Endemic goitre--iodine deficiency disorders

Exploring the potential of genetic analysis in historical blood spots for patients with iodine-deficient goiter and thyroid carcinomas in Switzerland and Germany (1929-1989)

Iodine deficiency-induced goiter continues to be a global public health concern, with varying manifestations based on geography, patient's age, and sex. To gain insights into clinical occurrences, a retrospective study analyzed medical records from patients with iodine deficiency-induced goiter or thyroid cancer who underwent surgery at the Community Hospital in Riehen, Switzerland, between 1929 and 1989. Despite today's adequate iodine supplementation, a significant risk for iodine-independent goiter remains in Switzerland, suggesting that genetic factors, among others, might be involved. Thus, a pilot study exploring the feasibility of genetic analysis of blood spots from these medical records was conducted to investigate and enhance the understanding of goiter development, potentially identify genetic variations, and explore the influence of dietary habits and other environmental stimuli on the disease.Blood prints from goiter patients' enlarged organs were collected per decade from medical records. These prints had been made by pressing, drawing, or tracing (i.e., pressed and drawn) the removed organs onto paper sheets. DNA analysis revealed that its yields varied more between the prints than between years. A considerable proportion of the samples exhibited substantial DNA degradation unrelated to sample collection time and DNA mixtures of different contributors. Thus, each goiter imprint must be individually evaluated and cannot be used to predict the success rate of genetic analysis in general. Collecting a large sample or the entire blood ablation for genetic analysis is recommended to mitigate potential insufficient DNA quantities. Researchers should also consider degradation and external biological compounds' impact on the genetic analysis of interest, with the dominant contributor anticipated to originate from the patient's blood.

Iodine and Myo-Inositol: A Novel Promising Combination for Iodine Deficiency

Despite universal salt iodization programmes implemented over the last decades, iodine deficiency remains a major public health problem in many countries worldwide. Endeavors are still required to ensure sufficient iodine intake in the populations at risk in order to eliminate deficiency. Iodine is crucial for the synthesis of thyroid hormones triiodothyronine (T₃) and thyroxine (T₄), as well as for the thyroid health. When iodine levels are insufficient, T₄ attests toward the lower limit of the physiological range, causing subtle fluctuations in the T₃:T₄ ratio. Monitoring these variations may be an accurate way to assess patient's iodine status. Recently, a number of published clinical studies documented a growing interest toward the use of myo-inositol in thyroid diseases. Myo-inositol, a carbocyclic polyol, regulates the generation of hydrogen peroxide (H₂O₂) in thyrocytes, crucial for iodine organification and thyroid hormone biosynthesis. Thus, combined supplementation of iodine and myo-inositol may promote higher iodine availability in thyrocytes improving thyroid functionality. This review presents novel strategies for the diagnosis and the management of iodine deficiency, focusing on the potential role of myo-inositol combined with iodine.

Transport, Metabolism, and Function of Thyroid Hormones in the Developing Mammalian Brain

Ever since the discovery of thyroid hormone deficiency as the primary cause of cretinism in the second half of the 19th century, the crucial role of thyroid hormone (TH) signaling in embryonic brain development has been established. However, the biological understanding of TH function in brain formation is far from complete, despite advances in treating thyroid function deficiency disorders. The pleiotropic nature of TH action makes it difficult to identify and study discrete roles of TH in various aspect of embryogenesis, including neurogenesis and brain maturation. These challenges notwithstanding, enormous progress has been achieved in understanding TH production and its regulation, their conversions and routes of entry into the developing mammalian brain. The endocrine environment has to adjust when an embryo ceases to rely solely on maternal source of hormones as its own thyroid gland develops and starts to produce endogenous TH. A number of mechanisms are in place to secure the proper delivery and action of TH with placenta, blood-brain interface, and choroid plexus as barriers of entry that need to selectively transport and modify these hormones thus controlling their active levels. Additionally, target cells also possess mechanisms to import, modify and bind TH to further fine-tune their action. A complex picture of a tightly regulated network of transport proteins, modifying enzymes, and receptors has emerged from the past studies. TH have been implicated in multiple processes related to brain formation in mammals-neuronal progenitor proliferation, neuronal migration, functional maturation, and survival-with their exact roles changing over developmental time. Given the plethora of effects thyroid hormones exert on various cell types at different developmental periods, the precise spatiotemporal regulation of their action is of crucial importance. In this review we summarize the current knowledge about TH delivery, conversions, and function in the developing mammalian brain. We also discuss their potential role in vertebrate brain evolution and offer future directions for research aimed at elucidating TH signaling in nervous system development.

Comparison of Iodine Concentrations in Kitchen Salt and Urine with the Thyroid Volume of Schoolchildren from Ribeirão Preto, São Paulo, Brazil: Warning of Worsening After 10 Years of Study

Background: In 2007 and 2015, two studies were conducted in Ribeirão Preto, São Paulo, Brazil, on schoolchildren of both sexes attending schools of three different socioeconomic levels (school 1: low; school 2: middle; school 3: high). Methods: Iodine concentrations were measured in samples of kitchen salt from the home provided by the schoolchildren and in urine samples, and these levels were compared to the thyroid volume by clinical assessment. Results: In 2007, a marked discrepancy in iodine concentrations was found in salt samples in 300 schoolchildren of both sexes (age range 8-10 years). Urinary iodine excretion >100 μg/L was detected in all cases, and 55.2% had concentrations of >300 μg/L (considered to be the upper limit by the World Health Organization). There was no increase in thyroid volume among the schoolchildren. In 2015, after a change in the norms for salt iodination from 20-60 to 15-45 mg/kg, the study was repeated in 295 schoolchildren (age range 8-10 years) from the same three schools studied previously. An improved standardization of iodine concentration was observed in the salt samples provided by the children, as well as a significant reduction in ioduria, with 10.9% of the samples showing an iodine concentration of <100 μg/L and with a reduction to 30.5% of samples with >300 μg/L. An increase in thyroid volume was also observed in a greater proportion of children from school 1, with a 7.92%, 5.19%, and 0.85% prevalence of goiter at schools 1, 2, and 3, respectively. Conclusions: Despite the limitations of the present study, which include sample size and thyroid evaluation by palpation, it is inferred that the iodination of the Ribeirão Preto schoolchildren studied is adequate. However, the individual iodine intake of some students was <100 μg/L, and some students also had an increased thyroid volume, raising the possibility of a deterioration of iodine intake in 2015 compared to 2007.

The comparison of thyroxine versus thyroxine plus oral iodine in the treatment of congenital hypothyroidism due to iodine deficiency

AIM

Iodine deficiency is one of the most important causes of congenital hypothyroidism. In addition to thyroid hormone replacement, iodine supplementation is also given to newborns with congenital hypothyroidism due to iodine deficiency. We aimed to determine whether it is beneficial to administer iodine supplementation in addition to the L-thyroxine (L-T4) treatment of newborns with congenital hypothyroidism due to iodine deficiency.

MATERIALS AND METHODS

Of 51 newborns, 26 who were diagnosed with congenital hypothyroidism due to iodine deficiency were treated with L-T4. The remaining 25 cases were given L-T4 plus 100 μg/day of oral iodine. Free triiodothyronine (fT3), free thyroxine (fT4), thyroid-stimulating hormone (TSH), thyroglobulin (TG), thyroid volume, urine iodine and breast milk iodine levels were measured in the first and third months of treatment, and the data were compared between the two groups.

RESULTS

First- and third-month values of fT3, fT4, TSH, TG and thyroid volume for both groups were statistically similar. There was no significant difference between the two groups in respect to falling levels of fT3 and TSH, the rate of increase of fT4 levels or the shrinkage rate of thyroid volume.

CONCLUSION

In this study, the addition of oral iodine to L-T4 treatment provided no benefit compared to treatment with L-T4 alone.

Influence of iodization programmes on the epidemiology of nodular goitre

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.

Thyroid surgery

Diseases of the thyroid are common and surgical treatment is often the preferred option. Thyroid surgery is becoming subspecialised and falls within the repertoire of maxillofacial, and head and neck surgeons. Multidisciplinary management of most patients with diseases of the thyroid is key to providing the best care particularly for those with malignancies and retrosternal extension. To reduce postoperative complications a meticulous search for, and protection of the recurrent laryngeal nerve and parathyroid glands, with an incision along the skin crease in the lower neck, which can be extended for neck dissection, are paramount. Recent advances in thyroid surgery include ultrasound-guided cervical plexus block, use of the Harmonic Scalpel(®) (Ethicon Endo-Surgery, Inc., USA), intraoperative nerve stimulation to monitor the recurrent laryngeal nerve, use of TissuePatch™ 3 (Tissuemed Ltd., Leeds, UK) adhesive sealant, and minimal access surgery.

Trace elements status in multinodular goiter

Importance of iodine and selenium in thyroid metabolism is well known, but the roles of other essential trace elements including copper, zinc, manganese and iron on thyroid hormone homeostasis remain unclear. The aim of this study was to investigate the status of those trace elements in benign thyroid diseases and evaluate possible links between trace element concentrations and thyroid hormones. The study group was composed of 25 patients with multinodular goiter. Concentrations of thyroid hormones (plasma-free thyroxine, FT(4); free triiodothyronine, FT(3); and thyrotropin, TSH), selenium, copper, zinc, manganese and iron in plasma, and urinary iodine were determined. The results were compared with those of a healthy control group (n=20) with no thyroid disorder. A mild iodine deficiency was observed in the patients with multinodular goiter whereas urinary iodine levels were in the range of "normal" values in healthy controls. All patients were euthyroid, and their thyroid hormone concentrations were not significantly different from the control group. Plasma selenium, zinc and iron concentrations did not differ from controls, while copper and manganese levels were found to be significantly higher in the patients with multinodular goiter indicating links between these trace elements and thyroid function and possibly in development of goiter. Besides iodine, there was a significant correlation between plasma copper concentration and FT(3)/FT(4) ratio.

Estudo da prevalência das doenças tireoidianas em pacientes tireoidectomizados no Hospital da Santa Casa de Goiânia

OBJETIVO: O Estado de Goiás deixou de ser oficialmente considerado como região endêmica de bócio em 1995. O objetivo deste estudo é verificar a correspondência entre os diagnósticos das doenças tireoidianas (bócio endêmico, tireoidites e câncer), observados nos laudos anátomo-patológicos e nas observações dos inquéritos epidemiológicos. MÉTODO: Estudo retrospectivo de 1399 pacientes submetidos a tireoidectomias na Santa Casa de Misericórdia de Goiânia de 1993 a 2003, e que resultaram em 1610 diagnósticos anátomo-patológicos. RESULTADOS: Os resultados dos exames anátomo-patológicos dos pacientes revelaram: a) adenoma folicular 155 (9,63%); b) outros adenomas 29 (1,8%); c) bócio adenomatoso 87 (5,4%); d) bócio colóide 981 (60,9%); e) carcinoma folicular 36 (2,24%); f) carcinoma indiferenciado 3 (0,19%); g) carcinoma papilífero 93 (5,78%); h) cistos 9 (0,56%); i) bócio difuso tóxico 75 (4,66%); j) outras tireoidites 12 (0,75%); l) outras neoplasias malignas 6 (0,38%) e m) tireoidite linfocítica 124 (7,71%). CONCLUSÕES: O perfil observado com uma prevalência alta de tireoidite linfocítica e carcinoma papilífero se correlaciona realmente com região não endêmica.

Assessment of iodine deficiency and goitre incidence in parts of Yewa Area of Ogun State, Southwestern Nigeria

This study was carried out to determine the occurrence, prevalence and contributing factors to the incidence of goitre in Yewa north local government area of Ogun state, southwestern Nigeria. To achieve these objectives, soil, water, and cassava tubers were collected from four villages -- Igbogila, Egua, Sawonjo and Imoto and from Lagos (about 250 m to the ocean) as a reference location, in order to determine their iodine concentrations. The results of the analyses indicated a soil mean iodine range of 2.1-5.8 microg g(-1); a cassava mean iodine value of 2.3-3.5 mug g(-1) and a drinking water mean iodine value of generally <1.0 microg L(-1) in all the four villages. These values of iodine in soil and water of the four villages are considered low when compared with the soil iodine value of 7.4 microg g(-1) and water iodine value of 6.1 microg L(-1) obtained from Lagos. The limestone unit of the study area remains an inhibiting factor in the bioavailability of the iodine because of its alkalinity. Statistical analysis has shown that there was significant difference between iodine concentration in the soils and the drinking water, and a correlation between the soil iodine and organic matter content at p < 0.05. The correlation between soil iodine and granulometric fractions occurred at p < 0.01. Potential goitrogens in the commonly consumed cassava products might also have contributed to the prevalence of goitre in the study area. Both the females and the adults (i.e., less mobile groups) were found to be vulnerable to goitre development in these villages.

Iodine deficiency and goitre in schoolchildren in Melbourne, 2001

OBJECTIVE

To assess iodine status and goitre prevalence in a sample of schoolchildren in Melbourne.

DESIGN

Cross-sectional study of urinary iodine excretion and presence of goitre in a sample of schoolchildren from Years 5-12 attending two urban schools.

PARTICIPANTS

607 children aged 11-18 years consented to thyroid gland palpation and 577 provided a urine sample on the day of examination in August 2001.

OUTCOME MEASURE

Iodine status of the study population, based on median urinary iodine values categorised as normal (> or = 100 microg/L), mild (50-99 microg/L) or moderate-severe (< 50 microg/L), and classified according to sex, school year and presence of goitre.

RESULTS

76% (439/577) of students had abnormal urinary iodine values, with 27% (156/577) having values consistent with moderate-severe deficiency. The median urinary iodine excretion for the total group was 70 microg/L, with values for school years 5-12 ranging from 62 microg/L (Year 12) to 76 microg/L (Year 9). The median urinary iodine value in girls was lower than that in boys (64 microg/L v 82 microg/L), and girls had significantly lower urinary iodine values overall (P < 0.002). There was no association between goitre grade and moderate-severe (< 50 microg/L; P = 0.39) or mild (50-99 microg/L; P = 0.07) urinary iodine deficiency.

CONCLUSIONS

We found mild iodine deficiency in a cohort of schoolchildren in Melbourne. Our results support other data showing mild iodine deficiency in Sydney and Tasmania and the argument for a national study of iodine nutrition.

Regional differences in the incidence of rheumatoid arthritis in Finland in 1995

OBJECTIVE

To investigate regional differences in the incidence of rheumatoid arthritis (RA).

METHODS

Those subjects entitled to receive drug reimbursement for chronic inflammatory joint diseases in 11/21 central hospital districts (population base about 1.8 million adults) in Finland during 1995 were studied. The incidence rates from these central hospital districts were compared.

RESULTS

A total of 1213 subjects were entitled to drug reimbursement for chronic inflammatory joint disease which had started at the age of 16 or over. Of these, 598 subjects satisfied the American Rheumatism Association 1987 criteria for RA. The age adjusted incidence of RA was 31.7/100 000 (95% CI 29.2 to 34.4) and varied significantly (p<0.001) among the central hospital districts, ranging from 16.3 to 44.8/100 000.

CONCLUSION

There are regional differences in the incidence of RA. The reasons for these are probably environmental rather than genetic.

Evaluation of goiter endemia by ultrasound in schoolchildren in Val Sarmento (Italy)

Ultrasonography is an excellent and objective method for assessing thyroid volume, especially in children where clinical evaluation is inaccurate. The aim of this study was to evaluate the presence of goiter by thyroid ultrasound and palpation in 244 schoolchildren, 6 to 14 years old, living in some rural villages of Val Sarmento, a mountain area of Basilicata, Italy. In 1996 we revealed the presence of endemic goiter in 25% of the schoolchildren evaluated by palpation, according to World Health Organization (WHO) criteria, and in 15.9% of the schoolchildren evaluated by ultrasonography (7.5 MHz linear probe). The median urinary iodine excretion, taken from an extemporaneous sample of the first urines in the morning, was 62.2 microg/l. This study includes Val Sarmento, an area with mild-moderate grade (Grade I) of iodine deficiency, suggesting the need for iodine prophylaxis. Furthermore, it proves that the measurement of thyroid volume by ultrasonography is an essential instrumental method for a correct epidemiological study of endemic goiter, particularly in areas where there is mild iodine deficiency.

Epidemiological survey of goiter and iodine deficiency in Veneto region

The aim of this paper was to determine goiter prevalence and urinary iodine excretion in the Veneto region. It is known since ancient times that goiter prevalence has affected mainly the mountainous areas in Italy. An extensive epidemiological survey was carried out in school-aged children, visiting 5,439 students and testing 1,883 urinary samples. A goiter prevalence of 8.8% was found in the Region; 7.7% of grade 1A and 1.1% of grade 1B respectively; in the pre-mountainous area the prevalence was higher than 10% (11.7% in the Treviso area and 12.7% in the Vicenza area). Urinary iodine excretion was less than 100 mcg/cr in about 45% of all examined children, with a peak of 20% under 50 mcg/cr in the Vicenza district. According to the WHO criteria, the goiter prevalence in the Veneto area can be considered under the limits of epidemic standards. Nevertheless we feel that in light of the urinary data a prophylaxis with iodine added salt should be recommended in any case.