Regression of Endemic Goitre and of Changes in Iodine Metabolism during 10–15 Years in the East of Finland

Abstract

In Savonlinna in the east of Finland in 1959 the thyroid uptake was 60–70% in control subjects and in patients with nontoxic goitre (NTG) and with hyperthyroidism and the urinary excretion of stable iodine was 45–60 µg/day. Fourteen patients with NTG, 3 hyperthyroid patients and one healthy control subject were studied in greater detail. The thyroid turnover was normal in NTG with the exception of two patients in whom it was increased. The faecal excretion of iodine was 20 µg/day, the renal iodine clearance 37 ml/min and the calculated iodine concentration in the iodide compartment 0.75–0.90 µg/l. The distribution of <sup>131</sup>I was similar in the control subject and in NTG patients. In a few patients substantial proportions of precipitable iodine were found in the urine and non-butanol-extractable iodine in the blood. In 1969 the uptake was 30–34% in controls and euthyroid goitre patients. The urinary excretion of iodine was 219 µg/day. The goitre incidence in school children in Savonlinna and the surrounding communities was generally 1%, in two communities 6 and 13%, respectively. The figures are markedly lower than those reported in the early 1950s (15–30%). It is concluded that owing to intensified iodine prophylaxis during the last 10 years the endemic goitre is rapidly regressing in this area.