Effects of tobacco smoking on findings in chest computed tomography among asbestos-exposed workers

Our plain-English summary of Effects of tobacco smoking on findings in chest computed tomography among asbestos-exposed workers, by T. Vehmas, L. Kivisaari, M.S. Huuskonen, et al (The European Respiratory Journal, 2003).

The study

• Authors: T. Vehmas, L. Kivisaari, M.S. Huuskonen, M.S. Jaakkola
• Journal: The European Respiratory Journal
• Published: 2003;21(5):866-71
• Cited by: 22 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

This study examined the effects of smoking on the findings in chest computed tomography (CT) in 587 asbestos-exposed construction workers (11 females, 576 males, mean age 62 yrs; 18 never-smokers, 406 exsmokers and 163 current smokers). The workers were imaged with spiral CT and high-resolution CT. A total of 13 radiological signs were scored by three radiologists independently. The workers' medical data, smoking habits and occupational exposures were collected at an interview. The effects of smoking status and smoked pack-yrs (0-87.5) on the CT signs were studied using multivariate analysis adjusted for confounding factors. Smoking increased all emphysema signs and contributed to bronchial wall thickening. Smoking was negatively associated with curvilinear and septal lines as well as with parenchymal bands. In persons who had smoked <10 pack-yrs, smoking was positively related to paraseptal emphysema and to bronchial wall thickening and negatively related to septal lines, subpleural nodules and honeycombing. Smoking was related to several abnormal computed tomography signs even among those with relatively small exposure. Computed tomography can detect changes due to smoking at an early stage.

In plain English

This Finnish cross-sectional study looked at whether tobacco smoking was linked to findings on chest CT scans in construction workers who had an asbestos-related occupational disease (asbestosis or bilateral pleural plaques). Of 602 workers scanned, 587 (576 men and 11 women, aged 38 to 80) had usable smoking and CT data. Of these, 18 were never-smokers, 406 ex-smokers and 163 current smokers. Three radiologists who did not know the workers' smoking histories scored 13 CT signs. The analyses were adjusted for age, occupation and years of asbestos exposure. All types of emphysema were linked to smoking, more strongly in current smokers. Bronchial wall thickening was also linked to smoking. Some other signs, including subpleural curvilinear lines and subpleural septal lines, were less common among smokers. Among 108 workers who had smoked up to 10 pack-years, paraseptal emphysema and bronchial wall thickening were linked to smoking. The authors concluded that CT can detect changes due to smoking at an early stage. They noted that there were only 18 never-smokers and that the results cannot be applied directly to the general population.

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 (CT and high-resolution CT imaging plus interview)
• Who was studied: 587 construction workers in Finland with an asbestos-related occupational disease (from 602 imaged; 85 with asbestosis, 601 with bilateral pleural plaques), 576 men and 11 women aged 38 to 80 (mean 62); 18 never-smokers, 406 ex-smokers, 163 current smokers
• Exposure: Tobacco smoking (smoking status and cumulative pack-years, 0 to 87.5, mean 23.7). All workers had occupational asbestos exposure (2 to 48 years, average 26), which was adjusted for. Fiber types were not stated.
• Main results:
  • All types of emphysema were related to smoking, with stronger effects in current smokers.
  • For panlobular emphysema, current smokers had higher scores than nonsmokers, but this was not statistically significant (p=0.057).
  • Bronchial wall thickness was positively related to smoking status (p=0.001) and to pack-years in both current and ex-smokers (p=0.001).
  • Subpleural curvilinear lines were inversely related to smoking status (p=0.003) and to pack-years (p=0.001).
  • Subpleural septal lines were lower in ex-smokers (p=0.039) and in current smokers (p=0.045) than in never-smokers.
  • The text reports that parenchymal bands were less frequent among current and ex-smokers than among nonsmokers (p=0.033).
  • Ground-glass opacities had only a marginal positive association with pack-years in ex-smokers (p=0.094).
  • In the subgroup who had smoked 10 pack-years or less (n=108), paraseptal emphysema (p=0.038) and bronchial wall thickening (p=0.018) were positively related to smoking.
  • In the same 10-pack-year-or-less subgroup, subpleural septal lines (p=0.034) and subpleural nodules (p=0.050) decreased with increasing pack-years.
  • In that subgroup, honeycombing was more frequent among never-smokers than smokers, but this was not statistically significant (p=0.076).
• The authors' conclusion: The authors concluded that smoking was related to several abnormal CT signs even among workers with relatively minor exposure of up to 10 pack-years, indicating that CT can detect smoking-related changes at an early stage.
• Limitations the authors state:
  • The workers all had asbestos-related disease, so the results cannot be applied directly to the general population.
  • There were only 18 never-smokers.
  • Respiratory symptoms and coexisting diseases were not adjusted for.
  • Scoring was subjective rather than based on exact measurements.
  • Signs were scored on different scales (0 to 5 or 0 to 3), so the regression coefficients are not directly comparable.
  • Exposure to environmental (secondhand) tobacco smoke was not asked about.

Topics

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

Medical terms in this study, explained in our Lexicon: High-Resolution CT (HRCT), Habit, Occupational Exposure, Multivariate Analysis, Confounding, Emphysema, Honeycombing.

Related studies

• Findings from high resolution computed tomography of the lung and pleura of symptom free workers exposed to amosite who had normal chest radiographs and pulmonary function tests — S. Neri, A. Antonelli, et al. (1994)
• 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)
• Emphysema findings associated with heavy asbestos-exposure in high resolution computed tomography of finnish construction workers — O. Huuskonen, L. Kivisaari, et al. (2004)
• Effect of tobacco smoking on the presence of asbestosis at postmortem and on the reading of irregular opacities on roentgenograms in asbestos-exposed workers — E. Hnizdo, G.K. Sluis-Cremer (1988)
• Effect of tobacco smoking on the presence of asbestosis at postmortem and on the reading of irregular opacities on roentgenograms in asbestos-exposed workers — A. Kraut, J. Godbold, et al. (1989)
• High resolution computed tomography and lung function in asbestos-exposed workers with normal chest radiographs — C.A. Staples, G. Gamsu, et al. (1989)

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