Does quantity of smoking reduction predict later abstinence: a posteriori evidence from a randomized control trial

Abstract

BACKGROUND AND AIM: Behavioral and nicotine replacement therapy (NRT) are effective in helping smokers reduce smoking first before complete cessation. We examined whether the percentage reduction in cigarette consumption predicted later abstinence. METHODS: A posteriori analysis was done on 928 smokers who did not want to quit and participated as subjects in the intervention group of a randomized controlled trial of counseling and free NRT for 8 weeks. Reduction was analysed as the percentage of decrease in self-reported daily cigarette consumption at different follow-ups (1-week, 1- & 3-month) compared with that at baseline. Logistic regression model was used to examine if smoking reduction quantity predicted quitting at 6-month follow-up. FINDINGS: Reducing smoking by less than 50% in all the early follow-ups was not significant predictors of abstinence. Smoking reduction by 50% or more at 1 week (OR=1.95, 95%CI:0.96-3.95) and 1 month (OR=5.96, 95%CI:1.37-25.98), and reduction by 75% or more at 3 months (OR=7.24, 95%CI:1.94-27.01) were predictive to abstinence. Progressively increasing the reduction quantity from 1 week to 3 months (OR=2.68, 95%CI:1.37- 5.25), or from 1 month to 3 months (OR=2.34, 95%CI:1.24-4.43) can increase the chance of abstinence. CONCLUSIONS: Greater smoking reduction predicted greater success in cessation. To increase the effectiveness of the smoking reduction intervention, clinicians should advise the smokers who do not wish to quit to reduce smoking by 50% or more, and to reduce further until total abstinence is achieved.