (16.6%) in the preprophylaxis period to 34 of 114 (28.0%) in the last 25 yr after prophylaxis. After salt prophylaxis, thyroiditis was more frequent in patients with papillary carcinoma (36.2%) than in those with nonpapillary tumors (14.7%) (chi(2), p < 0.02). These observations indicate that a high dietary intake of iodine may be associated with a high frequency of papillary carcinoma and thyroiditis, and that thyroiditis is more commonly associated with papillary carcinoma than with other thyroid tumors. The occurrence of non-Hodgkin's lymphomas only in the postprophylaxis period may be linked to an increase in thyroiditis.

National study on the prevalence of iodine deficiency disorders among schoolchildren 8-12 years of age in Bahrain

A cross-sectional survey of primary-school children in Bahrain was conducted to estimate the prevalence of goitre and iodine deficiency according to age, sex and area of residence. During January-May 1999, 1600 children were randomly chosen from all government schools. Children were examined for goitre and of those, 50% were randomly selected for urinary iodine level assessment. Only 26 children (1.7%) had goitre. Although median urinary iodine was above 100 microg/L, 121 of 749 children (16.2%) had low urinary iodine levels. Although iodine deficiency does not pose a significant public health problem in Bahrain, education about the nutritional value of iodized salts in the prevention of this disorder could increase public awareness.