Ischemic Heart Disease Among Atomic Bomb Survivors: Possible Mechanism(s) Linking Ischemic Heart Disease and Radiation Exposure

Abstract

It has been demonstrated that exposure to atomic bomb radiation appears to be associated with an increased risk of ischemic heart disease (IHD). In addition, atomic bomb radiation dose is associated with many of the IHD risk factors such as high blood pressure, hypertension, high cholesterol level, inflammatory markers, and aortic arch calcification. Because visceral fat accumulation or metabolic syndrome clusters many of the IHD risk factors such as obesity, insulin resistance, dyslipidemia, glucose intolerance, hypertension, and inflammatory markers, and predicts IHD, results observed in atomic bomb survivors led us to hypothesize that visceral fat accumulation or metabolic syndrome may explain the association between atomic bomb radiation and IHD. Therefore, to examine this possibility, we used fatty liver, which is a surrogate marker of visceral fat accumulation or metabolic syndrome, and examined whether fatty liver: (1) clusters the IHD risk factors; (2) is related to radiation dose; and (3) predicts IHD in atomic bomb survivors. We defined that fatty liver: (1) is associated with obesity (P < 0.001), hypertension (P < 0.001), hypercholesterolemia (P < 0.001), low-HDL cholesterol (P < 0.001), hypertriglyceridemia (P < 0.001), and diabetes mellitus (P < 0.001); (2) is associated with atomic bomb radiation (P = 0.02); and (3) predicts IHD (P = 0.04). These results suggest that visceral fat accumulation or metabolic syndrome might be involved in the basic mechanism(s) explaining the association between atomic bomb radiation and IHD.