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| Fig. 1: Sasaki in Hiroshima Peace Park. Sadako Sasaki died of Leukemia at the age of 12 as a result of radiation from the atomic bombing of Hiroshima. (Source: Wikimedia Commons) |
On August 6th, 1945, after obtaining approval from the United Kingdom because of the Quebec Agreement, the United States dropped a Uranium gun-type bomb on Hiroshima, Japan. Three days later, the United States dropped another bomb on Nagasaki, Japan. These two bombs remain as the first and only use of atomic weapons in warfare. It is estimated that 129,000-226,000 people died. Most of these deaths occurred due to the initial blasts, but many deaths occurred in the ensuing months due to negative effects of radiation. Furthermore, even to the present day, the effects of radiation are still affecting the populations in these areas. This paper will serve as an examination of the increased risk of leukemia to people exposed to higher amounts of radiation from the atomic bombs that Americans dropped in 1945.
Scientists when describing the magnitude of risk radiation poses on the short term and long term health of a certain population, use a measurement called excess absolute risk (EAR). EAR describes the difference of an occurrence of a certain disease in an exposed population and a similar population with no exposure. [1] This measurement provides a good description of how much radiation is negatively affecting a population in a specific category of disease. It must be understood that the age of exposure plays an important role in determining someone's risk. A person exposed at the age of 10 is often two times as likely to be at risk than a person exposed to radiation at 40. [1]
The Radiation Effects Research Foundation (RERF) is one of the many players that have studied hundreds of thousands of residents of these two cities that were survivors of the blasts from the bombings. [2] RERF has found that survivors have a statistically significant higher chance of obtaining Leukemia, especially those exposed at an age when their organs were still developing. (See Fig. 1.) Deaths due to stomach, liver, breasts, ovary, and other major cancer have been significantly higher in samples of survivors than they are in other cohorts. [2] This shows that the atomic bombings that occurred in Japan not only killed hundreds of thousands of innocent people on impact, but they have also caused many other deaths and ill health effects due to the lasting radiation that is present from these weapons being used in warfare. Leukemia chances increase after exposure to moderate and high does of radiation, but it is unclear whether the risk of Leukemia is increased after low doses of radiation exposure. [3]
According to a study carried out by Lange et al., who studied one hundred fifty cases of leukemia from 1948 to 1952, many variables including the amount of exposure to radiation, sex, and age all had different amounts of influence on leukemia occurrence. Statistical analysis of the data collected on the Hiroshima bombings showed that there was no influence of sex on the occurrence of leukemia among atomic bomb survivors within the city. [4] This is an interesting notion because there were 24 cases of Leukemia being studied following the radiation exposure in the city and twenty of them were males. [4] The reasoning for this happening was due to the increased occupational exposure of males. Modern research shows no indication that the occurrence of leukemia following an increase of radiation exposure is not affected by the sex of the subject. [4] In the exposed series there were ten cases of leukemia of subjects with 6 to 9 years of age, sixteen cases 10 to 19, fourteen cases 20 to 29, thirteen cases 30 to 39, nine cases 40 to 49, eight cases 50 to 59, and five cases occurring after the age of 60. By contrast, in the non exposed series, there were sixteen cases between the ages of 1 and 5, six cases from 6 to 9. In the other age groups, there were six cases in the 10 to 19 age group, five cases 20 to 29, four cases 30 to 39, four cases 40 to 49, five cases 50 to 59, and three cases beyond the age of 60. It is apparent that natural factors that do not include radiation, such as sex and age, are not enough to explain exposed groups in any discussion of comparative incidence or type of leukemia. Recent information indicates that most young infants were evacuated from the cities prior to the bombings. [4] Studies have also shown that the amount of exposure to radiation is the largest factor that contributes to the explanation of why there has been an increased incidence of leukemia within the victims of the bombing. All humans live in environments that contain radiation from things like the sky and rocks. Victims who received four gray or more at the time of detonation died from radiation sickness, but those who received less likely survived. A gray is a unit that describes the amount of damage that ionizing radiation can due to tissues and organs within the human body. The risk of Leukemia increases as one is exposed to more rays.
In a study carried out by The Atomic Bomb Casualty Commission (ABCC) showed that not only was Leukemia incidence higher in the 120,000 people studied that were present at the initial blast, but Leukemia incidence was also higher in the first-generation offspring of the survivors. [5] Studies have shown that there are a myriad of health problems that are higher in the children of survivors from the bombings.
Logan Panchot. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for non-commercial purposes only. All other rights, including commercial rights, are reserved to the author.
[1] E. E. Douple et al., "Long-Term Radiation-Related Health Effects in a Unique Human Population: Lessons Learned From the Atomic Bomb Survivors of Hiroshima and Nagasaki," Disaster Med. Public Health Pre. 5, S122 (2011).
[2] K. Kodama, K. Mabuchi, I. Shigematsu, "A Long-Term cohort Study of the Atomic-Bomb Survivors," J. Epidemiol. 6, No. 3 Suppl., S95 (1996).
[3] K. Furukawa et al., "Long-Term Trend of Thyroid Cancer Risk Among Japanese Atomic-Bomb Survivors: 60 Years After Exposure." Int. J. Cancer 132, 1222 (2013).
[4] R. D. Lange, W. C. Moloney, and T. Yamawaki, "Leukemia in Atomic Bomb Survivors: I. General Observations," Blood 9, 574 (1954).
[5] K. Kamiya et al., "Long-Term Effects of Radiation Exposure on Health," Lancet 386, 469 (2015).
