Cross-sectional studyindependent cross-checkfull text checked★ key study I-CHK-137 in-depth review
Living near poultry farms was not linked to pneumonia in a later Dutch study
Risk of pneumonia among residents living near goat and poultry farms during 2014-2016.
Overview
Post PM et al.. PLoS One 2019 · PMID 31609989 · DOI 10.1371/journal.pone.0223601
In 90,183 residents, living near poultry farms was not linked to pneumonia in 2014-2016; living near goat farms was.
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?
Is the earlier association between pneumonia and proximity to goat and poultry farms confirmed in 2014-2016?
- How was the study done?
Population-based study of GP electronic medical records with several regression and kernel models
- How many people, animals or samples were studied?
90,183 persons
- What was actually found?
Adults, single-level regression: poultry farm within 500 m OR 1.03 (0.92-1.16), within 1000 m OR 1.02 (0.95-1.10); goat farm within 500 m OR 1.60 (1.25-2.03). Kernel analysis: poultry farms 0.6% risk increase in 2014 only; goat farms PAR 6.0-7.8%. Authors: 'associations with proximity to poultry farms are not supported by the present study'. Limitations: no data on smoking or socioeconomic status; exposure by distance only. Funded by Dutch Ministries of Health and Agriculture.
- How large was the observed effect?
Adults, single-level regression: poultry farm within 500 m OR 1.03 (0.92-1.16), within 1000 m OR 1.02 (0.95-1.10); goat farm within 500 m OR 1.60 (1.25-2.03). Kernel analysis: poultry farms 0.6% risk increase in 2014 only; goat farms PAR 6.0-7.8%. Authors: 'associations with proximity to poultry farms are not supported by the present study'. Limitations: no data on smoking or socioeconomic status; exposure by distance only. Funded by Dutch Ministries of Health and Agriculture.
- What do the results mean in everyday life?
The pneumonia risk near poultry farms seen earlier was not confirmed.
- What are the study's limitations?
No individual confounder data (smoking, SES); Distance as exposure proxy
- What does it say about Elawady's specific claim?
Weakens the respiratory-risk part of the claim; does not affect avian influenza.
- Do the results apply to Germany and Europe?
Netherlands (EU).
- What can explicitly not be concluded from this study?
Cannot rule out small effects or effects near very large farms.
Scientific in-depth review
1. Full reference
- Authors
- Post PM et al.
- Journal
- PLoS One
- Year
- 2019
- Identifier
- PMID 31609989 DOI 10.1371/journal.pone.0223601
- Verification
- verified – PubMed efetch 2026-10-26; Crossref 2026-10-26
- Retracted
- no
- Corrections
- none
- Extent checked
- full text
- Conflicts of interest and funding
Funded by the Dutch Ministry of Health, Welfare and Sport and Ministry of Agriculture (full text)
2. Research question
Is the earlier association between pneumonia and proximity to goat and poultry farms confirmed in 2014-2016?
3. Study design and population
- Study design
- Cross-sectional study – Population-based study of GP electronic medical records with several regression and kernel models
- Population
Residents of a livestock-dense area (Noord-Brabant/Limburg), GP records
- Country
Netherlands
- Period
2014-2016
- Sample size
90,183 persons
- Inclusion and exclusion criteria
as described in the abstract
4. Methods and endpoints
- Exposure / intervention
Residence within 500-2000 m of goat or poultry farms
- Comparator
No farm within buffer
- Endpoints
GP-registered pneumonia
- Statistical methods
as reported in the abstract
5. Actual results
- Results
Adults, single-level regression: poultry farm within 500 m OR 1.03 (0.92-1.16), within 1000 m OR 1.02 (0.95-1.10); goat farm within 500 m OR 1.60 (1.25-2.03). Kernel analysis: poultry farms 0.6% risk increase in 2014 only; goat farms PAR 6.0-7.8%. Authors: 'associations with proximity to poultry farms are not supported by the present study'. Limitations: no data on smoking or socioeconomic status; exposure by distance only. Funded by Dutch Ministries of Health and Agriculture.
- Absolute risks
not reported
- Authors' conclusion
Association with goat farms confirmed; association with poultry farms not supported in 2014-2016.
6. Strengths
- Large population
- Several statistical approaches
- Designed as confirmation study
7. Weaknesses
- No individual confounder data (smoking, SES)
- Distance as exposure proxy
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
Ecological exposure; residual confounding.
9. Assessment of the statistical interpretation
Poultry ORs close to 1 with CIs excluding effects much above 10-16%; the earlier 11% increase (A-CHK-18) was not replicated.
10. Relevance to the specific claim
Direct replication test of the poultry-farm pneumonia association cited by the archive (A-CHK-18).
11. Independent contrary findings
12. Transferability to Germany and Europe
13. Overall methodological judgement
In 90,183 residents, living near poultry farms was not linked to pneumonia in 2014-2016; living near goat farms was.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | moderate |
| Risk of bias | some concerns |
| Precision of results | high |
| Directness | direct |
| Reproducibility | not replicated |
| Consistency with the overall evidence | inconsistent |
| Regional transferability | moderate |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
15. Linked fact checks
- Poultry production is a source of zoonotic avian influenza and respiratory risks for people (H7N9 from wet-market poultry; pneumonia near poultry farms). – Studies contradicting or limiting the claim