Summary
This review article summarizes the findings of 16 studies that assess multiple health risks of humans living near animal feeding operations (AFOs), described as “industrial” or “modern.” Evidence suggests an increased risk for Q fever in humans living near goat production during a Q fever outbreak (primarily in the Netherlands). Other associations (such as lower and upper respiratory tract infections, methicillin-resistant staphylococcus aureus, infectious diseases) could not be made with confidence and the risk for confounded results was high for most studies.
Some strengths of this article are the broad range of health hazards considered and the thorough assessment of risk of bias for the studies included. A limitation of this review is that due to the heterogeneity of studies and outcomes measured, a quantitative summary of outcomes is not possible. In conclusion, the authors highlight the heightened risk for Q fever of residents living near farmed-goat facilities during a Q fever outbreak, but highlight the need for further research to gain reliable data about long-term health effects associated with living near AFOs.
Objective
The objective of this review was to update a systematic review of associations between living near an animal feeding operation (AFO) and human health.
Methods
The MEDLINE® and MEDLINE® In-Process, Centre for Agricultural Biosciences Abstracts, and Science Citation Index databases were searched. Reference lists of included articles were hand-searched. Eligible studies reported exposure to an AFO and an individual-level human health outcome. Two reviewers performed study selection and data extraction.
Results
The search returned 3702 citations. Sixteen articles consisting of 10 study populations were included in the analysis. The health outcomes were lower and upper respiratory tracts, MRSA, other infectious disease, neurological, psychological, dermatological, otologic, ocular, gastrointestinal, stress and mood, and other non-infectious health outcomes. Most studies were observational and used prevalence measures of outcome. An association between Q fever risk and proximity to goat production was reported. Other associations were unclear. Risk of bias was serious or critical for most exposure-outcome associations. Multiplicity (i.e., a large number of potentially correlated outcomes and exposures assessed on the same study subjects) was common in the evidence base.
Conclusions
Few studies reported an association between surrogate clinical outcomes and AFO proximity for respiratory tract-related outcomes. There were no consistent dose-response relationships between surrogate clinical outcome and AFO proximity. A new finding was that Q fever in goats is likely associated with an increased Q fever risk in community members. The review results for the non-respiratory health outcomes were inconclusive because only a small number of studies were available or the between-study results were inconsistent.