Background and aims: This study aims to (i) examine the effectiveness of internet-based smoking cessation programs; (ii) describe the number and type of behavior change techniques (BCTs) employed; and (iii) explore whether BCTs included in internet-based smoking cessation programs are related to program effectiveness.
Methods: MEDLINE, CINAHL, EMBASE, PsycINFO, and CENTRAL databases were searched. Randomized controlled trials were included if they described the study of a smoking cessation program delivered via the internet; included current adult tobacco smokers from the general population; and were written in English. Random effects meta-analyses and meta-regressions were used to examine program effectiveness (pooled odds ratios, by outcome measure, i.e., 7 day point prevalence abstinence [PPA], 30 day PPA, other abstinence measure) in short- and long-term outcomes, and examine the associations between BCT number and type (individual BCTs and BCT domain) and program effectiveness.
Results: Results from 45 studies were included (n = 65,736). Intervention effectiveness was found in the short term for all outcome measures (OR = 1.29, 95% CI 1.12, 1.50, p = .001), for "prolonged abstinence" (OR = 1.43, 95% CI 1.09, 1.87, p = .009), and "30 day PPA" (OR = 1.75, 95% CI 1.13, 2.72, p = .013). Internet-based programs were effective in the long term for all outcome measures (OR = 1.19, 95% CI = 1.06, 1.35, p = .004) and for "prolonged abstinence" (OR = 1.40, 95% CI 1.19, 1.63, p < .001). On average, interventions used more BCTs than comparison groups (6.6 vs. 3.1, p = .0002). The impact of specific individual BCTs and BCT domains on effectiveness was examined and is reported.
Conclusions: Internet-based smoking cessation interventions increased the odds of cessation by 29 per cent in the short term and by 19 per cent in the long term. Internet-based smoking cessation intervention development should incorporate BCTs to increase effectiveness.