Nicotine Dependence and Quit Self-Confidence in a Smoking Cessation Program Using a Group-Based Digital Peer-Supported App and Cigarette Consumption-Adjusted Nicotine Aids Among Japanese Workers: Retrospective Cohort Study.

Background: Completion rates for smoking cessation treatments under Japan's national health insurance system remain suboptimal. A workplace cessation program, combining nicotine gum or patches with a group-based digital peer-supported app, has reported high cessation success rates. Although nicotine dependence is generally associated with lower cessation success, and self-confidence is generally associated with higher success, these associations may differ by tobacco product type. Evidence on these relationships in app-based cessation programs remains limited. Objective: This study aimed to examine the independent and combined associations of nicotine dependence and self-confidence in quitting with smoking cessation success among cigarette-only smokers, heated tobacco product-only users, and dual users. Methods: This retrospective cohort study used data from a workplace cessation program in Japan. Participants were eligible if they were employed, owned a smartphone, and self-enrolled in the program. Recruitment was conducted through workplace promotion and individual outreach, primarily via email from companies. The program combined a digital peer-support app with nicotine gum or patches, adjusted according to cigarette consumption. The app included anonymous peer-support group chats of up to 5 participants, where participants shared progress, photos, and comments. Nicotine dependence was assessed by the time to the first cigarette after waking (high: ≤30 min; low: >30 min). Self-confidence for quitting was rated on a 0-10 scale and dichotomized at the median. A 4-level variable combined nicotine dependence and self-confidence for quitting. Logistic regression analyses were conducted by tobacco product type, and odds ratios (ORs) and 95% CIs were estimated. Results: A total of 2143 participants were included in the analysis. Their mean age was 46.5 (SD 10.9) years, and approximately 90% were men. Overall cessation success was 53.8% (1152/2143). Participants with high self-confidence had a higher cessation success rate than those with low self-confidence (529/834, 63.4% vs 623/1309, 47.6%), with an OR of 1.81 (95% CI 1.55-2.12). Nicotine dependence was significantly associated with cessation success only among cigarette-only smokers; those with low nicotine dependence had a higher OR than those with high dependence (OR 1.59, 95% CI 1.07-2.37). Across all tobacco product types, the subgroup with low nicotine dependence and high self-confidence showed the highest cessation success, followed by the subgroup with high nicotine dependence but high self-confidence. Conclusions: By distinguishing cigarette-only smokers, heated tobacco product-only users, and dual users in a workplace cessation program, this study provides novel, product-specific evidence regarding nicotine dependence and self-confidence related to cessation success. This study extends prior research beyond cigarette-only smokers by examining tobacco user groups and suggests that self-confidence may predict cessation across tobacco product types, whereas the role of nicotine dependence may be product-specific. These findings may inform tailored, scalable smoking-cessation support in workplaces; however, they should be interpreted with caution because cessation outcomes were self-reported.