Mark P. Little1, Tamara V. Azizova2, Dimitry Bazyka3, Simon D. Bouffler4, Elisabeth Cardis5, Sergey Chekin6, Vadim V. Chumak3, Francis A. Cucinotta7, Florent de Vathaire8, Per Hall9, John D. Harrison4, Guido Hildebrandt10,11, Victor Ivanov6, Valeriy V. Kashcheev6, Sergiy V. Klymenko3, Michaela Kreuzer12, Olivier Laurent13, Kotaro Ozasa14, Thierry Schneider15, Soile Tapio16, Andrew M. Taylor17, Ioanna Tzoulaki18, Wendy L. Vandoolaeghe18, Richard Wakeford19, Lydia B. Zablotska20, Wei Zhang4, Steven E. Lipshultz21
22 June 2012
Background: Although high doses of ionizing radiation have long been linked to circulatory disease, evidence for an association at lower exposures remains controversial. However, recent analyses suggest excess relative risks at occupational exposure levels.
Objectives: We performed a systematic review and meta-analysis to summarize information on circulatory disease risks associated with moderate- and low-level whole-body ionizing radiation exposures.
Methods: We conducted PubMed/ISI Thomson searches of peer-reviewed papers published since 1990 using the terms “radiation” AND “heart” AND “disease,” OR “radiation” AND “stroke,” OR “radiation” AND “circulatory” AND “disease.” Radiation exposures had to be whole-body, with a cumulative mean dose of < 0.5 Sv, or at a low dose rate (< 10 mSv/day). We estimated population risks of circulatory disease from low-level radiation exposure using excess relative risk estimates from this meta-analysis and current mortality rates for nine major developed countries.
Results: Estimated excess population risks for all circulatory diseases combined ranged from 2.5%/Sv [95% confidence interval (CI): 0.8, 4.2] for France to 8.5%/Sv (95% CI: 4.0, 13.0) for Russia.
Conclusions: Our review supports an association between circulatory disease mortality and low and moderate doses of ionizing radiation. Our analysis was limited by heterogeneity among studies (particularly for noncardiac end points), the possibility of uncontrolled confounding in some occupational groups by lifestyle factors, and higher dose groups (> 0.5 Sv) generally driving the observed trends. If confirmed, our findings suggest that overall radiation-related mortality is about twice that currently estimated based on estimates for cancer end points alone (which range from 4.2% to 5.6%/Sv for these populations).