Researchers Begin Studying Downwinder Thyroid Data

A federal study to find out whether people exposed to radioactive iodine releases at the Hanford Nuclear Reservation have a higher incidence of thyroid disease has entered a new phase, an official said Tuesday.

The data-collection phase of the $18 million Hanford Thyroid Disease Study by the Fred Hutchison Cancer Research Center in Seattle ended in September, when the last clinic was held, project manager Peggy Adams Myers said.

Now, data collected from medical exams and telephone questionnaires will be analyzed and sent to the federal Centers for Disease Control and Prevention in Atlanta, Myers said.

A draft report is expected by the end of September 1998, with final conclusions at the end of the year or early 1999.

The results should give the study’s 3,566 participants an answer to the question of whether they are at a greater-than-average risk of thyroid disease.

“We will never be able to tell an individual, ‘Your disease was or was not caused by Hanford emissions,’ ” Myers said.

“But we will be able to tell people either they are, or are not, at a greater risk of thyroid disease. It’s a peaceof-mind issue.”

Researchers used Washington state birth records to identify about 5,200 people born in seven counties near the federal Hanford reservation between 1940 and 1946.

From 1943 until the mid-1970s, radioactive chemicals and gases were released - accidentally and intentionally - from reactors and plants that made uranium and plutonium for nuclear weapons.

Radioactive iodine-131, a short-lived byproduct of those processes, attacks the thyroid gland.

Children living near the reservation were exposed to iodine principally through milk from cows that ate contaminated grass, or through leafy vegetables from local gardens.

The majority of the study participants, about 2,350, live in Washington state. The remainder now live in nearly all 50 states and outside the United States.

Participants were asked to fill out questionnaires about their health, to undergo physical examinations by physicians who are thyroid experts and to submit to blood and thyroid ultrasound tests.

Researchers then called the participants’ mothers or other close relatives to try to determine their early eating habits - especially the amounts of local milk and vegetables consumed in childhood, Myers said.

The information was then plugged into a computer model developed by the Hanford Dose Reconstruction Study to come up with individual estimates of iodine doses based on where the participants lived, what they ate and other factors, she said.

“If we find the most thyroid disease in people with higher doses, it is an indication that means the higher the dose, the more disease,” she said.

“If we find there is no correlation, then the dose doesn’t have anything to do with thyroid disease.”

One of the difficulties was getting people to remember their daily lives 50 years ago, Myers said.

“When you’re asking someone’s mom what their child ate as an infant, how much milk they drank … it’s hard to remember,” Myers said.

The study staff worked with a psychiatrist to help people remember, she said.

Another difficulty was locating people who have moved.

The researchers found about 95 percent of the 5,200 people they set out to locate, “which is astounding,” Myers said.

Of those, she said about 700 refused to to participate in the study.

“Some were anxious to find answers, some we had to talk into participating, and others didn’t really feel they had been affected,” Myers said. “It ran the whole gamut.”

The data portion of the study, funded by the CDCP in Atlanta, took about five years, Myers said. Its results should be helpful to the thousands of people who wonder whether living near Hanford as children affected their health, she said.

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