Janjivan Bureau
Exposure to ionizing radiation at high doses causes cancer. But there is uncertainty at low doses typically received by radiation workers and patients undergoing diagnostic radiation procedures. To reduce this uncertainty, any study must include a very large number of exposed individuals over a long period of time. Such a landmark study of 3,08,297 radiation workers employed in France, the UK and U.S., published online in The Lancet Haematology, (June 21, 2015) provided strong evidence of positive association between protracted low-dose radiation exposure and leukaemia.
In the WHO International Agency for Research on Cancer (IARC) coordinated study, they used the radiation dose due to external exposure to individual workers who wore dose measuring devices during their service. The study followed them up to 60 years after exposure. The average annual dose was 1.1 mGy.
The Nature on June 30, 2015 stated that the study has now provided the strongest support yet for the idea that long-term exposure to low-dose radiation increases the risk of leukaemia, although the rise is only minuscule.
“The finding will not change existing guidelines on exposure limits for workers in the nuclear and medical industries, because those policies already assume that each additional exposure to low-dose radiation brings with it a slight increase in risk of cancer,” Nature added
“The health risk of low-dose radiation is really very tiny, but the public is very concerned,” Bill Morgan told the journal. He heads a systems-biology programmed in low-dose radiation at the Pacific Northwest National Laboratory in Richland, Washington, and chairs the committee on radiation effects at the International Commission on Radiological Protection (ICRP) in Ottawa, Canada.
“It is a solid, unusually large study of individuals exposed to very low doses of ionizing radiation,” Nature quoted epidemiologist Jørgen Olsen, director of the Danish Cancer Society Research Center in Copenhagen.
