Phenotypic and genetic relationship between BMI and cigarette smoking in a sample of UK adults

In addition to the health hazards posed individually by cigarette smoking and obesity, the combination of these conditions poses a particular impairment to health. Genetic factors have been shown to influence both traits and, to understand the connection between these conditions, we examined both the observed and genetic relationship between adiposity (an electrical impedance measure of body mass index (BMI)) and cigarettes smoked per day (CPD) in a large sample of current, former, and never smokers in the United Kingdom. In former smokers, BMI was positively associated with cigarettes formerly smoked; further, the genetic factors related to a greater number of cigarettes smoked were also responsible for a higher BMI. In current smokers, there was a positive association between BMI and number of cigarettes smoked, though this relationship did not appear to be influenced by similar genetic factors. We found a positive genetic relationship between smoking in current/former smokers and BMI in never smokers (who would be unmarred by the effects of nicotine). In addition to CPD, in current smokers, we looked at two variables, time from waking to first cigarette and difficulty not smoking for a day, that may align better with cigarette and food ‘craving.’ However, these smoking measures provided mixed findings with respect to their relationship with BMI. Overall, the positive relationships between the genetic factors that influence CPD in smokers and the genetic factors that influence BMI in former and never smokers point to common biological influences behind smoking and obesity.     

The relationship of white blood cell and platelet counts to cigarette smoking in adult Nigerians

This study was undertaken to examine the relationship between cigarette-smoking and total white blood cell count (wbcc) and platelet count (pc) in adult Nigerians. We also studied the relationship of the white blood cell and platelet counts to the duration of the smoking habit and number of cigarette smoked per day. Three hundred and fifty-two healthy male adults, aged 18-52 years, were studied. They were randomly allocated to two groups--176 smokers and 176 non-smokers. The smoking habit was assessed from a minimum period of 1 year and a minimum number of 5 cigarettes per day. Results revealed that platelet count was higher for the regular Nigerian smoker than for non-smoker. The difference between mean platelet counts for smokers and non-smokers was statistically significant (t = 2.64 p = 0.0046). Man WBC count in smokers was slightly higher than for non-smokers. However, unlike in the case of platelet counts, the mean difference in WBC count between smokers and non-smokers is not statistically significant (t = 0.07, p value = 0.9442). Similar studies based on white population has showed statistically significant increases in wbcc and pc in smokers.     

A cross-sectional investigation of biomarkers of risk after a decade of smoking

Two groups of 20 healthy volunteers with cigarettes of different tar yield were compared with a group of 20 never smokers over 24?h for several biomarkers. All groups were of similar mean ages and the smokers had smoked for a homogeneous period of approximately 10?yr. The groups were assessed using routine medical parameters as well as biomarkers of recent smoke exposure and other biomarkers that were under evaluation as possible markers of risk for smoking-associated diseases. All biomarkers of exposure—carbon monoxide, nicotine plus its five major metabolites, and 4-(methylnitrosamine)-1-(3-pyridyl)-1-butanol (NNAL)—were significantly elevated in smokers. For biomarkers of potential risk evaluated in the blood, white cells and immunoglobulin (Ig) G showed a decrease related to smoking status (p?<?.01). Interleukin 6 levels were higher in smoker groups compared to never smokers, with a significant increasing trend across the groups (p?<?.05). Among the urinary biomarkers studied, 11-deydro-thromboxane B2, 2,3-dinor-thromboxane B2, and thymidine glycol showed significant increasing trends across the groups (p?<?.01). The results suggest that after the first decade or less of smoking, changes in inflammatory, immunological, and cardiovascular function can be observed. However, further studies on larger groups will be required to better understand the kinetics of these subtle effects observed early in smokers and their relationship with the potential risk of subsequent smoking-associated disease.     

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.     

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.     

Neurocognitive consequences of cigarette smoking in young adults--a comparison with pre-drug performance

The present study examined effects of current and past regular cigarette smoking in young adult subjects. One hundred and twelve 17-21-year-old subjects, assessed since infancy, were evaluated using a battery of neurocognitive tests for which commensurate measures were obtained at 9-12 years of age, prior to the initiation of regular smoking. Smokers, determined by urinalysis and self-report, were categorized as heavy (>9 cigarettes per day) and light (<9 cigarettes per day) current smokers and former smokers, the latter having smoked cigarettes regularly in the past but not for at least 6 months. A third of the subjects were currently smoking cigarettes regularly with half of these being heavy smokers. Among former smokers, the average duration of smoking was slightly less than 2 years. Overall IQ, memory, processing speed, vocabulary, attention and abstract reasoning were the primary outcomes with comparisons being made between each of the three user groups and a control group who never smoked regularly. After accounting for potentially confounding factors including clinical assessment, marihuana use and pre-drug performance in the relevant cognitive domain, current regular smokers did significantly worse than non-smokers in a variety of cognitive areas predicated upon verbal/auditory competence including receptive and expressive vocabulary, oral arithmetic, and auditory memory. This impact of current smoking appears to behave in a dose-response and duration-related fashion. In contrast, former smokers differed from the non-smokers only in the arithmetic task. These results suggest that regular smoking during early adulthood is associated with cognitive impairments in selected domains and that these deficits may be reversed upon cessation. Together, the findings add to the body of evidence to be used in persuading adolescents and young adults against the initiation of smoking and, if currently smoking, the advantages of stopping.     

Factors affecting exposure to nicotine and carbon monoxide in adult cigarette smokers

Exposure to cigarette smoke among smokers is highly variable. This variability has been attributed to differences in smoking behavior as measured by smoking topography, as well as other behavioral and subjective aspects of smoking. The objective of this study was to determine the factors affecting smoke exposure as estimated by biomarkers of exposure to nicotine and carbon monoxide (CO). In a multi-center cross-sectional study of 3585 adult smokers and 1077 adult nonsmokers, exposure to nicotine and CO was estimated by 24 h urinary excretion of nicotine and five of its metabolites and by blood carboxyhemoglobin, respectively. Number of cigarettes smoked per day (CPD) was determined from cigarette butts returned. Puffing parameters were determined through a CreSS® micro device and a 182-item adult smoker questionnaire (ASQ) was administered. The relationship between exposure and demographic factors, smoking machine measured tar yield and CPD was examined in a statistical model (Model A). Topography parameters were added to this model (Model B) which was further expanded (Model C) by adding selected questions from the ASQ identified by a data reduction process. In all the models, CPD was the most important and highest ranking factor determining daily exposure. Other statistically significant factors were number of years smoked, questions related to morning smoking, topography and tar yield categories. In conclusion, the models investigated in this analysis, explain about 30-40% of variability in exposure to nicotine and CO.     

Patterns of intermittent smoking: An analysis using Ecological Momentary Assessment

Non-daily smokers comprise a substantial proportion of US smokers, but there has been little study of their patterns of smoking, which are often assumed to reflect “social smoking.” We used Ecological Momentary Assessment methods to study smoking patterns in 27 non-daily smoking adults who recorded each cigarette smoked over three weeks by leaving a voice mail message indicating their circumstances at the time of smoking. All told, 689 cigarettes were recorded over 589 person-days of observation. On average, participants smoked on 67% of days, averaging 2.1 (SD = 0.91) cigarettes per day on days they smoked; 22% of all cigarettes were smoked in bouts (within an hour of another cigarette). Altogether, 19% of cigarettes were smoked when drinking alcohol and 29% when participants were socializing. Smoking patterns varied widely across participants. A pair of hierarchical cluster analyses distinguished three groups: Those who smoked primarily (81% of cigarettes) in the daytime (Early smokers; n = 15, 58% of total sample), those who smoked primarily (75% of cigarettes) at night (Late smokers; n = 7, 27%), and a distinct, classic “Social smoking” group (n = 4, 15% of total sample), who smoked mostly at night but also primarily when socializing or drinking (86% of their cigarettes), in the evening (71% of their cigarettes), on weekends (65% of their cigarettes), and in bouts (71% of their cigarettes). Overall, results suggest that non-daily smoking patterns are quite heterogeneous, and that many non-daily smokers may not be primarily social smokers.     

CYP2A6 Genotype and Smoking Behavior in Current Smokers Screened for Lung Cancer

Functional CYP2A6 genetic variation partially determines nicotine metabolism. In 2005, we examined functional CYP2A6 variants associated with reduced metabolism (CYP2A6*2, CYP2A6*9, CYP2A6*4), smoking history, and change in smoking in 878 adult smokers undergoing lung cancer screening in an urban setting. At one year, 216 quit smoking for more than 30 days while 662 continued smoking. Compared to subjects who smoked 30 cigarettes per day at baseline, the odds of a reduced metabolism genotype was 52% higher in subjects smoking 20–29 cigarettes per day and 86% higher in subjects smoking less than 20 cigarettes per day (p-trend = 0.016). Reduced metabolism genotypes appeared unrelated to quitting. Though related to smoking dose, CYP2A6 may not influence cessation.     

Alcohol drinking and cigarette smoking: an exploration of the association in middle-aged men and women

The association of alcohol and cigarette consumption was explored among 13,673 black or white persons aged 40-49 years, who received check-ups from mid-1979 to 1985. Alcohol use was strongly associated with number of cigarettes smoked per day, but not with tar-yield, mentholation and presence of filters. Duration of cigarette use, frequency and depth of inhalation, proportion of cigarette smoked and greater time from arising to first cigarette were significantly related to alcohol use in some but not all race-sex groups. Among smokers who consumed alcohol, liquor drinkers smoked the most cigarettes per day and wine drinkers the least. Thus, the association between alcohol drinking and cigarette smoking is strong in middle-aged persons but there are race- and sex-related disparities when specific aspects of smoking behaviour are considered.     

Acute Phenylalanine/Tyrosine Depletion Reduces Motivation to Smoke Cigarettes Across Stages of Addiction

The neurobiology of tobacco use is poorly understood, possibly in part because the relevant mechanisms might differ depending on past nicotine exposure and degree of addiction. In the present study we investigated whether these factors might affect the role of dopamine (DA). Using the acute phenylalanine/tyrosine depletion method (APTD), DA synthesis was transiently decreased in three groups of abstinent smokers (n=47): (1) early low-frequency smokers, who had smoked a maximum of five cigarettes per day for less than one year, (2) stable low-frequency smokers smoking at the same level as early low-frequency smokers for at least 3 years, and (3) stable high-frequency smokers, who smoked a minimum of 10 or more cigarettes per day for at least 5 years. Motivation to obtain tobacco was measured using a progressive ratio breakpoint schedule for nicotine-containing and de-nicotinized cigarettes. Compared with a nutritionally balanced control mixture, APTD decreased the self-administration of nicotine-containing cigarettes, and this occurred in all three groups of smokers. The results suggest that DA influenced the willingness to sustain effort for nicotine reward, and this was seen in participants at all three levels of cigarette addiction. In the transition from sporadic to addicted use, the role of DA in the motivation to seek drug may change less than previously proposed.     

WHOLE BLOOD AGGREGATION AND PLASMA LYSO-PAF RELATED TO SMOKING AND ATHEROSCLEROSIS

1. Aggregation of diluted whole blood (impedance method) and thromboxane B2 production during aggregation were measured in cigarette smokers and non-smokers, aged 41-68 years, with (n = 14) and without (n = 15) major symptomatic peripheral vascular disease. The plasma level of the lyso derivative of platelet activating factor (lyso-PAF) was also measured using a bioassay with 14C-serotonin labelled rabbit platelets, after extraction and acetylation to active PAF. 2. Aggregation to ADP and collagen was significantly less in non-smokers without vascular disease (n = 8) than in the other three groups (P less than 0.01; ANOVA). Thromboxane B2 production was not significantly different between the groups. There was no significant difference in plasma lyso-PAF between groups. No change was found in any variable after smokers smoked two cigarettes. 3. In these older age subjects, both vascular disease and the smoking habit were associated with greater whole blood aggregation. However, current smoking and the smoking of two cigarettes did not affect aggregation in subjects with vascular disease and plasma lyso-PAF levels were not consistently related to either smoking or vascular disease.     

Risk perception and intention to quit among a tri-ethnic sample of nondaily,light daily,and moderate/heavy daily smokers

Introduction

Although the relationship between risk perceptions and quit intentions has been established, few studies explore the potential impact of smoking level on these associations, and none have done so among diversely-aged samples of multiple ethnicities.

Methods

Participants, ranging in age from 25 to 81, were 1133 nondaily smokers (smoked ≥ 1 cigarette on 4 to 24 days in the past 30 days), 556 light daily smokers (≤ 10 cigarettes per day), and 585 moderate to heavy daily smokers (> 10 cigarettes per day). Each smoking level comprised approximately equal numbers of African Americans, Latinos, and Whites. A logistic regression analysis, adjusted for sociodemographics, self-rated health, time to the first cigarette of the day and smoking level, was used to examine the association between risk perception (perceived risk of acquiring lung cancer, lung disease, and heart disease) and intention to quit (≤ 6 months versus > 6 months/never). A second adjusted model tested moderation by smoking level with an interaction term.

Results

Greater risk perception was associated with a higher odds of planning to quit within 6 months (AOR = 1.34, CI_.95 = 1.24, 1.45). Smoking level did not moderate this association (p = .85).

Conclusions

Results suggest that educating all smokers, irrespective of their smoking level, about increased risk of developing smoking-related diseases might be a helpful strategy to enhance their intention to make a smoking quit attempt.     

视觉模拟标尺评估吸烟者尼古丁渴求强度的能力初探

目的:探讨视觉模拟标尺(VAS)评估吸烟者尼古丁渴求强度的能力。方法:在知情同意的前提下,采用VAS和Fagerstrm尼古丁依赖检验量表(FTND)对广告招募的北京市区211例吸烟史≥1a、每日吸烟≥10支,并有戒烟动机的吸烟者进行横断面现场调查,以VAS分和FTND总分的相关分析评估VAS评估吸烟者尼古丁渴求强度的能力,并以吸烟者吸烟量、吸烟深度、呼气一氧化碳(CO)浓度和尿中可替宁浓度等指标来验证。结果:VAS与FTND呈线性正相关(P=0.000);VAS与日吸烟量、吸烟深度、呼气CO浓度、尿液可替宁浓度呈正相关(P均<0.01)。饮酒组与非饮酒组中VAS与FTND皆呈正相关(P=0.000)。非饮酒组中VAS与日吸烟量、吸烟深度、呼气CO浓度都呈正相关(P均<0.05)。饮酒组中VAS与日吸烟量、尿液可替宁浓度呈正相关(P均<0.01)。结论:VAS对吸烟者中尼古丁渴求强度有较好的评估能力,推荐该量表可以用来作为评价尼古丁渴求强度的工具。同时,在VAS结合自报吸烟深度评价饮酒者的尼古丁渴求程度时,应当考虑饮酒因素的影响。     

Correlates of motivation to quit smoking in methadone-maintained smokers enrolled in a smoking cessation trial

Cigarette smoking is a clear problem among methadone-maintained persons, yet little is known about factors that may be associated with their motivation to quit smoking. A sample of 255 smokers, enrolled in a smoking cessation research protocol, completed measures of their smoking motivation, smoking habit, quitting history, and intent to quit in the future. Both zero-order correlational and multivariate linear regression analyses indicated that only number of cigarettes smoked per day and expectancies for success with smoking cessation were associated significantly with motivation to quit smoking. These results have implications for understanding motivational processes among methadone-maintained smokers and may help in the design of interventions that will assist this population with quitting smoking.     

Investigation into the risk of ultra-low tar cigarettes and lung cancer

We present analyses relating cigarette type to lung cancer based on a case-control study in five European countries. The analyses involved 3561 cases and 2301 controls with diseases not associated with smoking. Subjects completed a detailed questionnaire, including a lifetime smoking history. Analyses included never smokers, and those who smoked for at least 80% of the “critical period” from 2 to 20 years before diagnosis, ignoring those who ever smoked pipes or cigars, or chewed tobacco. The main analysis compares risk in those who, in the critical period, smoked ultra-low tar (ULT) cigarettes (machine yield ≤3 mg tar/cigarette) for 8 + years, with those who only smoked full flavour (FF) cigarettes (≥10 mg tar/cigarette). After adjustment for sex, age, country, education, age of starting smoking, mean cigarette consumption and mean tar level 21–50 years before interview, the odds ratio (OR) was 0.73 (95% confidence interval (CI) 0.50–1.06). Other analyses showed a modest, not statistically significant, reduction in risk with tar reduction. Risk in ULT smokers for 8 + years was substantially higher than in never smokers (OR 16.27, 95% CI 10.14–26.09). The study was prematurely terminated due to cost overrun, limiting the power to detect an association. More evidence is needed, particularly on lifetime ULT smoking.     

Nicotine content of cigarettes and the smoking habit: Their relevance to subjective ratings of preferences in smokers

One lettuce-leaf and three tobacco cigarettes with different nicotine content were smoked by 24 habitual smokers in the course of 4 successive sessions. Their previous smoking habits were found to be significantly related to their preferences for the various cigarettes. Whilst the heavy smokers (>10 cigarettes per day) preferred only the tobacco cigarettes and strongly disliked the lettuce-leaf, light smokers disliked mostly the highest nicotine cigarette. These ratings were also related to differences in the nicotine intake. It is suggested that these findings support the importance of nicotine in the smoking habit, although other factors may be related to the likableness of tobacco smoking. The relevance of this type of study is discussed.This work was supported by the Tobacco Research Council.     

Discounting delayed and probabilistic monetary gains and losses by smokers of cigarettes

Rationale Nicotine dependence has been associated with impulsivity and discounting delayed/uncertain outcomes. Objectives This study had two main objectives: (1) to examine the relationship between the number of cigarettes consumed per day and the degree to which delayed and uncertain monetary gains and losses are discounted by smokers, and (2) to determine the relationship between the estimated dose of nicotine intake per day and the degree to which four types of discounting occur. Methods Twenty seven habitual smokers and 23 never smokers participated in this experiment. They were required to choose between immediate and delayed monetary rewards (or losses), or between guaranteed and probabilistic rewards (or losses). Results The degree to which delayed monetary gains were discounted was significantly and positively correlated with both the number of cigarettes smoked and the estimated dose of nicotine intake per day. Conversely, there was no relationship between smoking and the remaining three types of discounting. Also, mild smokers in our sample did not differ from never smokers in discounting monetary gains or losses. Conclusions In general, our results suggest that both the frequency of nicotine self-administration, as well as the dosage, are positively associated with greater delay discounting of gains. One neuropsychopharmacological explanation for this effect is that chronic nicotine intake may induce neuroadaptation of the neural circuitry involved in reward processing.     

Factors associated with smoking menthol cigarettes among treatment-seeking African American light smokers

Background

Smoking menthol cigarettes is more prevalent among African Americans (AA) compared to Whites. Menthol has been found to be inversely related to smoking cessation among AA, yet little is known about the factors associated with menthol smoking among AA light smokers. This study examines baseline demographic, psychological, and smoking factors associated with smoking menthol cigarettes among AA light smokers (≤10 cigarettes per day).

Methods

Participants (n = 540) were enrolled in a double blind, placebo-controlled randomized trial of bupropion in combination with health education counseling for smoking cessation. Bivariate differences between menthol and non-menthol smokers were explored and baseline factors associated with smoking menthol cigarettes were identified.

Results

Participants averaged 46.5 years in age, predominantly female (66.1%), and smoked an average of 8.0 cpd (SD = 2.5). The majority (83.7%) smoked menthol cigarettes. In bivariate analysis, menthol cigarette smokers were younger (mean age: 45 vs. 52 years p < 0.0001), were more likely to be female (68% vs. 52% p = 0.003) and had smoked for shorter duration (28 vs. 34 years p < 0.0001) compared to non-menthol smokers. While depression and withdrawal scores were slightly higher and exhaled carbon monoxide values were lower among menthol smokers, the differences were not statistically significant.

Conclusions

Among AA light smokers, younger individuals and females were more likely to smoke menthol cigarettes and may be more susceptible to the health effects of smoking. Appropriately targeted health education campaigns are needed to prevent smoking uptake in this high-risk population.     

Effects of abstinence and smoking on information processing in adolescent smokers

RATIONALE: Although adolescent smokers appear to display some of the hallmark features of dependence, the biological and behavioral effects of smoking in this population are poorly understood. OBJECTIVES: This study aimed to define empirically the effects of abstinence and smoking in adolescent smokers, using indices validated in adult smokers. METHODS: Subjects were 16 young novice smokers (five male, 11 female), ages 14-18 years. A modified Stroop task measured the ability to inhibit attention to smoking-related cues; the classic Stroop task measured the ability to inhibit a pre-potent response (i.e. reading a word); a rapid information processing (RIP) task measured vigilance. RESULTS: Abstinence increased and smoking decreased the intrusiveness of smoking cues. Parallel effects were seen in commission errors on the RIP task. These effects were restricted to heavier smokers (>11 cigarettes/day). Subjective withdrawal effects predicted the intrusiveness of smoking words during abstinence. The number of cigarettes smoked per day predicted the beneficial effect of smoking on the classic as well as modified Stroop tasks. The physiological effects of abstinence and smoking predicted RIP performance. CONCLUSIONS: Abstinence impairs and smoking improves inhibitory information processing in young novice smokers in a manner similar to adult smokers. Daily frequency of smoking is a critical moderator of these effects.