Effectiveness of postal smoking cessation advice: a randomized controlled trial in young men with reduced FEV1 and asbestos exposure

Our plain-English summary of Effectiveness of postal smoking cessation advice: a randomized controlled trial in young men with reduced FEV1 and asbestos exposure, by S. Humerfelt, G.E. Eide, G. Kvåle, et al (The European Respiratory Journal, 1998).

The study

• Authors: S. Humerfelt, G.E. Eide, G. Kvåle, L.E. Aarø, A. Gulsvik
• Journal: The European Respiratory Journal
• Published: 1998;11(2):284-90
• Type of article: Randomized trial
• Cited by: 47 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

There have been few community-based randomized, controlled intervention trials for cessation in high-risk smokers. In such a trial we evaluated the effects of postal smoking cessation advice in smokers with asbestos exposure and/or reduced forced expiratory volume in one second (FEV1). All men aged 30-45 yrs (n=22,392) living in 34 municipalities in western Norway were invited to a cross-sectional community survey. Information on smoking habits and occupational asbestos exposure were obtained from self-administered questionnaires and measurements of FEV1 were performed with dry-wedge bellow spirometers. Among 16,393 participants we identified a group of 2,610 smokers with previous occupational asbestos exposure and/or adjusted FEV1 in the lowest quartile. A random half (n=1,300) received a mailed personal letter from a respiratory physician with a person-specific health advice to quit smoking and a pamphlet on smoking cessation. The remaining smokers (n=1,310) acted as controls and did not receive any information. Twelve months after the intervention, information on smoking habits was re-examined using a postal questionnaire. Among the respondents (n=2,282), smoking cessation was reported altogether by 13.7% in the intervention group versus 9.9% in the control group (p<0.01). The 1 yr sustained quit rate (no smoking at all during the last year) was 5.6 versus 35% (p<0.05), respectively. Measurements of carbon monoxide in expired air (with < or = 10 parts per million) confirmed self-reported nonsmoking in samples of the two groups. In a community this simple postal smoking cessation advice from a respiratory physician based on person-specific risk factors improved the 1 yr sustained success rate by 60% in identified high-risk smokers.

In plain English

This randomized controlled trial in rural western Norway tested whether a mailed letter could help high-risk smokers quit. From a 1988 to 1989 lung function survey of men aged 30 to 45, the authors selected 2,610 current smokers. Each had reported previous occupational asbestos exposure, had lung function (FEV1) in the lowest quarter for their age and height, or both. In January 1990, 1,300 randomly chosen men received a signed personal letter from a respiratory physician. It reminded them of their own risk factors, urged them to quit, and came with a pamphlet. The other 1,310 men received nothing. A year later, among men who answered a follow-up questionnaire, 13.7% of the letter group and 9.9% of the control group reported not smoking. Men who had not smoked at all for the preceding year made up 5.6% of the letter group and 3.5% of the control group. The authors described this as a 60% improvement. Breath carbon monoxide tests in a sample of men supported the self-reports. The authors cautioned that fewer men in the letter group answered the follow-up, and that carbon monoxide was measured only once, in samples that were not representative.

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: Randomized controlled trial of mailed smoking cessation advice, with a postal questionnaire 12 months later and breath carbon monoxide validation in a subsample
• Who was studied: 2,610 male current smokers aged 30 to 45. They were drawn from 16,393 men who attended a cross-sectional survey in 34 rural municipalities in western Norway (October 1988 to October 1989). All had self-reported previous occupational asbestos exposure, age- and height-adjusted FEV1 in the lowest quartile, or both. Of the 2,610, 1,186 had asbestos exposure only, 1,014 had reduced FEV1 only, and 410 had both.
• Exposure: The intervention was a personal letter mailed on January 15, 1990 by a respiratory physician. It reminded each man of his own answers on smoking and asbestos exposure and of his FEV1 result, and strongly advised him to quit. It came with a Norwegian Cancer Society pamphlet. Controls received no information. Asbestos exposure was self-reported previous occupational exposure; no fiber types, products or doses are given.
• Main results:
  • Among men who answered the follow-up questionnaire, 13.7% (n=148) of the intervention group versus 9.9% (n=119) of the control group reported not smoking (p<0.01).
  • Counting non-responders as still smoking (intention to treat), cessation rates were 11.4% in the intervention group versus 9.1% in the control group (p=0.05).
  • The 1-year sustained quit rate (no smoking at all in the preceding 12 months, by March 1991) was 5.6% in the intervention group versus 3.5% in the control group (p<0.05). The authors described this as a 60% improvement.
  • The letter's effect was higher in men with reduced FEV1 (OR=1.7; 95%CI 1.2 to 2.5) than in men with asbestos exposure (OR=1.2; 95%CI 0.8 to 1.7). This difference in effect was not statistically significant.
  • After adjustment for age, age at smoking onset, daily cigarette consumption and subgroup, the postal advice remained an independent predictor of quitting. Older age at smoking onset and low daily cigarette consumption also predicted quitting.
  • Breath carbon monoxide testing was done in men from 11 municipalities near Bergen who had reported quitting. Based on these results, the cumulative 18-month success rates were 6.5% (35 out of 537) in the intervention group versus 3.6% (21 out of 589) in the control group (p<0.05).
• The authors' conclusion: The authors concluded that postal smoking cessation advice from a respiratory physician improved the 1-year sustained quit rate by 60% in the identified high-risk smokers.
• Limitations the authors state:
  • The authors said selection bias may have affected the results. The follow-up response rate was lower in the intervention group (83%) than in the control group (92%), and non-responders in the intervention group may have been more likely to still be smoking.
  • Carbon monoxide, which has a short half-life, was measured only once and only in samples of men that were not representative.
  • Smokers were included regardless of their motivation to quit. The authors said this was reflected in the modest 1-year sustained quit rate of 5.6%.
  • Neither the letter nor the pamphlet mentioned nicotine replacement. The authors suggested that adding such information could possibly have improved success rates.

Topics

Medical terms in this study, explained in our Lexicon: FEV1, Asbestos Exposure, Habit.

Related studies

• Effectiveness of smoking cessation advice for asbestos workers — A. Johnson, P. Farrow, et al. (2006)
• Healthcare provider smoking cessation advice among US worker groups — D.J. Lee, L.E. Fleming, et al. (2007)
• A pilot study of telephone-based smoking cessation intervention in asbestos workers — O.Y. Osinubi, J. Moline, et al. (2003)
• Study of smoking behavior in asbestos workers — O.Y. Osinubi, A.A. Afilaka, et al. (2002)
• Beta-carotene supplementation and cancer risk: a systematic review and metaanalysis of randomized controlled trials — N. Druesne-Pecollo, P. Latino-Martel, et al. (2010)
• Mailing strategies and costs of recruiting heavy smokers in CARET, a large chemoprevention trial — B. Valanis, J. Blank, et al. (1998)

Browse more research in The European Respiratory Journal, or return to medical research.