BACKGROUND: We examined the relationship between pulmonary function (FEV 1 ) and confirmed recovery from three lower-respiratory symptoms (LRSs) (cough, dyspnea, and wheeze) up to 9 years after symptom onset. METHODS: The study included white and black male World Trade Center (WTC)-exposed firefighters who reported at least one LRS on a medical monitoring examination during the first year after September 11, 2001. Confirmed recovery was defined as reporting no LRSs on two consecutive and all subsequent examinations. FEV 1 was assessed at the first post-September 11, 2001, examination and at each examination where symptom information was ascertained. We used stratified Cox regression models to analyze FEV 1 , WTC exposure, and other variables in relation to confirmed symptom recovery. RESULTS: A total of 4,368 firefighters met inclusion criteria and were symptomatic at year 1, of whom1,592 (36.4%) experienced confirmed recovery. In univariable models, first post-September 11,2001, concurrent, and difference between first post-September 11, 2001, and concurrent FEV 1 values were all significantly associated with confirmed recovery. In adjusted analyses, both first post-September 11, 2001, FEV 1 (hazard ratio [HR], 1.07 per 355-mL difference; 95% CI, 1.04-1.10) and FEV 1 % predicted (HR, 1.08 per 10% predicted difference; 95% CI, 1.04-1.12) predicted confirmed recovery. WTC exposure had an inverse association with confirmed recovery in the model with FEV 1 , with the earliest arrival group less likely to recover than the latest arrival group (HR, 0.73;95% CI, 0.58-0.92). CONCLUSIONS: Higher FEV 1 and improvement in FEV 1 after September 11, 2001, predicted confirmed LRS recovery, supporting a physiologic basis for recovery and highlighting consideration of spirometry as part of any postexposure respiratory health assessment.
Pulmonary-function; Pulmonary-function-tests; Respiratory-function-tests; Sound; Lung-function; Lung-irritants; Etiology; Physiopathology; Emergency-responders; Rescue-workers; Fire-fighters; Humans; Men; Lung-disease; Medical-monitoring; Medical-examinations; Spirometry; Environmental-exposure; Employee-exposure; Exposure-assessment
Mayris P. Webber, DrPH, MPH, New York City Fire Department, Bureau of Health Services, 9 Metrotech Center, Brooklyn, NY 11201