Compulsive smoking: the development of a Rasch homogeneous scale of nicotine dependence

Development and initial validation of a new self-report measure to assess perceived dependence on tobacco and nicotine products

How nicotine is administered has evolved from cigarettes to various delivery systems. Assessing perceived dependence on nicotine-containing products now requires accounting for product specificity while allowing comparisons across products and users. This study aims to develop a new self-report measure to assess perceived dependence on tobacco and nicotine products (TNPs) among exclusive and poly-TNP users. A draft version of the new measure, the ABOUT-Dependence, was constructed based on literature review, qualitative research, and expert opinion. Data for scale formation and psychometric assessment was obtained through a US-based web survey (n = 2334) that included additional dependence measures for convergent validity assessment. Qualitative research confirmed a preliminary conceptual framework with seven sub-concepts. Following a cognitive debriefing, 19 items were considered to best represent the different sub-concepts. Psychometric findings supported a three-domain structure [i.e., behavioral impact (five items), signs and symptoms (five items), and extent/timing of use (two items)] and an overall total composite score. The data confirmed convergent and known-group validity, as well as test-retest reliability. The ABOUT-Dependence is a 12-item, psychometrically sound, self-report measure that may be used as a tool for research and further understanding of perceived dependence across the spectrum of TNP and TNP users.

Antibody response of smokers to the COVID-19 vaccination: Evaluation based on cigarette dependence

Smokers may have lower antibody titers after vaccination with a coronavirus disease 2019 (COVID-19) mRNA vaccine. However, to the best of our knowledge, no study has evaluated antibody titers after COVID-19 vaccination based on the level of smokers' cigarette dependence. In this study, we measured the level of serum anti-severe acute respiratory syndrome coronavirus 2 (anti-SARS-CoV-2) spike protein receptor-binding domain (S-RBD) immunoglobulin-G (IgG) by enzyme linked immunosorbent assay of 55 actively smoking Japanese social workers (firefighters, paramedics, and rescue workers) who had received two doses of the BNT162b2 vaccine. Further, we assessed their cigarette dependence using the Fagerstrom Test for Nicotine Dependence (FTND), measured their serum cotinine levels, and tested for their correlation with anti-RBD IgG levels. Serum anti-SARS-CoV-2 S-RBD protein IgG levels after BNT162b2 vaccination showed a significant negative correlation with FTND (ρ = -0.426, p = 0.001). In addition, serum cotinine level showed a significant positive correlation with FTND (ρ = 0.470, p = 0.000). However, no significant negative correlation was noted between serum cotinine and serum anti-SARS-CoV-2 S-RBD protein IgG levels (ρ = -0.156, p = 0.256). Our results suggest that smokers with strong cigarette dependence have inadequate anti-SARS-CoV-2 S-RBD protein IgG levels after COVID-19 mRNA vaccination.

Psychometric properties of Fagerstrom Test of Nicotine Dependence: A systematic review

The Fagerstrom test for nicotine dependence (FTND) is a widely used test for assessing physical nicotine dependence. However, there is a need to assess the psychometric properties of FTND to assess its role in treatment outcome studies. The aim of the present investigation was to review the psychometric properties of the FTND. A broad systematic literature search was performed from Pubmed and PsycINFO from 2000 to 2019. The publication language was limited to English. Two review authors performed the study selection and extracted the data. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and the Rayyan software used to screen relevant studies. A total of 1471 articles retrieved from the search, of which 33 studies fulfilled the inclusion criteria. Eleven studies related to testing the reliability of the FTND were analyzed. Twenty-five studies evaluated the Cronbach alpha of the test. Analysis of the studies revealed the questionable psychometric qualities of the adapted versions of the test across different cultures and ethnicity. It also suggested that it may not tap the appropriate constructs that would predict smoking patterns in light smokers, e-cigarette smokers, and smokeless tobacco users. Thus, further research must focus on improving the psychometric properties of FTND to enhance the measurement of nicotine dependence.

E-cigarette Dependence Measures in Dual Users: Reliability and Relations With Dependence Criteria and E-cigarette Cessation

BACKGROUND

Electronic cigarettes (e-cigarettes) have drastically changed the nicotine and tobacco product landscape. However, their potential public health impact is still unclear. A reliable and valid measure of e-cigarette dependence would likely advance assessment and prognostication of the public health impact of e-cigarettes. The aim of this research was to examine the internal consistency, structure, and validity of three e-cigarette dependence scales.

METHODS

Adult dual users (smokers who also vape, N = 256) enrolled in an observational cohort study (45.1% women, 70.7% white). At baseline, participants completed the e-cigarette Fagerström Test of Cigarette Dependence (e-FTCD), the e-cigarette Wisconsin Inventory of Smoking Dependence Motives (e-WISDM), and the Penn State Electronic Cigarette Dependence Index (PS-ECDI). All participants provided a urine sample for cotinine analysis and reported e-cigarette use at 1 year.

RESULTS

The e-WISDM subscales had the highest internal consistency (α = .81-.96), then the PS-ECDI (α = .74) and e-FTCD (α = .51). A single-factor structure for the e-FTCD and an 11-factor structure for the e-WISDM were supported, but the PS-ECDI did not have a single-factor structure. All three e-cigarette dependence scales were highly correlated with validation criteria including continued e-cigarette use at 1 year, but not with e-liquid nicotine concentration or cotinine.

CONCLUSIONS

The e-WISDM and PS-ECDI had stronger internal consistency than did the e-FTCD, despite the e-FTCD's single-factor structure, but all 3 measures appear to be valid measures of e-cigarette dependence as suggested by their significant relations with self-perceived addiction, heavy use, early use after overnight deprivation, and continued use over time.

IMPLICATIONS

This research provides empirical support for three e-cigarette dependence measures: the e-FTCD, the PS-ECDI, and the e-WISDM among dual users of e-cigarettes and combustible cigarettes. The PS-ECDI and e-WISDM are more reliable, but all three measures were strongly correlated with key dependence constructs such as heavy use and continued use over time.

Item Response Theory analysis of Fagerström Test for Cigarette Dependence

INTRODUCTION

The Fagerström Test for Cigarette Dependence (FTCD) and the Heaviness of Smoking Index (HSI) are the gold standard measures to assess cigarette dependence. However, FTCD reliability and factor structure have been questioned and HSI psychometric properties are in need of further investigations. The present study examined the psychometrics properties of the FTCD and the HSI via the Item Response Theory.

METHODS

The study was a secondary analysis of data collected in 862 Italian daily smokers. Confirmatory factor analysis was run to evaluate the dimensionality of FTCD. A Grade Response Model was applied to FTCD and HSI to verify the fit to the data. Both item and test functioning were analyzed and item statistics, Test Information Function, and scale reliabilities were calculated. Mokken Scale Analysis was applied to estimate homogeneity and Loevinger's coefficients were calculated.

RESULTS

The FTCD showed unidimensionality and homogeneity for most of the items and for the total score. It also showed high sensitivity and good reliability from medium to high levels of cigarette dependence, although problems related to some items (i.e., items 3 and 5) were evident. HSI had good homogeneity, adequate item functioning, and high reliability from medium to high levels of cigarette dependence. Significant Differential Item Functioning was found for items 1, 4, 5 of the FTCD and for both items of HSI.

CONCLUSIONS

HSI seems highly recommended in clinical settings addressed to heavy smokers while FTCD would be better used in smokers with a level of cigarette dependence ranging between low and high.

Then and now: Consumption and dependence in e-cigarette users who formerly smoked cigarettes

Electronic cigarette use, or vaping, continues to be a focus for regulators and policy makers in public health, particularly since it can compete with or be a substitute for smoking. This study investigated characteristics of nicotine dependence and consumption in a sample of vapers who formerly smoked cigarettes. We recruited 436 (80% male) vapers from several internet discussion forums; 95% of whom previously smoked, but ceased after commencing vaping. These participants completed a retrospective version of the Fagerström Test for Nicotine Dependence (FTND-R), as well as a version modified to suit current vaping (FTND-V), along with measures of consumption. Nicotine dependence appears to reduce markedly when smokers transition to vaping. However, 'decoupling' is observed in the relationship between consumption and dependence in vaping, and the FTND-V showed inadequate psychometric properties. Older and female vapers tend to employ a low-power, higher nicotine-concentration style of vaping. Overall, nicotine concentration tended to increase over time, although this effect was moderated by users' intentions to reduce their intake. Indicators of smoking addiction do not appear to be applicable to vaping, with respect to both internal consistency and relationship to consumption. This suggests that motivations for vaping are less dominated by nicotine delivery (negative reinforcement), and may be driven more by positive reinforcement factors. Nevertheless, e-liquid nicotine concentration was associated, albeit weakly, with dependence among e-cigarette users. Finally, vapers are heterogeneous group with respect to style of consumption, with a high-power/lower nicotine set-up more common among younger men.

Validity of the Italian version of the Severity of Dependence Scale (SDS) for nicotine dependence in smokers intending to quit

The objective was to test the psychometric properties of an Italian version of the Severity of Dependence Scale, a five-item measure designed to assess the compulsive dimension of drug dependence. 635 smokers enrolled in a tobacco dependence treatment program served as the participants. The Fagerström Test for Nicotine Dependence was used as a comparative measure. Dimensionality of the Severity of Dependence Scale and the Fagerström Test for Nicotine Dependence was assessed by factor analysis. Prediction of smoking at one year was evaluated by logistic regression. Factor analysis yielded a two-factor solution; however, the second factor explained very little variance. Factor 1 had a Cronbach's alpha of .66 (overall Scale coefficient = .44). The total Severity of Dependence Score predicted smoking at one year (OR = 1.10).

The Fagerström test for nicotine dependence: do revisions in the item scoring enhance the psychometric properties?

Despite widespread use, considerable literature has shown that the Fagerström Test for Nicotine Dependence (FTND; Heatherton, Kozlowski, Frecker, & Fagerström, 1991) has questionable psychometric properties, generally reflecting relatively poor properties of reliability and validity. One factor that may be affecting the psychometric qualities of the scale is the use of a dichotomous, forced-choice response format for certain items, in which respondents are asked to answer each question with a Yes or No response. This scoring approach is especially problematic when used to measure dimensional constructs, such as nicotine dependence, in which a dimensional construct is forced into a categorical construct. The purpose of the current study was to examine whether revising the response format utilized in the FTND would lead to an enhancement in the psychometric properties of this scale. This question was examined by removing the forced-choice response criteria on items 2, 5, and 6 of the FTND and revising the response options to reflect a 4-point Likert response set (0 = never, 1 = sometimes, 2 = most of the time, 3 = always). Participants consisted of 343 smokers from the community. Results revealed that the revised scoring approach resulted in a significant incremental improvement in scale reliability and enhanced convergent validity, showing a stronger association with smoking outcomes than the FTQ or FTND. Findings are discussed in terms of recommendations for scale revision and usage.

Are oral health complaints related to smoking cessation intentions?

OBJECTIVE

Smoking influences oral health in several ways (such as the occurrence of periodontitis, teeth discolouration and oral cancer); therefore, smoking behaviour should be addressed in dental care. Dentists can play a role in primary and secondary prevention of tobacco dependence. They see their patients repeatedly over time. This study investigates whether oral health complaints can be seized as an opportunity to start smoking cessation counselling.

METHODS

A structured patient questionnaire in a sample of 1101 smokers (52.1% women, mean age 40.4 years) in a convenience sample of 87 primary care dental practices. The I-change model was used to describe factors influencing behavioural change. Dependent factors such as intention to quit smoking and related factors (attitude, social support and self-efficacy) were analysed in relation to independent factors such as oral health complaints (gingiva problems, gingiva inflammation, oral cancer and discoloured teeth) using a general linear model (univariate analysis), multinomial logistic regression analysis and multiple linear regression analysis.

RESULTS

A total of 56.3% had discoloured teeth, 27% of the smokers had a problem with their gums and 15.7% had gingiva inflammation. We found no direct relation between oral health complaints and the intention to quit smoking. However, teeth discolouration was positively related to attitudes towards smoking cessation [β, Confidential interval (95%); 1.92 (1.45-2.40 for advantages and -0.86(-1.18 to -0.53) for disadvantages] and negatively to self-efficacy regarding quitting [-2.69 (-3.49 to 1.88)].

CONCLUSIONS

We found no direct relation between oral health complaints and the intention to quit smoking, but oral health complaints and especially teeth discolouration were related to factors influencing the quit intention. Patients with discoloured teeth are more likely to have a positive attitude towards smoking cessation but are uncertain to persist smoking cessation. It is suggested that teeth discolouration can be a good entrance for addressing smoking cessation in daily dental practice.

Measuring smoking-related preoccupation and compulsive drive: evaluation of the obsessive compulsive smoking scale

RATIONALE

Tobacco use for many people is compulsive in nature. Compelling theories of how smoking becomes compulsive exist but are largely based on extrapolation from neuroscience findings. Research on smokers is impeded, in part, by a lack of instruments that specifically measure compulsive smoking.

OBJECTIVE

This study evaluated the measurement structure and validity of the Obsessive Compulsive Smoking Scale (OCSS), a ten-item questionnaire designed to measure compulsive smoking.

METHODS

Participants were 239 daily smokers (>/=1 cigarette/day), including 142 students at a public university in Chicago and 97 veterans treated at the VA Boston Healthcare System. The OCSS and questionnaires measuring current and past smoking, cigarette craving, automatic smoking, and nicotine dependence were administered.

RESULTS

Factor analysis with maximum likelihood extraction and oblique rotation revealed two correlated underlying factors, interpreted as "Preoccupation with Smoking" and "Compulsive Drive." The measurement structure was consistent across students and veterans, and confirmed in an independent sample of adults (n = 95). Veterans exhibited higher OCSS scores (full scale and subscales) than students. Across groups, higher OCSS scores were positively correlated with smoking intensity, craving, and nicotine dependence. OCSS full-scale and compulsive drive scores, but not smoking preoccupation scores, were inversely correlated with past month smoking reduction and minutes since last cigarette.

CONCLUSIONS

The OCSS is a valid and reliable inventory for measuring the degree to which daily smokers are preoccupied with smoking and engage in compulsive tobacco use, and may be useful for advancing understanding of core smoking phenotypes or for tailoring cessation therapies.

Nicotine withdrawal sensitivity, linkage to chr6q26, and association of OPRM1 SNPs in the SMOking in FAMilies (SMOFAM) sample

BACKGROUND

Nicotine withdrawal symptoms are related to smoking cessation. A Rasch model has been used to develop a unidimensional sensitivity score representing multiple correlated measures of nicotine withdrawal. A previous autosome-wide screen identified a nonparametric linkage (NPL) log-likelihood ratio (LOD) score of 2.7 on chromosome 6q26 for the sum of nine withdrawal symptoms.

METHODS

The objectives of these analyses were to (a) assess the influence of nicotine withdrawal sensitivity on relapse, (b) conduct autosome-wide NPL analysis of nicotine withdrawal sensitivity among 158 pedigrees with 432 individuals with microsatellite genotypes and nicotine withdrawal scores, and (c) explore family-based association of single nucleotide polymorphism (SNP) at the mu opioid receptor candidate gene (OPRM1) with nicotine withdrawal sensitivity in 172 nuclear pedigrees with 419 individuals with both SNP genotypes and nicotine withdrawal scores.

RESULTS

An increased risk for relapse was associated with nicotine withdrawal sensitivity score (odds ratio, 1.25; 95% confidence interval, 1.10-1.42). A maximal NPL LOD score of 3.15, suggestive of significant linkage, was identified at chr6q26 for nicotine withdrawal sensitivity. Evaluation of 18 OPRM1 SNPs via the family-based association test with the nicotine withdrawal sensitivity score identified eight tagging SNPs with global P values <0.05 and false discovery rate Q values <0.06.

CONCLUSION

An increased risk of relapse, suggestive linkage at chr6q26, and nominally significant association with multiple OPRM1 SNPs were found with Rasch-modeled nicotine withdrawal sensitivity scores in a multiplex smoking pedigree sample. Future studies should attempt to replicate these findings and investigate the relationship between nicotine withdrawal symptoms and variation at OPRM1.

Psychometric properties of the Fagerström Test for Nicotine Dependence

OBJECTIVE

The Fagerström Test for Nicotine Dependence (FTND) is a screening instrument for physical nicotine dependence and is extensively used in various countries. The objective of the present report was to review articles related to the psychometric properties of the FTND.

METHODS

A systematic search for articles published up through December of 2007 was carried out in various electronic databases. The following search terms were used: 'Fagerström Test for Nicotine Dependence'; 'FTND'; 'psychometric'; 'validity'; 'reliability'; 'feasibility'; and 'factors'. We included articles published in English, Spanish or Portuguese and in which the psychometric properties of the FTND were evaluated.

RESULTS

Twenty-six studies related to the psychometric properties of the FTND were identified in the indexed literature. Analysis of the studies confirmed the reliability of the FTND for the assessment of nicotine dependence in different settings and populations.

CONCLUSIONS

Further validation studies using previously validated instruments as a comparative measure are needed before the extensive use of the FTND can be justified on the basis of its psychometric qualities.

Psychometric qualities of the Brazilian versions of the Fagerström Test for Nicotine Dependence and the Heaviness of Smoking Index

INTRODUCTION

This study examined the psychometric properties of the Brazilian versions of the Fagerström Test for Nicotine Dependence (FTND) and the Heaviness of Smoking Index (HSI).

METHODS

The test-retest reliability of the FTND was assessed in a sample of 61 smoking university students, with a 15-day interval between assessments. The interrater reliability was examined in 30 smoking patients of a psychosocial care center for alcohol and drug users (PCC-AD). The reliability coefficient was estimated by the kappa and intraclass correlation coefficients. The predictive validity, internal consistency, and factor structure of the FTND and the HSI were evaluated by factor analysis in 271 smokers treated at an emergency unit and at the PCC-AD. The gold standard was the nicotine dependence criteria of DSM-IV, as assessed by the Structured Clinical Interview for DSM-IV.

RESULTS

The FTND showed high reliability, with correlation coefficients of .92 for test-retest reliability and .99 for interrater reliability. Both the FTND and the HSI presented high levels of sensitivity and specificity. The internal consistency evaluation yielded a Cronbach's alpha coefficient of .83 for the FTND and of .56 for the HSI. An exploratory factor analysis found 2 factors in the FTND, which were validated by a confirmatory factor analysis.

DISCUSSION

The results obtained in this study confirm the validity and reliability of the Brazilian versions of the FTND and the HSI.

Association of tobacco dependence and quit attempt duration with Rasch-modeled withdrawal sensitivity using retrospective measures

AIM

To examine whether Rasch modeling would yield a unidimensional withdrawal sensitivity measure correlating with factors associated with successful smoking cessation.

DESIGN

The psychometric Rasch modeling approach was applied to estimate an underlying latent construct (withdrawal sensitivity) in retrospective responses from 1644 smokers who reported quitting for 3 or more months at least once.

SETTING

Web-based, passcode-controlled self-administered computerized questionnaire.

PARTICIPANTS

Randomly selected convenience sample of 1644 adult members of an e-mail invitation-only web panel drawn from consumer databases.

MEASUREMENTS

Lifetime Tobacco Use Questionnaire, assessing tobacco use across the life-span, including demographics and respondent ratings of the severity of withdrawal symptoms experienced in respondents' first and most recent quit attempts lasting 3 or more months.

FINDINGS

Rasch-modeled withdrawal sensitivity was generally unidimensional and was associated with longer periods of smoking cessation. One latent variable accounted for 74% of the variability in symptom scores. Rasch modeling with a single latent factor fitted withdrawal symptoms well, except for increased appetite, for which the fit was marginal. Demographic variables of education, gender and ethnicity were not related to changes in sensitivity. Correlates of greater withdrawal sensitivity in cessation attempts of at least 3 months included younger age at first quit attempt and indicators of tobacco dependence.

CONCLUSION

The relationship between tobacco dependence symptoms and Rasch-model withdrawal sensitivity defines further the relationship between sensitivity and dependence. The findings demonstrate the utility of modeling to create an individual-specific sensitivity measure as a tool for exploring the relationships among sensitivity, dependence and cessation.

Human neuronal acetylcholine receptor A5-A3-B4 haplotypes are associated with multiple nicotine dependence phenotypes

INTRODUCTION

Previous research revealed significant associations between haplotypes in the CHRNA5-A3-B4 subunit cluster and scores on the Fagerström Test for Nicotine Dependence among individuals reporting daily smoking by age 17. The present study used subsamples of participants from that study to investigate associations between the CHRNA5-A3-B4 haplotypes and an array of phenotypes not analyzed previously (i.e., withdrawal severity, ability to stop smoking, and specific scales on the Wisconsin Inventory of Smoking Dependence Motives (WISDM-68) that reflect loss of control, strong craving, and heavy smoking.

METHODS

Two cohorts of current or former smokers (N = 886) provided both self-report data and DNA samples. One sample (Wisconsin) comprised smokers making a quit smoking attempt, which permitted the assessment of withdrawal and relapse during the attempt. The other sample (Utah) comprised participants studied for risk factors for nicotine dependence and chronic obstructive pulmonary disease and included individuals originally recruited in the Lung Health Study.

RESULTS

The CHRNA5-A3-B4 haplotypes were significantly associated with the targeted WISDM-68 scales (Tolerance, Craving, Loss of Control) in both samples of participants but only among individuals who began smoking early in life. The haplotypes were significantly associated with relapse likelihood and withdrawal severity, but these associations showed no evidence of an interaction with age at daily smoking.

DISCUSSION

The CHRNA5-A3-B4 haplotypes are associated with a broad range of nicotine dependence phenotypes, but these associations are not consistently moderated by age at initial smoking.

Refining the tobacco dependence phenotype using the Wisconsin Inventory of Smoking Dependence Motives

The construct of tobacco dependence is important from both scientific and public health perspectives, but it is poorly understood. The current research integrates person-centered analyses (e.g., latent profile analysis) and variable-centered analyses (e.g., exploratory factor analysis) to clarify the latent structure of nicotine dependence and to guide distillation of the phenotype. Using data from 4 samples of smokers, latent profiles were derived using the Wisconsin Inventory of Smoking Dependence Motives subscale scores. Across all 4 samples, results revealed a unique latent profile that had relative elevations on 4 subscales (Automaticity, Craving, Loss of Control, and Tolerance). Variable-centered analyses supported the uniqueness of these 4 subscales as they constituted a distinct common factor and were the strongest predictors of relapse and other dependence criteria. Conversely, the remaining 9 motives carried little unique predictive validity regarding dependence. Applications of a factor mixture model further supported the presence of a unique class of smokers in relation to a common factor underlying the 4 subscales. The results suggest that a pattern of smoking that is heavy, pervasive, automatic, and relatively unresponsive to instrumental contingencies is a necessary and sufficient condition for severe nicotine dependence.

Validity of the Severity of Dependence Scale (SDS) construct applying the item response theory to a non-clinical sample of heroin users

AIMS

The purpose of this work is to study the validity of the Severity of Dependence Scale (SDS) construct by applying Rasch models to a non-clinical sample of heroin abusers.

SUBJECTS

982 (73% men) young people 30 years old or under (mean age 25.9 years) participated. All of them were captured from the community in the metropolitan areas of Madrid, Barcelona and Seville, between April 2002 and December 2003.

ANALYSIS

Dimensionality of the scale and calibration of items were studied using the Rating Scale model, which is a Rasch-type model. A factorial analysis was also performed to check the dimensionality of the scale.

RESULTS

The analysis of fit shows that all the items have infit and outfit values between +/- 2 logits, indicating that the data fit the model and that it may be assumed to be unidimensional. The principal components analysis also showed the existence of a principal factor that explains 52.5% of the variance observed. Item calibration found that they are between +0.89 and -1.04 logits on the scale.

CONCLUSION

The results show unidimensional structure of the SDS scale. Item calibration shows they are distributed along the continuum, which must be taken into account when calculating total scores. The study's limitations are noted.

Assessing tobacco dependence: a guide to measure evaluation and selection

Tobacco dependence is a key construct in tobacco research. This paper describes a construct validation approach to dependence assessment and describes key conceptual and psychometric criteria on which to evaluate putative measures of dependence. Five current dependence scales-the Fagerström Test for Nicotine Dependence; the Diagnostic and Statistical Manual of Mental Disorders (4th ed.); the Cigarette Dependence Scale; the Nicotine Dependence Syndrome Scale; and the Wisconsin Inventory of Smoking Dependence Motives-are examined with respect to these critical dimensions. Recommendations are made regarding the use of each measure.

The types of regular cigarette smokers: A latent class analysis

The present study sought to refine cigarette smoking exposure by examining whether individuals with a history of regular cigarette smoking could be classified into meaningful subgroups based on their smoking habits, nicotine dependence, and quit attempts. Data were obtained from 3,025 male and female twins aged 22-59 years who participated in two longitudinal studies based on the Virginia Twin Registry. Latent class analysis was used to identify the number and nature of subgroups of smokers reporting similar smoking habits based on 18 characteristics. Estimates of prevalence for different classes of smoking were obtained along with expected frequencies of endorsements for each smoking behavior by class. Distributions of demographic characteristics, psychopathology, and personality were examined as external validators. The results demonstrated considerable heterogeneity and revealed eight classes of smokers who differed in their degree of nicotine dependence, cessation attempts, and ability to quit smoking. Smoking classes ranged from individuals who were all former smokers with low nicotine dependence who attempted to quit once and were successful, to individuals who were all current smokers with little desire to quit, to individuals with high nicotine dependence with multiple quit attempts, only a subset of which were successful. Estimates of prevalence for each class were 9%-20%. Our findings support the idea that regular cigarette smokers are highly heterogeneous and highlight the need for smoking exposure refinement in future studies. Acknowledging the complexity of cigarette smoking and classifying smokers into more specific subgroups based on their smoking behavior in future studies will enable more accurate evaluation of disease etiology and risk and could lead to more appropriate smoking cessation interventions.

College smoking-cessation using cell phone text messaging

Although rates of smoking among college-aged students continue to rise, few interventions that focus on college smokers' unique motivations and episodic smoking patterns exist. The authors developed and evaluated a prototype program targeting college students that integrates Web and cell phone technologies to deliver a smoking-cessation intervention. To guide the user through the creation and initialization of an individualized quitting program delivered by means of cell phone text messaging, the program uses assessment tools delivered with the program Web site. Forty-six regular smokers were recruited from local colleges and provided access to the program. At 6-week follow-up, 43% had made at least one 24-hour attempt to quit, and 22% were quit--based on a 7-day prevalence criterion. The findings provide support for using wireless text messages to deliver potentially effective smoking-cessation behavioral interventions to college students.