Case-control studycited by the Tayebat archiveabstract only checked A-ABX-17 standard review
Antibiotics and breast cancer
Antibiotic use in relation to the risk of breast cancer.
Overview
Velicer CM et al.. JAMA 2004 · PMID 14970061 · DOI 10.1001/jama.291.7.827
More antibiotic use was linked to breast cancer, but cause and effect could not be determined.
Does the study support the specific claim? Unclear · Methodological quality: low
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Link.
- How was the study done?
Case-control.
- How many people, animals or samples were studied?
2266 cases.
- What was actually found?
Association.
- How large was the observed effect?
OR up to 2.14.
- What do the results mean in everyday life?
Not proof.
- What are the study's limitations?
Poor adjustment.
- What does it say about Elawady's specific claim?
Unclear.
- Do the results apply to Germany and Europe?
Moderate.
- What can explicitly not be concluded from this study?
Causation.
Scientific in-depth review
1. Full reference
- Authors
- Velicer CM, Heckbert SR, Lampe JW, Potter JD, Robertson CA, Taplin SH
- Journal
- JAMA
- Year
- 2004
- Identifier
- PMID 14970061 DOI 10.1001/jama.291.7.827
- Verification
- verified – PubMed E-utilities efetch, 2026-10-25
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
not stated in abstract/record (grants: NCI NIH HHS)
2. Research question
Antibiotic use and breast cancer
3. Study design and population
- Study design
- Case-control study – Case-control (health plan pharmacy records)
- Population
Women >19 y
- Country
USA
- Period
1993-2001
- Sample size
2266 cases; 7953 controls
4. Methods and endpoints
- Exposure / intervention
Cumulative days of antibiotics
- Comparator
None
- Endpoints
Incident/fatal breast cancer
- Statistical methods
OR adjusted for age, enrolment
5. Actual results
- Results
ORs 1.45 to 2.14 across increasing use categories; P trend <.001.
- Absolute risks
not reported
- Authors' conclusion
'It cannot be determined from this study whether antibiotic use is causally related to breast cancer'.
6. Strengths
- Pharmacy records
7. Weaknesses
- Minimal adjustment
- Confounding by indication
8. Risk of bias
- Orienting tool
- ROBINS-E
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- high
- Rationale
Adjusted only for age and enrolment.
9. Assessment of the statistical interpretation
10. Relevance to the specific claim
11. Independent contrary findings
12. Transferability to Germany and Europe
Moderate.
13. Overall methodological judgement
Weak evidence.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | low |
| Risk of bias | high |
| Precision of results | moderate |
| Directness | direct |
| Reproducibility | not replicated |
| Consistency with the overall evidence | unknown |
| Regional transferability | moderate |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Replication.
15. Linked fact checks
- Antibiotic use is associated with breast cancer (archive bibliography). – Studies with mixed or unclear results
Use by the Tayebat archive
Note: according to the archive, the studies were compiled by the archive operators. Whether Dr. Elawady himself cited this study is not established.
- What the archive says about the study
Bibliography only.
- A. What was actually studied?
Breast cancer.
- B. What did the authors find?
Association.
- C. What conclusions do the authors themselves draw?
Causality undetermined.
- D. What does the archive derive from it?
Implied harm.
- E. Is this derivation scientifically justified?
Not discussed; causality explicitly undetermined by authors.
- Adequacy of the interpretation (by the archive)
- not applicable