Response to varying the nicotine content of cigarettes in vulnerable populations: an initial experimental examination of acute effects

Abstract

Rationale: The purpose of this study was to begin researching the effects of very low nicotine content cigarettes in smokers especially vulnerable to dependence to assess their potential as a less dependence-producing alternative to current commercial cigarettes.

Methods: Participants were 26 adult, daily cigarette smokers from one of three populations: economically disadvantaged women of reproductive age (n = 9), opioid-dependent individuals (n = 11), and individuals with affective disorders (n = 6). Participants completed fourteen 2-4-h experimental sessions in a within-subjects research design. Sessions were conducted following brief smoking abstinence. Four research cigarettes varying in nicotine content (0.4, 2.4, 5.2, and 15.8 mg/g) were studied under double-blind conditions, assessing smoking topography, subjective effects, and relative reinforcing effects of varying doses in concurrent choice tests. Results were collapsed across vulnerable populations and analyzed using repeated measures ANOVA.

Results: No significant differences between doses were discernible in smoking topography. All doses were equi-effective at reducing nicotine withdrawal. Ratings of satisfaction from smoking were lower at the 0.4 compared to 15.8 mg/g dose. Participants preferred the 15.8 mg/g dose over the 0.4 and 2.4 but not the 5.2 mg/g doses in concurrent choice testing; no differences between the two lowest doses were noted.

Conclusions: All cigarettes effectively reduced nicotine withdrawal with no differences in smoking topography, suggesting minimal compensatory smoking. Dependence potential was lowest at the 0.4 mg/g dose. These initial results are promising regarding the feasibility of lowering nicotine content in cigarettes to very low levels in vulnerable populations without untoward effects.

Keywords: Abuse liability; Acute exposure; Cigarette smoking; Concurrent choice testing; Nicotine; Nicotine dependence; Nicotine withdrawal; Smoking topography; Tobacco; Very low nicotine content cigarettes; Vulnerable populations.

Figure 1

Panel A: Mean Minnesota Nicotine Withdrawal Scale (MNWS) total scores (solid bars) and desire-to-smoke item (open bars) scores before and every 15 minutes for one hour after smoking research cigarettes with varying nicotine content levels (0.4, 2.4, 5.2, and 15.8 mg/g tobacco). Panel B: Mean Questionnaire of Smoking Urges-Brief (QSU-b) Factor 1 (solid bars) and Factor 2 (open bars) scores across the same nicotine doses and time-course of assessments as in Panel A. Error bars represent ± one standard error of the mean. Note that there was a main effect of time for MNWS Total Score and Desire subscales (ps < .01), as well as both QSU Factors 1 and 2 (ps<.01) no main effects of dose nor interactions of dose and time. Note also that data points that share a letter code do not differ significantly (p < .05) from one another.

Figure 2

Panel A: Mean Breakpoint from the Cigarette Purchase Task across experimental cigarettes differing in nicotine content (mg/g). Panel B: Mean proportion of choices allocated to different nicotine dose cigarettes during separate 3-hour two-dose concurrent choice sessions. All possible two-dose comparisons across the four nicotine dose cigarettes (0.4, 2.4, 5.2, and 15.8 mg/g tobacco) were examined; only those that differed significantly are shown. The two-dose comparisons are shown on the x-axis with mean proportion of choices allocated to each shown on the y-axis. Asterisks in Panels A and B indicate significant dose differences at p < .05.