Featured Research

from universities, journals, and other organizations

Risk of cancer due to radiation exposure in middle age may be higher than previously estimated

Date:
October 27, 2010
Source:
Journal of the National Cancer Institute
Summary:
Contrary to common assumptions, the risk of cancer associated with radiation exposure in middle age may not be lower than the risk associated with exposure at younger ages, according to a new study.

New research suggests that the risk of cancer associated with radiation exposure in middle age may not be lower than the risk associated with exposure at younger ages.
Credit: iStockphoto

Contrary to common assumptions, the risk of cancer associated with radiation exposure in middle age may not be lower than the risk associated with exposure at younger ages, according to a study published online October 25 in the Journal of the National Cancer Institute.

Related Articles


It is well known that children are more sensitive than adults to the effects of radiation and that they have a greater risk of developing radiation-induced cancer than adults. Some data also suggest that, in general, the older a person is when exposed to radiation, the lower their risk of developing a radiation-induced cancer. On the other hand, statistical evidence from long-term studies of atomic bomb survivors in Japan indicates that for radiation exposure after about age 30, the risk of developing radiation-induced cancer does not continue to decline.

To explore this issue, David J. Brenner, Ph.D., D.Sc., at Columbia University in New York, and colleagues reanalyzed the Japanese atomic bomb survivor data assuming two different pathways through which radiation exposure can ultimately lead to cancer. The first is initiation of gene mutations that convert normal stem cells to premalignant cells that could eventually lead to cancer. The second is radiation induced promotion, or expansion, of the number of existing premalignant cells in the body. The initiation effect is more likely to play a role in children than in adults, they reason, because cells initiated at an early age have a longer time available to expand in number and progress on the pathway to cancer. The promotion effect, on the other hand, is more likely to be important for radiation exposures in middle age, because the adult body already contains larger numbers of premalignant cells.

The researchers developed a model based on these biological effects and applied the model to the Japanese atomic bomb survivor data. They found that the model was able to reproduce the cancer risk patterns associated with age at radiation exposure observed in these survivors. They then applied the same model to predict cancer risks as a function of age in the U.S. population and found that the cancer risks predicted by the model were consistent with the data in the age range from about 30 to 60.

The authors conclude that cancer risk after exposure in middle age may increase for some tumor types contrary to conventional wisdom. They add that these findings could have practical implications regarding x-ray diagnostic tests, which are predominantly performed on middle aged adults, as well as for occupations that involve radiation exposures, again where most exposures are in middle age.

"Overall, the weight of the epidemiological evidence suggests that for adult exposures, radiation risks do not generally decrease with increasing age at exposure," they write, "and the mechanistic underpinning described here provides this conclusion with some biological plausibility."

In an accompanying editorial, John D. Boice, Sc.D., of the International Epidemiology Institute, Rockville, Md., and Vanderbilt University, Nashville, notes that there are uncertainties in generalizing the Japanese data to a U.S. population. He also notes that other data and other models contradict the results of this study. However, he concludes that this biology-based model "raises provocative hypotheses and conclusions that, although preliminary, draw attention to the continued importance of low-dose radiation exposures in our society."


Story Source:

The above story is based on materials provided by Journal of the National Cancer Institute. Note: Materials may be edited for content and length.


Journal References:

  1. Igor Shuryak, Rainer K. Sachs, David J. Brenner. Cancer Risks After Radiation Exposure in Middle Age. Journal of the National Cancer Institute, 2010; DOI: 10.1093/jnci/djq346
  2. John D. Boice, Jr. Models, Models Everywhere—Is There a Fit for Lifetime Risks? Journal of the National Cancer Institute, 2010; DOI: 10.1093/jnci/djq412

Cite This Page:

Journal of the National Cancer Institute. "Risk of cancer due to radiation exposure in middle age may be higher than previously estimated." ScienceDaily. ScienceDaily, 27 October 2010. <www.sciencedaily.com/releases/2010/10/101025161028.htm>.
Journal of the National Cancer Institute. (2010, October 27). Risk of cancer due to radiation exposure in middle age may be higher than previously estimated. ScienceDaily. Retrieved October 30, 2014 from www.sciencedaily.com/releases/2010/10/101025161028.htm
Journal of the National Cancer Institute. "Risk of cancer due to radiation exposure in middle age may be higher than previously estimated." ScienceDaily. www.sciencedaily.com/releases/2010/10/101025161028.htm (accessed October 30, 2014).

Share This



More Health & Medicine News

Thursday, October 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Mind-Controlled Prosthetic Arm Restores Amputee Dexterity

Mind-Controlled Prosthetic Arm Restores Amputee Dexterity

Reuters - Innovations Video Online (Oct. 29, 2014) A Swedish amputee who became the first person to ever receive a brain controlled prosthetic arm is able to manipulate and handle delicate objects with an unprecedented level of dexterity. The device is connected directly to his bone, nerves and muscles, giving him the ability to control it with his thoughts. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Google To Use Nanoparticles, Wearables To Detect Disease

Google To Use Nanoparticles, Wearables To Detect Disease

Newsy (Oct. 29, 2014) Google X wants to improve modern medicine with nanoparticles and a wearable device. It's all an attempt to tackle disease detection and prevention. Video provided by Newsy
Powered by NewsLook.com
Can Drinking Milk Lead To Early Death?

Can Drinking Milk Lead To Early Death?

Newsy (Oct. 29, 2014) Researchers in Sweden released a study showing heavy milk drinkers face an increased mortality risk from a variety of causes. Video provided by Newsy
Powered by NewsLook.com
Obama: The US Will Not 'run and Hide' From Ebola

Obama: The US Will Not 'run and Hide' From Ebola

AP (Oct. 29, 2014) Surrounded by health care workers in the White House East Room, President Barack Obama said the U.S. will likely see additional Ebola cases in the weeks ahead. But he said the nation can't seal itself off in the fight against the disease. (Oct. 29) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

    Technology News



    Save/Print:
    Share:

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile: iPhone Android Web
    Follow: Facebook Twitter Google+
    Subscribe: RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins