Preplanned Studies: Assessing the Effectiveness of a Community-Based Smoking Cessation Intervention — Shenzhen City, Guangdong Province, China, 2022

In China, there are over 300 million smokers, with approximately 19.8% having attempted to quit within the past 12 months (1). While numerous studies have demonstrated that cessation medication and counseling can improve quit rates (2–3), a mere 4.6% and 3.2% of those who tried to quit within the past 12 months reported using smoking cessation medication or receiving cessation counseling, respectively (1). This suggests that current cessation services are insufficient in addressing the needs of smokers aiming to quit.

In this study, the effectiveness of a comprehensive, community-based cessation intervention model was evaluated through a two-arm, parallel, cluster-randomized controlled trial conducted between August 2022 and March 2023 in Shenzhen, China. Eligible smokers were recruited through community health service centers (CHSC) and were assigned to receive either the community-based cessation intervention or self-help smoking cessation materials. Participants were followed up via telephone for three months. A total of 492 eligible participants were included in the analysis. The intervention group demonstrated a significantly higher self-reported quit attempt rate, 7-day point prevalence of abstinence rate (PPAR), smoking reduction rate, and continuous abstinence rate (CAR) compared to the control group at the three-month follow-up (59.75% vs. 40.63%, 33.05% vs. 21.88%, 33.47% vs. 23.05%, and 21.61% vs. 8.98%; P<0.05). Furthermore, participants who received the community-based cessation intervention [adjusted odds ratio (aOR)=3.530, 95% confidence interval (CI): 1.942–6.413], had lower perceived difficulty of quitting scores (aOR=0.872, 95% CI: 0.773–0.984), and were married (aOR=2.203, 95% CI: 1.025–4.736) exhibited a higher likelihood of achieving continuous abstinence (CA).

Twenty matched communities in Shenzhen were selected and randomized (1∶1) into either the intervention or control group. Eligible participants were current smokers over 18 years of age who planned to quit within one month and signed an informed consent form; individuals with psychiatric or psychological disorders were excluded (Figure 1). For the intervention group, a “3+1” smoking cessation service model, developed based on the “5A” (Ask, Advise, Assess, Assist, Arrange) and “5R” (Relevance, Risks, Rewards, Roadblocks, Repetition) principles (4), was provided by trained and assessed CHSC physicians. The “3+1” model comprised three face-to-face interventions at the initial visit, 7 days, and 1 month after the quit date, as well as one telephone intervention on the quit date. The first visit featured a 40-minute face-to-face cessation counseling session, while the following two face-to-face interventions lasted for at least 20 minutes on the seventh day and first month after the quit date. The telephone intervention on the quit date typically spanned approximately 5 minutes.

Figure 1. 

Flowchart of participant recruitment and progression throughout the study — Shenzhen City, China, 2022.

Moreover, in the intervention group, community workers implemented advocacy initiatives and established smoke-free environments, including smoke-free schools, smoke-free households, and smoke-free government buildings, to foster an anti-tobacco atmosphere. Participants in this group also received self-help cessation materials. Conversely, the control group was solely provided self-help cessation materials, distributed by CHSC physicians. The study gained ethical approval from the Ethical Review Committee of the China CDC (202128) and was registered in the Chinese Clinical Trial Registry (ChiCTR2200056242).

In the current study, participants lost to follow-up were treated as continuing smokers with no decrease in cigarette consumption relative to baseline. Outcome measures encompassed quit attempts, 7-day point prevalence of abstinence (PPA), CA, and smoking reduction at the three-month follow-up. Among these measures, a quit attempt referred to self-reported abstinence from smoking for 24 hours or longer; 7-day PPA denoted self-reported abstaining from smoking for the preceding seven consecutive days or more; CA described self-reported sustained abstinence from smoking since the designated quit date; and smoking reduction was characterized as self-reported reduction in daily cigarette consumption by half or greater in comparison to the initial visit, excluding participants who self-reported cessation. An intent-to-treat approach was employed for this study.

Data analysis was conducted using SAS software (version 9.4; SAS Institute, Inc., Cary, NC, USA). Continuous variables adhering to a normal distribution were described using means and standard deviations, whereas non-normally distributed variables were presented as medians and interquartile ranges. Categorical variables were summarized using frequencies and corresponding percentages. Unconditional logistic regression analysis was utilized to examine factors associated with 3-month continuous abstinence. Odds ratios (OR) and 95% CI were calculated. All P-values were two-sided, with P<0.05 indicating statistical significance.

In the current research, a sample of 492 participants was gathered, comprising 236 individuals from intervention communities and 256 from control communities. The mean age of the participants was 42.34±13.14 years, with a majority being male (95.12%). Most participants were married (81.91%) and employed (70.53%), and approximately one-third (33.13%) had obtained a college degree or higher educational attainment (Table 1).

At the three-month follow-up, successful smoking cessation was reported by 15.04% of participants. The CAR for the intervention group was 21.61%, which was significantly higher than the control group’s 8.98% [unadjusted odds ratio (cOR)=2.793, 95% CI: 1.646–4.739]. Participants with a shorter smoking history were more likely to quit (cOR=0.975, 95% CI: 0.954–0.997). Lower nicotine dependence was associated with a higher CAR, as low, moderate, and severe nicotine dependence levels resulted in CARs of 19.84%, 9.63%, and 10.91%, respectively (cOR=0.644, 95% CI: 0.458–0.905). Furthermore, higher CARs were observed among participants who perceived greater importance in quitting (cOR=1.134, 95% CI: 1.000–1.286), reported lower difficulty in quitting (cOR=0.904, 95% CI: 0.823–0.994), and expressed higher confidence in quitting (cOR=1.161, 95% CI: 1.044–1.291) (Table 1).

A logistic regression model was employed to investigate the predictors associated with CAR (1: cessation maintained for three months, 0: cessation not maintained for three months). The results revealed that participants in the intervention group had a higher likelihood of achieving continuous abstinence (aOR=3.530, 95% CI: 1.942–6.413), while perceiving greater difficulty in quitting smoking was associated with a reduced probability of sustaining abstinence for three months (aOR=0.872, 95% CI: 0.773–0.984). Additionally, married participants were more likely to remain abstinent from smoking for three months (aOR=2.203, 95% CI: 1.025–4.736) (Table 2).

A similar method was utilized to investigate differences between the intervention group and the control group in relation to quit attempts, PPA, and smoking reduction at a three-month follow-up. The findings revealed that a higher proportion of participants in the intervention group (59.75%) attempted to quit smoking as compared to the control group (40.63%), with an aOR of 3.063 and a 95% CI of 1.965–4.774. Moreover, the intervention group displayed a higher PPA rate (33.05%) in contrast to the control group (21.88%), with an aOR of 2.364 and a 95% CI of 1.481–3.773. Lastly, there was a statistically significant difference between the proportions of participants who reduced daily cigarette consumption by half or more in the intervention group (33.47%) compared to the control group (23.05%), with an aOR of 1.738 and a 95% CI of 1.942–6.413 (Table 2).