RERF Report No. 14-15

Paper published in the Asian Pacific Journal of Cancer Prevention

Summary Report for "Initial report for the Radiation Effects Research
Foundation F1 Mail Survey"
Caitlin M. Milder, Ritsu Sakata, Hiromi Sugiyama, Atsuko Sadakane, Mai Utada, Kismet A.
Cordova, Ayumi Hida, Waka Ohishi, Kotaro Ozasa, Eric J. Grant
Asian Pac J Cancer Prev 2016 (April); 17(3):1313-23(doi: 10.7314/APJCP.2016.17.3.1313)
Study Findings
The results of RERF’s self-administered questionnaire-based mail survey of children ofatomic bomb survivors (F1)* regarding health status, lifestyle, sociodemographics, diseasehistory, and mental health revealed, as expected, differences by gender and city. In terms ofpossible parental dose response findings, however, minor differences in self-reported mental
health and several other factors were observed, with no major or consistent differences detectedamong the groups based on parental dose (dose groups).
*The F1 population does not include those exposed in utero.
Explanation
We analyzed the results of a mail survey distributed between 2000 and 2006 torepresentative members of the F1 mortality cohort. The mail survey was conducted forcollection of medical history and lifestyle information to provide a baseline for later
epidemiological cohort follow-up studies and for confirmation of their willingness to participate
in an anticipated clinical examination survey.
1. Study Purpose
There has thus far been no solid evidence of effects from atomic bomb radiation in thechildren of atomic bomb survivors who were conceived after the bombings. However, at thetime this mail survey was performed, the cohort had reached middle age, a time during which
both cardiovascular disease and cancer risks naturally increase in a population. Such a natural
increase in numbers would make excess cases of health outcomes from radiation more easily
detectable, information that could help elucidate whether changes in health status are
attributable to radiation or to another cause. This study is the first step in analyzing the mailsurvey data and provides a snapshot of the recent health status of the F1 cohort. The baseline
data collected in this study will facilitate future follow-up studies to investigate possibleradiation effects while adjusting for lifestyle factors.

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2. Study Methods
Surveys were sent to 24,673 F1 mortality cohort members, 16,183 of whom responded.
The questionnaire included questions related to sex, age, height, weight, general health, medicalhistory, mental health status, smoking and drinking habits, eating habits, activity levels,sociodemographic status, and women’s health. We conducted descriptive analyses of therespondents by categories defined on the basis of five different variables: city (Hiroshima and/orNagasaki), sex, paternal radiation dose, maternal radiation dose, and combined parental dose.
Logistic regression analysis was used to determine if there were any differences by dose
category among disease history, mental health status, and women’s health. All analyses
controlled for age, as age was slightly different by dose group due to the initial design of thecohort.
3. Study Results
The overall mail survey response rate was 65.6%. The average age of participants wasaround 48 years. Certain differences in health and lifestyle factors were observed by city andsex. F1 members who resided in Hiroshima reported higher education levels than those of
Nagasaki residents; they also more frequently reported being currently married. In terms ofdifferences by sex, men reported higher education levels and employment than women; theyalso reported more hours of sleep and higher levels of drinking and smoking. In terms of disease
outcomes, a higher percentage of men reported lifestyle-related diseases such as hypertension,
diabetes, and hyperlipidemia, while women reported cancer and weight gain more frequently.
These disease findings were what would also be expected from the general Japanese population.
The differences by both city and sex were similar to those seen in the National Health andNutrition Survey and several studies connected with the Japanese Collaborative Cohort (JACC).
Likewise, the differences by sex reflected those in the general Japanese population. In terms ofpossible parental dose response findings, no major or consistent differences in health, lifestyle,sociodemographics, disease history, or mental health were seen among any of the dose groups.
Heterogeneity in disease history and mental health status, however, was observed among
one-parental dose categories including several linear trends, i.e., decreased frequencies of livercirrhosis and feelings of depression in men and decreased frequency of insomnia in women withincreased paternal dose, and increased exhaustion in women with increased total parental dose.
Study SignificanceThe mail survey collected lifestyle data that will be helpful for use in future follow-up
studies. These data provide a snapshot of the recent health status of the F1 cohort members andwill help to elucidate the effects of lifestyle and parental radiation exposure on health outcomes.
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This study revealed research tasks to be explored in the future, such as differences in lifestylefactors by birth cohort. Further research will be needed to continue studying potential effects ofparental radiation among the children of survivors.
The Radiation Effects Research Foundation has studied A-bomb survivors and their offspring in
Hiroshima and Nagasaki for around 70 years. RERF’s research achievements are considered the principal
scientific basis for radiation risk assessment by the United Nations Scientific Committee on the Effects ofAtomic Radiation (UNSCEAR) and for recommendations regarding radiation protection standards by theInternational Commission on Radiological Protection (ICRP). RERF expresses its profound gratitude to
the A-bomb survivors and survivors’ offspring for their cooperation in our studies.

§Asian Pacific Journal of Cancer Prevention (APJCP) is the official monthly electronic journal and an
official journal of the International Association of Cancer Registries. The journal covers various aspectsof cancer research as well as cancer prevention education issues. All of the papers published are freely
available as pdf files downloadable from http://www.apjcpcontrol.org or obtainable from the firstauthor. The APJCP is financially supported by the UICC Asian Regional Office and the NationalCancer Center of Korea, where the Editorial Office is housed. (Impact factor for 2014: 2.514)

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