This is a 2-year, randomized, two-arm study involving a 6-month period of progressive reduction in the nicotine content of cigarettes. During the first year (tapering/maintenance phases), subjects will smoke progressively reduced nicotine content (RNC) cigarettes over a period of six months, and then remain on the lowest nicotine content cigarette for an additional six months. Comparisons will be made with a control group in which subjects will smoke their usual normal nicotine yield cigarettes. There will be a one year follow-up phase during which subjects will be monitored and will be free to resume smoking a commercial cigarette of their choice, or to quit.~We hypothesize that smokers of cigarettes with progressively reduced nicotine content will experience a reduction in nicotine intake without compensatory oversmoking. This will serve to wean them from nicotine and result in a decreased level of nicotine dependence. Once this has occurred, subjects will then be able to maintain their reduced level of nicotine intake for the 6 months that they continue smoking the lowest level RNC cigarette. When they are again free to choose any smoking behavior (follow-up phase), as a result of the period of lowered dependence they will smoke fewer cigarettes and/or have a greater interest in quitting compared to the control group, whose level of nicotine dependence is hypothesized to be sustained throughout.~Primary Hypotheses:~Nicotine intake will be lower for the RNC group than for the control group.~Exposure to tobacco smoke gas phase constituents will be similar for the RNC and control group.~Exposure to tobacco smoke tar constituents will be similar for the RNC and control group.~Cardiovascular biomarkers of inflammation, platelet activation, endothelial dysfunction, and HDL cholesterol will be lower for the RNC group than for the control group.~Cigarette consumption, as measured by cigarettes-per-day (CPD), will be lower for the RNC group than for the control group.~Secondary hypotheses:~Over the course of tapering and maintenance and at follow-up, interest in quitting will be higher in the RNC group compared to the control group.~At follow-up, measures of cigarette consumption, nicotine intake, and exposure to tobacco smoke combustion constituents will be lower for the RNC group compared to the control group.
This is a 2-year study involving the progressive reduction in the nicotine content of cigarettes. The investigators believe that at the end of the study smokers of cigarettes with progressively reduced nicotine content will be weaned from nicotine. At the end of the study, the result will be a decreased level of nicotine dependence. When smokers are again free to choose any smoking behavior, they will smoke fewer cigarettes and/or have a greater interest in quitting compared to a control group that smokes their usual cigarettes.