Case-control studyindependent cross-checkabstract checked I-CAN-124 standard review
Smoking and bladder cancer in Alexandria
Epidemiology of bladder cancer in Alexandria, Egypt: tobacco smoking.
Overview
Bedwani R et al.. Int J Cancer 1997 · PMID 9334811 · DOI 10.1002/(sici)1097-0215(19970926)73:1<64::aid-ijc11>3.0.co;2-5
Egyptian men who smoked had 4-7 times the odds of bladder cancer; risk fell after quitting.
Does the study support the specific claim? No · Methodological quality: moderate
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Smoking and bladder cancer in Egypt.
- How was the study done?
Case-control.
- How many people, animals or samples were studied?
151 cases, 157 controls.
- What was actually found?
Strong dose-related risk.
- How large was the observed effect?
OR 6.6 current smokers.
- What do the results mean in everyday life?
Smoking causes cancer in Egypt too.
- What are the study's limitations?
Small, older.
- What does it say about Elawady's specific claim?
Contradicts the claim.
- Do the results apply to Germany and Europe?
Regional.
- What can explicitly not be concluded from this study?
Current prevalence.
Scientific in-depth review
1. Full reference
- Authors
- Bedwani R et al.
- Journal
- Int J Cancer
- Year
- 1997
- Identifier
- PMID 9334811 DOI 10.1002/(sici)1097-0215(19970926)73:1<64::aid-ijc11>3.0.co;2-5
- Verification
- verified – PubMed efetch 2026-10-26 + Crossref
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
not stated in abstract
2. Research question
Tobacco smoking and bladder cancer in Egyptian men
3. Study design and population
- Study design
- Case-control study – Hospital-based case-control study
- Population
Men in Alexandria, Egypt
- Country
Egypt
- Period
1994-1996
- Sample size
151 cases, 157 controls
- Inclusion and exclusion criteria
Incident histologically confirmed invasive bladder cancer; hospital controls with non-smoking-related conditions
4. Methods and endpoints
- Exposure / intervention
Cigarette smoking (also waterpipe, hashish)
- Comparator
Never smokers
- Endpoints
Bladder cancer
- Statistical methods
Multivariate logistic regression
5. Actual results
- Results
Ex-smokers OR 4.4 (1.7-11.7); current smokers 6.6 (3.1-13.9); >40 years of smoking OR 16.5; risk fell with time since quitting. Smoking plus schistosomiasis history OR 9.4. Cigarette smoking could explain 75% of male bladder cancer cases in Alexandria.
- Absolute risks
Attributable fraction 75% (male cases)
- Authors' conclusion
Strong association of cigarette smoking with bladder cancer in Egyptian men.
6. Strengths
- Egyptian population
- Dose-response and quitting gradient
7. Weaknesses
- Small
- Hospital controls
- Older study
8. Risk of bias
- Orienting tool
- ROBINS-E
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- some concerns
- Rationale
Case-control recall and selection bias.
9. Assessment of the statistical interpretation
OR CIs log-symmetric (recalculated); wide intervals.
10. Relevance to the specific claim
Egypt-specific evidence that smoking causes cancer, with dose-response and benefit of quitting.
11. Independent contrary findings
12. Transferability to Germany and Europe
Regional evidence consistent with global data.
13. Overall methodological judgement
Regional confirmation of smoking as a cause of cancer.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | moderate |
| Risk of bias | some concerns |
| Precision of results | low |
| Directness | direct |
| Reproducibility | replicated |
| Consistency with the overall evidence | consistent |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Recent Egyptian data.
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