Rationale: Spirometry is often performed annually to monitor lung health. Excessive FEV, loss in an individual is considered a useful indicator of the development of lung disease. Methods: Using medical monitoring data collected between 1973 and 2003 at a large chemical plant, longitudinal FEV, slopes (ml/yr) were calculated by simple linear regression for all workers (N = 1428) with > or = 5 valid measurements over > or = 10 years. Cases were defined by FEY, slopes below 5th percentile values (-65, -56 ml/yr for white and black males, and -50 ml/yr for white females). Cases (N=64) were matched with controls (N=94, FEV, slope range = -46 to 26 ml/yr) for race, gender, smoking status, year of birth, age, height, and calendar year of first test. Health information on medication use, respiratory symptoms and signs, and lung disease diagnoses was abstracted from existing plant medical records for the 4 years prior to the last spirometry. The significance of differences in frequencies of health outcomes was tested using matched paired chi square tests (McNemar's Test or Exact McNemar's Test). Results: Cases had a higher proportion of several respiratory health outcomes compared to controls, including medication use for respiratory diseases (24.3% vs. 4.7%, p<0.0001), diagnosis of COPD or emphysema (17.8% vs. 1.9%, p=0.0002), dyspnea (15% vs. 3.7%, p=0.0042), and wheezing or rhonchi on examination (10.3% vs. 1.9%, p=0.0225). Conclusions: This study expands the scientific basis for monitoring respiratory health using spirometry, by providing quantitative estimates of the increase in respiratory disorders (from 4 to 9 times) among individuals with accelerated FEY, declines.