title: Factors affecting FEV1 in workers with potroom asthma after their removal from exposure.
abstract: OBJECTIVE
  In this study the relationship has been studied between exposure time and potential prognostic factors and FEV1 percent predicted (FEV1-% pred) in workers with potroom asthma, after their transfer from exposure to exposure-free departments.
  
  
  METHODS
  Between 1970 and 1990 in a Dutch aluminium-production plant, 179 workers had been diagnosed as having potroom asthma. We carried out a follow-up study (n = 122) in the population still present at the factory 5 years after their relocation to an exposure-free department. In this study population, we examined the relationship between FEV1-% pred at follow-up, and exposure time: the time interval between start of exposure and diagnosis. To correct for confounding factors, we included age, pre-employment FEV1-% pred, allergy, medical treatment, and smoking in the analysis.
  
  
  RESULTS
  The mean FEV1-% pred at follow-up was within the normal range (90.3, SD 13.5). Long exposure time was significantly associated with a low FEV1-% pred at follow-up (P = 0.0046). Adjustment was necessary for pre-employment FEV1-% pred and current smoking as confounding factors.
  
  
  CONCLUSIONS
  Long duration of exposure is a factor affecting FEV1 in workers with potroom asthma. The results of this study give support for additional preventive measures to be taken, such as early recognition of work-related respiratory complaints and repeated education.
authors.affiliation: Department of Allergology, University Hospital, Groningen, The Netherlands.
authors.forename: B
authors.initials: B
authors.lastname: Sorgdrager
authors.forename: A J
authors.initials: AJ
authors.lastname: de Looff
authors.forename: T M
authors.initials: TM
authors.lastname: Pal
authors.forename: F J
authors.initials: FJ
authors.lastname: van Dijk
authors.forename: J G
authors.initials: JG
authors.lastname: de Monchy
mesh_terms: D000535:Aluminum; D001249:Asthma / Q000209:etiology / Q000503:physiopathology*; D015986:Confounding Factors, Epidemiologic; D005541:Forced Expiratory Volume; D006801:Humans; D008669:Metallurgy; D009426:Netherlands; D009784:Occupational Diseases / Q000503:physiopathology*; D016273:Occupational Exposure / Q000009:adverse effects; D011379:Prognosis; D012907:Smoking
chemical_list: D000535:Aluminum