Effect of smoking on attack rates of pulmonary and pleural lesions related to exposure to asbestos dust

Our plain-English summary of Effect of smoking on attack rates of pulmonary and pleural lesions related to exposure to asbestos dust, by G.H. McMillan, R.J. Pethybridge, G. Sheers (British Journal of Industrial Medicine, 1980).

The study

• Authors: G.H. McMillan, R.J. Pethybridge, G. Sheers
• Journal: British Journal of Industrial Medicine
• Published: 1980;37(3):268-72
• Cited by: 30 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 000841).

Abstract

In follow-up studies of samples of employees at two of Her Majesty's Dockyards the prevalence of asbestos-related lesions in smokers and ex-smokers was statistically significantly higher than in non-smokers even when differences in age and exposure risk were considered.

In plain English

This study followed up men who had been in 10% random samples of male civilian employees at HM Dockyards in Devonport (surveyed 1966) and Portsmouth (surveyed 1968). In 1977, 1012 of 1414 Devonport men and 719 of 1009 Portsmouth men were re-examined by chest radiograph. No exposure records existed, so each man's asbestos exposure was estimated from his occupation. Non-malignant asbestos-related lesions (pleural plaques, diffuse pleural thickening, parenchymal fibrosis) were found in 5.9% of non-smokers, 16.2% of smokers and 15.0% of ex-smokers at Devonport, and in 8.0%, 13.1% and 17.0% at Portsmouth. After allowing for age and exposure group, the observed counts differed significantly from what would be expected without a smoking effect at Devonport, but not at Portsmouth. All men with parenchymal fibrosis were, or had been, smokers. The authors concluded that the risk of an asbestos-related lesion is related to smoking habit as well as to exposure, and that smokers and ex-smokers may have a significantly higher risk than non-smokers. They noted that some rates rested on small numbers.

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: Follow-up (resurvey) study in 1977 of men first examined in earlier cross-sectional radiological surveys in 1966 and 1968, comparing the prevalence of asbestos-related lesions by smoking habit
• Who was studied: Men from 10% random samples of all male civilian employees at HM Dockyards, Devonport (1414 men, first examined 1966) and Portsmouth (1009 men, first examined 1968). In 1977, 1012 Devonport men and 719 Portsmouth men attended for radiographs.
• Exposure: Asbestos dust at work in naval dockyards (fiber types not stated). Men were placed in four exposure groups by occupation. Group 1 was laggers, asbestos sprayers, sailmaker laggers, asbestos storemen and painters afloat. 1970 was taken as the end of all exposure. Smoking habit was classed as non-smoker, smoker or ex-smoker.
• Main results:
  • Overall prevalence of asbestos-related lesions in 1977 was 13.6% at Devonport (4.1% for the same men in 1966) and 13.1% at Portsmouth (2.8% in 1968)
  • Prevalence fell as the occupational exposure risk group decreased, at both dockyards
  • Devonport: lesions in 13 of 222 non-smokers (5.9%), 79 of 489 smokers (16.2%) and 45 of 301 ex-smokers (15.0%)
  • Portsmouth: lesions in 13 of 163 non-smokers (8.0%), 46 of 350 smokers (13.1%) and 35 of 206 ex-smokers (17.0%)
  • At Devonport, after adjustment for exposure risk and age, observed numbers differed significantly from those expected if smoking had no influence (chi-squared 6.56, 2 degrees of freedom, p less than 0.05)
  • At Portsmouth the pattern was similar, but the differences between observed and expected rates were not statistically significant
  • All men with parenchymal fibrosis were current or former smokers. At Devonport this was 6 smokers and 6 ex-smokers; at Portsmouth, 4 smokers and 2 ex-smokers.
• The authors' conclusion: The authors concluded that, among men exposed to asbestos dust at work, the risk of an asbestos-related lesion is related to smoking habit in addition to duration and intensity of exposure and time since first exposure, and that smokers and ex-smokers may have a significantly higher risk than non-smokers
• Limitations the authors state:
  • Some rates were based on small numbers and should be treated with caution
  • The original 1960s surveys were not designed as the first phase of a follow-up study, which made tracing men and setting radiological criteria harder
  • No full-size chest radiographs existed from 1966 and 1968, so earlier prevalence could not be redefined
  • A non-smoker with parenchymal change could have been missed in a study of this size and design
  • No exposure records were available; exposure was estimated from occupation

Topics

The National Library of Medicine indexes this study under subjects our site covers: Pleural plaques and thickening, The Navy.

Related studies

• Comparison of independent randomised reading of radiographs with direct progression scoring for assessing change in asbestos-related pulmonary and pleural lesions — G.H. McMillan, C.E. Rossiter, et al. (1982)
• Development of radiological and clinical evidence of parenchymal fibrosis in men with non-malignant asbestos-related pleural lesions — G.H. McMillan, C.E. Rossiter (1982)
• Thoracic surgical problems in asbestos-related disorders — E.A. Gaensler, T.C. McLoud, et al. (1985)
• The calcification of fibrous pleural lesions produced in guinea-pigs by the injection of chrysotile asbestos dust — J.M. Davis (1971)
• Common problems in asbestos-related pulmonary diseases — A.H. Rubin (1986)
• 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)

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