Aim: To update conclusions of a previous review of smoking reduction on the extent to which (1) smokers spontaneously reduce their smoking, (2) smokers who try to quit and fail return to smoking less, (3) smokers can substantially reduce and maintain reductions via pharmacological and behavioral treatments and (4) smokers compensate when they reduce.
Method: Qualitative systematic review.
Data sources: Systematic computer searches and other methods.
Study selection: Published and unpublished studies of smokers not trying to stop smoking. We located 13-26 studies for each of the four aims.
Data extraction: The first author entered data with confirmation by second author.
Data synthesis: Due to the heterogeneity of methods and necessity of extensive recalculation, a meta-analysis was not feasible.
Results: Few daily smokers spontaneously reduce. Among those who try to stop smoking and relapse, some return to reduced smoking but whether they maintain this reduction is unclear. Nicotine replacement (and perhaps behavior therapies) can induce smokers not interested in quitting to make significant reductions in their smoking and maintain these over time. Some compensatory smoking occurs with reduction but significant declines in smoke exposure still occur.
Conclusions: These results indicate that reduction is feasible when aided by treatment. Whether reduction should be promoted will depend on the effect of reduction on health outcomes and future cessation.