Does dual use jeopardize the potential role of smokeless tobacco in harm reduction?

INTRODUCTION: The use of smokeless tobacco as part of a strategy to reduce the harm from cigarette smoking is a topic of debate within the tobacco control and public health communities. One concern voiced regarding endorsement of such a tactic is the possibility of actually increasing harm should current smokers adopt dual cigarette/smokeless tobacco use (dual use), which could lead to unintended consequences by perpetuating cigarette smoking, diminishing tobacco cessation, or increasing tobacco-related harm.
METHODS: Here, we review the available literature on health effects and trajectories of use among dual users from a variety of U.S. and European epidemiological studies.
RESULTS: These data suggest that there are not any unique health risks associated with dual use of smokeless tobacco products and cigarettes, which are not anticipated or observed from cigarette smoking alone. Furthermore, studies show that dual users smoke fewer cigarettes than exclusive smokers, and studies of tobacco use patterns over time (tobacco use trajectory data) indicate that dual users are more likely than exclusive cigarette smokers to cease smoking.
CONCLUSIONS: Overall, the concern about dual use appears to be contradicted by the evidence in the literature that dual use of smokeless tobacco and cigarettes may result in reduction in smoking-related harm as smoking intensity is decreased and smoking cessation increases.