Individuals with parents both exposed to A-bomb in WWII more likely to develop leukemia

A new study of people born within ten years of the Atomic bombing of Hiroshima who developed leukemia by the age of 35, finds that those whose parents both survived the blast were more likely to develop the blood cancer than those who only had one parent exposed to the bombing. Earlier studies, most of which were conducted by the joint Japan-U.S. operated Radiation Effects Research Foundation, have not shown a connection between people who develop leukemia and the exposure of their parents to an atomic bomb blast. The new study was headed by blood disease expert Nanao Kamada, a professor at Hiroshima University.

Professor Kamada said that this study is unprecedented in the volume of clinical data it collected on second-generation hibakusha. “Hibakusha” (被爆者) is a term that literally means “blast affected people” and is used to refer to survivors of the 1945 American atomic bombings of Hiroshima and Nagasaki.

The study found that 26 people born to two hibakusha parents had developed leukemia by the age of 35, while only six with only fathers exposed to the blast, and seventeen with only mothers exposed to the blast developed the disease. The study’s findings were released at an academic conference in Nagasaki. Professor Kamada says that the study demonstrated a distinct predisposition of second-generation hibakusha born between 1946 and 1973 to developing leukemia, and that more research was needed.

The researchers discovered that during the 50 year period after 1946 no fewer than 94 people born to survivors of the bombing had developed leukemia before reaching 35 years of age. The study used data on 119,331 second-generation hibakusha born within 27 years of 1946 compared with records on patients diagnosed with leukemia in Hiroshima prefecture. Of the 63,117 second-generation hibakusha born inside the ten year period after the bombing, 49 had developed leukemia.