The clinical significance of ferruginous bodies in sputa

Our plain-English summary of The clinical significance of ferruginous bodies in sputa, by J.W. McLarty, S.D. Greenberg, G.A. Hurst, et al (Journal of Occupational Medicine., 1980).

The study

• Authors: J.W. McLarty, S.D. Greenberg, G.A. Hurst, C.G. Spivey, L.H. Seitzman, L.R. Hieger, M.L. Farley, L.C. Mabry
• Journal: Journal of Occupational Medicine.
• Published: 1980;22(2):92-6
• Cited by: 31 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 000838).

Abstract

The clinical significance of ferruginous bodies in sputa was examined in a study of 674 former asbestos workers. Data from occupational histories and smoking behavior questionnaires, chest radiographs, spirometric measurements and counts of ferruginous bodies were obtained as part of a five-year surveillance program. Statistical analysis demonstrated that ferruginous bodies found in the sputa were significantly related to radiographic findings of interstitial pulmonary disease and pleural fibrosis and to spirometric findings of restrictive lung disease. Age and cigarette smoking were also found to be related to the presence of ferruginous bodies.

In plain English

The authors studied the records of 674 former workers from an amosite asbestos plant in Tyler, Texas, that made asbestos insulation products from 1954 to 1972. The workers were examined in the Tyler Asbestos Workers Program. The authors compared ferruginous bodies counted in the workers' sputum with work history, age, smoking, chest X-rays and breathing tests. Having ferruginous bodies was linked to longer employment and to older age at examination, but not to time since exposure. Smoking was linked to ferruginous bodies in spontaneous sputum (30% of smokers versus 18% of nonsmokers, p less than 0.02) but not in aerosol-induced sputum. After adjusting for other factors, ferruginous bodies were significantly associated with irregular small opacities on X-ray, with pleural thickening, and with restrictive lung disease (forced vital capacity below 80% of expected). The authors concluded that ferruginous bodies in sputum were related to interstitial and pleural fibrosis and to restrictive lung disease. They noted that their routine laboratory methods did not use special techniques, and that such techniques would likely find ferruginous bodies in more workers.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Analysis of records from a medical surveillance program of former asbestos workers (sputum cytology, chest radiographs and spirometry), using chi-square tests, analysis of variance and multiple logistic regression
• Who was studied: 674 former asbestos workers examined at the Tyler Asbestos Workers Program (Tyler, Texas), which began in June 1974 and followed a cohort of 1095 former workers, 85% of whom were cigarette smokers
• Exposure: Employment at an amosite asbestos plant in Tyler, Texas, that manufactured asbestos insulation products from 1954 to 1972; the analysis used duration of employment and latency, not the intensity of exposure
• Main results:
  • Longer duration of employment was related to the presence of ferruginous bodies in both spontaneous and aerosol-induced sputum specimens (p < 0.001 for both)
  • Older age at examination was positively related to the presence of ferruginous bodies, and this remained highly significant after controlling for duration of employment, time since first exposure and smoking
  • Latency (time since first or last exposure) was not related to the presence of ferruginous bodies
  • In spontaneous sputum specimens, ferruginous bodies were present in 163 (30%) smokers and 19 (18%) nonsmokers (p < 0.02)
  • In aerosol-induced specimens, ferruginous bodies were present in 191 (34%) smokers and 32 (29%) nonsmokers (p > 0.30, not significant); the table text is garbled by OCR
  • Ferruginous bodies were significantly associated with irregular small opacities (ILO-U/C types s, t or u) on chest radiographs (p < 0.001), even after correcting for age, smoking and duration of employment
  • Ferruginous bodies were significantly associated with pleural thickening (p < 0.03), even after correcting for confounding factors
  • Ferruginous bodies were significantly associated with restrictive lung disease, defined as forced vital capacity below 80% of expected (p < 0.02), after correcting for smoking and employment factors; the severity of restrictive disease was also related to ferruginous bodies
  • Aerosol-induced specimens contained more ferruginous bodies than spontaneous specimens, but spontaneous specimens correlated more strongly with clinical factors
• The authors' conclusion: The authors concluded that ferruginous bodies in sputum were related to duration of exposure, were more common in older and smoking workers (probably because of less effective bronchial clearance), were not related to time since exposure, and were significantly related to radiographic interstitial and pleural fibrosis and to restrictive lung disease on spirometry
• Limitations the authors state:
  • The routine cytopathology methods used did not include special techniques (iron stain, electron microscopy or digestion); the authors considered it likely that such techniques would find ferruginous bodies in a much higher percentage of workers

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis.

Medical terms in this study, explained in our Lexicon: Ferruginous body, Chest X-Ray, Interstitial, Fibrosis, Restrictive Lung Disease.

Related studies

• Asbestos and other ferruginous bodies: their formation and clinical significance — A.M. Churg, M.L. Warnock (1981)
• A procedure for the isolation of amosite asbestos and ferruginous bodies from lung tissue and sputum — M.G. Williams, R.F. Dodson, et al. (1982)
• A method for extracting ferruginous bodies from sputum and pulmonary tissue — M.J. Smith, B. Naylor (1972)
• Ferruginous bodies in benign fibrous pleural plaques — P. Rosen, P. Gordon, et al. (1973)
• Ferruginous bodies: implications in the mechanism of fiber and particle toxicity — A.J. Ghio, A. Churg, et al. (2004)
• Analysis of ferruginous bodies in bronchoalveolar lavage from foundry workers — R.F. Dodson, M. O'Sullivan, et al. (1993)

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