A Legacy in Radiation Health
Important Findings of One of Our Oldest Ongoing Studies May Still Lie Ahead
On a lush hilltop overlooking the thriving city of Hiroshima, Japan, several half-moon shaped Quonset huts have perched over the city for more than 60 years. Nearly every day, several atomic bomb survivors journey to the buildings of the Radiation Effects Research Foundation (RERF) to undergo biannual health examinations. They give blood and go through various medical tests, which will not only monitor their health but also contribute to one of the largest and longest medical studies in history. The survivors' medical data compiled by RERF have served as the foundation for understanding how radiation impacts the human body and have helped establish radiation dose limits for protection standards as well as pave the way for the use of radiation in medical diagnoses and treatment.
Their contributions started in the early 1950s when President Truman turned to the National Academy of Sciences to study the long-term health effects of the atomic blast survivors in Hiroshima and Nagasaki and their future children. A cohort of about 120,000 residents selected from both cities has been followed, with about 35 percent of the survivors still alive today. The oldest is more than 100.
"The National Research Council was involved in the study from the beginning," said Evan Douple, the recently retired associate chief of research at RERF. "Those in the cohort were chosen because they knew where they were when the bomb dropped and their radiation doses could be estimated."
Roy Shore, vice chairman and executive director of RERF, underscored that its current research is still highly relevant. "We are just learning that cardiovascular risk is increased by radiation, but we don't know the full aspects yet." There are also recent findings about cataracts; the International Commission on Radiological Protection reduced the allowable radiation dose by tenfold because RERF research found that vision-impairing cataracts developed at doses much lower than had formerly been believed. They also found that those who were young when they were exposed have the greatest risk of developing cataracts.
As important research continues, Douple emphasizes that some of RERF's biggest discoveries may lie ahead. "What is remarkable is that the long-term study is not just about radiation effects but also a study about aging. The cohort is still important to follow, especially now that some of the youngest survivors are entering their cancer-prone years. It will be important to know the risk of exposure as a child compared to risk as an adult."
Technology may help tear down some unknown barriers to forge breakthroughs. "With the next generations of DNA sequencers, we can scan the DNA of survivors' frozen blood samples and know every base pair. If a participant comes down with Parkinson's disease, for example, and we have his samples going back for as many as 52 years, it may become possible to identify mechanisms of the disease process and early signals of change," Douple said.
Beyond the findings, RERF's institutional knowledge of conducting such an immense and complex study has made contributions to the field, especially following the Fukushima nuclear accident. "Several research groups near Fukushima had a strong interest in mounting long-term studies, but had no experience. We had an advisory role on how to establish such studies," Shore explained.
Just as the research and dedication of the survivors has flourished over the years, so too has the relationship between two countries. What began as a U.S.-led endeavor has evolved into a joint U.S.-Japanese effort. Today, less than 10 of the more than 200 staff members at RERF are Americans from the National Academies. And they continue to look for the best labs and manpower to collaborate and find answers not only for the survivors, but for everyone. "Our next step is to apply the best science and medicine to better understand mechanisms of disease," Douple said. -- Jennifer Walsh
The Radiation Effects Research Foundation is a project of the Division on Earth and Life Studies, administered through the Nuclear and Radiation Studies Board. Support for RERF is provided in a cooperative agreement between the U.S. Department of Energy and the National Academy of Sciences. RERF is managed by a binational board of directors consisting of resident directors with oversight provided by a board of councilors. Scientific research activities are carried out on the basis of recommendations of a binational, 10-member scientific council. On the web at www.rerf.or.jp is RERF's semiannual newsletter Update, which contains institutional news, as well as recent publications and investigations.