Familial and non-familial smoking: effects on smoking and nicotine dependence

Association of cytochrome P450 2A6 polymorphism, anxiety, and environmental factors with cigarette smoking by Thai adults

Background

The effects and associations of genetic variation, psychological, and environment factors associated with cigarette smoking and nicotine dependence remain largely unknown.

Objective

To determine the influence and association of functional genetic polymorphisms of cytochrome P450 2A6 (CYP2A6), anxiety, and environmental factors on cigarette smoking and nicotine dependence.

Method

A cross-sectional study was conducted at King Chulalongkorn Memorial Hospital, Thailand between October 2014 and June 2015. We recruited 127 Thai adult smokers when they visited for an annual physical check-up. Participants completed questionnaires regarding demographic characteristics, The Fagerstrom Test for Nicotine Dependence, and The Thai Hospital Anxiety and Depression Scale. Blood was collected for CYP2A6 genotyping to determine the enzyme metabolism level/group.

Results

Factors associated with significantly greater cigarette consumption were age and being ultrarapid/ extensive metabolizers (UM/EM). Anxiety and smoking by household family members were significantly associated with the degree of nicotine dependence. We observed associations between severe nicotine dependence and genotype (UM/EM) and age (b = 0.037; P = 0.005), intermediate metabolizers (IM) and age (b = 0.031; P = 0.43), UM/EM and anxiety (b = 0.258; P < 0.001), IM and anxiety (b = 0.285; P < 0.001), UM/EM and household smoking in the family members (b = 1.427; P = 0.003), and IM and smoking by household family members (b = 1.293; P = 0.024).

Conclusions

Information regarding the association between the gene encoding enzyme metabolism, anxiety, and their interactions may be beneficial for selecting treatment choices for smoking cessation for individual genotypic metabolizers.

What Are the Major Determinants in the Success of Smoking Cessation: Results from the Health Examinees Study

Understanding mechanisms underlying smoking-related factors should be prioritized in establishing smoking prevention and cessation policy. The aim of this study was to identify factors significantly associated with smoking initiation and/or smoking cessation as well as the most important determinants of successful smoking cessation in a developed non-Western setting. Based on multiple logistic regression models, the odds ratios (ORs) for smoking initiation and cessation were estimated among males (N = 24,490) who had participated in the Health Examinees (HEXA) study. The Cox proportional hazards regression model was used to assess the association between selected predictors of smoking cessation and the likelihood of reaching this goal. Finally, Kaplan–Meier curves were constructed to illustrate the distribution of time from age at smoking initiation to age at smoking cessation. We found that the ORs for successfully quitting smoking increased with age, married status, educational achievement, having a non-manual job, drinking cessation and disease morbidity. Those exposed to secondhand smoking showed less likelihood of quitting smoking. A continual decrease in the ORs for successfully quitting smoking was observed according to increased smoking duration, smoking dose per day and lifetime tobacco exposure (p_trend <0.001). Among the selected predictors, lifetime tobacco exposure, educational attainment, alcohol drinking status and birth cohort were the major determinants in the success of smoking cessation. Our findings suggest that lifetime tobacco exposure, educational attainment, alcohol drinking status and birth cohort can determine success in smoking cessation. Public interventions promoting a smoke-free environment are needed to reinforce discouraging the initiation of, reducing, and quitting cigarette smoking.

The diversity of young adult wheeze: a cluster analysis in a longitudinal birth cohort

BACKGROUND

Cluster analyses have enhanced understanding of the heterogeneity of both paediatric and adult wheezing. However, while adolescence represents an important transitional phase, the nature of young adult wheeze has yet to be clearly characterised.

OBJECTIVES

To use cluster analysis to define, for the first time, clinically relevant young adult wheeze clusters in a longitudinal birth cohort.

METHODS

K-means cluster analysis was undertaken among 309 currently wheezing subjects at 18 years in the Isle of Wight birth cohort (N = 1456). Thirteen disease-characterising clustering variables at 18 years were used. Resulting clusters were then further characterised by severity indices plus potential risk factors for wheeze development throughout the 1st 18 years of life.

RESULTS

Six wheeze clusters were identified. Cluster 1 (12.3%) male-early-childhood-onset-atopic-wheeze-with-normal-lung-function had male predominance, normal spirometry, low bronchodilator reversibility (BDR), intermediate bronchial hyper-responsiveness (BHR), high atopy prevalence and more admissions. Cluster 2 (24.2%) early-childhood-onset-wheeze-with-intermediate-lung-function had no specific sex association, intermediate spirometry, BDR, BHR, more significant BTS step therapy and admissions. Cluster 3 (9.7%) female-early-childhood-onset-atopic-wheeze-with-impaired-lung-function showed female predominance, high allergic disease comorbidity, more severe BDR and BHR, greatest airflow obstruction, high smoking prevalence, higher symptom severity and admissions. Cluster 4 (19.4%) female-undiagnosed-wheezers had adolescent-onset non-atopic wheeze, low BDR and BHR, impaired but non-obstructed spirometry, high symptom frequency and highest smoking prevalence. Cluster 5 (24.6%) female-late-childhood-onset-wheeze-with-normal-lung-function showed no specific atopy association, normal spirometry, low BDR, BHR and symptom severity. Cluster 6 (9.7%) male-late-childhood-onset-atopic-wheeze-with-impaired-lung-function had high atopy and rhinitis prevalence, increased BDR and BHR, moderately impaired spirometry, high symptom severity and higher BTS step therapy.

CONCLUSIONS AND CLINICAL RELEVANCE

Young adult wheeze is diverse and can be classified into distinct clusters. More severe clusters merit attention and are associated with childhood onset, atopy, impaired lung function and in some, smoking. Smoking-associated undiagnosed wheezers also merit recognition. Better understanding of young adult wheeze could facilitate better later adult respiratory health.

Current cigarette smoking among HIV-positive current and former drug users: associations with individual and social characteristics

Cigarette smoking is endemic among HIV-positive populations and is related to substantial morbidity and mortality. Research has largely focused on individual-level characteristics associated with smoking, with less attention to social factors. We aimed to explore individual- and social-level characteristics associated with current cigarette smoking among people living with HIV. Data came from 358 individuals on antiretroviral therapy interviewed in a study on informal HIV caregiving, conducted in Baltimore, MD, USA. Most participants (75 %) were current smokers and 45 % reported current illegal drug use. In adjusted logistic regression analyses, current drug use (aOR 2.90, 95 % CI 1.58-5.30), 12-step program participation (aOR 1.74, 95 % CI 1.02-2.97), and having a main Supporter who is a current smoker (aOR 1.93, 95 % CI 1.12-3.33) were associated with current smoking. Findings suggest the importance of social-level factors in cigarette smoking among HIV seropositive drug users and have implications for developing targeted smoking cessation interventions for smokers living with HIV.

Protecting children from taking up smoking: parents' views on what would help

ISSUE ADDRESSED

The present study investigated what factors the parents of children in low-income areas of Auckland, New Zealand, thought could help protect their children from smoking initiation.

METHODS

Participants in a large quasi-experimental trial that tested a community-, school- and family-based smoking-initiation intervention were asked in a questionnaire 'What could we do to help you protect your children from smoke and taking up smoking?' Free-text responses were divided into distinct meaning units and categorised independently by two of the researchers.

RESULTS

1806 participants (70% of parents who returned the questionnaire) completed the question. The majority of respondents (80%) were either Pacific Island or Māori mothers and 25% were current smokers. Five main categories of suggested strategies for preventing smoking initiation were identified: building children's knowledge of the ill-effects of smoking; denormalising smoking; reducing access to tobacco; building children's resilience; and health promotion activities. The most common suggestion was to educate children about smoking.

CONCLUSION

Building children's knowledge of smoking risks was the main strategy parents proposed. There was some support for banning smoking in most public areas and for tougher moves to stop tobacco sales to minors. Few parents suggested innovative or radical strategies, such as banning the sale of tobacco, fining children for smoking or use of competitions. So what? To ensure reductions in smoking initiation for lower socioeconomic and Māori and Pacific Island people, further research should engage Māori, Pacific Island and lower socioeconomic parents in a process that elicits innovative thinking about culturally acceptable strategies.

Adolescence is a period of development characterized by short- and long-term vulnerability to the rewarding effects of nicotine and reduced sensitivity to the anorectic effects of this drug

This study compared nicotine intake and changes in food intake and weight gain in naïve adolescent, naïve adult, and adult rats that were exposed to nicotine during adolescence. An extended intravenous self-administration (IVSA) model was used whereby rats had 23-hour access to saline or increasing doses of nicotine (0.03, 0.06, and 0.09 mg/kg/0.1 mL infusion) for 4-day intervals separated by 3-day periods of abstinence. Rats began IVSA as adolescents (PND 32-34) or adults (PND 75). A separate group of rats was exposed to nicotine via osmotic pumps (4.7 mg/kg) for 14 days during adolescence and then began nicotine IVSA as adults (PND 75). The rats that completed the nicotine IVSA regimen were also tested for nicotine-seeking behavior during extinction. The results revealed that nicotine intake was highest in adolescents followed by adults that were pre-exposed to nicotine during adolescence as compared to naïve adults. A similar pattern of nicotine-seeking behavior was observed during extinction. In contrast to nicotine intake, naïve adults displayed robust appetite and weight suppressant effects of nicotine, an effect that was absent in adolescents and adults that were pre-exposed to nicotine during adolescence. Our findings suggest that adolescence is a unique period of enhanced vulnerability to the reinforcing effects of nicotine. Although adolescents gain weight faster than adults, the food intake and weight suppressant effects of nicotine are reduced during adolescence. Importantly, our findings suggest that adolescent nicotine exposure produces long-lasting consequences that enhance nicotine reward and promote tolerance to the anorectic effects of this drug.

Animal models of nicotine exposure: relevance to second-hand smoking, electronic cigarette use, and compulsive smoking

Much evidence indicates that individuals use tobacco primarily to experience the psychopharmacological properties of nicotine and that a large proportion of smokers eventually become dependent on nicotine. In humans, nicotine acutely produces positive reinforcing effects, including mild euphoria, whereas a nicotine abstinence syndrome with both somatic and affective components is observed after chronic nicotine exposure. Animal models of nicotine self-administration and chronic exposure to nicotine have been critical in unveiling the neurobiological substrates that mediate the acute reinforcing effects of nicotine and emergence of a withdrawal syndrome during abstinence. However, important aspects of the transition from nicotine abuse to nicotine dependence, such as the emergence of increased motivation and compulsive nicotine intake following repeated exposure to the drug, have only recently begun to be modeled in animals. Thus, the neurobiological mechanisms that are involved in these important aspects of nicotine addiction remain largely unknown. In this review, we describe the different animal models available to date and discuss recent advances in animal models of nicotine exposure and nicotine dependence. This review demonstrates that novel animal models of nicotine vapor exposure and escalation of nicotine intake provide a unique opportunity to investigate the neurobiological effects of second-hand nicotine exposure, electronic cigarette use, and the mechanisms that underlie the transition from nicotine use to compulsive nicotine intake.

Predictors of nicotine dependence symptoms among never-smoking adolescents: a longitudinal analysis from the Nicotine Dependence in Teens Study

BACKGROUND

Recent cross-sectional studies suggest some adolescents who have never smoked cigarettes experience nicotine dependence (ND) symptoms and that exposure to second-hand smoke, social exposure to smoking, and alcohol use are plausible correlates. The aim of this study was to replicate and extend these findings by investigating possible predictors of ND symptoms longitudinally.

METHOD

Participants included 847 secondary school students who had never smoked cigarettes enrolled in the Nicotine Dependence in Teens Study. Adolescents completed self-report questionnaires measuring smoking status, ND symptoms, and risk factors for ND in smokers (i.e., socio-demographic indicators, social exposure to smoking, psychosocial indicators, and substance use) in 20 survey cycles from 7 to 11th grade. Generalized estimating equations, which account for repeated measures within individuals, were used to test the predictors of ND symptoms.

RESULTS

Consistent with previous research, 7.8% of never-smokers across all cycles endorsed at least one ND symptom. Younger age (p ≤ .001), country of birth (p ≤ .05), peer smoking (p ≤ .001), teacher smoking (p ≤ .05), depression (p ≤ .05), stress (p ≤ .001), lower self-esteem (p ≤ .05), impulsivity (p ≤ .05), and alcohol use (p ≤ .001) predicted greater ND symptoms in multivariable modeling.

CONCLUSIONS

Replicating previous cross-sectional findings, peer smoking and alcohol use predicted ND symptoms among never-smoking adolescents. Extending these findings, previous predictors only observed among ever-smokers, including socio-demographic and psychosocial indicators, also predicted ND symptoms. This longitudinal investigation demonstrated the temporal relation of the predictors preceding ND symptoms. Future research should consider longer prospective studies with younger children to capture early onset of ND symptoms and with longer follow-up to detect eventual smoking uptake.

Smoking cessation-specific parenting and parental smoking as precursors of adolescent smoking cognitions and quitting

Relatively little is known about if and through which mechanisms parents influence adolescents' smoking cessation. The present study used Social Cognitive Theory as a theoretical framework to test whether parental smoking and smoking cessation-specific parenting (SCSP) predicted readiness to quit smoking and actual smoking cessation one year later. Both direct paths between parent factors and outcomes, and indirect paths via adolescents' smoking-specific cognitions (pros of smoking and quitting, and self-efficacy) were examined in a sample of 530 adolescents in the ages of 13 to 18 who smoked daily and weekly at baseline. The main findings show that although parental smoking and SCSP were significantly associated with cognitions (cross-sectionally), neither the parent factors nor cognitions predicted readiness to quit smoking or actual cessation one year later. Baseline SCSP did predict readiness to quit one year later. Parents may be more influential in shaping adolescents' beliefs and readiness to quit than in facilitating actual cessation.

Smoking family, secondhand smoke exposure at home, and nicotine addiction among adolescent smokers

INTRODUCTION

Smoking family predicts adolescent smoking, but whether the level of nicotine addiction is affected by exposure to secondhand smoke (SHS) is unclear. We investigated the associations of smoking family and SHS exposure at home with morning smoking and heavier smoking among Chinese adolescent smokers.

METHODS

In a school-based anonymous survey, 2182 adolescent smokers reported their smoking behaviors, smoking status of family members and peers, and SHS exposure at home and outside home in the past 7 days. Families with one or more smoking members (excluding the subject) were classified as smoking families and otherwise as non-smoking families. Smoking or wanting to smoke first thing in the morning (morning smoking), and consuming more cigarettes (heavier smoking) denoted higher levels of nicotine addiction. Regression analysis yielded adjusted odds ratios (AORs) for morning smoking and β-coefficients for heavier smoking adjusting for potential confounders.

RESULTS

Living with siblings and other co-residing family members who smoked was significantly associated with morning smoking and heavier smoking. Compared with non-smoking families without SHS exposure at home, the AORs (95% CI) for morning smoking were 0.99 (0.76 to 1.29) for 0 day/week, 1.19 (0.95 to 1.50) for 1-3 days/week, 1.76 (1.41 to 2.21) for 4-7 days/week (p for trend <0.001) and 1.50 (1.23 to 1.83) for any days/week of SHS exposure at home in smoking families. Similarly, 4-6 days/week of SHS exposure at home significantly predicted heavier smoking.

CONCLUSION

Living with smoking family members and SHS exposure at home are associated with nicotine addiction in Chinese adolescent smokers.

Epidemiological evidence on count processes in the formation of tobacco dependence

INTRODUCTION

Large-sample epidemiological studies of tobacco cigarette smoking routinely assess so-called "lifetime prevalence" of tobacco dependence. This work delves into the earliest stages of smoking involvement, focusing on newly incident tobacco cigarette smokers in the very recent past, and examines hypothesized subgroup variation in count processes that become engaged once smoking starts. Here, the term "count process" has two components: (a) whether smoking will be persistent and (b) the rate of smoking, conditional upon membership in a latent class of smokers who will persist, as estimated under the zero-inflated Poisson (ZIP) model for complex survey data.

METHODS

We estimate these ZIP parameters for nationally representative samples of newly incident smokers in the United States (all with smoking initiation within 24 months of assessment). Data are from the 2004-2007 National Surveys on Drug Use and Health.

RESULTS

Once cigarette smoking started, roughly 40%-45% persisted, and the estimated median rate was five smoking days/30 days, conditional on membership in the latent class of persistent smokers. Among non-Hispanic recent-onset cigarette smokers, Whites, Black/African Americans, Asians, and Native American/Alaskan Natives did not differ, but recent-onset smokers of Hispanic origin and those of Pacific Islander background had comparatively less cigarette involvement.

DISCUSSION

Tobacco prevention and control initiatives may require elaboration in the form of brief interventions, including interpersonal and social transactions that might constrain a mounting frequency of days of smoking before daily smoking starts, and until conventional smoking cessation medication aids become indicated. These very-early stage interventions (VESI) might be mounted within family or peer groups or in the primary care or school settings, but randomized trials to evaluate VESI interventions will be required.

Epidemiology, determinants, and consequences of cigarette smoking in African American women: an integrative review

Tobacco smoking is a national public health problem that has been associated with numerous adverse health effects, including increased disease and cancer rates. Previous review articles on smoking in specific demographic populations have focused on smoking in women and on smoking in African Americans, but have not considered the dual roles of ethnicity and gender in smoking behavior. African American women (AAW) are an important subgroup to study because they are distinct from non-AAW and their male African American counterparts on biopsychosocial factors that are relevant to smoking behavior. The purpose of the present review paper is to integrate and summarize the current literature on the epidemiology, determinants, and consequences of cigarette smoking among AAW, by contrasting them to relevant comparison groups (non-AAW and African American men). Evidence suggests that AAW are generally more likely to be light smokers and initiate smoking later. The prevalence rates of AAW smokers have decreased over the past 25years, yet AAW are disproportionately affected by several smoking-related illnesses when compared to their ethnic and gender comparison groups. AAW smokers are distinct from relevant comparison groups in metabolic sensitivity to nicotine, aspects of smoking topography, and several psychosocial factors that influence smoking. Although a small literature on smoking in AAW is emerging, further empirical research of AAW smokers could inform the development of tailored interventions for AAW.