Researchers Seek People Exposed to Radiation to Determine Thyroid Disease Link

Researchers Seek People Exposed to Radiation to Determine Thyroid Disease Link

Jan 29, 2004 5:00 PM

In an ongoing study of thyroid diseases related to nuclear testing at the Nevada Test Site, University of Utah School of Medicine researchers are looking to reconnect with people who went to grade school or high school in Washington County, Utah, in the early 1960s.

The 40-year study, funded by Centers for Disease Control and Prevention, is examining the effects of radioactive fallout from above-ground nuclear tests from 1951-1958.

U researchers led by Joseph L. Lyon,M.D., M.P.H., professor of public health and deputy associate chair for research in the Department of Family and Preventive Medicine, have completed Phases I and II of the study, and are now launching Phase III. Letters inviting past participants to join Phase III will go out in early February.

"Above-ground nuclear testing has forever impacted the lives of individuals in the Intermountain West and across the nation," said Lyon. "The radioactive cloud resulting from Event Harry, detonated on May 19, 1953, continues to have adverse effects on the families, communities and individuals in its path."

The goal of the study, officially named Epidemiologic Follow-Up of Thyroid Disease in Persons Exposed to Radiation Fallout from Atomic Weapons Testing at Nevada Test Site, is to find out whether exposure to radioactive fallout is associated with increased incidence of thyroid disease, especially thyroid tumors. A secondary purpose is to investigate the relationship between radiation and reproductive history, as well as radiation and family history of thyroid disease.

People who participate in Phase III will receive free medical tests and thyroid screening, and $50 in compensation.

In the 1950s, the U.S. government tested nuclear weapons at the Nevada Test Site in southern Nevada. The above-ground tests exposed much of the nation to radioactive fallout, particularly people in Washington County, Utah, and Lincoln County, Nevada. The nuclear fallout included radioactive iodine, or radioiodine, which is a major public health concern because it can damage the thyroid gland.

U researchers in 1965 began Phase I of the study on school children living in the two counties. Doctors examined their thyroid glands to find out if exposure to fallout from the Nevada Test Site is associated with thyroid disease. Researchers also examined a comparison group of children living in Graham County, Arizona, who were not as heavily exposed to fallout.

In 1985-1986 researchers re-examined these same people (Phase II) for thyroid disease and concluded that exposure to radioiodines generated at the Nevada Test Site increased the risk of thyroid tumors. But the correlation was limited by the small number of subjects in the highest exposure group and the relatively short time that had elapsed since exposure.

In Phase III, U researchers will examine the same people for the third time, and Lyon believes it will strengthen the earlier conclusions because Phase III extends the study by 15 years, which is important because thyroid disease may not occur until 40 years or longer after radiation exposure.

Phase III will include people who participated in the first two phases, were born between 1946 and 1958, and lived in Washington or Lincoln County for at least one year between January 1951 and December 1958. Study participants also will include children living in Graham County, Arizona, during the same time period.

Each study participant will receive a thyroid ultrasound scan, a thyroid examination, and must provide a small sample of blood. Also, study subjects will be asked to provide a medical history. Based on the results of the medical examination, the participant may need further evaluation. In the event that thyroid disease is detected or was reported in the past, medical records and pathology specimens will be collected and reviewed by medical experts.

"The findings from this study will provide valuable information about the health effects of early childhood exposure to radioactive iodine," says Lyon. "Each study subject's participation in this phase is crucially important and greatly appreciated."

Study participants can contact the study center (toll free 1-866-300-5936) or refer to the study's web site ( for more information.

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