Revised: June 10, 2013

Paper published by Radiation Research$Studies of the Mortality of Atomic Bomb Survivors, Report 14, 1950–2003: An
Overview of Cancer and Noncancer Diseases
Ozasa K, Shimizu Y, Suyama A, Kasagi F, Soda M, Grant EJ, Sakata R, Sugiyama H,Kodama K
Radiat Res 2012 (March); 177(3):229-43 (doi:10.1667/RR2629.1)[Findings of this study]
We followed the Life Span Study cohort during the period from 1950 through 2003 andelucidated effects of A-bomb radiation on mortality and causes of death using the DS02
dosimetry system. Excess relative risk (ERR) for all solid cancer mortality showed alinear dose-response relationship over the entire dose range, with no threshold observed,
with the lowest dose range with significant risk for all solid cancers 0 to 0.20 Gy. The
risk of all solid cancer mortality at the age of 70 years after exposure to 1 Gy at age 30
was 42% higher than that for unexposed individuals, increasing by about 29% per
decade decrease in age at exposure. With regard to site-specific cancers, significant
increase in cancer risk was observed for stomach, lung, liver, colon, breast, gallbladder,esophagus, bladder, and ovary, whereas rectum, pancreas, uterus, prostate, and kidneyparenchyma did not have significantly increased risk. Increased risks of non-cancer
diseases including those of the circulatory, respiratory and digestive systems wereobserved, but whether there was a causal relationship with radiation requires furtherinvestigation.
[Explanations]1) This report covers an additional six years of follow-up since the 13th LSS report
was published in 2003. This is the first time the DS02 dosimetry system has beenused for estimating individual dose and comprehensively analyzing radiation risk bycause of death. The subject population consisted of 86,611 directly exposed
A-bomb survivors with individual dose estimates available, from among the LSS
cohort of about 120,000 people. During the follow-up period, 50,620 people died,a number representing 58% of the original population, including 10,929 solid cancer
deaths.
2) ERR* at the age of 70 years after exposure at age 30 was 0.42/Gy (95% confidence
interval [CI]: 0.32, 0.53), while excess absolute risk** was 26.4 persons/Gy /10,000
person-year.

* In this paper, Excess relative risk (ERR) is equivalent to the value of relative risk minus one,indicating radiation exposure-related increase of relative risk. (Relative risk indicates how
many times risk increased with radiation exposure, compared to unexposed cases.)**In this paper, Excess absolute risk (EAR) is mortality in those exposed to radiation minus
mortality in unexposed individuals, indicating radiation exposure-related increase in absoluterisk.

3) Excess cancer deaths attributable to radiation exposure are estimated to account for
more than half of all solid cancer deaths in the dose range of 2 Gy or greater, withthe same being the case for about one-fourth in the range of 0.5 Gy-1 Gy and about
one-twentieth in the range of 0.1-0.2 Gy.
4) The linear dose-response relationship provided the best fit for the ERR data acrossthe entire dose range, but a concave curve was the best fit for data restricted to dose
< 2 Gy. This resulted because risk estimates for exposure to around 0.5 Gy werelower than those in the linear model.
The Radiation Effects Research Foundation has studied A-bomb survivors inHiroshima and Nagasaki for more than 60 years. RERF’s research achievements are
considered the principal scientific basis for assessment of radiation risk by the United
Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) andrecommendations regarding radiation protection standards by the International
Commission on Radiological Protection (ICRP).
$Radiation Research, the official monthly journal of the US Radiation Research Society,publishes original and review articles dealing with radiation effects and related subjects
in the areas of physics, chemistry, biology and medicine (impact factor in 2010: 2.578).
Figures 1, 2, and 4 were revised, based on the errata (Radiat Res 2013 (April);
179(4):e0040-41), on June 10, 2013.

Figure 1
Cause of death

AII causes
AII solid cancer
Cancers of Specific sitesab
ERR/Gy (95%CI ) Cause

0.22 (0.18, 0.26)

50,6200.47 (0.38, 0.56)

10,929cEsophagus

0.51 (0.11, 1.06)

339

Stomach0.28 (0.14, 0.42)

3,125

Colon0.54 (0.23,0.93)

621

Rectum0.17 (-0.17,0.64)

427

Liver

0.36 (0.18, 0.58)

1,519

Gallbladder0.45 (0.10, 0.90)

419

Pancreas0.08 (-0.18, 0.44)

513

Other digestive system

1.29 (0.14, 3.25)

84

Lung

0.63 (0.42, 0.88)

1,558

Breast1.60 (0.99, 2.37)

330

Uterus0.22 (-0.09, 0.64)

547

Ovary

0.79 (0.07, 1.86)

157

eProstate

0.33 (NA , 1.25)

130

Bladder

1.12 (0.33, 2.26)

183

Kidney parenchyma

0.52 (-0.15, 1.75)

80

Renal pelvis and ureter

2.62 (0.47,7.25)

33

Other solid cancer

0.47 (0.24, 0.76)

Lymphoid and hematopoietic malignancies

864
c, d

Iymphoma

0.16 (-0.13,0.59)

284

Multiple myeloma

0.54 (-0.04,1.58)

93

0.65 (0.26, 1.14)

518

Malignant

Other neoplasmscNon-neoplastic diseases and other causes
Blood diseases

1.70 (0.96, 2.70)

238

Circulatory diseases

0.11 (0.05, 0.17)

19,054

Respiratory diseases

0.21 (0.10, 0.33)

5,119

Digestive diseases

0.11 (-0.01, 0.24)

3,394

Genitourinary diseases

0.14 (-0.06, 0.38)

1,309

Infectious diseases-0.02 (-0.15, 0.13)

1,962

Other diseases

0.01 (-0.1, 0.12)

4,847

External causes-0.11 (-0.21, 0.02)

2,432

abcde

Excess relative risk (ERR) was estimated using the linear dose model, with adjustments made for city,sex, age at exposure, and attained age.
The horizontal lines show 95% confidence intervals.
The size of the plotted points is proportional to the number of deaths.
ERR of leukemia was 3.1 (95% CI: 1.8, 4.3) at 1 Gy and 0.15 (-0.01, 0.31) at 0.1 Gy based on alinear-quadratic model.
The lower limit of 95% CI was lower than zero, but a specific value could not be calculated.

Figure 3．Excess absolute risk (EAR)

Figure 2．Excess relative risk (ERR)
60

22050

EAR/10 person-years/Gy

Age at exposure: 10 years
1.5

G20
1

Age at exposure: 10 years
3040R/ER

430

30
0.5

40

20
1050

50

40
0030

4050

60

7080

30

40506070

80

Attained age

Attained age

Modification of radiation risk for all solid cancer mortality by age at exposure and attained age
ERR/Gy: excess relative risk at 1 Gy
EAR/104 person-year/Gy: excess absolute risk (number of increase for every 10,000 people) at 1 Gy
・ Risk increased with decrease in age at exposure.

(ERR increased by about 30% per decade decrease in

age at exposure.)・ Relative risk declined with increase in number of years after the atomic bombing (with increasing attained
age of subjects).

(ERR decreased by 10-15% per decade with increase in attained age.)・ On the other hand, since cancer mortality increased with aging of the subjects, excess cancer deaths(EAR) increased.

Solid cancer
LQ (<2Gy)
1.6

LQ

1.4

L

1.2
1.0
0.8

ERR

0.6
0.4
0.2
0.0
-0.2
0.0

0.5

1.0

1.5

2.0

2.5

3.0

Weighted Colon Dose (Gy)Figure 4. Dose-response relationships of excess relative risk (ERR) with all solid cancer mortality in relation
to radiation exposure.
The linear model (L) provided the best fit for ERR dose response across the entire dose range, with thelinear-quadratic model (LQ) for the data restricted to dose < 2 Gy. This resulted because risk estimates for
exposure to around 0.5 Gy were lower than those in the linear model. In the figure, the dots and verticalbars show point estimates of risk and 95% confidence intervals specific to each dose category.

The dottedlines represent 95% CI with the linear model (L), which provided the best fit over the entire dose range.