title: Livestock-associated risk factors for pneumonia in an area of intensive animal farming in the Netherlands.
abstract: Previous research conducted in 2009 found a significant positive association between pneumonia in humans and living close to goat and poultry farms. However, as this result might have been affected by a large goat-related Q fever epidemic, the aim of the current study was to re-evaluate this association, now that the Q-fever epidemic had ended. In 2014/15, 2,494 adults (aged 20-72 years) living in a livestock-dense area in the Netherlands participated in a medical examination and completed a questionnaire on respiratory health, lifestyle and other items. We retrieved additional information for 2,426/2,494 (97%) participants from electronic medical records (EMR) from general practitioners. The outcome was self-reported, physician-diagnosed pneumonia or pneumonia recorded in the EMR in the previous three years. Livestock license data was used to determine exposure to livestock. We quantified associations between livestock exposures and pneumonia using odds ratios adjusted for participant characteristics and comorbidities (aOR). The three-year cumulative frequency of pneumonia was 186/2,426 (7.7%). Residents within 2,000m of a farm with at least 50 goats had an increased risk of pneumonia, which increased the closer they lived to the farm (2,000m aOR 1.9, 95% CI 1.4-2.6; 500m aOR 4.4, 95% CI 2.0-9.8). We found no significant associations between exposure to other farm animals and pneumonia. However, when conducting sensitivity analyses using pneumonia outcome based on EMR only, we found a weak but statistically significant association with presence of a poultry farm within 1,000m (aOR: 1.7, 95% CI 1.1-2.7). Living close to goat and poultry farms still constitute risk factors for pneumonia. Individuals with pneumonia were not more often seropositive for Coxiella burnetii, indicating that results are not explained by Q fever. We strongly recommend identification of pneumonia causes by the use of molecular diagnostics and investigating the role of non-infectious agents such as particulate matter or endotoxins.
authors.affiliation: Centre for Infectious Diseases, Epidemiology and Surveillance, Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands.|European Programme for Intervention Epidemiology Training (EPIET), European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden.
authors.forename: Gudrun S
authors.initials: GS
authors.lastname: Freidl
authors.affiliation: Centre for Infectious Diseases, Epidemiology and Surveillance, Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands.
authors.forename: Ineke T
authors.initials: IT
authors.lastname: Spruijt
authors.affiliation: Institute for Risk Assessment Sciences (IRAS), Division of Environmental Epidemiology, Utrecht University, Utrecht, the Netherlands.|Netherlands Institute for Health Services Research (NIVEL), Utrecht, Netherlands.
authors.forename: Floor
authors.initials: F
authors.lastname: Borlée
authors.affiliation: Institute for Risk Assessment Sciences (IRAS), Division of Environmental Epidemiology, Utrecht University, Utrecht, the Netherlands.
authors.forename: Lidwien A M
authors.initials: LA
authors.lastname: Smit
authors.affiliation: Centre for Infectious Diseases, Epidemiology and Surveillance, Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands.
authors.forename: Arianne B
authors.initials: AB
authors.lastname: van Gageldonk-Lafeber
authors.affiliation: Institute for Risk Assessment Sciences (IRAS), Division of Environmental Epidemiology, Utrecht University, Utrecht, the Netherlands.
authors.forename: Dick J J
authors.initials: DJ
authors.lastname: Heederik
authors.affiliation: Netherlands Institute for Health Services Research (NIVEL), Utrecht, Netherlands.
authors.forename: Joris
authors.initials: J
authors.lastname: Yzermans
authors.affiliation: Netherlands Institute for Health Services Research (NIVEL), Utrecht, Netherlands.
authors.forename: Christel E
authors.initials: CE
authors.lastname: van Dijk
authors.affiliation: Centre for Infectious Diseases, Epidemiology and Surveillance, Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands.
authors.forename: Catharina B M
authors.initials: CB
authors.lastname: Maassen
authors.affiliation: Centre for Infectious Diseases, Epidemiology and Surveillance, Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands.
authors.forename: Wim
authors.initials: W
authors.lastname: van der Hoek
mesh_terms: D000328:Adult; D000368:Aged; D000822:Animal Husbandry; D000818:Animals; D000829:Animals, Domestic; D016997:Coxiella burnetii / Q000472:pathogenicity; D057286:Electronic Health Records; D005260:Female; D006801:Humans; D058751:Livestock / Q000382:microbiology*; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D011014:Pneumonia / Q000453:epidemiology*; D011778:Q Fever / Q000453:epidemiology; D012307:Risk Factors; D055815:Young Adult