Jon O Ebbert, Muhamad Y Elrashidi, Lindsay F Stead

Use of smokeless tobacco (ST) can lead to tobacco dependence and long-term use can lead to health problems including periodontal disease, cancer, and cerebrovascular and cardiovascular disease. To assess the effects of behavioural and pharmacologic interventions for the treatment of ST use. We searched the Cochrane Tobacco Addiction Group specialised register in June 2015. Randomized trials of behavioural or pharmacological interventions to help users of ST to quit with follow-up of at least six months. We used standard methodological procedures as expected by the Cochrane Collaboration. We summarised outcomes as risk ratios (RRs). For subgroups of trials with similar types of intervention and without substantial statistical heterogeneity, we estimated pooled effects using a Mantel-Haenszel fixed-effect method. We identified 34 trials that met the inclusion criteria, of which nine were new for this update, representing over 16,000 participants. There was moderate quality evidence from two studies suggesting that varenicline increases ST abstinence rates (risk ratio [RR] 1.34, 95% confidence interval (CI) 1.08 to 1.68, 507 participants). Pooled results from two trials of bupropion did not detect a benefit of treatment at six months or longer (RR 0.89, 95% CI 0.54 to 1.44, 293 participants) but the confidence interval was wide. Neither nicotine patch (five trials, RR 1.13, 95% CI 0.93 to 1.37, 1083 participants) nor nicotine gum (two trials, RR 0.99, 95% CI 0.68 to 1.43, 310 participants) increased abstinence. Pooling five studies of nicotine lozenges did increase tobacco abstinence (RR 1.36, 95% CI 1.17 to 1.59, 1529 participants) but confidence in this estimate is low as the result is sensitive to the exclusion of three trials which did not use a placebo control.Statistical heterogeneity was evident among the 17 trials of behavioural interventions: eight of them reported statistically and clinically significant benefits; six suggested benefit but with wide CIs and no statistical significance; and three had similar intervention and control quit rates and relatively narrow CIs. Heterogeneity was not explained by study design (individual or cluster randomization), whether participants were selected for interest in quitting, or specific intervention components. In a post hoc subgroup analysis, trials of behavioural interventions incorporating telephone support, with or without oral examination and feedback, were associated with larger effect sizes, but oral examination and feedback alone were not associated with benefit.In one trial an interactive website increased abstinence more than a static website. One trial comparing immediate cessation using nicotine patch versus a reduction approach using either nicotine lozenge or brand switching showed greater success for the abrupt cessation group. Varenicline, nicotine lozenges and behavioural interventions may help ST users to quit. Confidence in results for nicotine lozenges is limited. Confidence in the size of effect from behavioural interventions is limited because the components of behavioural interventions that contribute to their impact are not clear.