Predominant form of non-toxic goiter in Greece is now autoimmune thyroiditis

Endemic non-toxic goiter (NTG) in Greece has been attributed primarily to i odine deficiency. Thirty years ago about 60% of the prepubertal boys and gi rls examined in endemic goiter regions presented with NTG and among them th yroid 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 iodin e supplementation on them in Greece at present, we performed two cross-sect ional clinical studies and a retrospective pathology one: (i) thyroid gland volume and urinary iodine excretion (UIE) were assessed in a representativ e sample of 1213 schoolchildren from previously endemic and non-endemic reg ions; (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 Ath ens and Heraklion; and (iii) we compared the prevalence of autoimmunity amo ng fine needle aspiration smears of benign thyroid pathologies performed by the same pathologist between 1985 and 1986 (975 cases) and between 1994 an d 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 per centage was only 1.7% in areas without such a history. In Athens (61.6%) an d Heraklion (58.5%) a substantial number of NTG patients were AAB positive and biochemically hypothyroid. UIE in Athens did not differ between patient s with autoimmune goiter (ATG) and simple goiter. The prevalence of autoimm une stigmata in pathology smears has increased from 5.94% (years 1985-1986) to 13.91% (years 1994-1995) (P<0.05). We conclude that: (ii the persistenc e of endemic goiter in regional foci despite iodine deficiency correction s uggests a possible Pole for a naturally occurring goitrogen: (iii) ATG is t he predominant form of NTG in Greece nowadays: and (iii) the Eve-fold decre ase in the prevalence of NTG during the past 30 years followed by the incre ase of ATG map support the relative character of the latter.