RERF Life Span Study, Adult Health Study, and F1 Cohorts (Hiroshima and Nagasaki)

Lead Contact and/or Principal Investigator (PI):

  • Kotaro Ozasa, M.D., Ph.D.
    Radiation Effects Research Foundation (RERF)
    Hiroshima/Nagasaki, Japan

Funded Since: 1947
Funding Source: U.S. Department of Energy and Japan Ministry of Health, Labour and Welfare
Year(s) of Enrollment: 1950 for main cohort, 1958 for clinical sub-sample, and 2002 to 2006 for F1 cohort (children of atomic bomb survivors)
Study Website: Web Site Policy

The main cohort, called the Life Span Study (LSS), consisted of about 120,000 persons of all ages and both genders in 1950 of whom more than 90,000 were exposed to atomic bomb radiation, with a wide range of exposure doses. About 45,000 LSS participants completed questionnaires in the late 1960s and periodically since then on sociodemographic, lifestyle, and other disease risk factors.

Mortality and cancer incidence follow-up of the LSS cohort is continuing, and about 40 percent of participants are still alive.  The numerous published resultsExternal Web Site Policy have included papers on cancer incidence in relation to radiation and other risk factors, histopathologic studies of various cancer sites, factors that serve as effect-modifiers, and molecular studies of selected cancers.

A clinical subsample, the Adult Health Study (AHS), of about 17,000 participants was established in 1958 and has received biennial clinical examinations since that time. Extensive clinical data, along with sociodemographic, lifestyle, and medical history information, are available on AHS participants, and biological samples were stored beginning in 1969. The AHS data permit studies on pre-clinical conditions, disease biomarkers, and non-cancerous diseases.

In 2001, a study was initiated to clinically examine about 12,000 children of the atomic bomb survivors, and preparations are currently under way for a longitudinal study of this cohort.

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