title: Ambient Air Pollution-related Mortality in Dairy Cattle: Does It Corroborate Human Findings?
abstract: Despite insights for humans, short-term associations of air pollution with mortality to our knowledge have never been studied in animals. We investigated the association between ambient air pollution and risk of mortality in dairy cows and assessed effect modification by season.
  
  
  
  We collected ozone (O3), particulate matter (PM10), and nitrogen dioxide (NO2) concentrations at the municipality level for 87,108 dairy cow deaths in Belgium from 2006 to 2009. We combined a case-crossover design with time-varying distributed lag models.
  
  
  
  We found acute and delayed associations between air pollution and dairy cattle mortality during the warm season. The increase in mortality for a 10 μg/m increase in 2-day (lag 0-1) O3 was 1.2% (95% confidence interval [CI] = 0.3%, 2.1%), and the corresponding estimates for a 10 μg/m increase in same-day (lag 0) PM10 and NO2 were 1.6% (95% CI = 0.0%, 3.1%) and 9.2% (95% CI = 6.3%, 12%), respectively. Compared with the acute increases, the cumulative 26-day (lag 0-25) estimates were considerably larger for O3 (3.0%; 95% CI = 0.2%, 6.0%) and PM10 (3.2%; 95% CI = -0.6%, 7.2%), but not for NO2 (1.4%; 95% CI = -4.9%, 8.2%). In the cold season, we only observed increased mortality risks associated with same-day (lag 0) exposure to NO2 (1.4%; 95% CI = -0.1%, 3.1%) and with 26-day (lag 0-25) exposure to O3 (4.6%; 95% CI = 2.2%, 7.0%).
  
  
  
  Our study adds to the epidemiologic findings in humans and reinforces the evidence on the plausibility of causal effects. Furthermore, our results indicate that air pollution associations go beyond short-term mortality displacement. (See video abstract at http://links.lww.com/EDE/B105.).
authors.affiliation: From the aCentre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium; bDepartment of Social and Environmental Health Research, cDepartment of Medical Statistics, London School of Hygiene & Tropical Medicine (LSHTM), London, United Kingdom; dPublic Health and Surveillance, Scientific Institute of Public Health (WIV-ISP), Brussels, Belgium; eBelgian Interregional Environment Agency, Brussels, Belgium; and fDepartment of Public Health and Primary Care, Leuven University, Leuven, Belgium.
authors.forename: Bianca
authors.initials: B
authors.lastname: Cox
authors.forename: Antonio
authors.initials: A
authors.lastname: Gasparrini
authors.forename: Boudewijn
authors.initials: B
authors.lastname: Catry
authors.forename: Frans
authors.initials: F
authors.lastname: Fierens
authors.forename: Jaco
authors.initials: J
authors.lastname: Vangronsveld
authors.forename: Tim S
authors.initials: TS
authors.lastname: Nawrot
mesh_terms: D000393:Air Pollutants / Q000032:analysis / Q000633:toxicity*; D000397:Air Pollution / Q000009:adverse effects* / Q000032:analysis / Q000706:statistics & numerical data; D000818:Animals; D001530:Belgium / Q000453:epidemiology; D002417:Cattle; D018592:Cross-Over Studies; D003612:Dairying; D004781:Environmental Exposure / Q000009:adverse effects* / Q000032:analysis / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008962:Models, Theoretical; D009026:Mortality; D009585:Nitrogen Dioxide / Q000032:analysis / Q000633:toxicity; D010126:Ozone / Q000032:analysis / Q000633:toxicity; D052638:Particulate Matter / Q000032:analysis / Q000633:toxicity; D012621:Seasons; D013997:Time Factors
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D010126:Ozone; D009585:Nitrogen Dioxide