Cohort studyindependent cross-checkabstract checked★ key study I-CAN-123 in-depth review
Cancer in Hiroshima and Nagasaki survivors
Solid Cancer Incidence among the Life Span Study of Atomic Bomb Survivors: 1958-2009.
Overview
Grant EJ et al.. Radiat Res 2017 · PMID 28319463 · DOI 10.1667/RR14492.1
Radiation raised solid cancer risk even at doses of 0-100 mGy; most cancers in survivors were due to other causes.
Does the study support the specific claim? No · Methodological quality: high
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Radiation dose and cancer.
- How was the study done?
Cohort, 1958-2009.
- How many people, animals or samples were studied?
105,444 people.
- What was actually found?
Dose-related increase, also at low doses.
- How large was the observed effect?
ERR 0.64/Gy (women).
- What do the results mean in everyday life?
Not only massive exposures matter.
- What are the study's limitations?
Low-dose shape uncertain.
- What does it say about Elawady's specific claim?
Contradicts 'only Hiroshima-like exposures'.
- Do the results apply to Germany and Europe?
High.
- What can explicitly not be concluded from this study?
Smoking effects (adjusted, not studied).
Scientific in-depth review
1. Full reference
- Authors
- Grant EJ et al.
- Journal
- Radiat Res
- Year
- 2017
- Identifier
- PMID 28319463 DOI 10.1667/RR14492.1
- Verification
- verified – PubMed efetch 2026-10-26 + Crossref
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
NIH and other grants (PubMed)
2. Research question
Solid cancer incidence in relation to radiation dose, adjusted for smoking
3. Study design and population
- Study design
- Cohort study – Prospective cohort (Life Span Study of atomic bomb survivors)
- Population
Atomic bomb survivors and unexposed residents of Hiroshima and Nagasaki
- Country
Japan
- Period
Follow-up 1958-2009
- Sample size
105,444 subjects; 22,538 incident first primary solid cancers
- Inclusion and exclusion criteria
Alive and cancer-free at start of follow-up
4. Methods and endpoints
- Exposure / intervention
Weighted absorbed colon dose
- Comparator
Lower/zero dose
- Endpoints
Solid cancer incidence
- Statistical methods
Poisson regression; ERR and EAR models adjusted for smoking
5. Actual results
- Results
992 of 22,538 solid cancers associated with radiation exposure. Female ERR 0.64 per Gy (0.52-0.77); male linear-quadratic ERR 0.20 at 1 Gy; lowest dose range with significant sex-averaged linear dose response 0-100 mGy (P=0.038). Risks remain elevated >60 years after exposure.
- Absolute risks
992 radiation-associated cases (4.4% of solid cancers)
- Authors' conclusion
Solid cancer risks remain elevated >60 years after exposure; dose-response shape uncertain.
6. Strengths
- Large, long follow-up
- Individual dose estimates
- Smoking adjustment
7. Weaknesses
- Dose-response shape uncertain at low doses
8. Risk of bias
- Orienting tool
- ROBINS-E
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- low
- Rationale
High-quality cohort.
9. Assessment of the statistical interpretation
Radiation-associated share recalculated as 4.4%.
10. Relevance to the specific claim
Confirms Elawady's point that massive radiation causes cancer, but shows a dose response down to 0-100 mGy and that most cancers in survivors had other causes, including smoking (adjusted for).
11. Independent contrary findings
Supports the correct part of the claim (high-dose radiation causes cancer).
12. Transferability to Germany and Europe
High.
13. Overall methodological judgement
Refutes 'only massive exposures cause cancer'.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | high |
| Risk of bias | low |
| Precision of results | high |
| Directness | indirect |
| Reproducibility | replicated |
| Consistency with the overall evidence | consistent |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Exact low-dose shape.
15. Linked fact checks
- Smoking (and similar exposures) should not be blamed for cancer; only massive exposures such as Hiroshima cause cancer, and there is 'no such thing as early death' from smoking. – Studies contradicting or limiting the claim
- Cancer is the body's own plan ('a self plan'): body cells are ordered to transform because this was necessary for the person's life; it is not caused by external agents. – Studies contradicting or limiting the claim