Cardiovascular disease among atomic bomb survivors

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.

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.