Studies of serum triiodothyronine, thyroxine and thyrotropin concentrations in endemic goiter in greece

ABSTRACT. The serum concentrations of triiodothyronine (T3) and thyrotropin (TSH) measured by radioimmunoassay, and that of thyroxine (T4), measured by competitive protein binding assay, were assessed in goitrous and non- goitrous subjects residing in an area of moderate iodine deficiency in Greece. Results were compared to those obtained in a group of age-matched control subjects residing in Boston, an area of adequate iodine intake. Serum T4 concentrations were within the normal range in both goitrous and non-goitrous Greek subjects, but were nevertheless significantly lower than in the Boston con trols. Serum T3 concentrations in the nongoitrous Greek subjects were similar to those in the Boston group, but values in the goitrous Greek subjects were significantly increased. Serum TSH concentrations in the Greek subjects were, with one exception, within the normal range and were almost identical to those in the Boston controls. It is suggested that endemic iodine deficient goiter in Greece is the result of an increased sensitivity of the iodine-deficient thyroid to the stimulatory effect of TSH on thyroid size and on the secretion of T3 relative to T4. © 1973 by The Endocrine Society

Prevention and treatment of endemic iodine-deficiency goiter by iodination of a municipal water supply

A recently described method for the prevention and treatment of endemic iodine deficiency and goiter, introduction of iodine into a public water supply, was tested in Troina a town of about 13, 000 inhabitants in northeast Sicily. There, before initiationof the program, a goiter endemic of moderate severity was present, as evidenced by goiterprevalence of 55% in school children. Iodine deficiency in nongoitrous adults was indicated by daily urinary iodine excretion of 40.7 ± 2.6 μg (mean ± SE) and 24-hthyroid radioiodine uptake of 50.8 ± 2.4%. Iodination of the water supply was initiated in November 1979 using a stream-splitting device that diverts a controlled fractionof the total water flow to a canister containing iodine crystals, where the water becomessaturated with iodine (˜300 mg/liter) before returning to the main stream. Except for a 15-month interruption during which governmental authorization of the programwas being reconfirmed, treatment of the water has continued to the present time, initially at a level of 81 ± 25 μg/liter (mean ± SD) and since resumption at a level of 46.5 ± 5 μg/liter. Iodination of the water was followed by a prompt and marked reduction in goiter prevalence, and by improvement in biochemical indices of iodine deficiency. By April 1983, overall goiter frequency in school children had declined to 6.1%, and large goiters (WHO Grade 2) had virtually disappeared. By January 1984, daily urinary iodine excretion had increased to 85.6 ± 6.5 (SEM) μg and radioiodine uptake had decreased to 40.7 ± 4.7%. Serum thyroid-related hormone concentrations were as follows (pretreatment vs. November-December 1983): T4 5.8 ± 0.3 vs. 8.4 ± 0.3 μgdl; T3 1.6 ± 0.05 us. 1.2 ± 0.06 ng/ml; TSH, 3.7 ± 0.2 us. 2.2 ± 0.1 μU/ml; all changes being statistically significant. By late 1983, serum T4 T3 and TSH values in Troina were almost identical to those in Catania, a community in which iodine deficiency is not present (goiter prevalence in school children, 2.2%). In contrast, in Troina serum T4 concentrations were significantly higher and serum TSH concentrations were significantly lower than those in Maniaci, a iodine-deficient town near Troina, in which the water was not iodinated. Iodinated water was well tolerated by the population of Troina, and no adverse effectsof water iodination, including any increase in the frequency of hyperthyroidism, was observed. At present prices, the cost of the water iodination program in Troina would be approximately 4 cents (U.S.) per person per year. We conclude that iodination of public watersupplies is highly efficacious, safe, and cost-effective, and where applicable, affords promise in the prophylaxis and treatment of endemic iodine deficiency and goiter, © 1986 by The Endocrine Society.SCOPUS: ar.jinfo:eu-repo/semantics/publishe