Perinatal loss and neurological abnormalities among children of the atomic bomb: Nagasaki and Hiroshima revisited, 1949 to 1989

Article Abstract:

Although early evaluation of the effects on unborn infants of the atom bombs dropped on Hiroshima and Nagasaki in 1945 indicated that the mother's distance from the bomb's hypocenter was a critical factor, more recent studies have found that some consequences, such as severe mental retardation, are more highly associated with the gestational age of the fetus at the time of the bomb (ATB). Other factors associated with such a catastrophic event that could influence fetal development, such as malnutrition resulting from food shortages, and infections, must be considered when evaluating the damaging effects attributed to the bombs. Observation of radiation effects on fetuses at different gestational ages ATB has provided important data about the vulnerability of the developing brain. Early studies of these and related issues are reviewed. In Nagasaki, the overall morbidity and mortality for the offspring of 30 women, pregnant ATB, who were within 2,000 meters of the hypocenter and who developed radiation sickness, was 60 percent. For a group the same distance from the hypocenter who did not develop radiation sickness, mortality was 6.2 percent, and morbidity among the surviving children was 1.5 percent. Mortality for infants born to mothers four to five thousand meters from the hypocenter was 6.2 percent, with a 0.9 percent morbidity for survivors. Figures from Hiroshima showed a high incidence of microcephaly (abnormally small head) and retardation in children whose mothers had been close to the blast. These effects were confined to children who were between 7 and 15 weeks gestational age ATB. Later studies helped establish that the maximum vulnerability to radiation occurs from the beginning of the eighth week through the 15th week. This is a period when neurons (brain cells) proliferate the most, and when they migrate to take up their proper positions in the brain. Exposure at earlier times may be harmful, but fetuses so exposed do not survive to be evaluated for retardation. A discussion of the anatomical findings in selected cases is provided. The pain and suffering of the families of the 'pika' (the Japanese word for the bomb flash) children are described, as well as its stigmatizing effect in Japanese society. The parents wonder who will care for their children, as they near the end of their own lives. (Consumer Summary produced by Reliance Medical Information, Inc.)

Research, Statistics, Embryology, Animal embryology, Prenatal influences

---

Cancer risk among atomic bomb survivors: the RERF Life Span Study

Article Abstract:

From the population who survived the atomic bomb attacks on Hiroshima (159,000) and Nagasaki (125,000) in 1945, a group of 120,128 people was selected to participate in a Life Span Study, begun in 1950. The group was composed of 91,228 bomb survivors who had been exposed to radiation; 26,517 people who were not living in either city at the time of the bombing; and 2,383 people whose radiation dose could not be determined. Death records in Japan are complete, and reports concern subjects who were followed between 1950 and 1985. Regular medical examinations have been performed since 1958 on a subgroup that makes up approximately 20 percent of the group. The report concerns mainly solid tumors, although leukemia (a cancer of white blood cells) is discussed briefly. Findings with respect to the leukemia show that it is the most frequent cancer in the cohort. Increased risk began to be observed one to three years after the bombings, peaked several years thereafter, and then declined. A new method of computing the doses of radiation (dosimetry), the DS86 system, takes into account the distance of the survivor from the blast's epicenter, shielding, posture, orientation, and age. Ninety-five percent of the bomb survivors had DS86 dose estimates available. Cancer risks were calculated using this approach. Overall, a greater risk for malignant tumors has been found for survivors, but not in all parts of the body. Cancer has increased in a dose-related fashion (the incidence is higher in people who received a higher dose) in the esophagus, stomach, and colon (large intestine), but not in the rectum, liver, gallbladder, or pancreas. The incidence of cancer of the lung, breast, ovary, and urinary tract, has also increased, as has the incidence of multiple myeloma (another kind of white blood cell cancer). Uterine and prostatic cancers have not yet shown an increase, nor has malignant lymphoma. Relative risk is higher for survivors who were younger at the time of the bombing. Solid tumors, unlike leukemia, begin to appear after survivors reach the age when such tumors are more often seen. The value of using risk coefficients (for evaluating relative risk) for analyzing data on bomb survivors is evaluated. (Consumer Summary produced by Reliance Medical Information, Inc.)

Measurement, Radiation, Radiation measurement

---

Cancer risk among children of atomic bomb survivors: a review of RERF epidemiologic studies

Article Abstract:

In utero exposure to radiation from the atomic bombs dropped on Hiroshima and Nagasaki in August 1945 is associated with an increased incidence of microcephaly (abnormally small head) and an increased frequency of mental retardation (for those who were exposed during gestational weeks eight through 15). In addition, somatic mutations (mutations in cells of the body) caused by the bombs are associated with an elevated cancer risk in survivors, an effect that is strongest for those exposed at the youngest ages. The frequency of genetic mutations (mutations in the germ cells transferred to the next generation) was investigated by the Radiation Effects Research Foundation (RERF). The group examined genetic mutations and cellular abnormalities in children born to atomic bomb survivors, including both children who were in utero at the time of the bombings, and children conceived afterwards who had at least one parent who was a survivor (the F1 population). Results from studies that considered several variables have not revealed a genetic effect from the bombs on children of survivors. When cancer risks were evaluated among children who were in utero at the time of the bombings, and among the F1 generation, it appeared that risk increases over the age of 40 for the in utero group with increasing maternal radiation dose. The relatively small number of people (920) exposed to higher doses before birth, and the small number of cancer cases (18), make statistical analysis difficult. The highest-dose in utero group had an inexplicably low leukemia risk. No elevation in cancer risk, including leukemia, associated with increasing parental dose (measured as dose to the gonads) has yet been detected in F1 population members who were less than 20 years old between 1946 and 1982. Possible reasons for the observations of other research groups that contradict these findings are evaluated. (Consumer Summary produced by Reliance Medical Information, Inc.)

Genetic aspects, Radioactive fallout, Radiation Effects Research Foundation

Similar abstracts:

• Abstracts: Morals and moralism in the debate over euthanasia and assisted suicide. When too much is too little
• Abstracts: Partner notification and confidentiality of the index patient: its role in preventing HIV. Syphilis in San Diego County 1983-1992: crack cocaine, prostitution, and the limitations of partner notification
• Abstracts: Fetal vesicorectal fistula causing oligohydramnios in the second trimester: case report. Fetofetal transfusion syndrome: Do the neonatal criteria apply in utero?
• Abstracts: Effect of stage of disease and drug dose on zidovudine susceptibilities of isolates of human immunodeficiency virus
• Abstracts: Nonsteroidal anti-inflammatory drug-associated azotemia in the very old. The exclusion of the elderly and women from clinical trials in acute myocardial infarction

This website is not affiliated with document authors or copyright owners. This page is provided for informational purposes only. Unintentional errors are possible.