Researchers in the Netherlands found that exposure to livestock farms alone carries little risk for developing inflammatory bowel disease (IBD).
Their findings suggest that residents in livestock-dense areas may be protected from developing IBD. Poultry farms, however, are a potential risk for infection, but only for neighboring residents.
The study, “Healthcare utilization prior to the diagnosis of inflammatory bowel diseases and the influence of livestock exposure: A longitudinal case-control study,” was published in the journal Plos One.
After an increased prevalence of IBD was observed in residents of an area rich in farms and livestock, several studies were conducted that seemed to support the hypothesis that residents in livestock-dense areas may be more prone to IBD.
In the new study, researchers aimed to investigate whether exposure to livestock contributed to the development of these diseases, along with looking at IBD patients’ visits to a doctor and prescriptions filled before their diagnosis.
Investigators used electronic health records from 2006–2013 of general practitioners in the Netherlands. The study consisted of patients with a new diagnosis of IBD who lived in areas with a high density of livestock (141 patients) and low livestock density (109 patients). Controls in the study included people with low back pain (10,469 patients).
Researchers analyzed the link between disease and drug prescriptions in the reporting year and in the three years before an IBD diagnosis, as well as the participants’ residential proximity to livestock.
Areas with a high density of livestock farms, called the exposed area, were compared with land with a lower density of livestock farms, called the reference area.
The analysis indicated that problems in the gastrointestinal tract associated with the development of IBD were not linked to the area of residency.
Residents with infections of the GI tract living in the reference area (low density of livestock) showed a significantly higher risk for developing IBD compared to those living in the exposed area (high livestock density).
This association was only found in those living within 500 meters of poultry farms. In general, exposure to livestock, as an environmental factor, contributed little to the development of IBD, according to the study.
“These results support the hypothesis that residents in livestock-dense areas generally are protected from the development of inflammatory diseases,” researchers wrote.
The use of prescription drugs, especially antidiarrheal and intestinal anti-inflammatory and anti-infective agents, in the reporting year and the three years before a patient’s diagnosis, were associated with the development of IBD in both reference and exposed areas.
This study “suggests that exposure to livestock farms on its own contributes minimally to the development of inflammatory bowel diseases. Nonetheless, having infections appeared to be a risk factor for neighboring residents of poultry farms,” researchers wrote.
Additional research is needed to explain the increased prevalence of IBD in residents of areas with a high density of livestock, the study concluded.