Smoking and duration of asbestos exposure in the production of functional and roentgenographic abnormalities in shipyard workers

Our plain-English summary of Smoking and duration of asbestos exposure in the production of functional and roentgenographic abnormalities in shipyard workers, by J.L. Pearle (Journal of Occupational Medicine., 1982).

The study

• Author: J.L. Pearle
• Journal: Journal of Occupational Medicine.
• Published: 1982;24(1):37-40
• Cited by: 19 articles, as counted by NIH iCite
• Read it: PubMed
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 000702).

Abstract

Functional and roentgenographic abnormalities in 131 asbestos-exposed shipyard workers were assessed in terms of duration of asbestos exposure and smoking history to determine the relative contributions of these factors. Both exposure and smoking contributed to the frequency of abnormalities in FEV1 and FVC. In contrast, airways obstruction (FEV1/FVC less than 70%) was unrelated to exposure but correlated closely with smoking. Abnormalities in DLCO were minimally associated with asbestos exposure, but were strongly related to smoking history, suggesting that diffusion impairment in these workers is more likely to be related to smoking and emphysema than to interstitial disease. Significant roentgenographic pleural abnormalities were associated with both duration of exposure and smoking. Interstitial disease did not correlate with exposure and was only mildly associated with smoking. Smoking contributes to many of the functional and roentgenographic abnormalities in asbestos-exposed workers.

In plain English

This study examined 131 male shipyard workers, including electricians, pipe fitters and boilermakers, referred to UCLA Medical Center for suspected asbestos-related lung disease. Each had at least seven years of asbestos dust exposure. The article does not say which fiber types these workers encountered. The author grouped workers by years of exposure and by smoking history, then compared breathing tests and chest X-rays read by a radiologist. Reduced FVC (a lung-volume measure) was found in 16% of workers with mild exposure, against 34% and 35% of those with moderate and heavy exposure. Airway obstruction was not associated with exposure length, but was found in 6% of nonsmokers against 32% of heavy smokers. Reduced diffusing capacity occurred in 3% of nonsmokers and 20% of heavy smokers. Significant pleural thickening or plaques rose from 16% with mild exposure to 30% with heavy exposure, and from 9% of nonsmokers to 25% of heavy smokers. Significant (grade 2 or 3) interstitial changes, seen in 8% of workers, did not correlate with exposure duration. The author concluded that smoking contributes to many of these abnormalities.

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: Cross-sectional study of referred workers, comparing lung function test results and chest X-ray findings across groups defined by duration of asbestos exposure and smoking history
• Who was studied: 131 male shipyard workers (occupations included electrician, pipe fitter, boilermaker) referred to UCLA Medical Center for suspected asbestos-related lung disease. Each had a documented asbestos exposure history of at least seven years. Seventy-six percent had smoking histories.
• Exposure: Duration of asbestos dust exposure, grouped as mild (under 15 years), moderate (15 to 29 years) and heavy (30 years or more). Smoking history was grouped as nonsmokers (0 pack-years), light (1 to 9), moderate (10 to 19) and heavy (20 pack-years). The fiber types these workers were exposed to were not reported.
• Main results:
  • FEV1 (air forced out in one second) was reduced in 28% of all workers. It was reduced in 16% of nonsmokers and 34% of heavy smokers, a statistically significant difference (p less than .05).
  • Low FVC was found in 29% of workers overall. It occurred in 16% of workers with mild asbestos exposure, against 34% (moderate) and 35% (heavy). Both were significantly greater than in the mild exposure group.
  • Airways obstruction (FEV1/FVC under 70%) was present in 21% of workers. It was not associated with exposure duration.
  • Airways obstruction was found in 6% of nonsmokers and in 32% of heavy smokers, a significantly greater number.
  • Diffusing capacity (DLCO) was reduced in 14% of workers. It was reduced in 3% of nonsmokers and 20% of heavy smokers, a significant difference. For the workers as a whole, no clear association with exposure duration was evident.
  • Significant pleural disease (thickening or plaques, grade 2 or 3) was found in 21% of workers. It occurred in 16% of those with mild exposure and 30% of those with heavy exposure.
  • Significant pleural disease was found in 9% of nonsmokers, 25% of heavy smokers and 24% of all smokers combined. Both differences from nonsmokers were significant.
  • Significant (grade 2 or 3) interstitial disease, meaning X-ray abnormalities consistent with asbestosis, was found in 8% of workers. It did not correlate with duration of exposure for the workers as a whole or in any sub-category.
  • Significant interstitial disease was found in 3% of nonsmokers and in 8% to 12% of each smoking category. In the mild exposure group, no nonsmokers had it, compared with 19% of heavy smokers and 22% of all smokers combined. The figure for all smokers combined was significantly greater than for nonsmokers.
• The authors' conclusion: The author concluded that smoking contributes in varying degrees to many of the abnormalities seen in workers with suspected asbestos-related disease, including FEV1, FVC, airway obstruction, diffusing capacity, pleural disease and interstitial disease. The author also concluded that many of the functional and X-ray abnormalities in asbestos-exposed workers are due, at least in part, to causes other than asbestos.
• Limitations the authors state:
  • The author suggested that the lack of correlation between exposure duration and interstitial disease may reflect, among other factors, the difficulty of classifying and describing interstitial abnormalities on a chest X-ray.
  • The workers were a referral population. The author argued they were nonetheless representative because their rates of abnormal tests matched other reported series.

Topics

Medical terms in this study, explained in our Lexicon: Asbestos Exposure, FEV1, FEV1/FVC Ratio, Diffusing Capacity (DLCO), Emphysema, Interstitial.

Related studies

• Spirometric impairments in long-term insulators. Relationships to duration of exposure, smoking, and radiographic abnormalities — A. Miller, R. Lilis, et al. (1994)
• The relation among pulmonary function, chest roentgenographic abnormalities, and smoking status in an asbestos-exposed cohort — L. Rosenstock, S. Barnhart, et al. (1988)
• Radiographic abnormalities in asbestos insulators: effects of duration from onset of exposure and smoking. Relationships of dyspnea with parenchymal and pleural fibrosis — R. Lilis, A. Miller, et al. (1991)
• 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)
• Smoking and roentgenographic opacities in US Navy asbestos workers — A.M. Ducatman, B.F. Withers, et al. (1990)
• Radiographic abnormalities among asbestos-cement workers. An exposure-response study — M.M. Finkelstein, J.J. Vingilis (1984)

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