Varenicline was associated with a reduction in ST use among ST users who had no intention of quitting in the next 30 days. Consistent with the mechanism of varenicline, ST users reported significantly decreased reinforcing effects of ST. ST users reported that reduction increased their confidence in maintaining reduction and quitting.
We observed lower abstinence rates than in previous ST reduction trials. In a larger trial (N
= 66) investigating the effect of switching ST users not interested in quitting but willing to reduce to ST products with less nicotine, subjects were randomized to controlled ST use or to ad lib ST use. At 12 weeks, 17.1% of subjects in the controlled ST use group achieved biochemically confirmed 7-day point prevalence abstinence compared with 25.8% in the ad lib group (Hatsukami et al., 2007
). In another study (N
= 106) investigating the effects of tobacco-free snuff or no snuff among ST users not interested in quitting but willing to reduce, 34.6% of subjects in the tobacco-free snuff group reduced their ST by 50% at Week 12 compared with 25.9% in the control group (Hatsukami et al., 2008
). Subjects in the second trial received counseling on behavioral methods for reduction, while we provided no counseling. Also, subjects in these trials were younger with fewer years of regular ST use than in our trial, which may have an effect on the observed differences in abstinence rates.
We noted that one half of our subjects reported having previously reduced their ST in preparation for quitting and 80% endorsed that this was an important technique in preparation for quitting. Although this likely reflects the type of ST user we recruited, this observation may provide insight into the general population of ST users. Research in smokers suggests that those planning to reduce are doing so as part of a quit attempt with the most common goal of a 50% reduction over a month (Hughes, Callas, & Peters, 2007
). In combination with data suggesting that reduction decreases tobacco use and increases abstinence rates among smokers (Stead & Lancaster, 2007
), our data suggests exciting new potential avenues of research among ST users not interested in quitting.
Subject recruitment was challenging because potential subjects eligible by telephone frequently reported their intention to quit when they attended the screening visit. These subjects endorsed a vague intent to quit but without a firm quit date. This observation seemed to confirm observations made by previous investigators who concluded that “many reducers report intention to quit because it is the socially desirable response … but have no real plans to quit” (Hughes et al., 2007
). We excluded individuals who maintained new intentions to quit and included only those with no intention in the next 30 days.
Our study has significant limitations. First, the medication intervention was open label without a control group. Second, we did not collect biochemical measures to determine nicotine or toxicant exposure reduction or elimination, but reductions in these markers have been observed in previous trials of ST reduction (Hatsukami et al., 2007
). Finally, we used the previously validated mCEQ and modified it for ST users but have not validated this tool. Other than changing “smoking” and “cigarettes” with “chewing” and “chew,” the only major adaptation was modifying “did you enjoy the sensations in your throat and chest” to “did you enjoy the sensations in your cheek and gum.”
We observed that varenicline may facilitate reduction among ST users willing to reduce who have not set a quit date. Both the efficacy and the clinical utility of this approach need to be explored.