Systematic review and meta-analysis of circulatory disease from exposure to low-level ionizing radiation and estimates of potential population mortality risks.
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.


OBJECTIVE
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).
Radiation Epidemiology Branch, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Rockville, Maryland 20852-7238, USA. mark.little@nih.gov
Mark P
MP
Little
Tamara V
TV
Azizova
Dimitry
D
Bazyka
Simon D
SD
Bouffler
Elisabeth
E
Cardis
Sergey
S
Chekin
Vadim V
VV
Chumak
Francis A
FA
Cucinotta
Florent
F
de Vathaire
Per
P
Hall
John D
JD
Harrison
Guido
G
Hildebrandt
Victor
V
Ivanov
Valeriy V
VV
Kashcheev
Sergiy V
SV
Klymenko
Michaela
M
Kreuzer
Olivier
O
Laurent
Kotaro
K
Ozasa
Thierry
T
Schneider
Soile
S
Tapio
Andrew M
AM
Taylor
Ioanna
I
Tzoulaki
Wendy L
WL
Vandoolaeghe
Richard
R
Wakeford
Lydia B
LB
Zablotska
Wei
W
Zhang
Steven E
SE
Lipshultz
D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000209:etiology* / Q000401:mortality*; D004307:Dose-Response Relationship, Radiation; D004781:Environmental Exposure; D006801:Humans; D016273:Occupational Exposure; D011832:Radiation Injuries / Q000453:epidemiology / Q000209:etiology* / Q000401:mortality*; D011834:Radiation Monitoring; D011839:Radiation, Ionizing