Effects of nicotine gum dose by level of nicotine dependence.

We used the Heaviness of Smoking Index, a subset of the Fagerstrom Test for Nicotine Dependence, to classify 608 cigarette smokers planning a cessation attempt as low or high in nicotine dependence. Subjects within each level of dependence were then randomly assigned to placebo, 2-mg, or 4-mg nicotine gum treatment. Subjects were also provided brief (5-10 min per visit) behavioral counseling during a 1-year period of follow-up. At 1 year post-cessation, quit rates were 11.2, 19.5, and 18.4% for low-dependence smokers receiving placebo, 2-mg, and 4-mg gum, respectively (plinear trend = 0.20). For high-dependence smokers, quit rates at 1 year were 6.1, 15.7, and 20.7% for the placebo, 2-mg, and 4-mg gum conditions, respectively (plinear trend = 0.002). The interaction of nicotine-gum dose and dependence group was not significant (p = 0.42), nor did the 2-mg and 4-mg doses differ significantly in effectiveness, though both 2-mg and 4-mg gum were significantly more effective than placebo gum. We also found a significant dose-related effect for nicotine gum to moderate post-cessation heart-rate decline. Other variables related to abstinence at 1 year post-cessation were a longer period of abstinence on a prior quit attempt, being married, higher education level, and having a non-smoking spouse or significant other. Results indicate that nicotine gum is a significant aid to smoking cessation, more than doubling the odds of successful cessation compared to the odds for placebo-gum users. The 4-mg dose provided a non-significant increase in cessation rates for high-dependence smokers. Smoking history and demographic variables also have a significant impact on the outcome of a quit-smoking attempt.