Meta-analysiscited by the Tayebat archiveabstract checked★ key study A-DRY-02 in-depth review
Large review links more dairy with slightly more prostate cancer
Dairy products, calcium, and prostate cancer risk: a systematic review and meta-analysis of cohort studies.
Overview
Aune D et al.. Am J Clin Nutr 2015 · PMID 25527754 · DOI 10.3945/ajcn.113.067157
About 7% higher risk per 400 g dairy a day and 9% per 50 g cheese a day.
Does the study support the specific claim? Partly · Methodological quality: high
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Summarise cohort studies on dairy and prostate cancer.
- How was the study done?
Meta-analysis of 32 prospective studies.
- How many people, animals or samples were studied?
Men in many countries.
- What was actually found?
Small increases with dairy, milk, low-fat milk and cheese.
- How large was the observed effect?
RR 1.07 per 400 g/d total dairy; 1.09 per 50 g/d cheese.
- What do the results mean in everyday life?
A small relative risk increase; absolute risk not reported.
- What are the study's limitations?
Observational; screening bias possible.
- What does it say about Elawady's specific claim?
Supports a modest association; cheese not safer than milk.
- Do the results apply to Germany and Europe?
Includes European data.
- What can explicitly not be concluded from this study?
Causation; that cheese is safer than milk.
Scientific in-depth review
1. Full reference
- Authors
- Aune D, Navarro Rosenblatt DA, Chan DS, Vieira AR, Vieira R, Greenwood DC, Vatten LJ, Norat T
- Journal
- Am J Clin Nutr
- Year
- 2015
- Identifier
- PMID 25527754 DOI 10.3945/ajcn.113.067157
- Verification
- verified – PubMed E-utilities efetch, 2026-10-25
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
COI not stated in PubMed record; WCRF Continuous Update Project (funding details not in abstract).
2. Research question
Are dairy and calcium intakes associated with prostate cancer risk?
3. Study design and population
- Study design
- Meta-analysis – Systematic review and dose-response meta-analysis of prospective studies (WCRF Continuous Update Project).
- Population
Men in prospective cohorts.
- Country
Multinational
- Period
Search to April 2013
- Sample size
32 studies
- Inclusion and exclusion criteria
Prospective studies on dairy/calcium and prostate cancer.
4. Methods and endpoints
- Exposure / intervention
Total dairy, milk, low-fat milk, cheese, calcium sources.
- Comparator
Per dose increments
- Endpoints
Total, advanced, fatal prostate cancer.
- Statistical methods
Random-effects dose-response meta-analysis.
5. Actual results
- Results
Total dairy RR 1.07 (1.02-1.12; n=15) per 400 g/d; total milk 1.03 (1.00-1.07) per 200 g/d; low-fat milk 1.06 (1.01-1.11) per 200 g/d; cheese 1.09 (1.02-1.18; n=11) per 50 g/d; dietary calcium 1.05 (1.02-1.09) per 400 mg/d. Dairy calcium positive, non-dairy and supplemental calcium not; supplemental calcium associated with fatal prostate cancer.
- Absolute risks
not reported
- Authors' conclusion
High intakes of dairy products, milk, low-fat milk, cheese and dietary/dairy calcium may increase total prostate cancer risk; other components of dairy rather than fat and calcium may be involved.
6. Strengths
- Systematic, dose-response, prospective studies only
- Part of WCRF CUP with standardised methods
7. Weaknesses
- Small relative risks
- Possible detection bias (PSA screening)
- Heterogeneity and residual confounding
- Overlaps with other meta-analyses (not independent confirmations)
8. Risk of bias
- Orienting tool
- AMSTAR 2
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- some concerns
- Rationale
Methodologically solid review; primary studies observational.
9. Assessment of the statistical interpretation
Statistically significant but small RRs; clinical significance modest.
10. Relevance to the specific claim
Core evidence for C-DRY-04; contradicts C-DRY-11 because cheese is allowed.
11. Independent contrary findings
I-DRY-11 (inverse association with colorectal cancer).
12. Transferability to Germany and Europe
Includes European cohorts.
13. Overall methodological judgement
Good-quality meta-analysis showing small positive associations; cheese not exempt.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | high |
| Risk of bias | some concerns |
| Precision of results | moderate |
| Directness | direct |
| Reproducibility | partly replicated |
| Consistency with the overall evidence | consistent |
| Regional transferability | moderate |
| Adequacy of the interpretation (by the archive) | essentially correct but incomplete |
14. Open questions
Aggressive vs indolent disease; causal component.
15. Linked fact checks
- Dairy consumption increases prostate cancer risk (7% per 400 g/day; 34% for more than 2.5 servings/day). – Studies supporting the claim
- Fresh milk, yogurt (incl. laban rayeb, ayran, labneh) and white/cottage cheese are harmful and must be avoided, whereas aged cheeses (cheddar, mozzarella, romi), processed cheese triangles, cream (qeshta), butter and ghee are allowed. – Studies contradicting or limiting the claim
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
Each 400 g/day of dairy raised prostate cancer risk by 7%, with cheese and low-fat milk driving similar increases.
- A. What was actually studied?
Dose-response association of dairy types and calcium with prostate cancer.
- B. What did the authors find?
RR 1.07 per 400 g/d dairy; cheese 1.09 per 50 g/d; low-fat milk 1.06 per 200 g/d.
- C. What conclusions do the authors themselves draw?
May increase risk.
- D. What does the archive derive from it?
Uses it to show dairy causes prostate cancer and supports avoiding dairy.
- E. Is this derivation scientifically justified?
Figures correct; causal language ('raised') overstates; the archive mentions cheese but the system allows cheese - the study contradicts the system's own split.
- Adequacy of the interpretation (by the archive)
- essentially correct but incomplete