3.3.1 Overall Quit Rates
The quit rates yielded from smoking-cessation interventions for young adults varied among the included studies, depending on the measures and the follow-up period. Most studies relied on self-reported 7-day abstinence rates. Table 3 presents the detailed information.
For text-based interventions, all four studies reported that quit rates in the intervention group were higher than the control groups, although none were statistically significant. One study reported quit rates of 44% at 1 month (Ybarra et al., 2013), and abstinent rates were 40% based on self-reported 7-day abstinence rates at 3-month follow-up (Ybarra et al., 2013). Another study reported quit rates of 12.5% at 6 months (self-reported 7-day abstinence) and 6.3% (30-day abstinence; Haug et al., 2013). Another study with tailored text messages reported quit rates of 18.8% at 12-month follow-up based on self-reported a 30-day abstinence (Skov-Ettrup et al., 2014). In Graham et al’s study, with intention-to-treat, the 7-month 30-day point prevalence abstinence rate was 24.1% (314 of 1304) among “This is Quit- text message program” participants and 18.6% (239 of 1284) in the control group (Odds ratio = 1.39 (1.15–1.68), p < .001).
For the social media–based interventions, all three studies reported quit rates based on 7-day abstinence rates. All studies conducted a Facebook-based intervention and compared it to quit rates of the control group referred to the smokefree.gov site. One group tested the intervention with a RCT study design, and quit rates were 13.6%, 18.6%, and 21.8% at 3 months, 6 months, and 1 year based on the self-reported 7-day abstinence (Ramo et al., 2018). The other two studies reported the outcomes without a control group and quit rates, and the other study stated a self-reported 7-day abstinence rate of 8.6% for sexual and gender minority (SGM) individuals and 15.4% for non-SGM young adults at 3-month follow-up, and 18.8% and 15.4% at 6-month follow-up, respectively (Vogel et al., 2019).
Two studies tested a phone or virtual counseling as an intervention compared to the control group. One RCT study tested the quit line, and yielded biochemically verified quit rates of 11%, 8.1%, and 6.7% at 1-, 3-, and 6-month follow-up (Sims et al., 2013), which were higher than the control group with a self-help booklet–based treatment group. Similarly, Zanis et al. (2011) tested the quit line intervention as a control group compared to the in-person counseling, and it resulted in a 10.2% self-reported 30-day quit rate at 3-month follow-up; brief direct counseling resulted in 19.8% quit rates in the intervention group.
Two studies used app-based or web-based interventions. In a randomized controlled trial study, the intervention group used a comprehensive evidence-based smoking cessation smartphone app where participants customized a cessation plan and were reminded of how much money they had saved (Baskereville et al., 2018). Participants in the control group received a self-help guide developed by Health Canada for young adult smokers called Pathways to Quit. Intention-to-treat analysis (last observation carried forward) showed that continuous abstinence (N = 1599) at 6 months and 30-day point prevalence abstinence at 6 months were not significantly different (Baskereville et al., 2018). At the 6-month follow-up, secondary measures of quit attempts and the number of cigarettes smoked per day did not show significant differences between groups (Baskereville et al., 2018). Overall satisfaction, perceived helpfulness, and frequency of use were higher and statistically significant in the control group compared to the intervention group (Baskereville et al., 2018). Participants in the intervention group in another study were asked to visit the U@Uni website and view online resources on health behaviors in the form of text and video and downloaded the U@Uni smartphone app at the beginning of the second semester (Epton et al., 2014). The control group did not receive any resources. The intervention had a statistically significant effect on smoking status (current smoker) at the 6-month follow-up, with fewer smokers in the intervention group (8.7%) than in the control group (13.0%; OR = 1.92, p =. 010) (Epton et al., 2014).
Three studies tested in-person counseling interventions using a RCT design. Zanis et al. (2011) reported a bio-chemically confirmed 30-day abstinence rate of 19.8% at 3 months, compared to the control group, which reported 10.2% quit rates based on telephone Quitline intervention. Harris et al. (2010) described a self-reported quit rate of 31.4% at post-intervention and a bio-chemically verified 30-day abstinence rate of 20.4% at 6 months, which became slightly lower than the control group at 6 months compared to quit rates of 28.0% and 20.4% in the control arm, respectively (Harris et al., 2010). The study conducted by Orsal & Ergun (2021) examined the effects of peer education on the decision to quit smoking, factors that encourage smoking, self-efficacy, and behavior change among students who apply to the Youth Friendly Center to quit smoking. Results showed that participants in the experimental group had a higher quit rate than the control group (p > 0.01) and that 94% of students in the intervention group were free of nicotine addiction and had successfully quit at the seventh and eighth follow-up (p < 0.001).
One study provided a booklet-based intervention with a booster phone call (Travis & Lawrance, 2009) with three arms of the RCT study, and this study reported a 11.4% self-reported 7-day abstinence rate at 3-month follow-up, compared to the usual care group or other booklet-based program, which was statistically significant. One pharmacological intervention reported a 7-day abstinence rate with a nicotine patch of 19.6%, which was significantly higher than the Varenicline (15.7% or placebo 9.8%) groups (Tuisku et al., 2016).
3.3.2 Quit Attempts and Other Outcomes
In addition to the overall quit rates, other self-reported outcomes (i.e., quit attempts, readiness to quit, and stage of change) were used to evaluate the effects of smoking-cessation interventions (Harris et al., 2010; Haug et al., 2013; Ramo et al., 2018). For example, American college students who received up to four one-on-one MI sessions for smoking cessation reported significantly greater quit attempts at the end of treatment (Odds Ratio = 1.75, 95% CI [1.11, 2.74], p = 0.02) and 6-month follow-up (Odds Ratio = 1.66, 95% CI [1.11, 2.47], p = 0.01) than college students who received MI for fruits and vegetables (Harris et al., 2010). However, such an increase was not seen in the web- or text message–based interventions. For example, the Tobacco Status Project (TSP) Facebook smoking-cessation intervention did not increase quit attempts (Odds Ratio = 0.94, 95% CI [0.22–3.73], p = 0.929) or the readiness to quit smoking (Odds Ratio = 0.927, 95% CI [0.089–9.68], p = 0.947) over a period of 12 months among young adults in the United States (Ramo et al., 2018). In Switzerland, there were no differences in quit attempts (Odds Ratio = 1.18, 95% CI [0.81–1.72], p = 0.38) and stage of change (p = 0.69), whether vocational school students were daily smokers and had received a weekly SMS text-message intervention or not (Haug et al., 2013).