Narrative reviewindependent cross-checkabstract checked I-SRC-126 standard review
Diseases that seem less common in smokers
What Is the Real Impact of Smoking on Diseases Alleged to Benefit from It?
Overview
Yılmaz M et al.. Eur Addict Res 2025 · PMID 41129423 · DOI 10.1159/000549064
A few conditions such as ulcerative colitis and Parkinson's disease are less common in smokers, but this does not outweigh the harms of smoking.
Does the study support the specific claim? Partly · Methodological quality: low
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Review claimed benefits of smoking
- How was the study done?
Narrative review
- How many people, animals or samples were studied?
8 conditions
- What was actually found?
Some inverse associations, often confounded
- How large was the observed effect?
not applicable
- What do the results mean in everyday life?
No reason to smoke
- What are the study's limitations?
Narrative
- What does it say about Elawady's specific claim?
Only a tiny kernel; claim remains false
- Do the results apply to Germany and Europe?
High
- What can explicitly not be concluded from this study?
Causality of inverse associations
Scientific in-depth review
1. Full reference
- Authors
- Yılmaz M et al.
- Journal
- Eur Addict Res
- Year
- 2025
- Identifier
- PMID 41129423 DOI 10.1159/000549064
- Verification
- verified – PubMed efetch 2026-10-26; Crossref works record checked
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
No conflicts declared.
2. Research question
What is the real impact of smoking on diseases it is alleged to protect against?
3. Study design and population
- Study design
- Narrative review – Narrative review
- Population
Studies on 8 conditions
- Country
International
- Period
Published 2025
- Sample size
not applicable
- Inclusion and exclusion criteria
not stated
4. Methods and endpoints
- Exposure / intervention
Smoking/nicotine
- Comparator
Non-smokers
- Endpoints
Endometrial cancer, rheumatoid arthritis, ulcerative colitis, Parkinson's disease, uterine leiomyoma, pre-eclampsia, COVID-19, stress
- Statistical methods
Narrative
5. Actual results
- Results
Observational data suggest inverse associations for some conditions (e.g. ulcerative colitis, Parkinson's disease), but effects are often modest, mechanistically unclear and confounded; randomised evidence is scarce.
- Absolute risks
not applicable
- Authors' conclusion
Potential 'protective' effects of smoking do not outweigh its well-established detrimental consequences; cessation remains paramount.
6. Strengths
- Directly addresses the 'smoking benefit' argument
7. Weaknesses
- Narrative review, not systematic
8. Risk of bias
- Orienting tool
- none applicable
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- high
- Rationale
Narrative selection.
9. Assessment of the statistical interpretation
No quantitative synthesis.
10. Relevance to the specific claim
Fair acknowledgement: smoking is inversely associated with a few diseases (e.g. ulcerative colitis, Parkinson's disease). This is the only factual kernel that could be read as 'beneficial', and it does not offset the harms.
11. Independent contrary findings
I-SRC-113, I-INTB-21, I-CAN-01.
12. Transferability to Germany and Europe
Applicable.
13. Overall methodological judgement
Supports a fair, limited acknowledgement.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | low |
| Risk of bias | high |
| Precision of results | not applicable |
| Directness | direct |
| Reproducibility | unknown |
| Consistency with the overall evidence | consistent |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Role of nicotine apart from smoke.