Aims

It is not known whether the machine-smoked nicotine yield of usual brand of cigarette smoked is associated with the chances of success of quit attempts. This study aimed to assess this association.

Design

Prospective study.

Setting

Republic of Korea.

Participants

A total of 16 808 male smokers registered for the Quitline between 7 April 2006 and 31 December 2013. Of these, 13 176 participants who were > 19 years of age and provided data on their demographic characteristics, smoking-related behaviors, nicotine dependence, tobacco brands used and self-efficacy were included in this study.

Measurements

Machine-smoked nicotine yield was based on information provided by tobacco companies on cigarette packages that smokers reported as their usual brand. Ultra-low nicotine yield was defined as ≤ 0.1 mg machine-smoked nicotine yield per cigarette, whereas higher nicotine yield was defined as > 0.1 mg machine-smoked nicotine yield. Participant personal information and self-reported continuous abstinence at 1-month, 6-month and 1-year follow-up were recorded in electronic databases.

Findings

Continuous abstinence rates in the ultra-low nicotine yield versus higher nicotine yield groups were, respectively, 40.7 versus 34.6% at 1 month [odds ratio (OR) = 1.22, 95% confidence interval (CI) = 1.12-1.33], 22.7 versus 18.8% at 6 months (OR = 1.20, 95% CI = 1.08-1.32) and 19.5 versus 16.6% (OR = 1.19, 95% CI = 1.10-1.29) at 1 year. The association between ultra-low nicotine yield cigarette smoking and successful quitting was stronger among the smokers with higher cigarette dependence.

Conclusions

Male smokers who use the Korean Quitline are more likely to quit successfully if they smoke ultra-low nicotine yield cigarettes than if they smoke higher nicotine yield cigarettes.