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.

We hypothesize that the prevalence of FTC during the last decade in our center in Greece was very low due to correction of iodine deficiency and a relative increase in the prevalence of microPTC. More than 50% of PTC diagnosed during the last decade were microPTCs that were detected incidentally in older persons with preexisting MNG or a prominent hot nodule. This is one of the highest, if not the highest percentage of microPTCs that were incidentally detected. Despite many of these having features of invasiveness, most appear to remain clinically silent. Research is needed to identify factors predisposing microPTCs to evolve from a subclinical to a clinically apparent form.

Iodine metabolism has been studied in 20 patients with advanced chronic renal insufficiency due to primary renal disease, and thyroxine turnover in another 5 similar patients. Comparatively to 18 controls, the uremic patients had a lower urinary iodine excretion, and a much lower renal iodide clearance, which, however, was not as much decreased as the creatinine clearance. The normal relation between the renal iodide and creatinine clearances was disturbed when the latter was 6.3 ml/min or lower, and in these cases the renal iodide clearance exceeded the corresponding creatinine value. The plasma inorganic iodine (PII) was increased because of the iodide retention to (mean ± SE) 0.84 ± 0.17 µg/100 ml, compared to 0.12 ± 0.01 in the controls. The thyroidal iodide clearance (Th. Cl.) rate was decreased (22.8 ± 4.44 ml/min vs. 36.7 ± 6.48), but in spite of this decrease, the absolute iodine uptake (AIU) by the thyroid, which is calculated as AIU = Th. Cl. X PII, was increased (7.1 ± 1.37 vs. 1.9 ± 0.30 µg/h). The serum protein-bound iodine was normal. The PII, Th. Cl. and AIU values and the relation among them in renal insufficiency were comparable to those observed after chronic administration of small amounts of iodine. The radiothyroxine studies suggested an increased space of distribution and so, despite a decreased fractional turnover rate, an increased metabolic clearance and degradation rate.

Between November, 1966, and March, 1970, 2736 patients with single thyroid nodules were investigated at the Alexandra Hospital. Females were more frequently affected than males, with a ratio of females to males of about 7:1. The right lobe was one and a half times more frequently involved than the left. In both lobes the lower pole was six to eight times more commonly involved than the upper pole. Pathological data after surgical excision were available in 692 of these patients. Malignancy was proved in 81 cases. The overall incidence of carcinoma was 11.7 per cent. Malignant nodules were two to three times more frequent in persons aged below 20 and over 60 and in males than in females. The incidence of carcinoma in cold and warm nodules was 12.8 and 6.6 per cent respectively. No malignancy was foun in a hot nodule or in a toxic adenoma. The location of the nodule was not helpful in predicting malignancy. It is concluded that the incidence of malignancy in cold and warm single thyroid nodules in high, and for this reason surgical removal supplemented with replacement therapy is recommended.

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