Effects of nicotine on brain responses to emotional pictures.

Given that nicotine reduces negative affect, one would expect nicotine to have different effects on brain responses to emotionally negative stimuli than it does on responses to emotionally neutral or positive stimuli. However, no studies have assessed this possibility. The present study assessed the effects of nicotine patch versus placebo patch on brain event-related potential (ERP) responses to emotion-inducing negative, positive, and neutral color pictures in 16 smokers in a double-blind, counterbalanced, within-subjects design. The study included four experimental sessions. After overnight smoking deprivation (12 hr or more), active nicotine patches were applied to participants during one of the first two sessions and during one of the last two sessions. Placebo patches were applied during the other two sessions. Nicotine reduced frontal ERP processing voltage negativity (from 144-488 ms poststimulus onset) evoked by viewing emotionally negative pictures to a greater extent than it did when emotionally neutral pictures were viewed, whereas it had no effect on processing negativity evoked by positive pictures. Nicotine also enhanced P390 amplitudes evoked by emotionally negative pictures more than it did when emotionally neutral and positive pictures were viewed. Across picture types, nicotine (relative to placebo) reduced N300 amplitude (more at anterior and dorsal sites) and increased P390 amplitude. Overall, nicotine influenced ERPs to emotionally neutral and positive pictures less than it did to negative pictures.     

The effects of smoking deprivation and nicotine administration on emotional reactivity.

Although converging lines of evidence suggest that nicotine and mood are related at a fundamental biological level, this link has not been reliably demonstrated in laboratory studies. In this study, startle probe methodology was used to examine the effects of nicotine administration and deprivation on emotional processes associated with motivation. Smokers (N = 115) completed four laboratory sessions crossing deprivation (12-hr deprived vs. nondeprived) with nicotine spray (active vs. placebo). Participants viewed affective pictures (positive, negative, neutral) and pictures involving cigarette cues, while startle probes were administered. Deprivation decreased startle responding to cigarette cues, suggesting an activation of appetitive processes. Nicotine administration suppressed overall startle responding during deprivation. In addition, during deprivation, random exposure to negative stimuli over two blocks of trials resulted in decreased adaptation of the startle response, suggesting that some sensitization to negative emotional cues may take place during nicotine withdrawal. These effects are consistent with formulations of addiction, stressing that withdrawal may both increase the reinforcement salience of smoking stimuli and decrease habituation to negative emotional stimuli.     

Carry-over effects of smoking cue exposure on working memory performance.

The present study investigated the effects of drug cue exposure on working memory performance in cigarette smokers. Adult smokers (N = 23) deprived for 12 hr performed a working memory task during which they were exposed to three types of task-irrelevant stimuli: Pictures containing smoking related-content, pictures devoid of smoking content, and a fixation cross. Consistent with prior research, we found that drug cue exposure affected the processing of subsequent items (i.e., carry-over effects). Specifically, we found that working memory performance was worse on trials containing neutral pictures preceded by trials containing smoking cues compared with performance on trials containing neutral pictures preceded by trials not containing smoking-related stimuli. Previously observed effects of smoking cue exposure on cognitive processing were replicated but only after removing trials subject to carry-over effects. These results replicate and extend previous research demonstrating similar effects and highlight the significant methodological and conceptual implications of carry-over effects.     

Transient effects of smoking on the eye

PurposeTo investigate the immediate short-term effects of smoking in habitual smokers, on the tear film, pupil size and accommodative ability of the human eye.MethodsHabitual smokers were tested within 5 min of smoking a cigarette. The tear film analysis was undertaken using tear break–up time (TBUT), tear lipid layer thickness and tears meniscus height (TMH) measurements. Three different ways of tear break–up time (TBUT) were used; using fluorescein; a non-invasive TBUT using tearscope; and a video captured method with a corneal topographer. Pupil size was measured objectively using the video capture on the corneal topographer. Accommodative ability was checked by performing a ‘push up test' to measure amplitudes of accommodation (AoA) and by measuring defocus curves.ResultsForty-five participants were enrolled (mean age 22.0 ± 4.4 years). TBUT was reduced after smoking a cigarette with all three assessment methods and this reduction was statistically significant (p < 0.001). A reduction in lipid layer thickness was seen after smoking a cigarette with both methods used and was statistically significant (p < 0.01). A significant reduction in pupil size (p < 0.01) and in AoA (p < 0.001) was observed after smoking a cigarette. The difference in TMH and defocus curves, before and after smoking, were not statistically significant (p > 0.05).ConclusionThe study shows that there is an immediate adverse effect of smoking on TBUT and AoA which seems to be very transient.     

Craving, withdrawal, and smoking urges on days immediately prior to smoking relapse.

Rates of smoking relapse remain high, despite the wide availability of cessation aids. Presumably factors such as craving, withdrawal symptoms, and smoking urges are key contributors to relapse, but empirical support for this presumption is not conclusive and is complicated by the high variability in symptoms across individuals and time, as well as by the lack of an absolute symptom threshold for response. Data were analyzed from 137 female smokers, aged 18-40 years, who completed 30 days of a protocol for a longitudinal smoking cessation trial. Subjects were assigned a quit date and followed regardless of subsequent smoking status. At baseline, subjects completed written measures of nicotine craving, withdrawal symptoms, and smoking urges. They also completed these measures daily for 30 days, beginning on their quit date, Scores were standardized within subjects and graphed to identify temporal symptom patterns. A total of 26 women quit smoking and 111 relapsed (at least one cigarette puff). The intensity of subjects' craving, withdrawal, and smoking urges Factors 1 and 2 peaked on the day of relapse by an average of 1.4, 1.1, 1.2, and 1.1 standard deviations, respectively, with symptoms rising during the previous 2-5 days and dropping precipitously over the 2 days subsequent to relapse. Additionally, women who relapsed had higher absolute (unstandardized) symptom scores on their quit day than those who were abstinent for 30 days. These findings imply that escalation of withdrawal symptoms, craving, and smoking urges during a quit attempt may contribute to smoking relapse. Frequent symptom monitoring might be clinically important for relapse prevention.     

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.     

Misclassification of maternal smoking status and its effects on an epidemiologic study of pregnancy outcomes.

Reliance on self-reported smoking status among pregnant women can result in exposure misclassification. We used data from the Calcium for Preeclampsia Prevention trial, a randomized study of nulliparous women conducted from 1992 to 1995, to characterize tobacco exposure misclassification among women who reported at study enrollment that they had quit smoking. Urinary cotinine concentration was used to validate quit status, and factors associated with exposure misclassification and the effects of misclassification on associations between smoking and pregnancy outcomes were evaluated using logistic regression. Of 4,289 women enrolled, 508 were self-reported smokers and 771 were self-reported quitters. Of 737 self-reported quitters with a valid cotinine measurement, 21.6% had evidence of active smoking and were reclassified as smokers. Women who reported having quit smoking during pregnancy were more likely to be reclassified than women who reported quitting before pregnancy (p<.001). Among smokers, factors independently associated with misclassification of smoking status included fewer cigarettes smoked per day and fewer years smoked. After reclassification the odds ratio for a small-for-gestational-age birth among smokers decreased by 14%, and the smoking-related reduction in birth weight decreased by 15%. Effects of misclassification on the association with hypertensive disorders of pregnancy were present but less dramatic. In conclusion, use of self-reported smoking status collected at the time of study enrollment resulted in the introduction of bias into our study of smoking and pregnancy outcomes. The potential for this type of bias should be considered when conducting and interpreting epidemiologic studies of smoking and pregnancy outcomes.     

The asymmetrical effects of emotional loneliness vs. social loneliness on consumers’ food preferences

Loneliness, or perceived isolation, has been shown to engender unhealthy food consumption and obesity. In this research, we present loneliness as a multi-faceted phenomenon, comprised of social loneliness (stemming from deprivation of a broad social network or group membership) and emotional loneliness (stemming from lack of an intimate emotional attachment). Across four experiments conducted in online and lab settings, we find that different types of loneliness have asymmetrical effects on individuals' food attitudes and actual consumption, mediated by self-regulation. The research has significant implications to public health, consumer well-being, and social campaigns     

复方C卷烟添加剂的安全性及其降低卷烟危害作用

复方C是从多种药食两用功能性植物提取液中筛选的一种卷烟添加剂,对其在卷烟中应用的安全性及降低卷烟危害作用进行毒理学评价,结果表明:复方C对小鼠灌胃给药的半数致死剂量(LD₅₀)为15.1 mL/kg,对沙门氏菌株TA97、TA98、TA100和TA102均无致突变性,不诱发小鼠骨髓嗜多染红细胞微核率增加。与对照烟比较,使用复方C添加剂的试验卷烟,动物吸烟的急性致死毒性作用明显减轻,细胞毒性、细胞氧化损伤、细胞膜损伤和染色体基因突变显著降低。此外,添加2‰复方C的卷烟,感官评吸结果,烟气丰满、谐调、余味干净、舒适。提示复方C可用作降低卷烟危害性的卷烟添加剂。      

The effects of household and workplace smoking restrictions on quitting behaviours

OBJECTIVE: To assess the association of household and workplace smoking restrictions with quit attempts, six month cessation, and light smoking. DESIGN: Logistic regressions identified the association of household and workplace smoking restrictions with attempts to quit, six month cessation, and light smoking. SETTING: Large population surveys, United States. SUBJECTS: Respondents (n = 48,584) smoked during the year before interview in 1992-1993, lived with at least one other person, and were either current daily smokers or were former smokers when interviewed. MAIN OUTCOME MEASURES: The outcome measures were an attempt to quit during the last 12 months, cessation for at least six months among those who made an attempt to quit, and light smoking (< 15 cigarettes a day). RESULTS: Smokers who lived (odds ratio (OR) = 3.86; 95% confidence interval (CI) = 3.57 to 4.18) or worked (OR = 1.14; 95% CI = 1.05 to 1.24) under a total smoking ban were more likely to report a quit attempt in the previous year. Among those who made an attempt, those who lived (OR = 1.65, 95% CI = 1.43 to 1.91) or worked (OR = 1.21, 95% CI = 1.003 to 1.45) under a total smoking ban were more likely to be in cessation for at least six months. Current daily smokers who lived (OR = 2.73, 95% CI = 2.46 to 3.04) or worked (OR = 1.53, 95% CI = 1.38 to 1.70) under a total smoking ban were more likely to be light smokers. CONCLUSIONS: Both workplace and household smoking restrictions were associated with higher rates of cessation attempts, lower rates of relapse in smokers who attempt to quit, and higher rates of light smoking among current daily smokers.     

Rural adolescent attitudes toward smoking and weight loss: relationship to smoking status.

Perceptions that smoking contributes to weight loss are widespread among youth. We examined the association between weight loss and smoking to determine whether supportive attitudes were associated with smoking status and whether this is a particular problem in rural areas. High school students (N=730) completed a survey assessing smoking-related characteristics and behaviors. Attitudes assessed included perceptions of whether weight concerns were the reasons others smoke and personal beliefs about tobacco's effect on weight gain. Smoking status was categorized as never (44%), experimental (42%), and current (14%). Multinomial logistic regressions investigated relationships between attitudes and smoking, adjusting for weight goals, gender, ethnicity, parent/peer smoking, and body mass index. Both attitudinal measures were associated with smoking (p< .05). Nonsmokers and experimental smokers were more likely than current smokers to believe that people smoke to lose weight. Although current smokers were less likely to report that others smoke for weight control, they believed they would gain weight if they quit. Conversely, nonsmokers and experimental smokers were less likely to believe they would gain weight if they do not smoke compared with current smokers. Thus personal attitudes differ from attitudes toward others with respect to weight loss and smoking. Moreover, endorsement of these attitudes can reliably distinguish current versus experimental smokers and may help better clarify the transition to current smoker. Because weight concerns are a significant factor in youth smoking, these issues should be included in intervention efforts, particularly in rural communities where smoking rates are higher and age at initiation is earlier.     

Contextual consistency and adolescent smoking: testing the indirect effect of home indoor smoking restrictions on adolescent smoking through peer smoking.

The present study tested the indirect effect of home indoor smoking restrictions on adolescent smoking through peer smoking. Based on a bioecological perspective of development, we hypothesized that forbidding indoor smoking would reduce the likelihood of adolescent smoking by decreasing exposure to peer smoking, even when adolescents live with at least one household member who smokes. Participants were 163 adolescents (mean age = 16 years) from a suburban southeastern Pennsylvania community. Participants completed a self-report survey evaluating home indoor smoking restrictions, smoking behavior, peer smoking, alcohol use, and demographics. Structural equation modeling indicated that forbidding smoking indoors was associated with having fewer peers who smoke, which was associated with a lower level of smoking. The indirect effect was significant (beta = -.569, 95% CI -.90 to -.24), offering some preliminary ideas about why home indoor smoking restrictions reduce the risk of adolescent smoking. However, the nature and stability of these effects on adolescent smoking behavior remain to be investigated.     

The relationship of smoking cessation to sociodemographic characteristics, smoking intensity, and tobacco control policies.

The present study examined the relationship between recent smoking cessation activities and sociodemographic characteristics, smoking intensity, and tobacco control policies among daily smokers in the United States. The study used the U.S. Current Population Survey 1998-1999 Tobacco Use Supplement, supplemented with information on state-level tobacco control policies. The sample was limited to individuals aged 25 years or older who were smoking daily 1 year ago. We estimated frequencies and multivariate logistic equations for making a quit attempt and remaining abstinent at least 3 months. These measures were related to demographic characteristics, smoking intensity, and tobacco control policies. Younger, higher socioeconomic status (SES), and less intense (fewer cigarettes per day) daily smokers were more likely to make quit attempts, but the likelihood of remaining abstinent for those making a quit attempt was greater for older, higher SES, and heavy daily smokers. We found evidence that cessation behaviors were related to higher cigarette prices and the presence of state-level media/comprehensive campaigns, but less clear evidence exists for an association with bans restricting workplace smoking. The results indicate that certain types of smokers are more likely to attempt to quit and to have success and that the characteristics of these smokers differ. Price policies can have an important role in helping daily smokers to quit. Further research is needed regarding the role of quantity smoked.     

Acute effects of cigarette smoking on global cerebral blood flow in overnight abstinent tobacco smokers.

We examined whether cerebral vascular reactivity to 5% CO2/95% O2 would be a useful, independent measure of effects of tobacco smoking on global cerebral blood flow (gCBF). The acute effects during smoking one's favorite brand of cigarettes were determined after overnight tobacco abstinence. Positron emission tomography was used to quantitatively measure gCBF using H(2)15O in 10 right-handed young-adult male volunteer tobacco smokers. After a 12-hr abstinence, gCBF measurements were repeated six times at 15-min intervals: First baseline, 5% CO2/95% O2 inhalation, first cigarette smoking, second baseline, 5% CO2/95% O2 inhalation, and second cigarette smoking. Surprisingly, no significant change was seen in mean gCBF during smoking compared with baseline. However, the increase in arterial plasma concentration of nicotine correlated inversely with gCBF. Out of 19 smoking sessions, gCBF increased in 7, decreased in 7, and was unchanged in 5 sessions. The gCBF increased during smoking when baseline gCBF was relatively low, whereas gCBF decreased when baseline gCBF was relatively high. Both vascular reactivity and estimated gCBF plus arterial nicotine concentrations were useful measures to predict the changes in measured gCBF. These individual differences result in important bimodal effects of smoking on the brains of different young adult tobacco smokers.     

Examining the effects of tobacco treatment policies on smoking rates and smoking related deaths using the SimSmoke computer simulation model

OBJECTIVES: To develop a simulation model to predict the effects of different smoking treatment policies on quit rates, smoking rates, and smoking attributable deaths. METHODS: We first develop a decision theoretic model of quitting behaviour, which incorporates the decision to quit and the choice of treatment. A model of policies to cover the costs of different combinations of treatments and to require health care provider intervention is then incorporated into the quit model. The policy model allows for the smoker to substitute between treatments and for policies to reduce treatment effectiveness. The SimSmoke computer simulation model is then used to examine policy effects on smoking rates and smoking attributable deaths. RESULTS: The model of quit behaviour predicts a population quit rate of 4.3% in 1993, which subsequently falls and then increases in recent years to 4.5%. The policy model suggests a 25% increase in quit rates from a policy that mandates brief interventions and the coverage of all proven treatments. Smaller effects are predicted from policies that mandate more restricted coverage of treatments, especially those limited to behavioural treatment. These policies translate into small reductions in the smoking rate at first, but increase to as much as a 5% reduction in smoking rates. They also lead to substantial savings in lives. CONCLUSIONS: Tobacco treatment policies, especially those with broad and flexible coverage, have the potential to increase smoking cessation substantially and decrease smoking rates in the short term, with fairly immediate reductions in deaths.