Fallout From Atomic Bombs Still Causing Health Problems

Mar. 24 -- FRIDAY, March 14 (HealthDay News) -- Among Japanese survivors of the atomic bombs dropped by the U.S. on Hiroshima and Nagasaki, those exposed to radioactive fallout as young children appear to face a greater risk of developing adult cancers than those exposed while still in the womb, new research suggests.

To date, the risk posed by radiation exposure while in the womb has been a little-studied subject, even though many pregnant women worldwide face radiation exposure through their work or as patients.

"Clearly there's an increased risk for adult cancer among all those exposed to radiation, but risk following exposure in utero [in the womb] seems to be quite a bit smaller than risk among those exposed as young children," said study author Dale Preston, a principal scientist with the Hirosoft International Corp., a California-based consulting and software development company.

Preston conducted his study in association with researchers from the U.S. National Cancer Institute and scientists from the Radiation Effects Research Foundation (RERF), located in Hiroshima and Nagasaki. The findings are published in the March 19 issue of the Journal of the National Cancer Institute.

The RERF -- where Preston had previously worked for approximately two decades -- was founded five years after the dropping of the Hiroshima and Nagasaki bombs on Aug. 6 and Aug. 9, 1945, respectively.

Initially called the Atomic Bomb Casualty Commission, the foundation's mission is to examine the long-term impact of radiation exposure among Japan's 120,000-plus survivors of the bombings.

Cancer incidence rates weren't available for the years from 1945 to 1957, so the new study focused on survivors who were between the ages of 12 and 55 between 1958 and 1999. Nearly 2,500 of the male and female participants were in utero when the bombs fell, while nearly 15,500 were below the age of 6 at the time. None had any history of cancer prior to 1958. Radiation dosage exposures were determined, as was proximity of the child and/or pregnant mother to the location of each explosion epicenter.