Smoking intervention in subjects at risk of asbestos-related lung cancer

Our plain-English summary of Smoking intervention in subjects at risk of asbestos-related lung cancer, by H.P. Waage, L.J. Vatten, E. Opedal, et al (American Journal of Industrial Medicine, 1997).

The study

• Authors: H.P. Waage, L.J. Vatten, E. Opedal, B. Hilt
• Journal: American Journal of Industrial Medicine
• Published: 1997;31(6):705-12
• Cited by: 11 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

A smoking intervention counseling program was applied among asbestos-exposed male smokers younger than 65 years of age to examine the effect of an intervention based on risk communication. Intervention subjects (n = 431) were invited to a health status checkup combined with physician-delivered smoking intervention counseling. Control subjects (n = 141) received no intervention. After 1 year, 5% of the responders in the intervention group, versus 3.4% in the control group, had stopped smoking. Corresponding conservative estimates were 3.5% and 2.6%, respectively. The quitters had been exposed to a higher "dose" of asbestos but had smoked less, and for a shorter period, than had the continuing smokers. Counseling by a general physician increased successful quitting threefold, compared to counseling by a physician in a specialized institution. These results suggest a potential for smoking cessation among subjects at high risk of lung cancer due to asbestos exposure. General practice care may be an appropriate setting both for identification of such subjects and for intervention.

In plain English

In Telemark county, Norway, the authors tested whether physician counseling about the combined lung cancer risk of asbestos exposure and smoking helped men quit. The 572 men were under 65 in 1989 and had reported asbestos exposure and smoking in a 1982–1983 survey. Men in four municipalities (431) were offered a free checkup with counseling. Men in a fifth (141) were not contacted until the one-year evaluation. After one year, 5% of responding smokers in the intervention group had quit, versus 3.4% of responding controls (3.5% and 2.6% counting non-responders as smokers). Against the control group, the relative risk of quitting was 1.7 (95% confidence interval 0.5 to 6.0), which was not statistically significant. Against the intervention group's own earlier quit rate, it was 2.2 (1.2 to 4.1). At two years, quitters had longer and higher cumulative asbestos exposure than continuing smokers. Among participants, 13.5% quit when counseled in primary health care, versus 4.8% at a specialized occupational health department. The authors concluded that quitting is hard even for men at increased risk, and that primary health care delivery seems preferable.

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: Non-randomized controlled intervention study: allocation to intervention or control was by municipality of residence. Follow-up was by questionnaire at one year, plus a two-year evaluation of participants.
• Who was studied: 572 males living in five industrialized municipalities of Telemark county, Norway, who were younger than 65 years of age in 1989. They were drawn from responders to a 1982–1983 population-based questionnaire survey on asbestos exposure and smoking habits. 431 were in the intervention group and 141 in the control group. The intervention ran from March 1989 to February 1990.
• Exposure: Self-reported asbestos exposure; fiber types are not specified. Exposure was graded from 1 (low) to 4 (very high) by occupation, for example mechanics and electricians handling gaskets, automobile mechanics, carpenters, welders, ship engine room and industrial maintenance work, insulators and masons of industrial furnaces. Cumulative exposure was intensity multiplied by years. Smoking was measured as projected lifetime tobacco consumption. The intervention was a 30–60 minute physician counseling session with a brief health checkup, a risk leaflet, carbon monoxide monitoring and an offer of nicotine polacrilex.
• Main results:
  • In the intervention group, 348 of 419 eligible subjects (83.1%) responded to the invitation.
  • After one year, 5% of responders in the intervention group had stopped smoking. Counting all invited subjects (non-responders treated as smokers), the figure was 3.5%.
  • In the control group, 106 of 133 subjects (79.7%) answered. Three reported quitting after the program started: 2.6% as a conservative estimate, or 3.4% among responders.
  • Within the intervention group, the relative risk of cessation after the intervention, compared with the same group's cessation before it (1982/83–1989), was 2.2 (95% confidence interval 1.2 to 4.1).
  • Compared with the control group, the relative risk of cessation was 1.7 (95% confidence interval 0.5 to 6.0). The authors reported this increase as not significant.
  • At the two-year follow-up, 64.6% of participants responded. Fourteen reported being ex-smokers, of whom three had quit during the previous year. Twelve had stopped for more than two weeks but relapsed.
  • Quitters at two years had the greatest asbestos exposure. Mean duration was 28.7 years in quitters versus 21.2 years in continuing smokers, and mean cumulative exposure was 67.7 versus 43.7 (both P less than 0.001, Table III). Quitters had lower tobacco-related values, which the authors described as statistically insignificant or of borderline significance.
  • Among participants, successful quitting was 13.5% when counseling was done by primary health care (37 subjects), versus 4.8% at the specialized institution of occupational health (189 subjects). The authors reported this as statistically significant.
  • Previous cessation attempts were associated with successful quitting, and nicotine polacrilex prescription enhanced cessation attempts; the authors reported both as statistically significant. Ischemic heart disease, additional consultations and carbon monoxide monitoring did not increase the likelihood of cessation.
• The authors' conclusion: The authors concluded that quitting smoking is hard even for those at increased lung cancer risk from combined asbestos exposure and smoking. They also concluded that individual risk-based intervention enhanced motivation to quit among those with the greatest asbestos exposure, and that a strategy delivered by primary health care services seems preferable.
• Limitations the authors state:
  • Expired carbon monoxide was not monitored in subjects who received the intervention through primary health care.
  • Non-responders were assumed to be continuing smokers for the conservative estimates. The authors state that any bias from this assumption would be toward the null value.
  • The authors suggest the target group may already have been exhausted by public attention to asbestos since the mid-1970s, and so may have been more resistant to counseling than average smokers.

Topics

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

Medical terms in this study, explained in our Lexicon: Lung Cancer, Asbestos Exposure.

Related studies

• A pilot study of telephone-based smoking cessation intervention in asbestos workers — O.Y. Osinubi, J. Moline, et al. (2003)
• The effect of smoking on the risk of lung cancer mortality for asbestos workers in Great Britain (1971-2005) — G. Frost, A. Darnton, et al. (2011)
• The risk of lung cancer with increasing time since ceasing exposure to asbestos and quitting smoking — A. Reid, N.H. de Klerk, et al. (2006)
• The degree of roentgenographic parenchymal opacities attributable to smoking among asbestos-exposed subjects — S. Barnhart, M. Thornquist, et al. (1990)
• Asbestos, asbestosis, smoking, and lung cancer. New findings from the North American insulator cohort — S.B. Markowitz, S.M. Levin, et al. (2013)
• Healthcare provider smoking cessation advice among US worker groups — D.J. Lee, L.E. Fleming, et al. (2007)

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