A Cochrane review on cessation of smokeless, or spit, tobacco (moist ground tobacco, e.g. snuff, and chewing tobacco) included 34 studies with a total of more than 16 000 subjects. Twelve studies assessed the effect of pharmacological interventions and 17 the effect of behavioural interventions for smokeless tobacco (ST) use. Varenicline increased ST abstinence rates (OR 1.34, 95% CI 1.08 to 1.68; 2 trials, n=507) at 6 months. Two trials of bupropion did not detect a benefit of treatment after six months or longer (OR 0.86, 95% CI 0.47 to 1.57). Neither nicotine patch (RR 1.13, 95% CI 0.93 to 1.37; 5 trials, n=1083) nor nicotine gum (RR 0.99, 95% CI 0.68 to 1.43; 2 trials, n=310) increased abstinence. Nicotine lozenges did increase tobacco abstinence (RR 1.36, 95% CI 1.17 to 1.59; 5 trials, n=1529) but confidence in this estimate is low as the result is sensitive to the exclusion of 3 trials which did not use a placebo control. There was statistical heterogeneity among trials of behavioural interventions; 8 of them reported statistically and clinically significant benefits, 6 suggested benefit but with wide CIs, whilst 3 had similar intervention and control quit rates and relatively narrow CIs. Most trials included either telephone counselling, an oral examination and feedback about any ST induced mucosal changes, or both. In a post-hoc subgroup analysis there was some evidence that behavioural interventions which include telephone counselling might increase abstinence rates more than interventions with less contact. In one trial an interactive website increased abstinence more than a static website.
Comment: The quality of evidence is downgraded by inconsistency (variability in results across studies) and by limitations in study quality.