'We have exposed our kids'

Children living in the United States during the 1950s were exposed to radioactive iodine, or I-131, fallout during nuclear testing at the Nevada Test Site.

The fallout of I-131 after a mushroom cloud eruption, allowed “considerable amounts [of radioactive iodine] to be deposited onto pasture and to be transferred to people in dairy foods,” wrote Steven L. Simon, André Bouville and Charles E. Land in a 2006 article .

Basically, grazing animals ate grass contaminated with radioactive iodine, which then passed into the animal’s milk, and when people drank the milk, the radioactive iodine was absorbed by their thyroid gland and caused cancer.

Land, a National Cancer Institute senior investigator, predicted between 7,500 and 75,000 excess thyroid cancer cases resulted from the Nevada testing.

Cherry Wunderlich, a volunteer for the Thyroid Cancer Survivors’ Association , said she believes her thyroid cancer was caused by radioactive fallout.

Wunderlich calculated her exposure risk from the Nevada testing by visiting the National Cancer Institute’s I-131 information web page . Because she was a young child, living on a cattle ranch near the Nevada site during the testing era, and drank farm-fresh milk her risk was higher than many Americans.

One would assume that Cherry wouldn’t be the only Wunderlich child to be diagnosed with thyroid cancer.

“Of my five siblings, I was the only one to develop thyroid cancer,” Wunderlich said. She was diagnosed with thyroid cancer in 1999, almost four decades after her exposure.

Fallout doesn't explain increase in cases

Even so, experts say fallout probably plays a minor role in the current increase.

“My guess is that there’s got to be some thyroid cancers due to fallout, but it’s not what’s causing this big increase,” said Dr. Elaine Ron, a National Cancer Institute senior investigator.

Dr. Michael Tuttle, a thyroid cancer specialist at Memorial Sloane Kettering Hospital agrees. Most of the patients he treats for thyroid cancer were born a decade or more after nuclear testing ceased in the United States in 1961.

Because of the similarities between the 1950s and modern-day discussions, Tuttle said his concern is that “we’ve exposed our kids” to something 20 or 30 years ago, probably with well-meaning intentions.

The timing – the development of disease two or three decades after exposure – isn’t unique to Americans. From her study of 90,000 Japanese atomic bomb survivors, Ron said there’s a suggestion that a person’s risk of developing thyroid cancer peaks 15 to 30 years after radiation exposure.

The radiation-induced thyroid cancer model is the best model experts have, Tuttle said. Because the model shows the childhood thyroid is much more sensitive to radiation as a cause of cancer, he said he would assume it’s more sensitive to any other cause.

What else were kids exposed to?

“For me, I’d be looking at what kids were exposed to when they were less than 5 years old that then 15 or 20 years later led to the development of thyroid cancer, be it something they were wearing or eating or breathing or exposed to something external,” Tuttle said.

He said if you think about all the chemicals introduced in the 1960s and 1970s – ranging from everything in toothpaste to flame retardant materials in baby beds and baby blankets – they are chemicals that children were not exposed to in the 1940s or 1950s.

“It makes me wonder if we didn’t do something back then that we’re now seeing the consequences of,” Tuttle said.

More stories in this investigation: Are you at risk? | Treatment options and outlook | Not just a 'chick's disease' | Thyroid 101 | Thyroid cancer increase baffles researchers | Medical community does 'about face'