A post-Chernobyl rise in thyroid cancer in Connecticut, USA.

Recent analyses of children in Belarus and the Ukraine are the first to document large numbers of excess thyroid cancer cases only 4 years after exposure to radiation. In Connecticut (USA), a thyroid cancer increase of a much smaller magnitude occurred in 1990-93, 4-7 years after the Chernobyl accident, for both children and adults. Similar changes also occurred in the states of Iowa and Utah, which like Connecticut were exposed to low levels of radionuclides from Chernobyl fallout during May and June of 1986. Historical data from Connecticut also reveal substantial increases in thyroid cancer incidence about 5 years after large releases of iodine-131 from distant US nuclear weapons plants, after the largest atmospheric US atomic weapons tests in Nevada, and after substantial releases of iodine-131 from the Millstone nuclear power plant in Connecticut. Further analysis of this apparent 5-year latency period will enhance understanding of ionizing radiation's effects on thyroid function and on human health in general.