An experimental test of the influence of prior cigarette smoking abstinence on future abstinence.

Significant positive associations between early and later abstinence are often reported in clinical trials on smoking cessation, but those relationships do not permit causal inferences. The present study was conducted to examine experimentally whether prior smoking abstinence histories can directly facilitate later abstinence, using a contingency management procedure to manipulate prior abstinence. A total of 40 adult cigarette smokers who were not trying to quit were randomly assigned to one of two conditions: Contingent ALL (C-ALL), who earned monetary incentives contingent on smoking abstinence during three 5 day experimental periods; or Contingent LAST (C-LAST), who earned incentives independent of abstinence during the first two periods (i.e., noncontingent payments) and contingent on abstinence during the final period. The contingency management procedure was effective in establishing different abstinence histories in the two conditions during the first two periods. Comparison of abstinence levels between the C-ALL and C-LAST conditions during the third period showed significantly greater abstinence in the C-ALL condition, although nicotine withdrawal and other subject ratings generally did not differ significantly between the two conditions. These results provide experimental evidence that prior abstinence histories can directly influence subsequent efforts to abstain from smoking.     

Errors in interpreting abstinence curves in studies of smoking cessation.

Articles on smoking cessation often present curves representing the percentage of smokers still abstinent over time. The purpose of this paper is to illustrate how common conclusions from inspecting these curves may be misleading because they are based on assumptions of which readers are not aware. For example, when active and control abstinence curves converge, this is often interpreted to indicate a diminution of treatment effect size over time. We use illustrative data to show that this interpretation is correct if one assumes a treatment has a constant additive effect; however, if one assumes treatment has a constant multiplicative effect, then converging curves can still indicate a constant treatment effect. Converging abstinence curves are also often interpreted to indicate that the rate of relapse is greater in the active than the control group. We illustrate that this interpretation is correct if one is interested in cumulative relapse rate and uses all subjects in the denominator; however, if one is interested in relapse over a discrete subperiod of time (e.g., immediately after treatment stops), and thus uses only those at risk for relapse, then converging curves can still indicate a constant relapse rate. When trials interpret abstinence curves, they should make clear whether they are assuming additive or multiplicative effects of treatment and are discussing overall or local relapse rates. They should also report both additive and multiplicative effect sizes.     

Effects of smoking abstinence, smoking cues and nicotine replacement in smokers with schizophrenia and controls.

The mechanisms underlying the low smoking cessation rates among smokers with schizophrenia (SS) are unknown. In this laboratory study, we compared the responses of 21 SS and 21 non-psychiatric controls (CS) to manipulations of 5-hour smoking abstinence, transdermal nicotine replacement (0 mg, 21 mg and 42 mg), and in vivo smoking cues. Results indicate that SS were more sensitive than CS to the effects of acute abstinence on carbon monoxide (CO) boost, but not more sensitive to the effects of abstinence on urge levels or withdrawal symptoms. SS and CS did not differ in urge response to in vivo smoking cues, but SS were less consistent in their reactions. These findings suggest that heightened sensitivity to the effects of abstinence on smoke intake may partially account for the low cessation rates experienced by SS, but other potential mechanisms should be explored using behavioral laboratory models.     

Seasonal variations in the initiation of smoking among adolescents.

Numerous studies have identified a variety of reasons that youths give for starting smoking. Few efforts have been made, however, to identify seasonal variations in initiation. This study was an attempt to fill that void. We examined data from 342 youths participating in a mandated smoking education and cessation program in Texas. Data were collected based on responses to questions in participant workbooks, including an item asking participants about the month in which they started smoking. A total of 47% of the participants indicated that they started smoking in May through August (chi2 = 91.42, df = 3). Post-hoc analyses indicated that significantly more youths than expected began smoking in May and June, whereas significantly fewer youths than expected began smoking in September and November. Unsupervised time out of school during the first months of summer vacation is a period of increased danger for smoking initiation. The significantly lower rates during September seem to be related to the beginning of school.     

Belief about drug assignment and abstinence in treatment of cigarette smoking using nortriptyline.

This study assessed the relationship between beliefs about drug assignment and abstinence status in two treatment studies using nortriptyline hydrochloride as an adjunct to smoking cessation. Smokers (N = 345) drawn from two clinical trials were asked at the final follow-up (FFU) at 52 or 64 weeks whether they believed they had received active or placebo drug. Responses were obtained from 262 participants, or 76% of the sample. Biochemically verified abstinence was collected at end of treatment (EOT) and FFU. In both studies, participants were correct in guessing drug assignment. At FFU, belief about drug assignment was not related to abstinence for either active or placebo participants. Participants who received active drug and who were smoking at EOT were more likely to believe they had received placebo than active drug participants who were abstinent at EOT. We found no significant relationship between belief about drug and abstinence status for placebo participants at EOT. Baseline variables did not significantly predict correctness of drug identification. Participants who experienced drug side-effects not easily attributable to nicotine withdrawal were more likely to identify their drug assignment as nortriptyline. We conclude that experience during the active treatment period, including side-effects and treatment success, may be related to belief about drug assignment, that the field would be well served by at least two assessments of blindness in clinical trials, and that discrepancy between these findings and those regarding nicotine replacement therapy may be related to differences in dependent variables.     

A pilot study on voucher-based incentives to promote abstinence from cigarette smoking during pregnancy and postpartum.

We report results from a pilot study examining the use of vouchers redeemable for retail items as incentives for smoking cessation during pregnancy and postpartum. Of 100 study-eligible women who were still smoking upon entering prenatal care, 58 were recruited from university-based and community obstetric practices to participate in a smoking cessation study. Participants were assigned to either contingent or noncontingent voucher conditions. Vouchers were available during pregnancy and for 12 weeks postpartum. In the contingent condition, vouchers were earned for biochemically verified smoking abstinence. In the noncontingent condition, vouchers were earned independent of smoking status. Abstinence monitoring and associated voucher delivery was conducted daily during the initial 5 days of the cessation effort, gradually decreased to every other week antepartum, increased to once weekly during the initial 4 weeks postpartum, and then decreased again to every other week for the remaining 8 weeks of the postpartum intervention period. Contingent vouchers increased 7-day point-prevalence abstinence at the end-of-pregnancy (37% vs. 9%) and 12-week postpartum (33% vs. 0%) assessments. That effect was sustained through the 24-week postpartum assessment (27% vs. 0%), which was 12 weeks after discontinuation of the voucher program. Total mean voucher earnings across antepartum and postpartum were 397 US dollars (SD=414 US dollars) and 313 US dollars (SD=142 dollars) in the contingent and noncontingent conditions, respectively. The magnitude of these treatment effects exceed levels typically observed with pregnant and recently postpartum smokers, and the maintenance of effects through 24 weeks postpartum extends the duration beyond those reported previously.     

The first puff: forces in smoking initiation among Californians of Korean descent.

This study presents the correlates of initial exposure to cigarettes, variables associated with smoking prevalence and with continued smoking (or not) among adult Californians of Korean descent who have any initial exposure to cigarettes. Among those who have taken a puff, social contingencies contrast those who become current smokers from those who do not. Data were drawn from telephone interviews with adults (N = 2,830) developed from a random sampling of listed persons in California with Korean surnames during 2000-2001. Of the attempted interviews, 86% were completed; and 85% of the interviews were conducted in Korean. Nearly half of all respondents (49.0%) had been exposed to cigarettes, and 41.9% of these reported current smoking, according to Centers for Disease Control and Prevention criteria (currently smoke and have smoked 100 cigarettes during lifetime). Multivariate analysis suggests that social contingencies may influence both initial exposure to tobacco and continued smoking among Californians of Korean descent. Influences of acculturation on taking the first puff and on current smoking status diverged by gender. Social support increased the likelihood of the first puff among both genders, but the association was stronger among females than among males. Social reinforcers that lead to taking the first puff also discriminated between those who became current smokers and those who did not. Interventions should be directed at these variables among young Korean nonsmokers and new smokers.     

Effects of smoking abstinence and alcohol consumption on smoking-related outcome expectancies in heavy smokers and tobacco chippers.

Smoking cessation interventions often target expectancies about the consequences of smoking. Yet little is known about the way smoking-related expectancies vary across different contexts. Two internal contexts that are often linked with smoking relapse are states associated with smoking abstinence and alcohol consumption. This report presents a secondary analysis of data from two experiments designed to examine the influence of smoking abstinence, and smoking abstinence combined with alcohol consumption, on smoking-related outcome expectancies among heavy smokers and tobacco chippers (smokers who had consistently smoked no more than 5 cigarettes/day for at least 2 years). Across both experiments, smoking abstinence and alcohol consumption increased expectancies of positive reinforcement from smoking. In addition, alcohol consumption increased negative reinforcement expectancies among tobacco chippers, such that the expectancies became more similar to those of heavy smokers as tobacco chippers' level of subjective alcohol intoxication increased. Findings suggest that these altered states influence the way smokers evaluate the consequences of smoking, and provide insight into the link between smoking abstinence, alcohol consumption, and smoking behavior.     

The moderating effects of religiosity on the genetic and environmental determinants of smoking initiation.

Although a number of studies have shown that various measures of religiosity are inversely correlated with smoking behavior, none of these studies have used genetically informative samples to test for a gene-environment interaction between the determinants of smoking initiation and religiosity. We tested the moderating effects of three measures of religiosity (religious affiliation, organizational religious activity, and self-rated religiousness) on the genetic and environmental determinants of smoking initiation in 237 monozygotic twin pairs, 315 dizygotic twin pairs, 779 full-sibling pairs, and 233 half-sibling pairs in young adults surveyed from the third wave of the National Longitudinal Study of Adolescent Health. Primary analyses incorporated all sibling pairs, irrespective of whether they were concordant or discordant for the environmental moderator, in models designed to account for the confounding effects of a gene-environment correlation. High levels of self-rated religiousness attenuated the additive genetic component for smoking initiation and were associated with a lower prevalence of smoking initiation. Although all three measures of religiosity were associated with lower rates of smoking initiation, only self-rated religiousness moderated genetic influences on the liability for smoking.     

Depression during tobacco abstinence.

Many clinicians and scientists believe smoking cessation increases the risk of major depressive disorder (MDD), especially among those with a past history of the disorder. This literature review located seven empirical tests of this belief. All seven had significant methodological limitations. The incidence of MDD over 7-64 weeks postcessation was 0%-14% among all smokers who tried to stop, 3%-24% among smokers with a past history of MDD who tried to stop, and 1%-31% among smokers who became abstinent. Smokers with a past history of MDD were more likely to have postcessation MDD. Although some within-study comparisons suggest abstinence increased the incidence of MDD, a definitive conclusion cannot be made. Whether treatment with antidepressants prevented postcessation MDD also was unclear. This review makes methodological recommendations for more definitive studies.     

Perceived importance of being thin and smoking initiation among young girls

Background: Smoking among adolescents remains unacceptably high and the difference in potential risk factors for smoking initiation between male and female adolescents has been explored. Although the association between smoking initiation and dieting behaviour has been observed among girls, the mechanism of the association is unknown.

Objective: To examine prospectively the association between perceived importance of being thin at baseline and smoking initiation among girls.

Design: A four year prospective cohort survey including perceived importance of being thin at baseline and smoking behaviour, conducted in 1993 and 1996.

Setting and participants: 273 Massachusetts female adolescents aged 12–15 years at baseline who reported having smoked no more than one cigarette by the time of the baseline survey, drawn from households sampled by random digit dialling.

Main outcome measure: Progression to established smoking, defined as having smoked 100 or more cigarettes in their lifetime.

Results: After adjusting for age, smoking status at baseline, and race/ethnicity, girls who valued thinness most strongly and somewhat strongly were both more likely to have become established smokers, compared to the girls who valued thinness least strongly. The odds ratios are 4.5 (95% confidence interval (CI), 1.4 to 16.7) and 3.4 (95% CI 1.04 to 10.9), respectively.

Conclusions: The level of perceived importance of being thin among young female adolescents predicts future smoking initiation. Smoking prevention programmes designed for female adolescents may therefore benefit from the inclusion of content related to importance of being thin.

     

Role of snus in initiation and cessation of tobacco smoking in Sweden

Objective

To examine patterns of smoking and snus use and identify individual pathways of Swedish tobacco users in order to clarify whether snus use is associated with increased or decreased smoking.

Methods

Retrospective analysis of data from a cross‐sectional survey completed by 6752 adult Swedes in 2001–2 focusing on identifying tobacco use history by survey items on current and prior tobacco use and smoking initiation and cessation procedures.

Results

15% of the men and 19% of the women completing the survey were daily smokers. 21% of the men and 2% of the women were daily snus users. Almost all (91%) male daily smoking began before the age of 23 years, whereas initiation of daily snus use continued throughout the age range (33% of initiation after age 22). 20% of male primary snus users started daily smoking compared to 47% of non‐primary snus users. Thus, the odds of initiating daily smoking were significantly lower for men who had started using snus than for those who had not (odds ratio (OR) 0.28, 95% confidence interval (CI) 0.22 to 0.36). Among male primary smokers, 28% started secondary daily snus use and 73% did not. 88% of those secondary snus users had ceased daily smoking completely by the time of the survey as compared with 56% of those primary daily smokers who never became daily snus users (OR 5.7, 95% CI 4.9 to 8.1). Among men who made attempts to quit smoking, snus was the most commonly used cessation aid, being used by 24% on their latest quit attempt. Of those men who had used one single cessation aid 58% had used snus, as compared with 38% for all nicotine replacement therapy products together. Among men who used snus as a single aid, 66% succeeded in quitting completely, as compared with 47% of those using nicotine gum (OR 2.2, 95% CI 1.3 to 3.7) or 32% for those using the nicotine patch (OR 4.2, 95% CI 2.1 to 8.6). Women using snus as an aid were also significantly more likely to quit smoking successfully than those using nicotine patches or gum.

Conclusion

Use of snus in Sweden is associated with a reduced risk of becoming a daily smoker and an increased likelihood of stopping smoking.