Asbestos and radiation as combined exposures in pulmonary fibrosis.
Takaro-TK; Griffith-WC; Omri-K; Checkoway-H; Faustman-EM
Am J Respir Crit Care Med 2003 Apr; 167(7):A684
Both asbestos and radiation are etiologic agents in pulmonary fibrosis. The aim of this study is to determine whether concomitant radiation exposure in asbestos workers increases the incidence of pulmonary fibrosis. 1037 asbestos exposed former nuclear weapons workers from a medical surveillance program form the study cohort. PA chest radiographs and spirometry were performed. Fibrosis was defined by B-read opacity profusion category on chest radiographs >1/0, or spirometric evidence of restrictive disease. The cohort is largely male (85.5%) with an average age of 64.9 years. 663 workers had complete work histories, including external radiation badge doses and laboratory data. The demographic and fibrosis endpoints were similar in the entire cohort vs. 663 analyzed. Asbestos exposure based upon years in a potentially exposed job was divided into low (< 13 years) and high (> 13 years) dose groups. 26 (8.0%) of the high dose vs.l2 (3.6%) of the low dose group had ILO scores >1/0 indicating pulmonary fibrosis while 71(21.8%) of the high dose group verses 51(15.1%) of the low dose group have spirometry indicating restrictive disease consistent with pulmonary fibrosis (p<0.05). In a 2 x 4 table analysis (binary fibrosis x binary asbestos and radiation exposure) 27 (38.6%) in the high asbestos/high radiation (> 20mSv) group met the cases definition for fibrosis vs. 74 (25.4%) in the low/low group. Worker protection standards are based upon single exposures not accounting for the constellation of exposures frequently encountered. Deep dose external radiation may add to the fibrotic effect of asbestos in workers exposed to both toxicants.
Asbestos-dust; Asbestosis; Radiation; Pulmonary-system-disorders; Fibrosis; Etiology; Exposure-levels; Workers; Toxins; Respiratory-system-disorders; Humans; Lung-disease; Lung-fibrosis
Abstract; Conference/Symposia Proceedings
Work Environment And Workforce: Mixed Exposures
American Journal of Respiratory and Critical Care Medicine, 2003 International Conference, The American Thoracic Society, Seattle, WA, May 16-21, 2003
University of Washington, Seattle, Washington