HealthDay News — Evidence supports a causal association between radiation exposure and cardiovascular disease, although there is interstudy heterogeneity, according to a review published online March 8 in The BMJ.
Mark P. Little, D.Phil., from the National Cancer Institute in Bethesda, Maryland, and colleagues conducted a systematic review and meta-analysis involving 93 studies to examine the radiation-associated risks for cardiovascular disease.
The researchers found that the relative risk per Gy increased (excess relative risk per Gy, 0.11) for all cardiovascular disease, and relative risks increased for four major subtypes of cardiovascular disease (ischemic heart disease, other heart disease, cerebrovascular disease, all other cardiovascular disease). Interstudy heterogeneity was seen, possibly due to interstudy variation in unmeasured confounders or effect modifiers, which was reduced if attention was restricted to higher-quality studies or those at moderate doses (<0.5 Gy) or low-dose rates (<5 mGy/hour). Risks were larger per unit dose for lower dose and for fractionated exposures for ischemic heart disease and all cardiovascular disease. The estimated risk for mortality from cardiovascular disease was generally dominated by cerebrovascular disease, followed by ischemic heart disease (around 0.94 to 1.26 percent per Gy and around 0.30 to 1.20 percent per Gy, respectively).
“Our findings suggest that radiation detriment might have been significantly underestimated, implying that radiation protection and optimization at low doses should be rethought,” the authors write.
One author disclosed financial ties to the pharmaceutical, medical device, and medical technology industries.