Sputum cytokines and longitudinal decline in lung function in firefighters.
Josyula-AB; Kurzius-Spencer-M; Fleming-JL; Burgess-JL
Proc Am Thorac Soc 2005 May; 2(Abstracts):A813
Extensive variability in annual decline in lung function, not entirely explained by occupational exposures or smoking, has been observed in firefighters. Interleukin-8, -1 and tumor necrosis factor alpha (IL-8, IL-1, and TNF-a) are proinflammatory cytokines and IL-8 also is involved in recruitment of neutrophils into the lung. We hypothesize that elevated levels of these sputum cytokines are associated with a more rapid rate of decline in forced expiratory volume in 1 second (FEV1). Firefighters with at least five years of annual pulmonary function testing were included in this analysis. Medical records and questionnaires were used to collect medical histories. Induced sputum samples were collected from each participant and analyzed for IL-8, IL-1 and TNF-a by ELISA. In a preliminary analysis of 35 firefighters meeting the inclusion criteria and with complete data, the rate of decline in FEV1 averaged 0.030 +/- 0.039 L/yr. The cytokine concentrations were log-transformed to normalize their distributions. After adjusting for initial FEV1, height, age, ever-asthma, and ever-smoking, the log of IL-8 concentration was negatively associated with annual decline in FEV1 (p=0.012). Log transformed IL-l and IL-8 concentrations were highly correlated, and when IL-1 was included in the regression model instead of IL-8, it also had a significant negative association with the rate of FEV1 decline after adjustment (p=0.033). Log-transformed TNF-a was not a significant predictor of decline in FEV1 when added to the model (p=0.110). Sputum IL-8 and IL-1 concentrations are associated with the rate of decline in lung function in firefighters. Additional firefighters will be recruited to further test these relationships.
Lung-function; Fire-fighters; Fire-fighting; Neutrophils; Questionnaires; Medical-care; Sampling; Sputum-analysis; Lung-disorders; Pulmonary-system-disorders
Abstract; Conference/Symposia Proceedings
Issue of Publication
Proceedings of the American Thoracic Society. 2005 ATS International Conference, May 20-25, 2005, San Diego, California
University of California, School of Public Health, Los Angeles, CA