ArticlesRisk of death among children of atomic bomb survivors after 62 years of follow-up: a cohort study
Introduction
Children of radiation-exposed parents are predicted to have higher rates of mendelian and multifactorial genetic diseases. However, no clear epidemiological effects have been shown in the first filial (F1) generation of people after parental radiation exposure.1, 2, 3 Concerns of possible deleterious effects among children conceived after parental exposure to the atomic bombs in Hiroshima and Nagasaki led to the creation of the atomic bomb survivors F1 mortality cohort. Previous reports on this cohort have not noted increased cancer incidence or cancer mortality.4, 5, 6, 7, 8 Despite these findings, surveillance has continued as scientific interest and public attention have remained focused on the health effects of ionising radiation. Questions to be answered include the dangers of diagnostic radiography among children, the full effects of the Fukushima nuclear power plant disaster, and germline mutations that could be passed to following generations.
With nearly 63 years of follow-up, the F1 mortality cohort is the longest running study of children born to parents exposed to ionising radiation and has an instrumental role in establishing long-term health effects of parental radiation exposure. This report updates the radiation risks of death caused by cancer and non-cancer diseases among the children of the survivors of the atomic bombings up to 2010 and includes 10 additional years of follow-up since the last report.8
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Study design and participants
This study uses a prospective cohort design. Children conceived after the atomic bombings and born in Hiroshima and Nagasaki were identified via city birth records or by active recruitment at city offices where pregnant women could apply for supplemental rice allowances. Parents were interviewed or matched to a master list of survivors based on the 1950 Japanese National Census to determine parental exposure status. All singleton children with one or both parents within 2 km of the hypocentres
Results
The F1 mortality cohort consists of 76 814 people. Cohort members were excluded if they were not Japanese nationals (n=763), their residence could not be determined (n=663), had an unknown date of death (n=2), they explicitly withdrew from the study (n=8), or if they did not survive at least 1 day (n=51). Thus, 75 327 participants were analysed. Slightly more than half of the children were male and most were born in Hiroshima. Half of the cohort was born before 1955. Mothers tended to be
Discussion
We did not detect any associations between parental radiation exposure and mortality among children after the atomic bombings in Hiroshima and Nagasaki. Non-cancer-related mortality occurred more often in the early follow-up period whereas deaths caused by cancer tended to occur more often in the later period. This cohort included a high proportion of all children born to proximally exposed atomic bomb survivors who resided in Hiroshima or Nagasaki at the time of their child's birth. Our
References (29)
- et al.
Evidence relevant to untargeted and transgenerational effects in the offspring of irradiated parents
Mutat Res
(2013) - et al.
Minisatellite germline mutation rate in the Techa River population
Mutat Res
(2006) Sources and effects of ionizing radiation
(2001)The 2007 recommendations of the International Commission on Radiological Protection. ICRP publication 103
Ann ICRP
(2007)Health risks from exposure to low levels of ionizing radiation: BEIR VII Phase 2
(2006)- et al.
Mortality in the children of atomic bomb survivors and controls
Genetics
(1974) Cancer risk among children of atomic bomb survivors. A review of RERF epidemiologic studies. Radiation Effects Research Foundation
JAMA
(1990)- et al.
Mortality among the offspring (F1) of atomic bomb survivors, 1946-85
J Radiat Res
(1991) - et al.
Cancer incidence in children and young adults did not increase relative to parental exposure to atomic bombs
Br J Cancer
(2003) - et al.
Radiation-related mortality among offspring of atomic bomb survivors: a half-century of follow-up
Int J Cancer
(2003)