An early study of pulmonary asbestosis among manufacturing workers: original data and reconstruction of the 1932 cohort

Our plain-English summary of An early study of pulmonary asbestosis among manufacturing workers: original data and reconstruction of the 1932 cohort, by S.W. Borron, S.A. Forman, J.E. Lockey, et al (American Journal of Industrial Medicine, 1997).

The study

• Authors: S.W. Borron, S.A. Forman, J.E. Lockey, G.K. Lemasters, L.M. Yee
• Journal: American Journal of Industrial Medicine
• Published: 1997;31(3):324-34
• Type of article: Historical article
• Cited by: 7 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

A cross-sectional prevalence survey of asbestosis, including all 1,140 employees of a diversified asbestos products manufacturer, was conducted in 1932 by Drs. Anthony J. Lanza and Frank V. Meriwether. Occupational histories were obtained from workers in order to identify job tasks with exposure to asbestos and other fibrogenic dusts. Abbreviated medical histories, physical examinations, fluoroscopy, and chest radiographs were performed. Radiographs were interpreted according to applicable criteria for pneumoconiosis, the presence of which was confirmed in 327 subjects (29%). Among those, 64% had previous exposure to dusts in addition to asbestos, coal being the leading non-asbestos exposure. Thirty-six percent of cases had prior exposure only to asbestos dust. The original conclusions do not survive. Contemporaneous related documents suggest that the original authors believed asbestosis to be a milder form of lung disease than silicosis. It was subsequently recommended that the company institute pre-employment physicals, including chest radiographs; not hire people with prior coal-dust exposure; warn workers against excessive exposure to asbestos dust; remove those with disease to less dusty areas; and begin periodic medical surveillance for pneumoconiosis. The study, which has never appeared in the medical or scientific literature, holds important lessons for those concerned with occupational health today and in the future.

In plain English

This article reconstructed a never-published 1932 survey of lung disease at an asbestos products plant. Anthony J. Lanza and Frank V. Meriwether conducted a survey of all 1,140 employees of the Manville factory complex in New Jersey, which used work histories, physical examinations, fluoroscopy and chest X-rays. The present authors traced 1,123 of these workers in company records. The original investigators found X-ray evidence of lung disease in 327 workers (28.7%). They labeled 208 'pneumoconiosis' (mainly prior exposure to other dusts, usually coal) and 119 'asbestosis' (only or mainly asbestos exposure). Hourly workers were more likely than salaried staff to have a positive X-ray, and those with positive X-rays more often reported shortness of breath. The Textiles work category had the highest positive rate (43%). Years of company employment matched poorly with disease. The original conclusions do not survive. Recommendations in a company document included rejecting applicants with five or more years of coal mining and giving periodic chest X-rays. The authors called the study an acknowledgment of hazards recognized, though in part misunderstood, and of missed opportunities for prevention.

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: Historical reconstruction, by the present authors, of an unpublished 1932 cross-sectional prevalence survey of asbestosis. The reconstruction used surviving company medical, X-ray, personnel, workers' compensation and mortality records.
• Who was studied: All 1,140 employees of Manville's New Jersey factory complex (a diversified asbestos products manufacturer), examined between February and May 1932. The survey used medical and occupational histories, physical examinations, fluoroscopy and chest radiographs. Dr. Peter E. Sabatelle did the chest examinations and read the fluoroscopy, and Dr. Meriwether read the radiographs.
• Exposure: Asbestos dust in the plant's manufacturing departments, plus previous exposure to other fibrogenic dusts (mainly coal). Fiber types are not specified. A 1929 hygiene survey measured airborne dust of 0.33 to 44.7 million particles per cubic foot (mppcf) across departments; this total included other dusts such as cotton and cement.
• Main results:
  • The present authors identified 1,123 of the 1,140 original participants (98.5%) by name and clock number.
  • The original investigators identified 327 of 1,140 employees (28.7%) as having radiographic evidence of lung disease.
  • Of the 327 positive cases, 208 (63.6%) were classified as 'Pneumoconiosis' (predominantly prior non-asbestos dust exposure) and 119 (36.4%) as 'Asbestosis' (only or predominantly asbestos exposure).
  • All seven workers with Stage 3 radiographic changes were classified as 'Pneumoconiosis'. They had greater mean and median years of coal exposure than of asbestos exposure.
  • Hourly workers were significantly more likely than salaried personnel to have a positive radiograph (p = 0.001). There was no significant difference between males and females.
  • Workers with positive radiographs were significantly more likely to complain of dyspnea: 24/327 positive versus 24/796 negative (p = 0.002, odds ratio 2.43).
  • Positive and negative radiographs did not differ in workers' history of tuberculosis, influenza, chronic bronchitis or pneumonia, or in cough, sputum or hemoptysis.
  • The Textiles job category had 115 positives (43% of the department), the highest share. Hard Shingles (8, 12%) and Miscellaneous (16, 9%) were well below the 29% mean.
  • Compared with chest radiographs, fluoroscopy had a sensitivity of 76% (240/315), a specificity of 59% (459/777) and a positive predictive value of 47%.
  • Duration of company employment correlated poorly with the presence and stage of radiographic disease.
  • Radiographic changes appeared to correlate well with years of prior coal mining work and total years of dusty work, up to and including Stage 3.
  • An undated company summary document of study recommendations, which the authors believe Lanza submitted, included outright rejection of applicants with five or more years of coal mining.
  • The recommendations also called for periodic X-ray examination of employees exposed to dust.
  • The study resulted in a program of periodic physical examinations and chest radiographs at the plant. The authors found no records of job transfers based on the medical findings.
• The authors' conclusion: The authors concluded that the study is an acknowledgment of hazards recognized, though in part misunderstood, and of missed opportunities for prevention of human disease.
• Limitations the authors state:
  • The original investigators' conclusions and discussion do not survive, so the authors inferred them from related documents.
  • Sorting department titles into work categories more than 60 years later was uncertain, because department names and numbers had changed over time.
  • Physical examination findings were recorded too inconsistently to be used.
  • Key dust sampling details, such as sampling duration, were not recorded.
  • It is unlikely that any participant was entirely unexposed to asbestos, which weakens the 'exposed' versus 'non-exposed' grouping.
  • Positive cases were split into 'Pneumoconiosis' and 'Asbestosis' somewhat subjectively.
  • A healthy worker survivor effect cannot be excluded as an explanation for the poor link between employment duration and disease.

Topics

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

Medical terms in this study, explained in our Lexicon: Asbestosis, Fibrogenic, Chest X-Ray, Pneumoconiosis, Asbestos Exposure, Silicosis.

Related studies

• Asbestosis: interstitial pulmonary fibrosis and pleural fibrosis in a cohort of asbestos insulation workers: influence of cigarette smoking — R. Lilis, I.J. Selikoff, et al. (1986)
• Cohort study of workers employed in an Italian tire manufacturing plant, 1962-2004 — D. Mirabelli, A.M. Cacciatore, et al. (2012)
• Regarding "absence of radiographic asbestosis and the risk of lung cancer among asbestos-cement workers: extended follow-up of a cohort", by Murray Finkelstein, American Journal of Industrial Medicine 2010 — R.M. Ross (2011)
• DREM 2.0: Improved reconstruction of dynamic regulatory networks from time-series expression data — M.H. Schulz, W.E. Devanny, et al. (2012)
• Usual interstitial pneumonia in asbestos-exposed cohorts - concurrent idiopathic pulmonary fibrosis or atypical asbestosis? — R.L. Attanoos, F.S. Alchami, et al. (2016)
• Pulmonary function, smoking habits, and high resolution computed tomography (HRCT) early abnormalities of lung and pleural fibrosis in shipyard workers exposed to asbestos — S. Neri, P. Boraschi, et al. (1996)

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