Randomized Trial of Low-Nicotine Cigarettes and Transdermal Nicotine

Abstract

Introduction: A mandated reduction in the nicotine content of cigarettes may decrease smoking, but also increase demand for other nicotine products. The present study tested the impact of smoking cigarettes with very low nicotine content and concurrent use of a transdermal nicotine patch.

Study design: A balanced 2 × 2 factorial randomized clinical trial investigating the impact of cigarette nicotine content (double-blind, very low nicotine content versus normal nicotine content) and use of a transdermal nicotine patch (open label, patch versus no patch).

Setting/participants: Adult daily smokers (n=240) in the Pittsburgh, PA area.

Intervention: Participants were provided with research cigarettes and transdermal nicotine patches (if assigned to patch condition) for 7 weeks. Cigarettes were Spectrum brand (National Institute on Drug Abuse) and either 15.8 mg nicotine/g tobacco (normal nicotine content) or 0.4 mg nicotine/g tobacco (very low nicotine content). In the 7th week, participants were monetarily incentivized to abstain from smoking.

Main outcome measures: Participants reported daily cigarette use throughout the trial and the primary outcome was average number of cigarettes smoked per day (study + nonstudy) during Week 6. Participants were recruited from 2015 to 2017 and data were analyzed between 2017 and 2018.

Results: Assignment to very low nicotine content cigarettes and assignment to wear a nicotine patch both reduced the number of cigarettes smoked per day during Week 6 (p=0.001 and 0.04, respectively). However, assignment to the patch along with very low nicotine content cigarettes did not significantly reduce cigarette smoking compared with assignment to very low nicotine content cigarettes alone.

Conclusions: A mandated reduction in the nicotine content of cigarettes is likely to reduce the number of cigarettes smoked per day, but the added benefit of concurrent transdermal nicotine is unclear. Future studies should investigate whether alternative sources of noncombusted tobacco, such as e-cigarettes, enhance the effects of very low nicotine content cigarettes on smoking.

Trial registration: This study is registered at www.clinicaltrials.gov NCT02301325.

Copyright © 2019 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

Figures

Figure 1.

Number of total (A) and study (B) cigarettes smoked per day from baseline through Week 6 of the study. NNC, normal nicotine content; NRT, nicotine-replacement therapy; VLNC, very low nicotine content.

Figure 2.

Compliance with use of study cigarettes: (A) percent of subjects in each group who self-report using only study cigarettes in Week 6; (B) percent of participants with urinary total anatabine levels

Figure 3.

Intent to treat (A) and causal inference model (B) estimates for time to first lapse during the Week 7 abstinence incentive week. NNC, normal nicotine content; NRT, nicotine-replacement therapy; VLNC, very low nicotine content.