Cotinine levels in relation to smoking behavior and addiction in young adolescent smokers.

The goal of this study was to identify associations among self-reported nicotine exposure, nicotine addiction, and actual nicotine intake as measured by salivary cotinine levels in adolescent smokers. A total of 170 adolescent smokers with a mean age of 15 years were recruited from seven northern Californian public high schools. Data were collected on smoking behaviors, addiction, craving, and withdrawal. Nicotine dependence was assessed using a modified teen Fagerstr?m Tolerance Questionnaire (mtFTQ), a modified Nicotine Dependence Syndrome Scale (mNDSS), and a simple self-rating. Withdrawal was assessed using the Minnesota Withdrawal Questionnaire, and craving was assessed using a survey created by the authors. Salivary cotinine levels were collected from and analysed in participants who self-identified as smokers; data from the 54 participants who smoked in the past 4 days and whose salivary cotinine levels were greater than 0.1 ng/ml were used in the analysis. Among this group of adolescent smokers, the mean number of cigarettes smoked per day was 3.51 (SD = 3.44) and the mean level of salivary cotinine was 44.1 ng/ml (Mdn = 24.2). Even at this low level of nicotine exposure, cotinine was highly correlated with measures of nicotine dependence such as the mtFTQ (r = 0.497, p = .001), NDSS (r = 0.439, p = .002), timing of craving in the morning (r = -0.601, p = .000), and self-rated addiction (r = 0.562, p = .000). Most interesting, cotinine levels reached a plateau at around 4-5 cigarettes/day.     

The influence of gender, race, and menthol content on tobacco exposure measures.

Research has suggested that race, gender, and menthol cigarette use influence tobacco-smoke exposure measures and smoking-related disease risk. For example, a high proportion of Black smokers prefer menthol cigarettes and, despite smoking fewer cigarettes per day (CPD) than do Whites, tend to have higher cotinine levels. Additionally, Black males are more at risk for smoking-related lung cancer. High cotinine levels and smoking menthol cigarettes may lead to higher toxin intake, which contributes to increased disease risk. We explored the relationship between tobacco exposure variables (i.e., cotinine, CPD, carbon monoxide [CO], nicotine content, and nicotine dependence) with respect to race, gender, and menthol content in a sample of 307 smokers recruited from the greater Boston area to participate in a smoking cessation treatment trial. The pattern of correlations between tobacco exposure measures and cotinine showed a consistently positive correlation between cotinine and CO in all smokers and a correlation between cotinine and CPD in those who smoked nonmenthol cigarettes. Cotinine and CPD correlations varied by gender and race among menthol cigarette smokers. Consistently, we found a significant gender x race x menthol interaction on salivary cotinine level as well as cotinine/CPD ratio. These findings suggest that the relationship between number of cigarettes consumed and salivary cotinine is more complex than previously believed. It is not sufficient to look at race alone; researchers and clinicians need to look at race and gender concurrently, as well as type of cigarette consumed.     

Sex-related differences in serum cotinine concentrations in daily cigarette smokers

Self-reported use of cigarettes generally underestimates the true cigarette exposure of smokers. Serum cotinine is considered the best biomarker to evaluate tobacco exposure. This study determined whether or not there were any significant differences in serum cotinine concentrations between men and women when they reported smoking the same number of cigarettes per day. We analyzed cotinine and tobacco consumption data on 680 women and 840 men, aged 20 years or older, who smoked at least 100 cigarettes during their lifetime and were still actively smoking at the time of the National Health and Nutrition Examination Surveys (1999-2002). Overall, compared with men, women reported smoking fewer cigarettes per day (16.1 vs. 18.7, p<.001) and had lower serum cotinine concentrations (1163.3 nmol/L vs. 1343.9 nmol/L, p<.001). Women were more likely than men to smoke filtered (p = .018) and mentholated (p<.001) cigarettes. After adjustment for the number of cigarettes smoked per day, age, race, body mass index, poverty status, the use of either menthol or regular cigarettes, and the nicotine content in cigarettes, female compared with male smokers had lower serum cotinine concentrations (difference of 117.6 nmol/L; 95% CI = 42.6-192.6, p = .003). The difference was particularly notable in moderate to heavy smokers (i.e., those who smoked more than 15 cigarettes/day). These findings indicate that significant sex-related differences exist in serum cotinine levels among smokers, which suggests that self-reports may overestimate cigarette exposure in women compared with men.     

Salivary cotinine concentration versus self-reported cigarette smoking: Three patterns of inconsistency in adolescence.

The present study examined the extent and sources of discrepancies between self-reported cigarette smoking and salivary cotinine concentration among adolescents. The data are from household interviews with a cohort of 1,024 adolescents from an urban school system. Histories of tobacco use in the last 7 days and saliva samples were obtained. Logistic regressions identified correlates of three inconsistent patterns: (a) Pattern 1-self-reported nonsmoking among adolescents with cotinine concentration above the 11.4 ng/mg cutpoint (n = 176), (b) Pattern 2-low cotinine concentration (below cutpoint) among adolescents reporting having smoked within the last 3 days (n = 155), and (c) Pattern 3-high cotinine concentration (above cutpoint) among adolescents reporting not having smoked within the last 3 days (n = 869). Rates of inconsistency were high among smokers defined by cotinine levels or self-reports (Pattern 1 = 49.1%; Pattern 2 = 42.0%). Controlling for other covariates, we found that reports of nonsmoking among those with high cotinine (Pattern 1) were associated with younger age, having few friends smoking, little recent exposure to smokers, and being interviewed by the same interviewer as the parent and on the same day. Low cotinine concentration among self-reported smokers (Pattern 2) was negatively associated with older age, being African American, number of cigarettes smoked, depth of inhalation, and exposure to passive smoke but positively associated with less recent smoking and depressive symptoms. High cotinine concentrations among self-reported nonsmokers was positively associated with exposure to passive smoke (Pattern 3). The data are consonant with laboratory findings regarding ethnic differences in nicotine metabolism rate. The inverse relationship of cotinine concentration with depressive symptoms has not previously been reported. Depressed adolescent smokers may take in smaller doses of nicotine than nondepressed smokers; alternatively, depressed adolescents may metabolize nicotine more rapidly.     

Higher nicotine and carbon monoxide levels in menthol cigarette smokers with and without schizophrenia.

This study examined whether smoking menthol cigarettes was associated with increased biochemical measures of smoke intake. Expired carbon monoxide (CO) and serum nicotine and cotinine were measured in 89 smokers with schizophrenia and 53 control smokers immediately after smoking an afternoon cigarette. Serum nicotine levels (27 vs. 22 ng/ml, p = .010), serum cotinine levels (294 vs. 240 ng/ml, p = .041), and expired CO (25 vs. 21 ppm, p = .029) were higher in smokers of menthol compared with nonmenthol cigarettes, with no differences in 3-hydroxycotinine/cotinine ratios between groups when controlling for race. Backward stepwise linear regression models showed that, in addition to having a diagnosis of schizophrenia, smoking menthol cigarettes was a significant predictor of nicotine and cotinine levels. Individuals with schizophrenia or schizoaffective disorder smoked more generic or discount value brands (Basic, Doral, Monarch, USA, Wave, others) compared with control smokers (28% vs. 6%, p = .002) but did not smoke more brands with high nicotine delivery as estimated by the U.S. Federal Trade Commission method. Although rates of mentholated cigarette smoking were not higher in smokers with schizophrenia overall, they were significantly higher in non-Hispanic White people with schizophrenia compared with controls of the same ethnic/racial subgroup (51% vs. 28%, p<.0001). The higher exhaled CO in menthol smokers suggests that the higher nicotine levels are at least partly related to increased intake of smoke from menthol cigarettes, although menthol-mediated inhibition of nicotine metabolism also may be a factor. Menthol is an important cigarette additive that may help explain why some groups have lower quit rates and more smoking-caused disease.     

Cigarette nicotine yields and nicotine intake among Japanese male workers

OBJECTIVES: To analyse brand nicotine yield including "ultra low" brands (that is, cigarettes yielding less-than-or-equal 0.1 mg of nicotine by Federal Trade Commission (FTC) methods) in relation to nicotine intake (urinary nicotine, cotinine and trans-3'-hydroxycotinine) among 246 Japanese male smokers. DESIGN: Cross sectional study. SETTING: Two companies in Osaka, Japan. SUBJECTS: 130 Japanese male workers selected randomly during their annual regular health check up and 116 Japanese male volunteers taking part in a smoking cessation programme. MAIN OUTCOME MEASUREMENTS: Subjects answered a questionnaire about smoking habits. Following the interview, each participant was asked to smoke his own cigarette and, after extinguishing it, to blow expired air into an apparatus for measuring carbon monoxide concentration. Urine was also collected for the assays of nicotine metabolites. RESULTS: We found wide variation in urinary nicotine metabolite concentrations at any given nicotine yield. Based on one way analysis of variance (ANOVA), the urinary nicotine metabolite concentrations of ultra low yield cigarette smokers were significantly lower compared to smokers of high (p = 0.002) and medium yield cigarettes (p = 0.017). On the other hand, the estimated nicotine intake per ultra low yield cigarette smoked (0.59 mg) was much higher than the 0.1 mg indicated by machine. CONCLUSIONS: In this study of Japanese male smokers, actual levels of nicotine intake bore little relation to advertised nicotine yield levels. Our study reinforces the need to warn consumers of inappropriate advertisements of nicotine yields, especially low yield brands.     

Waterpipe smoking and nicotine exposure: a review of the current evidence.

The waterpipe, also known as shisha, hookah, narghile, goza, and hubble bubble, has long been used for tobacco consumption in the Middle East, India, and parts of Asia, and more recently has been introduced into the smokeless tobacco market in western nations. We reviewed the published literature on waterpipe use to estimate daily nicotine exposure among adult waterpipe smokers. We identified six recent studies that measured the nicotine or cotinine levels associated with waterpipe smoking in four countries (Lebanon, Jordan, Kuwait, and India). Four of these studies directly measured nicotine or cotinine levels in human subjects. The remaining two studies used smoking machines to measure the nicotine yield in smoking condensate produced by the waterpipe. Meta-analysis of the human data indicated that daily use of the waterpipe produced a 24-hr urinary cotinine level of 0.785 microg/ml (95% CI = 0.578-0.991 microg/ml), a nicotine absorption rate equivalent to smoking 10 cigarettes/day (95% CI = 7-13 cigarettes/day). Even among subjects who were not daily waterpipe smokers, a single session of waterpipe use produced a urinary cotinine level that was equivalent to smoking two cigarettes in one day. Estimates of the nicotine produced by waterpipe use can vary because of burn temperature, type of tobacco, waterpipe design, individual smoking pattern, and duration of the waterpipe smoking habit. Our quantitative synthesis of the limited human data from four nations indicates that daily use of waterpipes produces nicotine absorption of a magnitude similar to that produced by daily cigarette use.     

Smoking behaviour and toxin exposure during six weeks use of a potential reduced exposure product: Omni

Objective: To determine smoking behaviour, acceptability, and toxin exposure when smokers switch to the potential reduced exposure product—Omni cigarette.

Design: 12 week randomised, crossover study of Omni versus own cigarettes.

Participants: 19 light/ultralight and 15 regular smokers.

Outcomes: Cigarettes/day, smoking topography, craving, withdrawal symptoms, urinary cotinine plus its glucuronide (total cotinine), nicotine plus its glucuronide (total nicotine), and carcinogen metabolites (4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol plus its glucuronides and 1-hydroxypyrene).

Results: When switched to Omni, smokers smoked the same number of cigarettes/day, smoked Omni cigarettes less intensely (total puff volume = –11%) and had slightly lower total cotinine (–18%) levels than their own cigarettes, but had a slightly greater carbon monoxide boost/cig (+21%). Craving and withdrawal ratings were similar with Omni and own cigarettes. Carcinogen metabolite levels were somewhat but not significantly lower with Omni. About half of smokers rated Omni as better for their health and about two thirds stated it was weaker and worse tasting than their own cigarettes.

Conclusions: Although Omni may be an adequate behavioural and pharmacological substitute for traditional cigarettes, it may not decrease carcinogen exposure and may increase carbon monoxide. Replications with larger sample sizes and longer follow up are needed. These results indicate the need for regulation of reduced exposure and reduced risk claims.

     

Nicotine, cotinine, withdrawal, and craving patterns during smoking and nicotine nasal spray use: results from a pilot study with African American men.

Nicotine intake via smoking is highly variable. Individualized dosing of nicotine replacement therapy (NRT) may improve product efficacy, but a better understanding of the within-day and within-subject relationships between smoking, NRT use, nicotine and cotinine concentrations in blood, and cravings and withdrawal symptoms is needed to inform dosing algorithms. A pilot study was undertaken to collect data on these relationships and to assess the feasibility of the methods needed for this type of research, including a sophisticated statistical modeling technique (a two-part mixed-effects model with correlated random effects that accounts for clumping at zero). Because nicotine metabolism varies by gender and race, the sample was homogeneous with respect to these characteristics. In a within-subjects study, 27 African American adult male smokers carried a computerized cigarette dispenser for 1 week, capturing the time each cigarette was smoked. Subjects then entered an inpatient setting for 1 day of scheduled smoking (matched to data from the cigarette dispenser to create an ecologically valid schedule) and 4 days of ad libitum nicotine nasal spray use, while tobacco abstinent. Eight times per day, at 2-hour intervals, blood was drawn and ratings of cigarette cravings and withdrawal symptoms were obtained. On average, subjects used less than half of the manufacturer's recommended minimum daily dose of nicotine nasal spray. Large differences in nicotine and cotinine levels were observed between individuals. When predicting nicotine, cotinine, withdrawal, and cravings, we observed significant interactions between route of nicotine intake and a variety of independent variables.     

Sex-based and hormonal contraception effects on the metabolism of nicotine among adolescent tobacco-dependent smokers.

Variations in nicotine metabolism influence smoking patterns. Differences between sexes or related to sex hormones may affect nicotine metabolism. Because smoking initiation starts during adolescence, observations gathered from adolescent smokers might broaden our understanding of such sex-based differences. We tested the hypothesis that nicotine metabolism--as indexed primarily by the ratio of trans-3'-hydroxycotinine (3HC) to cotinine--is more rapid among adolescent girl smokers compared with boys and that regular use of hormonal contraceptives influences nicotine and cotinine metabolism. We also hypothesized that more rapid nicotine metabolism is associated with higher nicotine dependence as indexed by smoking frequency and morning urgency. Plasma samples of nicotine, cotinine, and 3HC concentrations were obtained from 120 adolescents (36 boys). Plasma nicotine and cotinine concentrations were similar in boys and girls. Median plasma 3HC concentrations were 44.45 ng/ml for girls versus 35.74 ng/ml for boys (p = .025), and median plasma 3HC-cotinine ratios were significantly higher in girls than in boys (0.317 vs. 0.253, p = .025). After stratifying girls into two groups based on use versus nonuse of hormonal contraception, plasma 3HC-cotinine ratios in girls using hormonal contraception (0.47) were substantially higher (p<.0001) than in boys (0.25) and were significantly higher than in girls not using hormonal contraception (0.28). Controlling for cigarettes smoked per day, ethnicity, and age did not modify these results. Although plasma nicotine, cotinine, or 3HC concentrations were significantly lower in less dependent adolescent smokers, nicotine and cotinine metabolite ratios were similar. This study showed that hormonal contraception in adolescent girls may accelerate cotinine metabolism, an effect likely related to induction of cytochrome P450 2A6 and independent of ethnicity and cigarette consumption. Prospective controlled studies are needed to further evaluate the role of hormonal contraception in patterns of adolescent smoking and nicotine metabolism.     

Race differences in nicotine dependence in the Collaborative Genetic study of Nicotine Dependence (COGEND)

In a general population sample from the Detroit site of the Collaborative Genetic Study of Nicotine Dependence (COGEND), we tested Black-White differences in nicotine dependence, measured by "how soon after wake-up the smokers smoked their first cigarette (time to first cigarette TTFC)", and its relationship with number of cigarettes per day (CPD). Analysis was conducted on respondents who have smoked > or =100 cigarettes in lifetime and were current smokers (n = 1,442; 1,087 Whites and 355 Blacks). In univariate analysis, we found no significant race differences on time to first cigarette (chi2 = 2.9, p value = 0.41), but significant race differences on CPD (chi2 = 154.3, p<.01), both categorized by the Fagerstr?m Test of Nicotine Dependence (FTND) cutoffs. We estimated the probability of TTFC < or =30 min given CPD using probit models. The interactions between race and CPD indicated significant differences in dependence at various levels of CPD. The same probability of nicotine dependence was associated with smaller increments in CPD for Blacks than for Whites. The data support the hypothesis that the relationship between CPD and nicotine dependence as reflected in relapse varies by race, and that Black smokers are dependent at lower levels of CPD than Whites.     

The effect of a novel smoking system--Accord--on ongoing smoking and toxin exposure.

Multiple potentially reduced exposure products (PREPs) are being introduced to the market, yet little is known about how they will be used and what their public health impact might be. To determine the impact of one such PREP--Accord--on ongoing smoking and toxin exposure, 11 smokers of light cigarettes were required to use increasing amounts of Accord (5, 10, and 15 per day) with the option of using their traditional cigarettes. Accord suppressed ongoing cigarettes per day and carbon monoxide (CO), but not cotinine, in a dose-dependent manner. Smoking 15 Accord per day decreased the number of traditional cigarettes smoked by 32% (-8.6 cigarettes per day) and CO levels by 27% (-5.9 ppm). However, Accord did not function as a perfect (i.e., one to one) substitute for cigarettes because the total number of nicotine products (Accord plus usual brand) per day increased by 24%. Participants believed that Accord was safer than traditional cigarettes but rated Accord as ineffective at suppressing cravings for cigarettes. These findings suggest that use of Accord results in significant decreases in cigarettes smoked and CO exposure. Whether these reductions will translate into health benefits or endure beyond 2 weeks is unknown. Because most PREPs will probably be used along with traditional cigarettes, their net health impact is a function of not only their toxicological profile but also their effect on ongoing smoking.     

Mentholated cigarettes and smoking cessation: findings from COMMIT. Community Intervention Trial for Smoking Cessation

OBJECTIVE: To examine the association between the use of menthol cigarettes and smoking cessation, amount smoked, and time to first cigarette in the morning. BACKGROUND: The majority of African American smokers smoke mentholated cigarettes. Some evidence suggests that African Americans may be more nicotine dependent than whites. One theory is that menthol in cigarettes is responsible for enhancing the dependence producing capacity of cigarettes; however, few studies have prospectively examined the association between menthol use and indicators of nicotine dependence. METHODS: Baseline smokers from the Community Intervention Trial for Smoking Cessation (COMMIT) completed a telephone tobacco use survey in 1988 and were re-interviewed in 1993. Use of mentholated cigarettes was assessed by self report at baseline. Indicators of dependence examined were six month cessation in 1993, amount smoked among continuing smokers in 1993, and time to first cigarette in the morning in 1988. Multivariate regression techniques were used to assess the association of baseline menthol use with these outcomes while controlling for other factors related to dependence. RESULTS: Overall, 24% of the sample smoked a mentholated brand in 1988. No consistent associations were observed for menthol use and indicators of dependence in both overall and race specific analyses. Factors significantly associated with increased menthol use were female sex, age 25-34 years, African American and Asian race/ethnicity, greater education, greater than 60 minutes to the first cigarette in the morning, two or more past quit attempts, and use of premium brand cigarettes. Canadian respondents and those who smoked 15-24 cigarettes per day had lower rates of menthol use. Use of mentholated cigarettes was not associated with quitting, amount smoked, or time to first cigarette in the morning. CONCLUSION: Future work is needed to clarify the physiological and sociocultural mechanisms involved in mentholated cigarette smoking.     

Tobacco craving predicts lapse to smoking among adolescent smokers in cessation treatment.

Previous research indicates that tobacco craving predicts relapse to smoking among adult smokers attempting to quit. We hypothesized a similar relationship between craving and lapse (any smoking following a period of abstinence) among adolescent smokers during the treatment phase of a clinical trial. A visit was considered a lapse visit if the participant reported smoking or had a carbon monoxide level of 7 ppm or greater subsequent to an abstinent visit. A total of 34 participants (mean age = 14.9 years [SD = 1.3]; mean cigarettes/day = 18.0 [SD = 7.6]; mean Fagerstr?m Test for Nicotine Dependence score = 6.8 [SD = 1.34]; 65% female), were included in the present analysis of 167 treatment visits. Logistic regression analyses showed a positive relationship between degree of craving, measured by the Questionnaire on Smoking Urges, and lapse during smoking cessation treatment (p = .013). Additionally, linear regression analyses demonstrated a strong positive association between cigarettes smoked per day and craving scores (p<.001). Taken together with other data, these findings suggest that degree of craving might influence tobacco abstinence for adolescent smokers. Thus monitoring and addressing craving appears useful to increase the success of adolescent smoking cessation.     

DRD2/ANKK1 TaqI polymorphism and smoking behavior of Egyptian male cigarette smokers.

Little is known about the genetic contribution to cigarette smoking and nicotine addiction in Egypt. The dopamine D2 receptor gene contains a TaqI repeat fragment length polymorphism creating two alleles with functional significance, DRD2*A1 and DRD2*A2. We investigated the relationship between these alleles and tobacco use in a study of 389 Egyptian male current smokers (mean age = 40 years; SD = 12). Participants were interviewed in 2004 on their smoking behaviors and quit attempts, and were given the Fagerstr?m Test for Nicotine Dependence (FTND). Blood samples were obtained and genotyped for DRD2 A1and A2 alleles. The frequencies of A1/A2, A1/A2, and A2/A2 genotypes were 6%, 29%, and 65%, respectively. We found no statistically significant association between genotype and age at onset of smoking, years of smoking, FTND score, or average number of cigarettes smoked per day. DRD2 genotype was associated with the number of cigarettes smoked in the past 48 hr (42.2 in A1 carriers vs. 37.6 in A2, p = .03), the previous quit duration (28% in A1 vs. 40% in A2 quit for more than 1 month, p = .05), and the depth of inhalation (82% in A1 vs. 72% in A2 inhaled the smoke deeply, p = .03). Logistic regression analysis including DRD2 genotype, FTND score, age at smoking initiation, marital status, and education as predictors showed that maximum duration of quit time was associated with FTND score (p = .003), DRD2 genotype (p = .01), marital status (p = .03), and age at smoking initiation (p = .04). These findings suggest a modest association between DRD2 genotype and quitting behavior in male cigarette smokers in Egypt.     

Effects of low nicotine content cigarettes on smoke intake.

Cigarettes with selective reductions in nicotine delivery have been considered as potential tools to prevent or treat nicotine dependence or to reduce harm by virtue of reduced nicotine and nitrosamine delivery. An important question is whether individuals smoke these products more intensively, as has been shown to occur with ventilated-filter cigarettes. To investigate this issue, we compared conventional highly ventilated filter cigarettes, having very low tar and nicotine yields when smoked by Federal Trade Commission method (1 mg tar, 2 mg carbon monoxide [CO],.2 mg nicotine), with low nicotine content cigarettes, manufactured from a genetically modified strain of tobacco, which had higher tar but lower nicotine yield (14 mg tar, 13 mg CO,.02 mg nicotine). A total of 16 cigarette smokers participated in two 8-hr sessions (order counterbalanced) during which they smoked each type of cigarette ad libitum. Expired-air CO, plasma nicotine, and smoking topography measures were collected. Subjects showed significant increases in smoking when using the highly ventilated filter cigarettes, and puff volume was significantly greater than with the low nicotine content cigarettes. Subjects achieved an expired-air CO level 74% as high as with the low nicotine content cigarettes; the latter produced CO levels similar to those measured at baseline when subjects smoked their habitual brands of cigarettes. Plasma nicotine levels obtained when subjects smoked the highly ventilated filter cigarettes also were significantly higher than when they smoked the low nicotine content cigarettes. These results indicate that the delivery of substantial amounts of smoke, with selective reductions in nicotine yield, appears to prevent compensatory smoking behavior. Further studies should determine whether similar results are obtained in naturalistic environments.     

Are menthol cigarettes a starter product for youth?

This study assessed the relationship between menthol use and nicotine dependence. Data from the National Youth Tobacco Survey indicated that menthol cigarette use was significantly more common among newer, younger smokers. Additionally, youth who smoked menthol cigarettes had significantly higher scores on a scale of nicotine dependence compared with nonmenthol smokers, controlling for demographic background and the length, frequency, and level of smoking. The study suggests that menthol cigarettes are a starter product that may be associated with smoking uptake by youth.     

吸烟者转抽加热卷烟的抽吸行为和烟碱暴露

为研究吸烟者转抽加热卷烟后抽吸行为和烟碱暴露水平的变化,招募50名抽吸卷烟的志愿者,分为两组,分别转抽加热卷烟IQOS和国内加热卷烟M。转抽前后通过问卷调查获得志愿者的基线资料,使用CReSS吸烟行为记录仪测试吸烟行为参数,采用HPLC-MS/MS测定志愿者基线和转抽后尿样中的烟碱暴露生物标志物。结果表明:①志愿者转抽加热卷烟后抽吸行为基本保持不变,抽吸容量和抽吸时间均未发生显著性改变,但抽吸间隔明显缩短,两组志愿者抽吸卷烟时抽吸间隔分别为（14.3±8.0）s和（15.3±9.0）s,转抽加热卷烟后抽吸间隔分别为（9.8±8.3）s和（9.7±5.4）s。②转抽后志愿者尿液中烟碱总代谢物和可替宁等烟碱暴露生物标志物的浓度水平也未发生显著性改变。③转抽IQOS后志愿者的抽吸行为与转抽M后的志愿者没有明显差异,两组志愿者尿液中烟碱总代谢物和可替宁的水平也近似。      

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 Fagerstr?m 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.     

Severity of nicotine dependence moderates performance on perceptual-motor tests of attention.

Acute abstinence from cigarette smoking by nicotine-dependent smokers has been linked with cognitive deficits, but the role of nicotine dependence per se in these effects is not known. We therefore tested the relationships of nicotine dependence and smoking history with performance in perceptual-motor, timed tests of attention. Nicotine-dependent smokers (n = 37) and nonsmokers (n = 48), 18-55 years old, took both the d2 Test of Attention and the Digit Symbol Test on each of 2 test days. For smokers, testing on one day began after ad libitum smoking (<45 min since last cigarette); and on the other day, it began after overnight abstinence (>13 hr since last cigarette). On each test day, there were two test blocks with an intervening break, when only the smokers each smoked one cigarette. There were no significant effects of abstinence or of smoking one cigarette on the performance of smokers; however, across conditions, the smokers' performance on both tests correlated negatively with severity of nicotine dependence but not lifetime cigarette consumption or cigarette craving. Smokers with high nicotine dependence performed more slowly on both tests than less dependent smokers or nonsmokers. The findings suggest that severity of nicotine dependence and slowness in perceptual-motor tasks of attention share an underlying basis.