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During an investigation of a novel interstitial lung disease in a cohort of nylon flock workers, a former worker was found to have developed bilateral synchronous pulmonary adenocarcinomas three decades after he quit smoking, suggesting that exposures in this industry might pose excessive risk of lung cancer. We conducted a retrospective cohort study of lung cancer incidence in the original study cohort (n=162) from August 15, 1998, to August 14, 2008. The Rhode Island Cancer Registry identified cohort members with lung cancer and provided age-gender-era-specific rates of lung cancer in Rhode Island. Five cases of lung cancer occurred among cohort members versus 1.61 cases expected for a standardized incidence ratio of 3.1 (95% CI, 1.01-7.23). The observed threefold increase in lung cancer incidence could not be readily ascribed to chance, study bias, or uncontrolled confounding. Workers in this industry should be notified of their potentially increased risk of lung cancer.

Purpose: To characterize the thin-section computed tomographic (CT) features of flock worker's lung (FWL) and to determine whether these features may be used to distinguish workers with FWL from flock workers who do not fulfill diagnostic criteria for FWL., Materials and Methods: Thin-section CT images obtained in 43 flock workers (including 11 with FWL) were reviewed independently by radiologists blinded to occupational and clinical details. CT features recorded included ground-glass opacities, consolidation, micronodules, reticular abnormality, and septal thickening. Thirty-five of the CT scans (including nine obtained in patients with FWL) were also studied by using quantitative image analysis. The Student t test was used to compare mean lung attenuation between the workers with FWL and those without it., Results: Every patient with FWL and 19 (59%) of the 32 exposed flock workers who did not meet criteria for the disease had an abnormal thin-section CT scan. The most common findings in FWL were ground-glass opacities and micronodules. Quantitative analysis showed a mean lung attenuation of -736.4 HU in patients with FWL, compared with -775.0 HU in workers without the disease (P <.05)., Conclusion: While ground-glass opacities, micronodules, or both were found in all cases of FWL, these abnormalities were also present in a substantial proportion of symptomatic flock workers who did not satisfy current criteria for FWL. Although nonspecific, these findings should suggest the diagnosis of FWL in exposed individuals.

Background: Two young men working at a nylon flocking plant in Rhode Island developed interstitial lung disease of unknown cause. Similar clusters at the same company's Canadian plant were reported previously., Objective: To define the extent, clinicopathologic features, and potential causes of the apparent disease outbreak., Design: Case-finding survey and retrospective cohort study., Setting: Academic occupational medicine program., Patients: All workers employed at the Rhode Island plant on or after 15 June 1990., Measurements: Symptomatic employees had chest radiography, pulmonary function tests, high-resolution computed tomography, and serologic testing. Those with unexplained radiographic or pulmonary function abnormalities underwent bronchoalveolar lavage, lung biopsy, or both. The case definition of "flock worker's lung" required histologic evidence of interstitial lung disease (or lavage evidence of lung inflammation) not explained by another condition., Results: Eight cases of flock worker's lung were identified at the Rhode Island plant. Three cases were characterized by a high proportion of eosinophils (25% to 40%) in lavage fluid. Six of the seven patients who had biopsy had histologic findings of nonspecific interstitial pneumonia, and the seventh had bronchiolitis obliterans organizing pneumonia. All seven of these patients had peribronchovascular interstitial lymphoid nodules, usually with germinal centers, and most had lymphocytic bronchiolitis and interstitial fibrosis. All improved after leaving work. Review of the Canadian tissue specimens showed many similar histologic findings. Among the 165-member study cohort, a 48-fold or greater increase was seen in the sex-adjusted incidence rate of all interstitial lung disease., Conclusions: Work in the nylon flocking industry poses substantial risk for a previously unrecognized occupational interstitial lung disease. Nylon fiber is the suspected cause of this condition.