Cigarette smokers' concurrent use of smokeless tobacco: dual use patterns and nicotine exposure.

Background: The concurrent use of cigarettes with other tobacco products, such as smokeless tobacco (SLT), is increasingly common. Extant work with cigarette smokers who also use SLT is based heavily on retrospective reports and between-group comparisons. The purpose of this study was to assess prospectively the patterns of dual users' product use and nicotine exposure on days when cigarettes were smoked exclusively (single use) versus concurrently with SLT (dual use).

Design: Forty-six dual cigarette-SLT users recorded their product use in real time via ecological momentary assessment for a 2-week longitudinal design. They responded to questions about situational factors (eg, location, mood) using this same diary, and collected saliva samples each night for later cotinine measurement. At the end of this 2-week period, users reported on their reasons for and beliefs about SLT use.

Results: Cotinine levels were significantly higher on dual versus single use days (mean±SEM=374.48±41.08 ng/mL vs 300.17±28.13 ng/mL, respectively; p<0.01), and the number of cigarettes logged was higher on dual versus single use days (11.13±0.98 vs 9.13±1.11, respectively; p<0.01). Product use was distinguished by situational factors, with the strongest predictor being location of use. Moreover, the most common reason for initiating (56.52%) and continuing (67.39%) SLT use was to circumvent indoor smoking restrictions.

Conclusions: Results support the idea of product supplementation rather than replacement among this convenience sample of dual users. For smokers whose primary motivation for SLT use involves situations where they would otherwise be tobacco free, the potential benefits of clean indoor air laws may be diminished.