Cardiovascular disease among atomic bomb survivors

Purpose: The profile of cardiovascular disease in Japan has been different from that in Western countries. Hypertension was the major cause not only for hemorrhagic stroke but also for ischemic stroke and heart disease in the past, and the influence of hypertension has decreased with calendar years because of reduced salt intake and westernization of lifestyle, and also improved medical care. The health status of atomic bomb survivors has reflected this profile as well as radiation effects. It is also likely that this cohort has been affected by the difficult conditions experienced in the aftermath of the war and atomic bombings. In this article, we tried to make a consistent interpretation of epidemiological findings of atomic bomb radiation effects on cardiovascular disease.
Conclusion: Among the atomic bomb survivors, radiation exposure was associated with some cardiovascular diseases that are often associated with hypertension, and dose response appeared to be primarily non-linear among those who were exposed at younger ages. These effects are thought to reflect the nature of whole body irradiation. But, some findings remain inconsistent, possibly because of possible misclassification in death certificate diagnoses in the Life Span Study as well as selected information from the Adult Health Study which was limited to participants, focused on specific outcomes, and gathered in selected periods of follow-up. Therefore, a comprehensive and balanced interpretation of the results from both groups is necessary.

研究背景与目的：日本心血管疾病（cardiovascular disease）的疾病谱与西方国家存在显著差异。既往研究显示，高血压不仅是出血性脑卒中（hemorrhagic stroke）与缺血性脑卒中（ischemic stroke）的主要致病因素，也是心脏病的重要诱因；随着年代推移，由于食盐摄入减少、生活方式西化以及医疗水平提升，高血压的致病影响逐渐减弱。原子弹幸存者的健康状况既体现了日本心血管疾病的上述疾病谱特征，也反映了辐射暴露的影响；此外，该研究队列（cohort）还可能受到战后及原子弹爆炸后遗留的艰难处境的影响。本文旨在对原子弹辐射暴露对心血管疾病影响的相关流行病学研究结果开展一致性解读。
研究结论：在原子弹幸存者中，辐射暴露与部分常与高血压相关的心血管疾病存在关联；在年轻时接受辐射暴露的幸存者中，剂量-反应关系主要呈现非线性特征。上述效应被认为反映了全身辐射照射的生物学特性。但仍有部分研究结果存在不一致性，这可能与寿命研究（Life Span Study）中死亡证明诊断可能存在分类错误，以及成人健康研究（Adult Health Study）存在的信息选择偏倚有关——该研究仅纳入特定参与者、仅聚焦特定结局指标，且仅在特定随访时段收集数据。因此，需对两项研究的结果进行全面且均衡的解读。