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Lung function more than a decade after World Trade Center (WTC) exposure: the influences of bronchial reactivity and corticosteroid therapy.
Aldrich-TK; Dhar-S; King-C; Crosse-T; Weakley-J; Christodoulou-V; Banauch-GI; Berger-KI; Weiden-MD; Hall-CB; Ye-F; Webber-MP; Prezant-DJ
Am J Respir Crit Care Med 2014 May; 189(Meeting Abstracts):A6495
Rationale: Inhalation of dust and toxins during rescue/recovery work at the WTC site led to an average 439ml decline in FEV1 for FDNY firefighters in the first post-9/11 year. Approximately 15% demonstrated new obstructive airways disease (OAD) and approximately 25% demonstrated bronchial hyperreactivity (BHR). This study assesses the subsequent (2002-2013) course of BHR and lung function among those with and without OAD, BHR, and corticosteroid treatment. Methods: From January to October 2013, 154 firefighters (72% never-smokers) with normal pre-9/11 spirometry, who had received methacholine challenge tests (MCT) within 2 years of 9/11/2001, underwent full lung function testing, including repeat MCT performed off respiratory medications. To adjust for aging, FEV1 was expressed as percent predicted (FEV1%). The difference between the 2013 FEV1% and the 1st post-9/11 FEV1% was used to describe lung function change subsequent to the initial post-9/11 decline. Results: Initially, post-9/11, 23 firefighters (15%) had BHR (PC20<8mg/ml); 6 of them (26%) were negative (PC20>16mg/ml) in 2013. Of 118 firefighters with initially negative MCTs, 17 (14%) were positive in 2013. 117 firefighters (76%) reported using inhaled and/or oral corticosteroids between 2001-2013. The initial pre-9/11 to post-9/11 FEV1% decline averaged 9.8 percentage points. Thereafter, FEV1% tended to decline further, averaging a 2.7 percentage point decrease over the subsequent 11 years. Excluding 2 firefighters with restrictive disease, a multiple regression model with dependent variable "subsequent" (2002-2013) change in FEV1%, showed significant negative contributions from initial change in FEV1% and smoking (p..005), and a positive contribution from approximate steroid dose (p=.03). Contribution of a composite index of BHR to the model approached statistical significance, with more reactive subjects tending to show decreasing FEV1% (p=.08). As shown in the figure, in firefighters without OAD (top two lines), the presence of BHR predicted greater decline in lung function between 2002-2013; in those with OAD (bottom two lines), the presence of BHR predicted absence of response to treatment (p<.04 for influence of OAD and of BHR on the 2002-2013 change in FEV1%, by 2-way ANOVA). Conclusion: Among WTC-exposed firefighters, new-onset OAD is often, but not always, accompanied by BHR, which may persist for a decade or longer. BHR is significantly associated with worsening lung function between 2002-2013, and helps to explain the persistence of OAD among many firefighters. Post-exposure corticosteroid treatment ameliorated some of the excess lung function decline. These findings suggest a substantial role of airway inflammatory disease in WTC-associated OAD.
Fire-fighters; Emergency-responders; Respiratory-system-disorders; Pulmonary-system-disorders; Lung-disorders; Pulmonary-function; Lung-function; Employee-exposure; Employee-health; Pulmonary-function-tests; Spirometry; Long-term-study; Vital-capacity; Particulate-dust; Dust-inhalation; Toxins; Airway-obstruction; Corticosteroids; Drug-therapy
S. Dhar, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, NY
American Journal of Respiratory and Critical Care Medicine
Albert Einstein College of Medicine, New York
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division