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Life Span Study Report 13 |
Technical Report No. 24-02
Studies of mortality of atomic bomb survivors. Report
13: Solid cancer and noncancer disease mortality: 1950-1997
Preston DL, Shimizu Y, Pierce DA, Suyama A, Mabuchi K
Radiat Res 160(4):381-407, 2003 |
Summary
This continues the series of general reports on mortality
in the cohort of atomic bomb survivors followed up by the
Radiation Effects Research Foundation. This cohort includes
86,572 people with individual dose estimates, 60% of whom
have doses of at least 5 mSv. We consider mortality for solid
cancer and for noncancer diseases with 7 additional years
of follow-up. There have been 9,335 deaths from solid cancer
and 31,881 deaths from noncancer diseases during the 47-year
follow-up. Of these, 19% of the solid cancer and 15% of the
noncancer deaths occurred during the latest 7 years. We estimate
that about 440 (5%) of the solid cancer deaths and 250 (0.8%)
of the noncancer deaths were associated with the radiation
exposure. The excess solid cancer risks appear to be linear
in dose even for doses in the 0 to 150-mSv range. While excess
rates for radiation-related cancers increase throughout the
study period, a new finding is that relative risks decline
with increasing attained age, as well as being highest for
those exposed as children as noted previously. A useful representative
value is that for those exposed at age 30 the solid cancer
risk is elevated by 47% per sievert at age 70. There is no
significant city difference in either the relative or absolute
excess solid cancer risk. Site-specific analyses highlight
the difficulties, and need for caution, in distinguishing
between site-specific relative risks. These analyses also
provide insight into the difficulties in interpretation and
generalization of LSS estimates of age-at-exposure effects.
The evidence for radiation effects on noncancer mortality
remains strong, with risks elevated by about 14% per sievert
during the last 30 years of follow-up. Statistically significant
increases are seen for heart disease, stroke, digestive diseases,
and respiratory diseases. The noncancer data are consistent
with some non-linearity in the dose response owing to the
substantial uncertainties in the data. There is no direct
evidence of radiation effects for doses less than about 0.5
Sv. While there are no statistically significant variations
in noncancer relative risks with age, age at exposure, or
sex, the estimated effects are comparable to those seen for
cancer. Lifetime risk summaries are used to examine uncertainties
of the LSS noncancer disease findings. |
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