Patients with overlapping diagnoses of asthma and COPD : is livestock exposure a risk factor for comorbidity and coexisting symptoms and infections?

Background: Epidemiological research on health effects of livestock exposure in population subgroups with compromised respiratory health is still limited. The present study explored the association between livestock exposure and comorbid/concurrent conditions in patients with overlapping diagnoses of asthma and COPD. 

Methods: Electronic health record data from 23 general practices in the Netherlands were collected from 425 patients diagnosed with both asthma and COPD, living in rural areas with high livestock density (“study area”). Data of 341 patients with the same overlapping diagnoses, living in rural areas with lower livestock density (“control areas”) were obtained from 19 general practices. First, the prevalence of comorbid disorders and symptoms/ infections were compared between the study and control area. Second, the examined health outcomes were analyzed in relation to measures of individual livestock exposure. 

Results: Pneumonia was twice as common among patients living in areas with a high livestock density (OR 2.29, 99% CI 0.96–5.47); however, there were generally no statistically significant differences in the investigated outcomes between the study and control area. Significant associations were observed between presence of goats within 1000 m and allergic rhinitis (OR 5.71, 99% CI 1.11–29.3, p < 0.01), number of co-occurring symptoms (IRR 1.69, 99% CI 1.03–2.77, p < 0.01) and anxiety (OR 8.18, 99% 1.5–44.7, p < 0.01). Presence of cattle within 500 m was associated with pneumonia prevalence (OR 2.48, 99% CI 1.05–5.84, p < 0.01). 

Conclusion: Livestock exposure is not associated with comorbid chronic conditions but appears to be a risk factor for symptomatic effects in patients with overlapping diagnoses of asthma and COPD.