Does the use of ingredients added to tobacco increase cigarette addictiveness?: a detailed analysis.

The possibility that ingredients added to tobacco contribute to the addictiveness of cigarette smoking was evaluated by comparing cessation rates of smokers of traditional blended cigarettes to those of smokers of flue-cured cigarettes. Such a comparison is a valid means of assessing cigarette ingredients as traditional blended cigarettes contain ingredients (>20), whereas flue-cured cigarettes contain no or very few ingredients. Separate analysis of 108 treatment groups and 108 control groups from randomized clinical trials of nicotine replacement therapy (NRT) were performed by multiple logistic regressions. The results of these analyses demonstrated slightly higher quit rates for smokers of blended cigarettes (OR = 1.90, 95% CI 1.70-2.13 and OR = 1.32, 95% CI 1.14-1.53 for treatment and control groups, respectively). The control groups were also investigated using classification tree analysis from which no difference in quit rates were observed for smokers of either type of cigarette. Further analyses showed that studies that utilized a high level of psychological support in conjunction with NRT produced at least a two-fold increase in quit rates compared to studies that utilized a low level of psychological support. It was also demonstrated that there is a large difference when results were reported by sustained abstinence compared to point prevalence. Additional meta-analyses found the pooled OR for NRT treatment to be in exact agreement with a recent review that assessed the effectiveness of NRT. Overall these results strongly suggest that ingredients used in the manufacture of traditional blended cigarettes do not increase the inherent addictiveness of cigarettes.