Meta-analysisindependent cross-checkabstract only checked I-DRY-07 standard review
Milk linked to slightly more Parkinson's, yogurt not
Dairy foods intake and risk of Parkinson's disease: a dose-response meta-analysis of prospective cohort studies.
Overview
Jiang W et al.. Eur J Epidemiol 2014 · PMID 24894826 · DOI 10.1007/s10654-014-9921-4
Absolute risk: 2-4 extra cases per 100,000 person-years per 200 g milk a day.
Does the study support the specific claim? Partly · Methodological quality: moderate
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Dairy and PD.
- How was the study done?
Meta-analysis.
- How many people, animals or samples were studied?
304,193 people.
- What was actually found?
Milk associated; yogurt not.
- How large was the observed effect?
RR 1.17 per 200 g/d milk.
- What do the results mean in everyday life?
Tiny absolute risk.
- What are the study's limitations?
Few studies.
- What does it say about Elawady's specific claim?
Supports weak link.
- 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
- Jiang W et al.
- Journal
- Eur J Epidemiol
- Year
- 2014
- Identifier
- PMID 24894826 DOI 10.1007/s10654-014-9921-4
- Verification
- verified – PubMed efetch 2026-10-25
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
not stated in abstract
2. Research question
Dairy intake and Parkinson's disease.
3. Study design and population
- Study design
- Meta-analysis – Dose-response meta-analysis of prospective cohorts.
- Population
304,193 subjects; 1,083 PD cases
- Country
Multinational
- Period
Search to April 2014
- Sample size
7 results
- Inclusion and exclusion criteria
Prospective cohorts.
4. Methods and endpoints
- Exposure / intervention
Dairy, milk, cheese, yogurt, butter
- Comparator
Lowest intake; dose
- Endpoints
PD.
- Statistical methods
Dose-response meta-analysis.
5. Actual results
- Results
Dairy RR 1.40 (1.20-1.63); men 1.66, women 1.15 (NS); milk 1.45 (1.23-1.73), cheese 1.26 (0.99-1.60), yogurt 0.95 (0.76-1.20), butter 0.76 (0.51-1.13); per 200 g/d milk 1.17 (1.06-1.30).
- Absolute risks
2-4 additional PD cases per 100,000 person-years per 200 g/day milk; 1-3 per 10 g/day cheese.
- Authors' conclusion
Dairy (milk, cheese) might be positively associated with PD, especially in men.
6. Strengths
- Dose-response; absolute risk reported
7. Weaknesses
- Few studies
- Observational
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
Small evidence base.
9. Assessment of the statistical interpretation
Moderate relative, very small absolute risk.
10. Relevance to the specific claim
Supporting C-DRY-09; contradicts the yogurt ban (C-DRY-11).
11. Independent contrary findings
Small absolute risk.
12. Transferability to Germany and Europe
Moderate.
13. Overall methodological judgement
Weak consistent association.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | moderate |
| 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) | not applicable |
14. Open questions
Mechanism.
15. Linked fact checks
- Milk intake, especially low-fat milk, increases the risk of Parkinson's disease (2.3-fold in the Honolulu study). – 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