Smoking Bouts Research Articles

Triangulating abuse liability assessment for flavoured cigar products using physiological, behavioural economic and subjective assessments: a within-subjects clinical laboratory protocol

IntroductionIn the USA, Food and Drug Administration regulations prohibit the sale of flavoured cigarettes, with menthol being the exception. However, the manufacture, advertisement and sale of flavoured cigar products are...

Dopaminergic genetic variation moderates the effect of nicotine on cigarette reward.

Cigarette smoking is influenced by nicotine’s effects on dopaminergic activity in the mesocorticolimbic pathway. This activity appears to be moderated by genetic variation, specifically a variable number tandem repeat (VNTR) polymorphism in the third exon of the dopamine receptor gene (DRD4). We examined whether this polymorphism along with three DRD4 single-nucleotide polymorphisms (SNPs: rs936460, rs936461, and rs12280580) moderate the influence of nicotine on subjective responses to cigarettes. White, non-Hispanic smokers (n = 96, cigarettes/day ≥15) attended two double-blind, counterbalanced experimental sessions, each preceded by overnight smoking abstinence. Participants smoked four nicotine (8.9 mg) or placebo (1.0 mg) cigarettes per session, with each cigarette followed by completion of the modified Cigarette Evaluation Questionnaire (mCEQ). We examined the mCEQ composite score via 2 × 2 × 4 ANOVAs with genotype (major homozygotes versus minor carriers) as the between-subject factor and nicotine content and smoking bout as within-subject factors. Although DRD4 VNTR variation did not moderate overall nicotine response, there was a moderation of nicotine response over successive cigarettes. Smokers with fewer than seven repeats for the DRD4 VNTR reported markedly reduced craving, increased satisfaction, and a greater calming effect in response to earlier smoked nicotine cigarettes, whereas those with seven or more repeats did not. In addition, minor carriers for all three DRD4 SNPs displayed blunted overall response to nicotine. These findings provide support for DRD4 variation as an informative predictor of subjective responses to nicotine. We discuss how these data may lead to improved tailoring of smoking cessation pharmacotherapies.

Acute Effects of "Hyping" a Black&Mild Cigarillo.

Cigars remain a widely used tobacco product among adolescent and adult populations. The appeal of a certain type of cigar, the cigarillo, may be enhanced by users' beliefs that their harm potential can be reduced by removing the inner tobacco liner before use (a.k.a. "hyping"). The purpose of this within-subject study was to compare the acute effects of smoking an original cigarillo, a modified ("hyped") cigarillo, and an unlit cigarillo. Twenty smokers (19 males, 1 female; 19 non-Hispanic blacks, 1 Hispanic "other") of at least 7 Black&Mild (B&M) cigarillos/week and at most 5 cigarettes/day completed the study. All participants reported hyping their cigarillos at least occasionally. Primary outcomes, assessed over two, 30-minute smoking bouts, included plasma nicotine, expired air carbon monoxide (CO) concentration, subjective ratings (product effects, nicotine abstinence symptoms), and puff topography. Mean plasma nicotine concentration increased significantly within (pre- to post-bouts), but not between, original and modified B&M conditions. Mean CO concentration was significantly lower for modified, relative to original, B&M smoking at all post-administration timepoints. Both smoked conditions significantly increased ratings of positive product effects (satisfaction, pleasant) and decreased abstinence symptom magnitude; however, ratings generally did not differ between these conditions. Overall, topography outcomes did not differ between modified and original B&M smoking. Results are consistent with a previous report in that "hyping" may decrease users' CO, but not nicotine, exposure. While these data collectively suggest reduced exposure to CO acutely with engagement in "hyping," longer-term assessments are needed to determine the impact on individual and public health.

Transient compensatory smoking in response to placebo cigarettes

To address the public health problems caused by smoking, researchers have suggested a gradual reduction in the nicotine content of cigarettes. There remain concerns, however, about the potential for smokers to compensate for reductions in nicotine content by altering their smoking behavior. Such compensatory behaviors may negate any potential cessation and/or harm reduction benefits. The purpose of this study was to quantify smoking behavior (e.g., puff number, volume, duration, interpuff interval, and peak flow) in response to cigarettes, varying only in nicotine content, administered repeatedly. Sixty-seven dependent smokers participated in this two-session, within-subject study. Moderate nicotine content and placebo cigarettes (Quest© brand) were administered in a double-blind and counterbalanced manner. Each session required 12 h of tobacco abstinence and included four ad lib smoking bouts of the condition-assigned cigarette with 40 minutes separating each bout. Placebo cigarettes produced increases in total puff volume and duration and decreases in total interpuff interval relative to cigarettes with moderate nicotine content. Differences in total puff volume and duration generally dissipated across smoking bouts, with differences in total puff volume nonexistent by the third and fourth bouts. Placebo cigarettes produce compensatory smoking during initial exposures; however, these effects appear to be short lived. These findings are consistent with the previous work where smoking compensation has been observed in response to a single cigarette, but not over several days of smoking.

Acute Effects of Cigarillo Smoking

Cigarillo smoking likely exposes users to many of the same toxicants (e.g., nicotine, carbon monoxide [CO]) as cigarette smoking. Yet, few controlled clinical laboratory studies evaluating of the effects of cigarillos exist. This study evaluated the cardiovascular response, toxicant exposure, subjective effects, and puffing topography of a popular cigarillo brand, Black & Mild (B&M). Sixteen B&M smokers (M ± SD = 1.9 ± 2.5 cigarillos/day for 3.4 ± 3.5 years) participated in 2 counterbalanced conditions: lit (ACTIVE) or unlit (SHAM) B&M in which they completed two 10-puff smoking bouts (30-s interpuff intervals). Plasma nicotine concentrations for ACTIVE increased significantly from pre-smoking (M ± SEM = 2.0 ± 0.0 ng/ml) to 5 min after Bouts 1 (5.3 ± 0.8 ng/ml) and 2 (4.9 ± 0.9 ng/ml) but did not increase above 2.0 ± 0.0 ng/ml at any timepoint for SHAM. Heart rate increased significantly from pre- to post-smoking for ACTIVE but not for SHAM. Average expired-air CO levels, collapsed across time, were 14.3 ± 0.8 ppm for ACTIVE and 4.5 ± 0.2 ppm for SHAM. Neither condition reduced symptoms of nicotine/tobacco abstinence reliably, although ratings for some measures were significantly lower for ACTIVE than for SHAM. ACTIVE, but not SHAM, produced a variety of positive effects related to product sensory characteristics (e.g., "satisfying," "pleasant"). Smoking topography did not differ across the two conditions. Ten puffs from a B&M cigarillo deliver active doses of nicotine and considerable amounts of CO but do not suppress abstinence-induced withdrawal symptoms reliably. The nicotine delivery profile suggests that cigarillo smoking may promote nicotine/tobacco dependence and the CO exposure likely poses significant health risks.

Temporal horizons of cigarette satiety: determining the window of time over which recent smoking influences motivation to smoke

One of the hallmarks of drug addiction is a limitation of the temporal horizon of events that affect the behavior of drug users. The purpose of this experiment was to examine the time period over which smoking was influenced by an earlier opportunity to smoke. Baseline sessions measured how much was smoked in a current opportunity when it was preceded by a 2-h wait time in which no smoking was allowed. After the baseline phase, we examined the effects of temporal distance when an earlier opportunity to smoke (upon completion of a fixed ratio 100) preceded current smoking (upon completion of a progressive ratio). Temporal distance between these two opportunities to smoke was varied from 0 to 120 min. We found that current smoking for the group was reduced from baseline levels when the temporal distance was 0 min. At temporal distances ranging from 30 to 90 min, the individual's smoking returned to levels that were similar to baseline. Breakpoints were also a function of earlier smoking, and latencies to first puff of the session followed a similar trend. These findings provide evidence of the limited temporal horizons related to smoking bouts of smokers and may provide a useful measure for metabolism differences across populations. In addition, we suggest that the quantitative description of satiety provided by our procedures may validate drug replacement therapies involved in cessation treatments.

Smoke constituent exposure and smoking topography of adolescent daily cigarette smokers

Adolescent smoking prevalence is a major health concern, with 24.4% reporting smoking in the past 30 days and 15.8% considered daily smokers. The purpose of this study was to characterize biobehavioral nicotine dependence, smoke constituent exposure and smoking topography in adolescent daily smokers. Relationships among biological markers of nicotine dependence (nicotine boost, carbon monoxide [CO] boost and cotinine levels) with existing self-report measures (modified Fagerström Tolerance Questionnaire [mFTQ] and the motivations for smoking scale) were examined. Gender differences were characterized. Fifty adolescents 13-18 years old were recruited for the study, 50% female. CO, plasma nicotine levels pre- and postcigarette, cotinine, and smoking topography were measured during a smoking bout with participant's usual cigarette. Average CO boost, pre- to postcigarette was 7.2 + 3.6 ppm, baseline cotinine level averaged 224.0 +/- 169.6 ng/ml and nicotine boost averaged 23.4 +/- 21.7 ng/ml. Mean puffs per cigarette was 14.2 +/- 6.3. Males had significantly higher total puff volumes, but similar smoke constituent exposure to females, and higher handling of cigarettes as smoking motive. In regression analysis, 35% of variance in tobacco use, as indicated by baseline cotinine concentration, was explained by maximum puff duration, postcigarette CO level, and nicotine dependence, as measured by the mFTQ. Results indicated adolescents had considerable smoke constituent exposure and nicotine dependence suggesting the importance of appropriate smoking cessation treatment.

Antinociceptive, subjective and behavioral effects of smoked marijuana in humans

The purpose of this study was to determine whether marijuana produced dose-dependent antinociception in humans and, if so, whether endogenous opiates modulate this effect. A total of five male regular marijuana users participated in three test sessions during which they smoked cigarettes containing 0% (placebo) and 3.55% Δ 9-tetrahydrocannabinol (Δ 9-THC) (active). Each of four controlled smoking bouts per session, spaced at 40-min intervals, consisted of nine puffs from active and placebo cigarettes (three cigarettes, three puffs per cigarette, one puff per min). During successive bouts, participants smoked 0, 3, 6 and 9 (0, 3, 9 and 18 cumulative) puffs from active marijuana cigarettes, with the remainder of puffs from placebo cigarettes. Test sessions were identical, except for naltrexone 0, 50 or 200 mg p.o. (randomized, double-blind) administration 1 h before the first smoking bout on the different days. Before smoking, between smoking bouts and postsmoking, participants completed an assessment battery that included antinociceptive (finger withdrawal from radiant heat stimulation), biological, subjective, observer-rated signs and performance measures. Marijuana produced significant dose-dependent antinociception (increased finger withdrawal latency) and biobehavioral effects. Naltrexone did not significantly influence marijuana dose-effect curves, suggesting no role of endogenous opiates in marijuana-induced antinociception under these conditions.

Smoke constituent exposure and stage of change in black and white women cigarette smokers

Differences in smoke constituent exposure by ethnicity and menthol preference and differences in decisional balance and habit strength by stage of change, ethnicity, and menthol preference were examined in this 2-factor study design. Ninety-five women, half of whom were Black and half of who smoked menthol cigarettes, participated in a cigarette smoking bout in the Clinical Research Center. Measures of smoking topography, plasma cotinine and nicotine, and expired carbon monoxide were obtained in addition to self-report of the pros and cons of smoking, time to first cigarette, and smoking history. Black women smoked significantly fewer cigarettes per day, but had higher cotinine levels compared to White women. Menthol smokers ( n = 49) had significantly larger puff volumes, higher cotinine levels, and shorter time to first cigarette compared to nonmenthol smokers ( n = 46). Precontemplators ( n = 44) were significantly lower on beliefs about the negative aspects of smoking compared to contemplators and those in preparation stage. Black women, all stages combined, had higher negative beliefs about smoking than did White women. Implications for assessment of smoking patterns and intervention are discussed.

Effects of spirometric administration of tobacco smoke containing varying amounts of nicotine on physiological measures and subject ratings

A previously developed spirometric methodology of tobacco smoke administration was evaluated by determining the effects of varying nicotine delivery on various physiological and subjective measures. Eight male tobacco smoking subjects were administered 60cc volumes of tobacco smoke drawn from University of Kentucky research cigarettes, or air. Subjects were exposed to four bouts of smoke administration conducted over an 8h day. Each smoking bout was separated by 2h and involved 20 smoke administrations at the rate of one every 30sec. Each smoke administration consisted of 60cc of air or 60cc drawn from 0.3, 1.2 or 2.7mg nicotine yield cigarettes, followed by 1 liter of air which forced the smoke or air deep into the lungs. Carbon monoxide (CO), blood pressure, and heart rate were measured before and after each smoking bout, and subject ratings of smoke effects were completed after each smoking bout. In a separate study, blood samples were collected on two occasions before and after administration of the two highest nicotine yield cigarettes to determine changes in nicotine plasma levels. Data indicated that the spirometric method produced: (1) similar CO boosts across nicotine yields, and (2) changes in heart rate, blood pressure, subject ratings and plasma nicotine levels which were directly related to the nicotine yield of cigarettes.

Effects of smoke deprivation interval on puff topography.

Our purpose in this series of three studies was to determine the effects of deprivation interval on smoking topography. In experiment 1, subjects were allowed to smoke ad libitum for 1 hour after 3, 30, and 300 minutes of tobacco smoke deprivation. An increased latency to the first cigarette developed after 3 minutes deprivation and an increase in the number of cigarettes smoked occurred after 300 minutes of deprivation. In experiment 2, puff number and spacing were held constant to determine if smokers would compensate for long deprivation intervals by more intense smoking, i.e., increased puff volume. Puff volumes and carbon monoxide (CO) boosts did not differ across smoking bouts preceded by either 30, 100, or 300 minutes of tobacco smoke deprivation. In experiment 3, average puff volumes and CO boosts were examined during smoking periods with short (3, 10, and 30 minutes) deprivation intervals. Subjects smoked less intensely (lower puff volumes and CO boosts) when smoking was spaced by 3 than by 30 minutes. We conclude that smokers do not increase puff volume after long deprivation intervals up to 300 minutes, but they may decrease puff volumes after short (3 minutes) deprivation intervals when puff number and spacing cannot be used as compensatory mechanisms.