| Ostapenko et al., Minsk, Belarus, New York, New York, Rockville, Maryland, USA, report the correlation between urinary iodine concentration and the following: serum Tg levels, thyroid volume and the presence of thyroid carcinoma and thyroid nodules, in 11,200 Belarusian subjects who were under the age of 18 at the time of the I-131 fallout. Moderate iodine deficiency (20-50 µ/L urine) was present in 27.3% and severe iodine deficiency (<20 µg/L) in 11.8%, and normal iodine excretion (>100 µg/L) in 32.1%. The mean serum Tg concentrations were 15.5, 20.4, and 10.3 ng/ml respectively. Antithyroid antibodies were similar in the three groups. When the two groups with iodine deficiency were taken together, thyroid volume was increased about 3 times in the iodine deficiency group as compared to the control group, the prevalence of thyroid nodules and thyroid carcinoma was not different in iodine deficiency and sufficiency, 7.3% vs 7.2%, and 0.46% vs 0.39% respectively. (Comment: Contrary to the general notion, this study does not confirm that development of benign and malignant nodules after exposure to I-131 is increased when iodine deficiency is present.) Yamashita et al., Nagasaki, Japan, completed a 10-year screening program examining more than 200,000 children around Chernobyl and found the highest prevalence of thyroid nodules and carcinoma in the Gomel region in Belarus. Therefore further studies were conducted in the Gomel area comparing children with regard to development of thyroid carcinoma either born before or after the Chernobyl accident. A total group of 21,000 children were examined. No increase in carcinoma development was seen in children born after the accident. The authors therefore conclude that short-lived radioactive fallout is highly suspected to have induced thyroid carcinoma in children at the time of the accident. |
