How Low Doses Of Radiation Can Cause Heart Disease And Stroke

ScienceDaily (Oct. 23, 2009) - A mathematical model constructed by
researchers at Imperial College London predicts the risk of cardiovascular
disease (heart attacks, stroke) associated with low background levels of
radiation. The model shows that the risk would vary almost in proportion
with dose.

Results, published October 23 in the open-access journal PLoS Computational
Biology, are consistent with risk levels reported in previous studies
involving nuclear workers.

Cardiovascular disease is the leading cause of death and one of the leading
causes of disability in developed countries, as reported in the paper and
also by the World Health Organization. For some time, scientists have
understood how high-dose radiotherapy (RT) causes inflammation in the heart
and large arteries and how this results in the increased levels of
cardiovascular disease observed in many groups of patients who receive RT.
However, in the last few years, studies have shown that there may also be
cardiovascular risks associated with the much lower fractionated doses of
radiation received by groups such as nuclear workers, but it is not clear
what biological mechanisms are responsible.

The Imperial College London team, led by Dr. Mark Little, has explored a
novel mechanism that suggests that radiation kills monocytes (a type of
white blood cell) in the arterial wall, which would otherwise bind to
monocyte chemo-attractant protein 1 (MCP-1). The resultant higher levels of
MCP-1 cause inflammation which leads to cardiovascular disease. As well as
being consistent with what is seen in nuclear workers, the changes in MCP-1
caused by dietary cholesterol that are predicted by the model are also
consistent with experimental and epidemiologic data.

If the mechanism is valid it implies that risks from low dose radiation
exposures (e.g., medical and dental X-rays), which until now have been
assumed to result only from cancer, may have been substantially
underestimated, say the authors.

The biological mechanism has yet to be experimentally tested. Further
research is planned to investigate this.

Web address: http://www.sciencedaily.com/releases/2009/10/091022202710.htm

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Journal reference:

Little MP, Gola A, Tzoulaki I. A Model of Cardiovascular Disease Giving a
Plausible Mechanism for the Effect of Fractionated Low-Dose Ionizing
Radiation Exposure. PLoS Computational Biology, 2009; 5 (10): e1000539
DOI: 10.1371/journal.pcbi.1000539

MLA
Public Library of Science (2009, October 23). How Low Doses Of Radiation Can
Cause Heart Disease And Stroke. ScienceDaily. Retrieved November 10, 2009,
from http://www.sciencedaily.com- /releases/2009/10/091022202710.htm