The predominant form of non-toxic goiter in Greece is now autoimmune thyroiditis.
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Endemic non-toxic goiter (NTG) in Greece has been attributed primarily to iodine deficiency. Thirty years ago about 60% of the prepubertal boys and girls examined in endemic goiter regions presented with NTG and among them thyroid autoimmunity was rarely detected. Although iodine supplementation has corrected this deficiency during the past 30 years, new cases of NTG still appear. To evaluate the prevalence and type of NTG and the effect of iodine supplementation on them in Greece at present, we performed two cross-sectional clinical studies and a retrospective pathology one: (i) thyroid gland volume and urinary iodine excretion (UIE) were assessed in a representative sample of 1213 schoolchildren from previously endemic and non-endemic regions; (ii) serum thyroxine, tri-iodothyronine, TSH, thyroid autoantibodies (AAB) (anti-thyroid peroxidase and anti-thyroglobulin antibodies) and UIE (in 60 patients) were measured in 300 consecutive patients with NTG from Athens and Heraklion; and (iii) we compared the prevalence of autoimmunity among fine needle aspiration smears of benign thyroid pathologies performed by the same pathologist between 1985 and 1986 (975 cases) and between 1994 and 1995 (2702 cases). We found that 12. 5% of the schoolchildren examined in regions with a previous history of endemic goiter had NTG, whereas this percentage was only 1.7% in areas without such a history. In Athens (61.6%) and Heraklion (58. 5%) a substantial number of NTG patients were AAB positive and biochemically hypothyroid. UIE in Athens did not differ between patients with autoimmune goiter (ATG) and simple goiter. The prevalence of autoimmune stigmata in pathology smears has increased from 5.94% (years 1985-1986) to 13.91% (years 1994-1995) (P<0.05). We conclude that: (i) the persistence of endemic goiter in regional foci despite iodine deficiency correction suggests a possible role for a naturally occurring goitrogen; (ii) ATG is the predominant form of NTG in Greece nowadays; and (iii) the five-fold decrease in the prevalence of NTG during the past 30 years followed by the increase of ATG may support the relative character of the latter. (+info)
Case-control study of thyroid cancer in Northern Italy: attributable risk.
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BACKGROUND: The percentage of thyroid cancer cases attributable to specific risk factors can be calculated to focus preventive strategies. The per cent population attributable risks (PAR) for thyroid cancer were estimated in relation to history of benign thyroid diseases, history of radiotherapy, residence in endemic goitre areas and selected indicators of a poor diet, using data from a case-control study conducted between 1986 and 1992 in Northern Italy. METHODS: Cases were 399 histologically confirmed incident thyroid cancers and controls were 617 patients, admitted to hospital for a wide range of acute, non-neoplastic, non-hormone-related diseases. The PAR were computed on the basis of multivariate odds ratios (OR) and on the distribution of risk exposure among cases, assuming they are representative of the general population of cases. RESULTS: A history of benign thyroid disease accounted for 18.9% of cases, radiotherapy for 1.2%, residence for > or =20 years in endemic goitre areas for 2.4% of cases, and their combination for 21.7% of thyroid cancer cases; selected indicators of a poor diet accounted for 40.9% of thyroid cancer cases in this population. The combination of all factors considered explained over 57% of thyroid cancer cases in both sexes. The estimates for thyroid-related conditions were higher in women than men, whereas the opposite was true for dietary indicators. The overall PAR were somewhat higher in people aged > or =45 years (63.8%) than in younger subjects, and for follicular (69.1%) rather than papillary (53.7%) cancers. CONCLUSIONS: Exposure to a few simply identified and potentially modifiable risk factors or indicators (benign thyroid disease, residence in endemic goitre area and a poor diet) explained about 60% of thyroid cancer cases in this Italian population, indicating the theoretical scope for prevention. (+info)
Endemic goiter with iodine sufficiency: a possible role for the consumption of pearl millet in the etiology of endemic goiter.
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BACKGROUND: Deficiencies of iodine, iron, and vitamin A are the 3 most common micronutrient deficiencies in developing countries, although control programs, when properly implemented, can be effective. OBJECTIVE: We investigated these deficiencies and their possible interaction in preschool children in the southern Blue Nile area of Sudan. DESIGN: Goiter, signs of vitamin A deficiency, and biochemical markers of thyroid, vitamin A, and iron status were assessed in 984 children aged 1-6 y. RESULTS: The goiter rate was 22. 3%. The median urinary iodine concentration was 0.79 micromol/L and 19.3% of the children had a concentration >1.57 micromol/L. Although serum thyroxine and triiodothyronine concentrations were within reference ranges, the median thyrotropin concentration was 3.78 mIU/L and 44% of the children had thyrotropin concentrations above normal. The mean urinary thiocyanate concentration was high (259 +/- 121 micromol/L). The prevalences of Bitot spots and night blindness were 2.94% and 2.64%, respectively, and 32% of the subjects had serum retinol binding protein concentrations <15 mg/L. A significant positive correlation was observed between thyrotropin and retinol binding protein. Whereas 88% of the children had hemoglobin concentrations <1.86 mmol/L, only 13.5% had serum ferritin concentrations below the cutoff of 12 microg/L and 95% had serum transferrin concentrations above the cutoff of 2.50 g/L. CONCLUSIONS: Our results indicate that goiter is endemic in this region of Sudan despite iodine sufficiency and that both anemia and vitamin A deficiency are health problems in the area. Moreover, consumption of millet, vitamin A deficiency, and protein-energy malnutrition are possible etiologic factors in this endemic area. (+info)
Short-term effectiveness of mandatory iodization of table salt, at an elevated iodine concentration, on the iodine and goiter status of schoolchildren with endemic goiter.
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BACKGROUND: Goiter rates and iodine deficiency usually show marked improvement in efficacy studies of mandatory iodization of salt, but little is known about the short-term effectiveness of mandatory iodization. OBJECTIVE: The aim of the study was to evaluate, after 1 y, the effectiveness of mandatory iodization of salt at an iodine concentration higher than that occurring under optional iodization on the goiter rates and iodine status of schoolchildren living in an endemically goitrous area. DESIGN: Goiters, measured by palpation, and urinary iodine concentrations of children in grades 4-7 in 4 schools in a known goitrous area in South Africa were assessed before and 1 y after the introduction of mandatory iodization at a higher iodine concentration than occurred with optional iodization. Estimates of the iodine concentration of iodized salt and the proportion of households using iodized salt were also made. RESULTS: Iodine concentration in table salt and household use of iodized salt improved within 1 y. Goiter rates, which varied at baseline from 14. 3% to 30.2% in the 4 schools, remained unchanged, with an overall mean (+/-SE) prevalence of 25.6 +/- 2.5% at baseline and of 27.5 +/- 2.7% 1 y later. The distribution of urinary iodine concentrations in the 4 schools improved substantially from the baseline deficient range. The overall median urinary iodine concentration increased from 0.17 to 1.47 micromol/L. CONCLUSIONS: Mandatory iodization of salt virtually eradicated iodine deficiency within 1 y in South African schoolchildren, but the goiter rate in these children did not decline. Measurement of goiters by palpation may not be appropriate in short-term evaluations of mandatory iodization programs. (+info)
Persistence of goiter despite oral iodine supplementation in goitrous children with iron deficiency anemia in Cote d'Ivoire.
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BACKGROUND: In developing countries, many children are at high risk of goiter and iron deficiency anemia. Because iron deficiency can have adverse effects on thyroid metabolism, iron deficiency may influence the response to supplemental iodine in areas of endemic goiter. OBJECTIVE: The aim of this study was to determine whether goitrous children with iron deficiency anemia would respond to oral iodine supplementation. DESIGN: A trial of oral iodine supplementation was carried out in an area of endemic goiter in western Cote d'Ivoire in goitrous children (n = 109) aged 6-12 y. Group 1 (n = 53) consisted of goitrous children who were not anemic. Group 2 (n = 56) consisted of goitrous children who had iron deficiency anemia. At baseline, thyroid gland volume and urinary iodine, thyrotropin, and thyroxine were measured by using ultrasound. Each child received 200 mg I orally and was observed for 30 wk, during which urinary iodine, thyrotropin, thyroxine, hemoglobin, and thyroid gland volume were measured. RESULTS: The prevalence of goiter at 30 wk was 12% in group 1 and 64% in group 2. The mean percentage change from baseline in thyroid volume 30 wk after administration of oral iodine was -45.1% in group 1 and -21.8% in group 2 (P < 0.001). Among the anemic children, there was a strong correlation between the percentage decrease in thyroid volume and hemoglobin concentration (r(2) = 0.65). CONCLUSION: The therapeutic response to oral iodine was impaired in goitrous children with iron deficiency anemia, suggesting that the presence of iron deficiency anemia in children limits the effectiveness of iodine intervention programs. (+info)
Iron supplementation in goitrous, iron-deficient children improves their response to oral iodized oil.
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OBJECTIVE: In developing countries, many children are at high risk for both goiter and iron-deficiency anemia. Because iron deficiency may impair thyroid metabolism, the aim of this study was to determine if iron supplementation improves the response to oral iodine in goitrous, iron-deficient anemic children. DESIGN: A trial of oral iodized oil followed by oral iron supplementation in an area of endemic goiter in the western Ivory Coast. METHODS: Goitrous, iodine-deficient children (aged 6-12 years; n=109) were divided into two groups: Group 1 consisted of goitrous children who were not anemic; Group 2 consisted of goitrous children who were iron-deficient anemic. Both groups were given 200mg oral iodine as iodized oil. Thyroid gland volume using ultrasound, urinary iodine concentration (UI), serum thyroxine (T(4)) and whole blood TSH were measured at baseline, and at 1, 5, 10, 15 and 30 weeks post intervention. Beginning at 30 weeks, the anemic group was given 60mg oral iron as ferrous sulfate four times/week for 12 weeks. At 50 and 65 weeks after oral iodine (8 and 23 weeks after completing iron supplementation), UI, TSH, T(4) and thyroid volume were remeasured. RESULTS: The prevalence of goiter at 30 weeks after oral iodine in Groups 1 and 2 was 12% and 64% respectively. Mean percent change in thyroid volume compared with baseline at 30 weeks in Groups 1 and 2 was -45.1% and -21.8% respectively (P<0.001 between groups). After iron supplementation in Group 2, there was a further decrease in mean thyroid volume from baseline in the anemic children (-34.8% and -38.4% at 50 and 65 weeks) and goiter prevalence fell to 31% and 20% at 50 and 65 weeks. CONCLUSION: Iron supplementation may improve the efficacy of oral iodized oil in goitrous children with iron-deficiency anemia. (+info)
Endemic goiter associated with high iodine intake.
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OBJECTIVES: This study assessed the relation of iodine content of household water to thyroid size and urinary iodine excretion in an area with high iodine concentration in the water. METHODS: The iodine content of household water and indicators of iodine status (thyroid size and urinary iodine level) were assessed in selected villages in Jiangsu Province, China. RESULTS: Water iodine levels were positively correlated with urinary iodine levels and indicators of thyroid size at the township level. CONCLUSIONS: Excess iodine in household water was the likely cause of endemic goiter and elevated urinary iodine levels in the study area. This finding affects public health policy on the institution of universal salt iodization for the elimination of iodine deficiency disorders. (+info)
Changes in serum thyroid hormone levels in newborn calves as a diagnostic index of endemic goiter.
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Maximum serum thyroxine (T4) and triiodothyronine (T3) levels of healthy calves were seen at 1 day after birth, and thereafter rapidly decreased until 5 days after birth. They stabilized until 2 weeks after birth, then gradually decreased until 4 weeks after birth. Serum T4 levels of calves with endemic goiter tended to be lower than those of healthy ones, but showed similar levels to those of adult cows. T3 levels of calves with goiter were similar to those of healthy ones, but showed higher variation. T4/T3 ratio of calves with goiter were significantly lower than those of healthy ones and adult cows. While individual levels of serum T4 and T3 at just after birth could not be considered as a diagnostic index, the T4/T3 ratio could be adopted as a diagnostic index of endemic goiter. (+info)