title: Exposure-response relations among laboratory animal workers exposed to rats.
abstract: OBJECTIVE
  To explore exposure-response relations in a cohort of laboratory animal workers.
  
  
  METHODS
  Exposure-response modelling was carried out in a cohort of 342 laboratory animal workers. Three exposure indices, divided into different exposure categories, were used in the analyses: intensity of exposure to rat urinary aeroallergen (RUA, the main allergen workers were exposed to), weekly duration of exposure to rats, and the product of the intensity and weekly duration of exposure. Outcomes studied were work related chest, eyes and nose, and skin symptoms that had started after employment at the sites, specific sensitisation, and a combination of symptoms and sensitisation. Cox proportional hazard modelling was used to explore exposure-response relations. Smoking, atopic status, age, and gender were taken into account.
  
  
  RESULTS
  We observed the clearest exposure-response relations for the intensity of exposure to RUA and the various endpoints. No clear exposure-response relations were observed for the weekly duration of exposure or the product of the intensity and weekly duration of exposure. The strongest and clearest exposure-response relations for symptoms were observed among rat sensitised workers, while the non-sensitised workers only showed small increased risks of developing symptoms without clear exposure-response relations. Sensitised workers were almost four times more likely to go on to develop chest symptoms compared to non-sensitised workers.
authors.affiliation: Department of Environmental Science and Technology, Imperial College of Science, Technology and Medicine, Royal School of Mines, London SW7 2BP, UK. m.nieuwenhuijsen@ic.ac.uk
authors.forename: M J
authors.initials: MJ
authors.lastname: Nieuwenhuijsen
authors.forename: V
authors.initials: V
authors.lastname: Putcha
authors.forename: S
authors.initials: S
authors.lastname: Gordon
authors.forename: D
authors.initials: D
authors.lastname: Heederik
authors.forename: K M
authors.initials: KM
authors.lastname: Venables
authors.forename: P
authors.initials: P
authors.lastname: Cullinan
authors.forename: A J
authors.initials: AJ
authors.lastname: Newman-Taylor
mesh_terms: D000328:Adult; D000485:Allergens / Q000009:adverse effects*; D017750:Animal Technicians; D000818:Animals; D000830:Animals, Laboratory; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D017056:Medical Laboratory Personnel; D009784:Occupational Diseases / Q000209:etiology*; D016273:Occupational Exposure / Q000009:adverse effects*; D016016:Proportional Hazards Models; D051381:Rats; D012130:Respiratory Hypersensitivity / Q000209:etiology*; D012907:Smoking / Q000009:adverse effects; D014556:Urine
chemical_list: D000485:Allergens