Situational factors in cigarette smoking

Situational factors related to smoking behavior in the natural environment were studied. Six subjects smoked all cigarettes over 10 days with a portable, electronic recording device which measured a number of frequency and time-based features of smoking. Subjects also coded activities and internal states associated with each cigarette smoked. Across subjects, there were considerable differences in the distribution of cigarettes smoked across the activity and internal states categories. Within subjects, all subjects showed variation in measures of smoking topography (number of puffs/cigarette, mean puff duration, total puff time/cigarette) as a function of situational variables. It did not appear that pharmacological factors could fully account for the substantial situational differences found. The results suggest that different factors may be involved in the control of different aspects of smoking topography.     

Peer modeling influences on smoking behavior of heavy and light smokers

Twelve heavy (>20 cigs/day) and twelve light (< cigs/day) male smokers were individually exposed to a high rate smoking confederate model in one session and a low rate smoking confederate model in another session. In both conditions, the model was “warm and friendly” to enhance his effectiveness. Cigarette frequency, inter-cigarette interval, and the various topographical components of smoking (puff frequency, percent tobacco burned, cigarette duration, puff duration, and average inter-puff interval) served as the dependent measures. Subjects smoked more cigarettes and took less time between cigarettes when exposed to a high rate model compared with exposure to a low rate model. Topography measures were not significantly influenced by the modeling conditions. There were no significant differences between heavy and light smokers with respect to any of the dependent measures.     

Smoking Topography in a Nonlaboratory Environment

The relationships between the number of cigarettes smoked/day and the number of puffs/cigarette, puff duration, and total puff time/cigarette were studied. Data were collected on 12 regular smokers for all cigarettes smoked over a 3-day period in a nonlaboratory environment. Between-subject variability was substantial on each of the topographical measures. Neither the number of cigarettes smoked per day nor the classification of Heavy (> 25 cigarettes/day) vs Moderate (< 25 cigarettes/day) smoking levels was related to the intensity with which cigarettes were smoked. Within-subject consistency on the topography measures indicates that smokers may have relatively unique smoking patterns.

Most studies of smoking in the natural environment employ number of cigarettes/day as their estimate of smoke exposure. However, total smoke exposure is determined by an interaction of various topographical features, including frequency (number of cigarettes/day, number of puffs/cigarette), durational (puff duration, interpuff interval, intercigarette interval), and volumetric (puff volume, inhalation volume) components. Employing cigarettes/day to estimate smoke exposure assumes a consistent relationship between cigarettes/day and other topographical features which contribute to total smoke exposure, but it is not clear that such a relationship exists. Laboratory studies of smoking behavior have found that cigarette frequency may vary independently of these other topographic components of smoking, lichtenstein and Antonuccio (1981) examined smoking topography in 24 male smokers while they smoked a cigarette during two 45-minute sessions. They found that cigarette rate was significantly related to intercigarette interval, but not to puff frequency, puff duration, cigarette duration, and amount of tobacco burned.

Results found in laboratory settings, however, have been found not to necessarily generalize to nonlaboratory environments. For example, OssipKlein, Martin, Lomax, Prue, and Davis (1983) examined six subjects smoking adlib in three settings: natural, clinical, and laboratory. They found that cigarette durations were shorter and that subjects took significantly longer and more puffs in a clinical or laboratory setting compared to a naturalistic setting. Thus, examination of the relationship between topographical features in naturalistic smoking would appear to require direct study outside the laboratory.

The present study is to our knowledge the first to examine topographical features of smoking and the relationship between number of cigarettes smoked/ day and other measures of smoking topography while the subject smoked ad-lib in a nonlaboratory environment. This information would potentially be important in examining the extent of individual differences in smoking topography, in assessing the extent to which cigarettes/day is related to other aspects of smoking behavior, and in determining whether categorizing smokers into smoking groups (e.g., moderate and heavy) on the basis of number of cigarettes/day accurately reflects the amount of total smoke exposure/day.     

Effects of acute tryptophan depletion on negative symptoms and smoking topography in nicotine-dependent schizophrenics and nonpsychiatric controls.

We studied the effect of acute tryptophan depletion (ATD), which transiently reduces brain serotonin, on negative symptoms and cigarette smoking topography in schizophrenic smokers. Nicotine-dependent schizophrenics (n=11) and nonpsychiatric controls (n=8) were examined after ingesting comparable mixtures that do and do not deplete plasma tryptophan. Tryptophan-depleting and placebo mixtures were administered double-blind and in counterbalanced order. Conditions were separated by a 1-week interval. Psychopathologic symptoms (negative symptoms, depression) and smoking topography (time to first puff, number of puffs per cigarette, puff duration, interpuff interval, cigarette duration, and percentage of cigarette smoked) were measured before ingestion and again beginning 5 h after each mixture, corresponding to the time of maximal tryptophan depletion. Analyses were conducted using repeated measures analyses of variance (psychopathologic symptoms) and analyses of covariance (smoking topography) controlling for cigarette length. We found that ATD influenced smoking topography in both schizophrenics and nonpsychiatric controls in a manner suggestive of increased desire to smoke. Schizophrenics exhibited increased puff duration and decreased cigarette duration. Controls displayed increased puff duration. ATD did not produce changes in negative symptoms or depression. Compromising brain serotonin via ATD appears to intensify smoking behavior in nicotine-dependent individuals directly, rather than indirectly through changes in either mood or psychopathologic symptoms.     

Topographical components of smoking behavior

Topographical characteristics of smoking behavior were studied using three subjects in single-case research designs. Five components of smoking topography were identified and monitored: inter-puff interval; cigarette duration; puff length; puff frequency; and percentage of tobacco burned. Following baselines, subjects were given instructions to modify inter-puff interval, cigarette duration, or both. Results showed that topographical components could be reliably monitored and were sensitive to instructional manipulation. A strong functional interrelationship among components was also observed. These findings support the use of topographical components of smoking as dependent variables. It is suggested that smoking topography be routinely assessed as part of a multiple measurement approach to the evaluation of smoking control programs. The modification of the individual topographical components is also an important step in the development of controlled smoking strategies.     

Mecamylamine pretreatment increases subsequent nicotine self-administration as indicated by changes in plasma nicotine level

Acute administration of mecamylamine, a centrally active nicotinic cholinergic agonist, has been shown to increase amount of smoking as indicated by smoking topography (e.g., puff rate, puff duration), expired carbon monoxide changes, and other inferential measures. In the present study, subjects showed significantly greater increases in plasma nicotine following smoking of two high-nicotine research cigarettes when pretreated with mecamylamine than when pretreated with placebo, even though no significant differences in puff volume or puff number were detected. Interestingly, none of our subjects reported nausea, although some achieved plasma nicotine levels at which nausea would typically be expected. We attribute the observed increases in nicotine intake to compensatory behavior designed to overcome mecamylamine's blocking effects.     

Effects of tetrahydrocannabinol content on marijuana smoking behavior, subjective reports, and performance

This study investigated the smoking topography of marijuana and its effect on heart rate, subjective reports, and cognitive/psychomotor task performance. Male subjects (N = 12) with histories of moderate marijuana use smoked ad lib one cigarette containing 0, 1.3, or 2.7% delta 9-THC on separate days. Smoking topography measures revealed smaller puff and inhalation volumes and shorter puff duration for the high marijuana dose compared to the low dose. No other smoking behavior differed between the active doses. Heart rate was increased dose dependently over placebo levels. Active marijuana also increased subjective reports of drug effect over placebo, but not dose dependently. Significant memory impairment was observed on a forward and reverse digit span task, and performance was impaired on the digit symbol substitution task by the high, but not low, dose of marijuana. Performance on a divided attention task was not affected by marijuana. Thus, although subjects adjusted their smoking of cigarettes varying in THC content, dose-related effects of marijuana were obtained on several measures. The observed differences and individual variation in smoking topography measures suggest that precise control of smoking behavior would improve the accuracy of marijuana dose delivery.     

A closed-loop control "playback" smoking machine for generating mainstream smoke aerosols.

A first generation smoking machine capable of reading and replicating detailed puffing behavior from recorded smoking topography data is presented. Unlike standard smoking machines, which model human puffing behavior as a steady periodic waveform with a fixed puff frequency, volume, and duration, this novel machine generates a mainstream smoke aerosol by automatically "playing-back" puff topography recordings. Because combustion chemistry is highly non-linear, representing real smoking behavior with a smoothed periodic waveform may result in a tobacco smoke aerosol with a significantly different chemical composition and physical properties than that generated by a smoker. The machine presented here utilizes a rapid closed-loop control algorithm coded in Labview to generate smoke aerosols for toxicological assessment and inhalation studies. To illustrate its use, dry particulate matter and carbon monoxide yields generated using the playback and equivalent periodic puffing regimens are compared for a single smoking session by a 26-year-old male narghile water-pipe smoker. It was found that the periodic puffing regimen yielded 20% less carbon monoxide (CO) than the played-back smoking session, indicating that steady periodic smoking regimens, which are widely used in tobacco smoke research, may not produce realistic smoke aerosols.     

History of marijuana use and tobacco smoking topography in tobacco-dependent adolescents

Adolescent tobacco smokers have higher rates of marijuana (MJ) use than nonsmokers. Because MJ smoking typically involves deeper inhalation and longer breathholding than tobacco smoking, we hypothesized greater puff volume, longer puff duration and puff interval, and higher puff velocity during tobacco smoking among (1) MJ-using teens; (2) teens whose onset of MJ smoking occurred before tobacco (MBT). One hundred and three tobacco-dependent adolescents presented for smoking cessation treatment (66.0% female, 71.0% European American, mean age 15.3+/-1.25 years) smoked one cigarette of their own brand in the laboratory prior to study entry. Topography and associated physiological measures among current recreational (<5 days in a 14-day period) MJ users (n=25), current heavy (>/=5 days in a 14-day period) MJ users (n=22) and current non-MJ-smoking teens (n=56) were compared. There were no differences in tobacco smoking topography or physiological measures by recent MJ-smoking history or by order of substance initiation. Significantly more African American than European American adolescent smokers reported MJ use before tobacco. Our findings in adolescent smokers are consistent with results from adult studies in which history of MJ smoking was not associated with changes in tobacco smoking topography.     

Smoking topography and carbon monoxide levels in smokers

Factors which effect the expired air carbon monoxide (CO) levels of smokers were examined in matched subject pairs who smoked an equal number of daytime cigarettes but had different CO levels (mean difference = 15.4 ppm). Measures of puff number, duration, and spacing, as well as the amount of CO increase per cigarette (CO boost), were assessed while subjects smoked a single cigarette in daily laboratory sessions. Subjects with relatively high CO levels had larger increases in CO after smoking a single cigarette than did individuals with low CO levels (p. less than .005) but did not differ on any other smoking topography measure. These data suggest that simple topography measures of puff number and duration may not contribute to between subject differences in tobacco smoke exposure, and that greater attention should be given to more refined measures such as puff volume and depth of inhalation. These data also suggest that the measurement of CO boost per cigarette may provide useful information regarding tobacco smoke intake.     

Towards a topographical model of narghile water-pipe café smoking: a pilot study in a high socioeconomic status neighborhood of Beirut, Lebanon

A pilot study of narghile water-pipe smokers in a cafe in the Hamra neighborhood of Beirut, Lebanon, was conducted to develop a preliminary model of narghile water-pipe smoking behavior for use in laboratory smoking machine studies. The model is based on data gathered from smoking sessions of 30 min or longer duration from 52 smoker volunteers using a differential pressure puff topography instrument, as well as anonymous visual observations of 56 smokers in the same cafe. Results showed that the "average" water-pipe cafe smoking session consists of one hundred seventy-one 530-ml puffs of 2.6-s duration at a frequency of 2.8 puffs/min. The implications of this comparatively high-intensity puffing regimen on the production of toxic smoke constituents are discussed.     

Smoking topography and abstinence in adult female smokers

Preliminary evidence, within both adults and adolescents, suggests that the intensity with which cigarettes are smoked (i.e., smoking topography) is predictive of success during a cessation attempt. These reports have also shown topography to be superior compared to other variables, such as cigarettes per day, in the prediction of abstinence. The possibility that gender may influence this predictive relationship has not been evaluated but may be clinically useful in tailoring gender-specific interventions. Within the context of a clinical trial for smoking cessation among women, adult daily smokers completed a laboratory session that included a 1-hour ad libitum smoking period in which measures of topography were collected (N = 135). Participants were then randomized to active medication (nicotine patch vs. varenicline) and abstinence was monitored for 4 weeks. Among all smoking topography measures and all abstinence outcomes, a moderate association was found between longer puff duration and greater puff volume and continued smoking during the active 4-week treatment phase, but only within the nicotine patch group. Based on the weak topography–abstinence relationship among female smokers found in the current study, future studies should focus on explicit gender comparisons to examine if these associations are specific to or more robust in male smokers.     

Relation of puff volume to other topographical measures of smoking

Puff volume, puff duration, interpuff interval, cigarette interval, puffing rate, and number of puffs per cigarette were recorded in eight normally smoking subjects during five daily one-hour laboratory sessions. Topographical measures showed wide variability across subjects, but measures were relatively stable within subjects. Puff volume was significantly positively correlated with puff duration for five subjects. As the cigarette was smoked, puff duration remained relatively constant, while puff volume decreased systematically and inter-puff interval increased initially and then decreased.     

Social interaction and smoking topography in heavy and light smokers.

The effects of social interaction on the topography of smoking behavior of heavy and light cigarette smokers was investigated. Smoking behavior was analyzed via closed circuit television monitoring during periods of informal interpersonal conversation and periods of isolation. Number of cigarettes smoked, number of puffs, cigarette duration, interpuff interval, puff duration, percent of tobacco burned, time with cigarette in mouth, and time with cigarette in hand were analyzed. Heavy and light smokers were affected differentially by the social conditions. Light smokers took more frequent and longer puffs when smoking alone with social interaction functioning to decrease the total amount of smoke inhaled. Heavy smokers were unaffected by the social conditions.     

Effects of smoked marijuana on heart rate, drug ratings and task performance by humans

Six subjects, reporting marijuana use between two and 30 times per month, participated in studies of the acute effects of smoked marijuana (0.0%, 2.0% and 3.5% Delta(9)-THC, w/w) on heart rate, ratings of drug effect and task performance. Marijuana was administered using a uniform-puffing procedure with monetary contingencies associated with puff and breathhold duration. In general, heart rate and ratings, of "High" and dose "Potency" were increased by marijuana, and performance on some tasks was altered by drug administration. The relative sensitivity of the measures varied across subjects, and no single measure, such as heart rate or verbal rating of drug effect, could be used to predict the behavioral effects of marijuana. Marijuana puff durations were decreased at the highest dose, but dose-related changes in heart rate and task performance indicated that the change in smoking topography did not result in complete compensation for increased cannabinoid concentrations in marijuana smoke.     

Smoke yield of cigarettes and puffing behavior in men and women

Puffing behavior (number of puffs, puff interval, puff duration, peak pressure, latency to peak pressure, average and total puff volume) was measured in 67 dependent male and 43 dependent female smokers when they smoked two cigarettes of their habitual brand under laboratory conditions. Test-retest reliability for the two cigarettes was high, and factor analysis showed that puff shape, puff volume, and puff frequency accounted for about 50% of variation obtained with the different puffing variables. Expiratory tidal CO levels increased with the number of cigarettes smoked before the tests and with the intensity of the smoking habit, but pre- to postsmoking tidal CO differences were similar for smokers of all types of cigarettes (0.1–1.7 mg standard machine smoking nicotine yield). Volume compensation for differences of smoke yield of the cigarettes was generally more pronouced in women than in men and, additionally, it was more pronounced for cigarettes with standard smoke nicotine yield below 0.9 mg than for cigarettes with standard smoke nicotine yield above 0.9 mg for both sexes. Only for women, partial correlation procedures suggested that nicotine might be more important in determining puffing behavior than CO and condensate yield, but there were also no women smoking the strongest cigarettes (1.3–1.7 mg nicotine yield). For both sexes, no compensation by adjusting the number of cigarettes smoked daily was obtained. Personality ratings, pulmonary functions, and cardiovascular functions were not, or only inconsistently, correlated with puffing behavior or type of cigarette.     

Relationships among measures of smoking topography

Interrelationships between puffing, puff duration, puff volume, and heart rate change were assessed in a sample of 63 chronic, high rate smokers. Results showed puff duration and volume were related for males and females, and that heart rate change was related to volume in males and puff duration in females. Puffs were not related to either volume or heart rate change in males or females. These results call into question research on smoking behavior which does not measure volume, and shows that components of puffing may not be used interchangeably, and that neither puffs nor puff duration are accurate predictors of volume of intake.     

Nicotine exposure in daily waterpipe smokers and its relation to puff topography

Waterpipe tobacco smoking is increasing in popularity worldwide and available evidence point to its addictive and harmful potential. This study is conducted to assess nicotine exposure in daily waterpipe smokers, and its correlation with puff topography parameters. Sixty-one waterpipe tobacco smokers (56 males; mean age±SD, 30.9±9.5years; mean number of weekly waterpipe smoking episodes 7.8±5.7) abstained from smoking for at least 24h, and then smoked tobacco from a waterpipe ad libitum in a laboratory setting. During the session puff topography parameters were monitored continuously, and pre- and post-smoking expired-air CO was measured. Before and after smoking, venous blood was sampled for the assessment of plasma nicotine using Gas Chromatography-Mass Spectrometry. The average pre- and post-smoking expired-air CO was 4±1.7 and 35.5±32.7ppm, respectively (i.e., a CO boost of 31.5ppm, p<.001). Mean plasma nicotine concentration increased from 3.07±3.05ng/ml pre-smoking to 15.7±8.7ng/ml post-smoking (p<.001). Plasma nicotine boost was correlated with total session time (Pearson correlation coefficient r=.31, p=.04), cumulative puff duration (r=.37, p=.01), mean puff duration (r=.34, p=.02), and total smoke inhaled in the session (r=.34, p=.02. These data show considerable nicotine exposure in daily waterpipe smokers, and that nicotine exposure is a function of waterpipe smoking patterns.     

How does puffing behavior alter during the smoking of a single cigarette?

We examined changes in puffing behavior during the course of a single cigarette in 76 subjects seen on 6 occasions each (456 cigarettes). The puff volume fell on average by 33% during a cigarette and puff duration by 39%, the interpuff interval rose by 75%, but the pressure drop and the maximum flow and pressure achieved during puffing hardly changed. There were highly significant differences between subjects but not between sessions, or when subjects were grouped according to tar yield of the cigarette or by sex. Individual puff volumes with a single cigarette were highly correlated with puff duration (except in a few individuals with irregular puffing patterns), but not generally with maximum flow rate, suggesting that most smokers reduce volume by taking shorter puffs. This is unlikely to reflect mechanical factors or smoke temperature, and may be a response to changing smoke composition. Variation in puffing patterns between individuals may reflect differences in sensitivity to smoke components and individuals who show little fall in puff volume also show small responses on switching to cigarettes with different tar and nicotine yields. The individual response to smoke might be assessed by an analysis of puffing on a single cigarette.     

Effects of single doses of alcohol and caffeine on cigarette smoke puffing behavior

Puffing behavior (number of puffs, puff duration, puff volume, peak pressure, peak flow, peak latency, and puff interval) and pre- to postsmoking delta tidal CO difference were measured in female subjects in order to assess separate and combined effects of ethanol and caffeine. The subjects smoked two cigarettes of their habitual brand in a preliminary familiarizing session and in each of the subsequent four test sessions. The treatments administered after smoking the first cigarette in the test sessions were: alcohol placebo and caffeine placebo; alcohol placebo and caffeine; alcohol and caffeine placebo; alcohol and caffeine. Test-retest reliability across the first cigarette of each session (which was not smoked under the influence of the treatments) was remarkably high for all the puffing parameters. Ethanol in the dose of 0.7 g/kg intensified cigarette smoking of the second cigarette by increasing delta tidal CO, average puff volume, and total puff volume per cigarette, whereas 0.5 g/kg ethanol and 5 mg/kg caffeine given alone or combined with ethanol failed to influence puffing behavior consistently.