FLOCK WORKERS LUNG - CHRONIC INTERSTITIAL LUNG-DISEASE IN THE NYLON FLOCKING INDUSTRY

Background: Two young men working at a nylon flocking plant in Rhode I sland developed interstitial lung disease of unknown cause. Similar cl usters at the same company's Canadian plant were reported previously. Objective: To define the extent, clinicopathologic features, and poten tial causes of the apparent disease outbreak. Design: Case-finding sur vey and retrospective cohort study. Setting: Academic occupational med icine program. Patients: All workers employed at the Rhode Island plan t on or after 15 June 1990. Measurements: Symptomatic employees had ch est radiography, pulmonary function tests, high-resolution computed to mography, and serologic testing. Those with unexplained radiographic o r pulmonary function abnormalities underwent bronchoalveolar lavage, l ung biopsy, or both. The case definition of ''flock worker's lung'' re quired histologic evidence of interstitial lung disease (or lavage evi dence of lung inflammation) not explained by another condition. Result s: Eight cases of flock worker's lung were identified at the Rhode Isl a nd plant. Th ree cases were characterized by a high proportion of eo sinophils (25% to 40%) in ravage fluid. Six of the seven patients who had biopsy had histologic findings of nonspecific interstitial pneumon ia, and the seventh had bronchiolitis obliterans organizing pneumonia. All seven of these patients had peribronchovascular interstitial lymp hoid nodules, usually with germinal centers, and most had lymphocytic bronchiolitis and interstitial fibrosis. All improved after leaving wo rk. Review of the Canadian tissue specimens showed many similar histol ogic findings. Among the 165-member study cohort, a 48-fold or greater increase was seen in the sex-adjusted incidence rate of all interstit ial lung disease. Conclusions: Work in the nylon flocking industry pos es substantial risk for a previously unrecognized occupational interst itial lung disease. Nylon fiber is the suspected cause of this conditi on.