Motivating smokers to quit using computer-generated letters that target either reduction or cessation: A population-based randomized controlled trial among smokers who do not intend to quit

Abstract

Background: This study examined the long-term efficacy of individualized counseling letters that targeted either smoking abstinence or reducing the number of cigarettes smoked per day to promote future cessation.

Methods: A nationwide random-digit-dialing telephone sample was used to identify smokers from the general adult population (participation proportion: 54.5%). In total, 1462 participants (48% female) who did not intend to quit within the next six months and who smoked ten or more cigarettes a day were randomized to one of two intervention groups or an assessment-only control condition. The interventions consisted of three tailored letters that were sent after baseline and follow-up assessments after three and six months. Follow-up data on smoking status were provided by 82% and 77% of the participants 12 and 24 months after study inclusion, respectively. Generalized estimation equation (GEE) models adjusted for potential baseline confounders and multiple imputation of missing follow-up data were used to estimate intervention effects.

Results: At 24-month follow-up prevalence of 7-day point abstinence was 8.4%, 12.9% and 14.7% in the control, abstinence intervention and reduction intervention condition, which corresponds to a number needed to treat of 22 (95%-CI: 11-707) and 16 (95%-CI: 9-53). Adjusted GEE analyses revealed that the smoking reduction intervention (ORadj=2.3, p<0.01) but not the abstinence intervention (ORadj=1.4, p=0.20) increased the odds of 6-month prolonged abstinence compared with the control condition. No significant differences appear when directly comparing both intervention groups.

Conclusion: Smoking reduction should be considered as an alternative intervention goal for smokers who are unable or unwilling to quit.

Keywords: Computer expert system; Population-based interventions; Reduced smoking; Self-help intervention; Smoking cessation.