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.
