A factorial randomized clinical trial of nicotine replacement therapy and treatment recommendations to quit vs continue e-cigarettes when quitting smoking in young adult dual users.

Introduction: Multiple tobacco product use has increased markedly in the US, especially dual use of cigarettes and e-cigarettes among young adults. Little is known regarding nicotine replacement therapy (NRT) for young adult dual users, or whether to recommend quitting vs continuing e-cigarettes during smoking cessation treatment.

Methods: This 2x2 factorial trial randomized 396 young adult dual users (aged 18-29; ≥5 cigarettes/day; used e-cigarettes on ≥10 of past 30 days) to receive 12 weeks of combination NRT vs No NRT to quit smoking, plus text-based treatment recommendations to Quit vs Continue E-cigarettes. The primary outcome was self-reported end-of-treatment 7-day point-prevalence abstinence (PPA) from cigarettes; a secondary outcome was end-of-treatment 30-day PPA from cigarettes.

Results: Participants were 26.0 (SD=6.8) years old, 52.8% female, and 26.5% non-white. At week-12, NRT increased 7-day PPA (NRT=50.5% vs No NRT=39.9%; OR=1.54, 95% CI=1.03, 2.29), but neither treatment recommendation (Quit E-cigarettes=48.0% vs Continue E-cigarettes=42.4%; OR=1.25, 95% CI=0.84, 1.85) nor the NRT-by-treatment recommendation interaction were significant. The direction and magnitude of main effects for 30-day PPA at week-12 were similar to 7-day PPA, but the NRT-by-treatment recommendation interaction was significant (p=0.04): smoking cessation was greatest for the NRT plus Quit E-cigarettes condition (47.1%) vs NRT plus Continue E-cigarettes (28.1%); No NRT plus Quit E-cigarettes (29.2%); and No NRT plus Continue E-cigarettes (30.4%) conditions (all p<0.05).

Conclusions: NRT is effective in promoting early smoking cessation among young adult dual users. Secondary findings indicate that pairing NRT with support to quit both products could enhance effects on prolonged cigarette abstinence.

Implications: Despite increases in dual use of cigarettes and e-cigarettes among young adults, there is a notable lack of research on smoking cessation treatments. This factorial randomized clinical trial investigated the effectiveness of nicotine replacement therapy (NRT) for smoking cessation with recommendations to quit vs continue using e-cigarettes during smoking cessation treatment among young adults who dually use cigarettes and e-cigarettes. Findings indicate that NRT is effective in achieving early cigarette abstinence in this population and suggest the strongest effects may be achieved among those who receive NRT combined with support to quit rather than continue using e-cigarettes during treatment.