TUESDAY, Oct. 26 (HealthDay News) --Middle-aged adults may face
as high a risk for developing cancer as a result of radiation
exposure as younger adults and children, new research suggests.
Although children are thought to be more sensitive to the
long-term impact of radiation and related cancer risks, the current
observation runs counter to some previous research suggesting that
as people age, their vulnerability to radiation-induced cancer
"Overall, the weight of the epidemiological evidence suggests that for adult exposures, radiation risks do not generally decrease with increasing age at exposure," a team of authors from Columbia University in New York City said in a news release.
The findings are published in the Oct. 25 online issue of the
Journal of the National Cancer Institute.
The study's conclusion is based on a review of data concerning
Japanese survivors of the atomic bomb, whose radiation cancers were
attributable to one of two causes: genetic mutations caused by
radiation that turned normal stem cells into precancerous cells, or
an increase in the number of already existing precancerous
Using a newly designed risk analysis model, the authors looked
at the age of the survivors at the time the bomb was dropped and
then tracked the ensuing incidence of cancer.
In turn, they used the same statistical framework to predict
cancer risk by age of radiation exposure among people aged 30 to 60
in the U.S. population.
The finding: For some types of tumors, cancer risk does appear
to increase following radiation exposure among individuals in this
age bracket -- a discovery they said could have practical
implications, since most X-ray procedures and jobs requiring
radiation exposure involve middle-aged people.
In an accompanying editorial, John D. Boice of the International
Epidemiology Institute in Rockville, Md., and Vanderbilt University
in Nashville, noted that prior studies contradict the current
findings and that generalizing the Japanese data to the U.S.
population may be problematic.
But he concluded that the current effort "raises provocative
hypotheses and conclusions that -- although preliminary -- draw
attention to the continued importance of low-dose radiation
exposures in our society."
For more on radiation exposure risk, visit the
U.S National Institutes of Health.