Links between radiation exposure and circulatory disease probed

7 October 2010

Clinicians who deliver radiation to the brain and heart are being urged to continue to minimise their patients’ exposure, while maintaining essential medical benefits.

New expert advice to the Health Protection Agency also highlights a need for further research to better understand links between radiation exposure and circulatory disease.

For many years scientists have found links between the development of circulatory disease, mainly heart disease, and exposure to ionising radiation at high doses. Because of that the Health Protection Agency’s Advisory Group on Ionising Radiation (AGIR) has reviewed recently published epidemiological studies and experimental work on the risks and potential causes of circulatory disease following exposures to ionising radiation.

One of the group’s key recommendations is that HPA urges clinicians who use radiation, for therapeutic or diagnostic purposes, to examine their working practices. Where possible, AGIR recommends, radiation doses to patients’ brains and hearts should be kept as low as possible. The group also suggests the health of patients exposed to medical radiation in this way should be studied to improve the future estimation of radiation risks.

Professor Bryn Bridges, the chairman of AGIR, concluded that: “High radiation doses are known to have effects on the heart. What is less clear is the magnitude of risk at the low dose levels commonly of concern in the protection of nuclear workers, the public and patients.

“Our report found evidence of risk down to around 0.5 Gray. Below that dose, interpretation is hindered by inadequate control of major lifestyle factors associated with heart disease. Furthermore, our understanding of the ways in which radiation might cause circulatory disease is too poor to justify the extrapolation of information obtained using high doses to the estimation of possible risk at low doses.”

Other recommendations made by the group are;

That the Health Protection Agency develops a research programme to improve understanding of how radiation can cause arteries to harden;
That HPA should continue to encourage people to lead healthy lives and avoid activities, such as smoking, likely to lead to an increase in the chances of developing circulatory disease;
Research looking to identify biomarkers of circulatory disease should be encouraged by the HPA. Such research would help determine if radiation is a causal factor in circulatory disease;
That further work is done to monitor the health of groups of people exposed to radiation, such as radiation workers, those who survived the Japanese atomic bomb blasts during the Second World War and those who took part in attempting to contain the damage done by the nuclear accident at Chernobyl, which should provide information on the risks of circulatory disease to those exposed.

Dr John Cooper, director of the HPA’s Centre for Radiation, Chemicals and Environmental Hazards, said: “I would like to thank AGIR for its diligent and thorough work in reviewing the evidence available in this complex area.

“It is reassuring that the committee was largely satisfied about present practices in relation to patient safety, radiation exposure and circulatory disease risk and recommends that clinicians working in this field should continue to maintain and spread best practice and where possible keep up with technical developments that reduce exposure of the brain, heart and blood system.

“One of the group’s core recommendations is for the HPA to begin a research programme into the role radiation has in causing cardiovascular disease. I am pleased to be able to report that the HPA is already in the process of setting up such a programme of work.”

Notes to Editors

The Health Protection Agency (HPA) has a statutory responsibility for advising UK government departments, and those with responsibility for using ionising and non-ionising radiation, on the risks to human health from the use of radiation.
The Advisory Group on Ionising Radiation (AGIR) was created to review work and advise HPA on the biological and medical effects of ionising radiation relevant to human health in the occupational, public health, medical and environmental fields and advise on research priorities.
The full AGIR report can be read here. And an HPA response to the report and its recommendations can be read here.
One gray (abbreviated Gy) is the unit of radiation dose used when one joule of energy from ionising radiation is absorbed by one kilogram of matter. A milligray (mGy) is 0.001 of a gray and on average a chest x-ray delivers a radiation dose of about 0.02mGy.
The new report can be viewed on the Radiation Publications page and the HPA’s formal response can be seen here on the Response Statements page.
For information on AGIR visit the Advisory Group on Ionising Radiation page.
Contact: Health Protection Agency Press Office, Centrefor Radiation, Chemical and Environmental Hazards, Chilton, Didcot, Oxfordshire OX11 0RQ, www.hpa.org.uk.

Tel +44 (0) 1235 822745 or 01235 822876 Fax +44 (0) 1235 822746
Email chilton.pressoffice@hpa.org.uk

Last reviewed: 7 October 2010