title: Longitudinal limits of normal decline in lung function in an individual.
abstract: OBJECTIVE
  The objectives of this study were to propose a method of calculating longitudinal limits of normal decline (LND) in forced expiratory volume in 1 second to identify individuals with an excessive decline in lung function and to compare the method with other published LND methods.
  
  
  METHODS
  We used longitudinal data from 11 workplace-based spirometric monitoring programs conducted from 1987 to 2001 on 12,729 workers to evaluate effectiveness of each LND method in identifying a "true" excessive decline in forced expiratory volume in 1 second defined using two criteria: slope >60 mL/year or >90 mL/year estimated over 5 or more years of follow up.
  
  
  RESULTS
  In comparison to the LND proposed by the American College of Occupational and Environmental Medicine, the proposed method had 5.0 to 2.7 times higher sensitivity over years 1 through 5 for the >60-mL/yr criterion.
  
  
  CONCLUSIONS
  The proposed LND method was more effective than the other methods for identifying excessive declines.
authors.affiliation: Division of Respiratory Disease Studies, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia 26505, USA. ehnizdo@cdc.gov
authors.forename: Eva
authors.initials: E
authors.lastname: Hnizdo
authors.forename: Kanta
authors.initials: K
authors.lastname: Sircar
authors.forename: Henry W
authors.initials: HW
authors.lastname: Glindmeyer
authors.forename: Edward L
authors.initials: EL
authors.lastname: Petsonk
mesh_terms: D000328:Adult; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008168:Lung / Q000502:physiology*; D008297:Male; D011237:Predictive Value of Tests; D012016:Reference Values; D012129:Respiratory Function Tests; D012680:Sensitivity and Specificity; D013147:Spirometry