Effect of reducing the nicotine content of cigarettes on cigarette smoking behavior and tobacco smoke toxicant exposure: 2-year follow up

Background and AimsA broadly mandated reduction of the nicotine content (RNC) of cigarettes has been proposed in the United States to reduce the addictiveness of cigarettes, to prevent new smokers from becoming addicted and to facilitate quitting in established smokers. The primary aim of this study was to determine whether following 7months of smoking very low nicotine content cigarettes (VLNC), and then returning to their own cigarettes, smokers would demonstrate persistently reduced nicotine intake compared with baseline or quit smoking. MethodsIn a community-based clinic 135 smokers not interested in quitting were randomized to one of two groups. A research group smoked their usual brand of cigarettes, followed by five types of research cigarettes with progressively lower nicotine content, each for 1month, followed by 6months at the lowest nicotine level (0.5mg/cigarette) (53subjects) and then 12months with no intervention (30subjects completed). A control group smoked their usual brand for the same period of time (50subjects at 6months, 38completed). Smoking behavior, biomarkers of nicotine intake and smoke toxicant exposure were measured. ResultsAfter 7months smoking VLNC, nicotine intake remained below baseline (plasma cotinine 149 versus 250ng/ml, P<0.005) with no significant change in cigarettes per day or expired carbon monoxide (CO). During the 12-month follow-up, cotinine levels in RNC smokers rose to baseline levels and to those of control smokers. Quit rates among RNC smokers were very low [7.5 versus 2% in controls, not significant). ConclusionsIn smokers not interested in quitting, reducing the nicotine content in cigarettes over 12months does not appear to result in extinction of nicotine dependence, assessed by persistently reduced nicotine intake or quitting smoking over the subsequent 12months.