ST. LOUIS -- Harvard researchers studying how early-life exposures are relevant to lifelong health will examine baby teeth left over from the famous Baby Tooth Survey in St. Louis, a Cold War-era study that measured radioactive fallout in about 320,000 donated teeth.

The St. Louis Post-Dispatch reported Harvard University neuroscientist and epidemiologist Marc Weisskopf is leading the study, funded by a federal grant. When he learned about five years ago of tens of thousands of baby teeth left over from the St. Louis study, he immediately saw the potential.

The Washington University-led St. Louis Baby Tooth Survey helped speed approval of the Limited Test Ban Treaty in 1963, which barred nuclear weapons tests in the atmosphere, outer space and under water.

The leftover teeth were discovered in 2001 and donated to a not-for-profit, the Radiation and Public Health Project, operated by Joe Mangano of Ocean City, New Jersey. The teeth are in a storage locker near his home.

A mutual friend introduced Mangano to Weisskopf.

"Teeth give this opportunity to get a picture of what is going on in early life," Weisskopf said, "and the idea that some 60,000 people whose baby teeth are sitting in a closet somewhere is very intriguing to me."

The Harvard study will look at how metals contribute to cognitive decline in older age. Part of the research will involve finding 1,000 adults in their 60s and 70s who participated in the Baby Tooth Survey and looking for associations between metal concentrations in their baby teeth and current cognitive health.

Most of the tooth survey participants are from the St. Louis area. The study involves testing the baby teeth of just 1,000 people, but researchers will attempt to contact all the donors of the leftover teeth. With some incisors, cuspids and molars coming from the same child, Weisskopf estimates that's about 60,000 people.

"Their information will be hugely valuable to us," he said, "and we will be looking at all sorts of things and they will be asked to participate in future studies."

The original idea of collecting baby teeth began the mid-1950s during the build-up of the Cold War between the U.S. and Soviet Union, which together tested hundreds of nuclear weapons. Testing in Nevada resulted in fallout over the Midwest.

A group of prominent St. Louis scientists and physicians formed the Citizens Committee for Nuclear Information, and with help from Washington University, created the Baby Tooth Survey to determine whether children's bodies were absorbing radioactive fallout.

Volunteers went to schools, churches, dental clinics and elsewhere distributing registration forms. Between 1958 and 1970, parents sent in thousands of teeth along with their information cards.

The study found children born at the height of the Cold War in 1963 had 50 times as much strontium 90, a radioactive isotope found in bomb fallout, in their teeth as children born in 1950, before most of the atomic bomb tests.