Past Results and Future Studies

    • Matters elucidated thus far

      1. Cancers of specific organs have increased among A-bomb survivors.

      2. Non-cancer diseases (cataract, benign thyroid tumor, heart disease, stroke, etc.) have also increased among survivors exposed to high doses of radiation.

      3. Survivors exposed to high doses of radiation tend to show deterioration of the immune system similar to that observed with aging.

      4. Many survivors exposed to high doses of radiation exhibit minor inflammatory reactions.

      5. Research thus far has not indicated any genetic effects in A-bomb survivors’ children.

      6. Observations made to date have not confirmed increased mortality or cancer incidence among A-bomb survivors’ children.


    • Cancers with increased incidence among A-bomb survivors

      In addition to deaths from leukemia, deaths from thyroid, breast, lung, colon, and stomach cancers are known to have increased. On the other hand, however, some cancers, such as of the uterus, pancreas, prostate, and others, have not increased.

      Relative risk of death due to cancer at 1 Sv of radiation exposure (1950-1997)

      Relative risk
      All cancers (excluding leukemia)
       Esophageal cancer
       Stomach cancer
        Colon cancer
        Lung cancer
       Breast cancer
       Urinary bladder cancer

      Note: Average relative risk for survivors exposed at age 30, both sexes combined. Risk for leukemia based on data collected between 1950 and 1990.


    • Matters to be elucidated in the next 10-20 years

      1. Are survivors exposed to atomic-bomb radiation when young more sensitive to the effects of radiation than those exposed when older?

      2. Are the cancers expected to increase different between survivors exposed when young and those exposed when older?

      3. Are the cancers that have not increased among the A-bomb survivors to date also unlikely to increase in the future?

      4. Are survivors exposed to atomic-bomb radiation when young more likely to contract non-cancer diseases, including cataract, heart disease, and stroke, than those exposed when older?

      5. In addition to radiation, what effects do such factors as smoking and diet have on cancer development?

      6. How do cancer and other diseases develop following radiation exposure?

      7. Are immunological disorders and inflammation associated with development of diseases induced by radiation?

      8. What genetic factors are involved in individual variation in susceptibility to disease and health effects of radiation?

      9. Are gene mutations increased among the children of survivors exposed to high doses of radiation?

      10. Have lifestyle-oriented diseases increased among A-bomb survivors’ children (now becoming middle-aged and elderly)?


    • Matters likely to take more than 20 years

      1. Why does radiation-induced cancer development vary from organ to organ?

      2. Are cancers induced by radiation different from those induced by other causes?

      3. How do non-cancer diseases increase among A-bomb survivors?

      4. Are lifestyle-oriented diseases expected to increase among A-bomb survivors’ children? If so, why?