Overview of RERF Research Programs
|The principal focus of the RERF research program
is the study the effects of radiation in the survivors of the atomic
bombings of Hiroshima and Nagasaki. Several fixed cohorts or sub-cohorts
were established to provide epidemiological and clinical data on
the health status and mortality of the survivors and their children.
Laboratory-based research studies in the fields of radiobiology,
immunology, genetics, and molecular epidemiology are carried out
to help interpret the various findings and contribute to the understanding
of the mechanisms of disease induction.
The Life Span Study consists of a large cohort from a general
population of both sexes and all ages. It encompasses a wide
range of accurately known doses and incorporates accurate
disease incidence and mortality recording and careful evaluation
and reporting of results. These features make this the most
informative epidemiological study in the world for establishing
radiation risks. There is a commitment to continue the follow
up for the complete lifetimes of all participants. Risks are
evaluated for cancer incidence, cancer mortality, and non-cancer
effects in relation to radiation dose.
Adult Health Study
The Adult Health Study is a clinical study of a sub-cohort
of the Life Span Study. Examinations of atomic-bomb survivors
are conducted every two years, providing a continuing health
profile of an aging population. In addition, blood samples
are collected under informed consent for future analysis.
This study is establishing the radiation-related risk of non-cancer
diseases and investigating age- and radiation-related physiological
changes. It will be continued throughout the lifetimes of
the survivors to quantify more exactly the radiation relationships
and risks of non-cancer diseases.
of Atomic-bomb Survivors (F1) Study
The children of the atomic-bomb survivors are being studied to determine
whether genetic effects might be apparent that could be related to parental
exposures. An initial study of birth defects did not reveal any discernable
effects. Subsequently, studies on mortality and cancer incidence, chromosome
abnormalities, and serum proteins were also conducted, but again no radiation
effect has been observed. Presently, continued mortality and cancer-incidence
follow-up and molecular studies on DNA are being conducted. Starting from
2002, a new clinical study was initiated to investigate lifestyle-related
diseases that are not observable at birth but start to appear after middle
age (e.g., hypertension, diabetes mellitus, etc.). This study was conducted
to examine over a period of four years about 12,000 people whom we have
contacted with the cooperation of the Second-generation A-bomb Survivors
Council and whose willingness to be examined was confirmed.
Please refer to the following report on the results of the above-mentioned study:
Report on the Health Effects Study of the Children of A-bomb Survivors (March 2007)[PDF: 426KB]
The clinical study (health examination) of the children of A-bomb survivors has been continued since November 2010 with about 12,000 people, almost the same participants from the previous study.
The in utero study is a unique evaluation of the lifetime health experience of a specially
exposed population, namely those in utero at the time of the bombings (about 3,600 persons). It is not known whether
the sensitivity to radiation effects of this group is similar to or greater
than that of the youngest postnatal group (0-5 years). The continued follow-up
of this cohort through middle and old age until mortality will be highly
Radiation biology studies are directed at understanding the
complex result of physical phenomena (location, type and amount
of energy deposition), biological reactions (damage consequences,
repair, adjustment processes) and endogenous factors (age,
sex, hormones, diet) involved in radiation response. Investigations
are specifically directed to DNA indications that cause or
predispose to breast cancer and to thyroid cancer. Speciallized
techniques are applied to blood or tissue samples in order
to distinguish changes in DNA that may have occurred as a
consequence of radiation exposure.
Evidence is emerging that atomic-bomb radiation led to certain
changes in the immune system of exposed persons. State-of-the-art
methods used to characterize cells of the immune system are
being applied to better understand these changes and to assess
their possible impact on health.
Radiation-induced effects not readily apparent in the body (i.e., at the
phenotypic level) may be discernable from molecular changes in DNA (i.e.,
at the genotypic level). This newly emerging field is being pursued at
RERF. Serum collected within the clinical program or tissue obtained from
autopsies and surgeries conducted on members of the epidemiological follow-up
program are studied in an attempt to better understand the mechanisms and
causes of disease.
The cytogenetics evaluations provide a means of assessing
radiation exposure (biological dosimetry) by evaluating the
types and amounts of structural damage in chromosomes.
Statistical analyses provide the means to assess relationships
between risk factors and disease in the face of the variability
inherent in data on disease rates or other health effects.
The basic activity of this program concerns risk assessment
through application of mathematical models to rates of disease
occurrence or death in order to identify and quantify radiation
effects. In addition, RERF statisticians collaborate with
other RERF scientists on study design and data analysis and
conduct methodological research to develop better methods
for the analysis of data on disease and health risks.
Assessing the risks of radiation exposure requires knowledge
of the dose of radiation received. There are no direct measurements
of dose for individual survivors. This program is concerned
with providing survivor dose estimates. Basic information
on radiation exposures are based on modern understanding of
the physics of the bombs and the results of extremely sensitive
measurements that can detect minute traces of the A-bomb radiation
exposure in various types of materials (concrete, granite,
copper, etc.). In order to estimate the dose received by an
individual survivor, this information is combined with historical
interview data pertaining to that survivor's location and
shielding at the time of the bombs. The dosimetry program
is also concerned with developing a better understanding of
the uncertainties in survivor dose estimates and how to account
for the effect of these uncertainties on risk estimates.