title: Exposure levels, determinants and IgE mediated sensitization to bovine allergens among Danish farmers and non-farmers.
abstract: BACKGROUND
  Bovine allergens can induce allergic airway diseases. High levels of allergens in dust from stables and homes of dairy farmers have been reported, but sparse knowledge about determinants for bovine allergen levels and associations between exposure level and sensitization is available.
  
  
  OBJECTIVE
  To investigate levels and determinants of bovine allergen exposure among dairy, pig and mink farmers (bedroom and stable), and among former and never farmers (bedroom), and to assess the prevalence of bovine allergen sensitization in these groups.
  
  
  METHODS
  In 2007-2008, 410 settled dust samples were collected in stables and in bedrooms using an electrostatic dust-fall collector over a 14 day period among 54 pig farmers, 27 dairy farmers, 3 mink farmers as well as 71 former and 48 never farmers in Denmark. For farmers sampling was carried out both during summer and winter. Bovine allergen levels (μg/m(2)) were measured using a sandwich ELISA. Determinants for bovine allergen exposure in stables and bedrooms were explored with mixed effect regression analyses. Skin prick test with bovine allergen was performed on 48 pig farmers, 20 dairy farmers, 54 former and 31 never farmers.
  
  
  RESULTS
  Bovine allergen levels varied by five orders of magnitude, as expected with substantially higher levels in stables than bedrooms, especially for dairy farmers. Bovine allergen levels in bedrooms were more than one order of magnitude higher for dairy farmers compared to pig farmers. Former and never farmers had low levels of bovine allergens in their bedroom. Bovine allergen levels during summer appeared to be somewhat higher than during winter. Increased bovine allergen levels in the bedroom were associated with being a farmer or living on a farm. Mechanical ventilation in the bedroom decreased bovine allergen level, significant for dairy farmers β=-1.4, p<0.04. No other significant effects of either sampling or residence characteristics were seen. Allergen levels in dairy stables were associated to type of dairy stable, but not to other stable or sampling characteristics. Sensitization to bovine allergens was only found in one pig farmer.
  
  
  CONCLUSIONS
  This study confirms high bovine allergen levels in dairy farms, but also suggests sensitization to bovine allergens among Danish farmers to be uncommon. Furthermore the importance of a carrier home effect on allergen load is emphasized. Whether the risk for bovine sensitization is related to the allergen level in the stable or the dwelling remains to be determined.
authors.affiliation: Department of Public Health, Section for Environment, Occupation and Health, Danish Ramazzini Centre, Aarhus University, Aarhus, Denmark; Department of Occupational Medicine, Danish Ramazzini Centre, Aarhus University Hospital, Aarhus, Denmark. Electronic address: vs@ph.au.dk.
authors.forename: V
authors.initials: V
authors.lastname: Schlünssen
authors.affiliation: Department of Public Health, Section for Environment, Occupation and Health, Danish Ramazzini Centre, Aarhus University, Aarhus, Denmark.
authors.forename: I
authors.initials: I
authors.lastname: Basinas
authors.affiliation: Institute of Prevention and Occupational Medicine of the German Social Accident Insurance (IPA), Institute of the Ruhr-University Bochum, Bochum, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Zahradnik
authors.affiliation: Department of Public Health, Section for Environment, Occupation and Health, Danish Ramazzini Centre, Aarhus University, Aarhus, Denmark.
authors.forename: G
authors.initials: G
authors.lastname: Elholm
authors.affiliation: Institute for Risk Assessment Science, Utrecht University, Utrecht, The Netherlands.
authors.forename: I M
authors.initials: IM
authors.lastname: Wouters
authors.affiliation: Institute for Risk Assessment Science, Utrecht University, Utrecht, The Netherlands.
authors.forename: H
authors.initials: H
authors.lastname: Kromhout
authors.affiliation: Institute for Risk Assessment Science, Utrecht University, Utrecht, The Netherlands.
authors.forename: D
authors.initials: D
authors.lastname: Heederik
authors.affiliation: Department of Public Health, Section for Environment, Occupation and Health, Danish Ramazzini Centre, Aarhus University, Aarhus, Denmark.
authors.forename: A C S
authors.initials: AC
authors.lastname: Bolund
authors.affiliation: Department of Occupational Medicine, Danish Ramazzini Centre, Aalborg University Hospital, Aalborg, Denmark.
authors.forename: Ø
authors.initials: Ø
authors.lastname: Omland
authors.affiliation: Institute of Prevention and Occupational Medicine of the German Social Accident Insurance (IPA), Institute of the Ruhr-University Bochum, Bochum, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Raulf
authors.affiliation: Department of Public Health, Section for Environment, Occupation and Health, Danish Ramazzini Centre, Aarhus University, Aarhus, Denmark.
authors.forename: T
authors.initials: T
authors.lastname: Sigsgaard
mesh_terms: D000485:Allergens / Q000032:analysis* / Q000276:immunology; D000822:Animal Husbandry; D000818:Animals; D002417:Cattle; D003718:Denmark / Q000453:epidemiology; D004391:Dust / Q000032:analysis / Q000276:immunology; D004781:Environmental Exposure / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay; D006798:Housing; D006799:Housing, Animal; D006801:Humans; D006967:Hypersensitivity / Q000453:epidemiology / Q000276:immunology*; D007073:Immunoglobulin E / Q000276:immunology*; D008297:Male; D008907:Mink; D016273:Occupational Exposure / Q000032:analysis*; D015995:Prevalence; D012424:Rural Population; D013552:Swine
chemical_list: D000485:Allergens; D004391:Dust; D007073:Immunoglobulin E
keywords: Bovine allergens; Bovine sensitization; Cow stables; Exposure assessment; Exposure determinants; Farming