Cigarette smoking

Nicotine dependence is associated with an increased risk of developing chronic, non-communicable inflammatory disease: a large-scale retrospective cohort study

Introduction

Chronic, non-communicable inflammatory diseases (CIDs) affect a large portion of the population, imposing a significant morbidity, encompassing a substantial mortality. Thus, they are a major medical burden with a high unmet need. CIDs develop over the span of several years, and the risk of developing CIDs has been linked to genetic and environmental factors. Thus, modification of environmental factors is a promising approach for the prevention of CIDs. Among modifiable environmental factors that have been linked to the CID risk is nicotine dependence. However, for only few CIDs, compelling evidence suggests that nicotine dependence increases (e.g., rheumatoid arthritis and asthma) or decreases (e.g., pemphigus) the CID risk. For most CIDs, there are inconsistent, scant, or no reports on the risk of CID associated with nicotine dependence.

Methods

To address this gap, we leveraged TriNetX, analyzing data from over 120 million electronic health records (EHRs). Using propensity score matching (PSM) to control for age, sex, ethnicity, and other CID risk factors, we contrasted the risk of developing any or any of the 38 CIDs in 881,192 EHRs from individuals with nicotine dependence to PSM-matched unexposed counterparts.

Results

The analytical pipeline was validated by demonstrating an increased risk of individuals exposed to nicotine dependence for subsequent diagnosis of myocardial infarction, malignant neoplasm of the lung, and chronic obstructive pulmonary disease. Overall, 16.8% of individuals with nicotine dependence developed CIDs, compared to 9.6% of individuals not exposed to nicotine dependence (hazard ratio 2.12, confidence interval 2.10-2.14, p < 0.0001). Investigating single CIDs, nicotine dependence imposed increased risks for 23 of the 38 investigated diseases, i.e., dermatomyositis, granulomatosis with polyangiitis, pyoderma gangrenosum, and immune thrombocytopenic purpura. The sex-stratified analysis revealed few sex-specific differences in CID risk.

Discussion

Our study emphasizes the importance of preventive measures targeting nicotine addiction to reduce the global burden of CIDs.

Viral and immunologic evaluation of smokers with severe COVID-19

Smoking negatively affects B cell function and immunoglobulin levels, but it is unclear if this immune dysfunction contributes to the risk of severe COVID-19 in smokers. We evaluated binding IgM, IgA and IgG antibodies to spike and receptor binding domain antigens, and used a pseudovirus assay to quantify neutralization titers in a set of 27 patients with severe COVID-19. We found no significant differences between binding and neutralization antibody responses for people with a smoking history and people who never smoked. High plasma viral load, but not antibody titers, was linked to an increased risk of death. Humoral immune dysfunction was not a major driver of severe COVID-19 in smokers.

Smoking-related dysregulation of plasma circulating microRNAs: the Rotterdam study

BACKGROUND

MicroRNAs (miRNAs) are post-transcriptional regulators of gene expression. Differential miRNA expression, which is widely shown to be associated with the pathogenesis of various diseases, can be influenced by lifestyle factors, including smoking. This study aimed to investigate the plasma miRNA signature of smoking habits, the potential effect of smoking cessation on miRNA levels, and relate the findings with lung cancer incidence.

RESULTS

A targeted RNA-sequencing approach measured plasma miRNA levels in 2686 participants from the population-based Rotterdam study cohort. The association between cigarette smoking (current versus never) and 591 well-expressed miRNAs was assessed via adjusted linear regression models, identifying 41 smoking-associated miRNAs that passed the Bonferroni-corrected threshold (P < 0.05/591 = 8.46 × 10^-5). Moreover, we found 42 miRNAs with a significant association (P < 8.46 × 10^-5) between current (reference group) and former smokers. Then, we used adjusted linear regression models to explore the effect of smoking cessation time on miRNA expression levels. The expression levels of two miRNAs were significantly different within 5 years of cessation (P < 0.05/41 = 1.22 × 10^-3) from current smokers, while for cessation time between 5 and 15 years we found 19 miRNAs to be significantly different from current smokers, and finally, 38 miRNAs were significantly different after more than 15 years of cessation time (P < 1.22 × 10^-3). These results imply the reversibility of the smoking effect on plasma levels of at least 38 out of the 41 smoking-miRNAs following smoking cessation. Next, we found 8 out of the 41 smoking-related miRNAs to be nominally associated (P < 0.05) with the incidence of lung cancer.

CONCLUSIONS

This study demonstrates smoking-related dysregulation of plasma miRNAs, which might have a potential for reversibility when comparing different smoking cessation groups. The identified miRNAs are involved in several cancer-related pathways and include 8 miRNAs associated with lung cancer incidence. Our results may lay the groundwork for further investigation of miRNAs as potential mechanism linking smoking, gene expression and cancer.

Gene Set Based Integrated Methylome and Transcriptome Analysis Reveals Potential Molecular Mechanisms Linking Cigarette Smoking and Related Diseases

Advanced integrative analysis of DNA methylation and transcriptomics data may provide deeper insights into smoke-induced epigenetic alterations, their effects on gene expression and related biological processes, linking cigarette smoking and related diseases. We hypothesize that accumulation of DNA methylation changes in CpG sites across genomic locations of different genes might have biological significance. We tested the hypothesis by performing gene set based integrative analysis of blood DNA methylation and transcriptomics data to identify potential transcriptomic consequences of smoking via changes in DNA methylation in the Young Finns Study (YFS) participants (n = 1114, aged 34-49 years, women: 54%, men: 46%). First, we performed epigenome-wide association study (EWAS) of smoking. We then defined sets of genes based on DNA methylation status within their genomic regions, for example, sets of genes containing hyper- or hypomethylated CpG sites in their body or promoter regions. Gene set analysis was performed using transcriptomics data from the same participants. Two sets of genes, one containing 49 genes with hypomethylated CpG sites in their body region and the other containing 33 genes with hypomethylated CpG sites in their promoter region, were differentially expressed among the smokers. Genes in the two gene sets are involved in bone formation, metal ion transport, cell death, peptidyl-serine phosphorylation, and cerebral cortex development process, revealing epigenetic-transcriptomic pathways to smoking-related diseases such as osteoporosis, atherosclerosis, and cognitive impairment. These findings contribute to a deeper understanding of the pathophysiology of smoking-related diseases and may provide potential therapeutic targets.

The Natural Compound Dehydrocrenatidine Attenuates Nicotine-Induced Stemness and Epithelial-Mesenchymal Transition in Hepatocellular Carcinoma by Regulating a7nAChR-Jak2 Signaling Pathways

Background

Exposure to nicotine has been observed associated with tumor progression, metastasis, and therapy resistance of many cancers. Hepatocellular carcinoma (HCC) is one major cancer related to the liver and the most difficult to treat malignancies worldwide. The underlying mechanism of nicotine in the stimulation of HCC tumorigenesis is still not studied well.

Methods

Classically, nicotine binds to nicotinic acetylcholine receptors (nAChRs) and induces many downstream cancer-associated signaling pathways. Big data analysis is used to explore the importance of a7nAChR-Jak2 axis in the progression of hepatocellular carcinoma. Bioinformatic analysis was performed to determine gene associated with a7nAChR-Jak2 axis of HCC patients. Biological importance of a7nAChR-Jak2 axis was investigated in vitro (Hun7 and HepG2 cell lines), and athymic nude mouse models bearing HepG2-HCC cells xenografts were established in vivo.

Result

We found that nicotine exposure stimulated the HCC tumorigenicity by inducing the expression of one of the key nAChRs subunit that is α7nAChR as well as the expression of Janus kinase (JAK)-2. In both the in vitro and in vivo studies, the reduced overexpression of α7nAChR and increased sensitization of HCC towards treatment is observed with dehydrocrenatidine (DHCT), a novel and potent JAK family kinase inhibitor. Interestingly, DHCT treatment results in the reduction of the epithelial-mesenchymal transition process which leads to a significant reduction of clonogenicity, migratory, and invasive ability of HCC cells. Moreover, DHCT treatment also inhibits the cancer stem cell phenotype by inhibiting the tumor-sphere formation and reducing the number of ALDH1+ cells population in nicotine-stimulated HCC cells.

Conclusions

Taken together, the presented results indicate the positive effect of inhibition of nicotine induced overexpression of α7nAChR and JAK2, unique to HCC. Thus, these findings suggest the nicotine effect on HCC progression via α7nAChR-mediated JAK2 signaling pathways, and DHCT treatment enhances the therapeutic potential of HCC patients via overcoming/reversing the effect of nicotine in HCC patients.

Knowledge and Beliefs of Jordanian Community Toward E-cigarettes: A National Survey

Electronic nicotine delivery systems were promoted publically as a healthier replacement for conventional cigarettes. Knowledge and beliefs of the public can drive their behaviours to adapt or reject the new habit. No previous research was conducted in Jordan to assess electronic cigarettes (e-cigarettes) prevalence, and limited data are available on public opinions and orientation toward this new habit. To assess prevalence of, knowledge, attitude and beliefs about e-cigarettes, and examine factors associated with plans of quitting or initiating e-cigarettes among adults in Jordan. A large cross-sectional face-to-face survey on a random sample of adult population aged ≥ 18 years was conducted over two months to include 1820 adults in Jordan. A representative sample was collected using proportionate random sampling technique, which enabled us to geographically categorise the study population. Reliability and validity measures were taken to ensure a comprehensive and appropriate study tool. The Statistical Package for Social Science (SPSS®) version 24 was used to conduct descriptive analysis, logistic regression, and Rao-Scott chi-square. Findings were considered statistically significant at p value < 0.05 (with a confidence limit at 95%). Of 2164 adults approached, 1820 completed the questionnaire (84.1% response rate). The prevalence of current e-cigarette smokers and dual smokers were 11.7% and 4.0%, respectively. Quitting conventional smoking (38.8%) and enjoying the flavour (32.5%) were the most common reasons to start vaping. Friends were the major source of information about e-cigarettes. There was evidence that adults aged 45-59 years were less likely to be dual smokers (OR 0.51; 95%CI 0.29-0.66; p = 0.03). Poor knowledge about the content (23.7%) and types of e-cigarettes (14.5%) was reported. Plans to reduce or quit e-cigarettes were significantly associated with three factors: smokers' knowledge about its content, social impression, smokers' satisfaction with e-cigarettes. Social impression was also associated with plans of initiating e-cigarettes. Most participants thought vaping cannot be harmful to children and pregnant women (73.1%) and cannot be addictive (58.2%). Electronic cigarettes were considered helpful in smoking cessation by 69.1% of participants. The proportions of adults who were currently electronic cigarette and dual smokers were 11.7% and 4.0%, respectively. Our research may provide insight to product and individual factors that were associated with plans to sustain, quit or initiate electronic smoking.

Dataset on perception among male secondary school students on underage smoking in Jordan

The World Health Organization (WHO) revealed in 2015 that the percentage of smokers in Jordan is one of the highest in the world, reaching 70.2% among males and consequently ranking first in the Middle Eastern region and second in the world. Cigarettes are the most widely abused substance among school students in Jordan. This poses severe health risks to the public. The WHO emphasizes that one of the most important public health goals related to smoking is to reduce its harmful effects on the individual as well as society and the prevention and treatment of injuries. This article explores the nature of smoking among school students, binge smoking, and the consequences of smoking. Secondary school students undergo developmental transitions, and this comes with debilitating effects such as the risky use of cigarettes, which adversely affects their health and educational achievements. This article comprises data obtained from 1166 participants (ages 14-17 years) from selected schools in Jerash, near Amman, Jordan. For data collection, a youth questionnaire on underage smoking was utilized. The article presents information on the participants' smoking demographic. Analyses of the data can provide insights into the reasons for the smoking habits of the youth, the negative effects of smoking on school students, strategies to reduce smoking consumption, level of consumption of daily smokers, health issues caused by smoking, the prevalence of smoking, the effect of smoker parents on stimulating their children, and common smoking areas. The data will be useful for institutions dealing with prevalent health problems in society (Smoking causes health problems that affect students' learning) as well as benefit future researchers.

Determining population stratification and subgroup effects in association studies of rare genetic variants for nicotine dependence

Supplemental Digital Content is available in the text.

Background

Rare variants (minor allele frequency < 1% or 5 %) can help researchers to deal with the confounding issue of ‘missing heritability’ and have a proven role in dissecting the etiology for human diseases and complex traits.

Methods

We extended the combined multivariate and collapsing (CMC) and weighted sum statistic (WSS) methods and accounted for the effects of population stratification and subgroup effects using stratified analyses by the principal component analysis, named here as ‘str-CMC’ and ‘str-WSS’. To evaluate the validity of the extended methods, we analyzed the Genetic Architecture of Smoking and Smoking Cessation database, which includes African Americans and European Americans genotyped on Illumina Human Omni2.5, and we compared the results with those obtained with the sequence kernel association test (SKAT) and its modification, SKAT-O that included population stratification and subgroup effect as covariates. We utilized the Cochran–Mantel–Haenszel test to check for possible differences in single nucleotide polymorphism allele frequency between subgroups within a gene. We aimed to detect rare variants and considered population stratification and subgroup effects in the genomic region containing 39 acetylcholine receptor-related genes.

Results

The Cochran–Mantel–Haenszel test as applied to GABRG2 (P = 0.001) was significant. However, GABRG2 was detected both by str-CMC (P= 8.04E-06) and str-WSS (P= 0.046) in African Americans but not by SKAT or SKAT-O.

Conclusions

Our results imply that if associated rare variants are only specific to a subgroup, a stratified analysis might be a better approach than a combined analysis.

The α9 Nicotinic Acetylcholine Receptor Mediates Nicotine-Induced PD-L1 Expression and Regulates Melanoma Cell Proliferation and Migration

Cigarette smoking is associated with an increased risk of melanoma metastasis. Smokers show higher PD-L1 expression and better responses to PD-1/PD-L1 inhibitors than nonsmokers. Here, we investigate whether nicotine, a primary constituent of tobacco, induces PD-L1 expression and promotes melanoma cell proliferation and migration, which is mediated by the α9 nicotinic acetylcholine receptor (α9-nAChR). α9-nAChR overexpression in melanoma using melanoma cell lines, human melanoma tissues, and assessment of publicly available databases. α9-nAChR expression was significantly correlated with PD-L1 expression, clinical stage, lymph node status, and overall survival (OS). Overexpressing or knocking down α9-nAChR in melanoma cells up- or downregulated PD-L1 expression, respectively, and affected melanoma cell proliferation and migration. Nicotine-induced α9-nAChR activity promoted melanoma cell proliferation through stimulation of the α9-nAChR-mediated AKT and ERK signaling pathways. In addition, nicotine-induced α9-nAchR activity promoted melanoma cell migration via activation of epithelial-mesenchymal transition (EMT). Moreover, PD-L1 expression was upregulated in melanoma cells after nicotine treatment via the transcription factor STAT3 binding to the PD-L1 promoter. These results highlight that nicotine-induced α9-nAChR activity promotes melanoma cell proliferation, migration, and PD-L1 upregulation. This study may reveal important insights into the mechanisms underlying nicotine-induced melanoma growth and metastasis through α9-nAChR-mediated carcinogenic signals and PD-L1 expression.

Cultural factors and the circadian rhythm of ST elevation myocardial infarction in patients in a Mediterranean island

INTRODUCTION

The circadian rhythm of onset of myocardial infarction shows an increased risk during the morning hours. However, it is not clear whether habits, culture and sunshine hours differentiate circadian rhythm. The aim of this study was to investigate the influence of cultural factors on the circadian rhythm of acute myocardial infarction with ST segment elevation in a Mediterranean island.

METHOD

The study was a retrospective correlational survey. It included 123 patients with ST elevation myocardial infarction (mean age 60.7±12.6; 82% men). The 24 h of a day were divided into four six-hour periods of time for study purposes (00:01-06:00; 06:01-12:00; 12:01-18:00; and 18:01-24:00) and the chi-square test was used for the analysis.

RESULTS

A morning peak of symptoms onset of ST-elevation myocardial infarction was detected during the period 06:01-12:00 (p=0.044). In patients who were smokers, a bimodal pattern involving a morning (06:01-12:00) and an afternoon-to-night peak (18:01-24:00) (p=0.005) was detected. For patients with a history of hypertension, a morning peak of their symptoms was also detected (p=0.028). Different circadian variations were found between patients over the age of 60 years old and patients under the age of 60 years old (p=0.025).

CONCLUSIONS

Patients with ST elevation myocardial infarction seem to follow a circadian rhythm with a peak of onset of symptoms in the morning. In the smokers' subgroup, a different circadian pattern was found. The habit of smoking is likely to affect the circadian rhythm of the onset of ST elevation myocardial infarction in the Mediterranean area and culture.

Cigarette smoking behaviour and blood metabolomics

BACKGROUND

Identifying circulating metabolites related to cigarette smoking may provide insight into the biological mechanisms of smoking-related diseases and the nature of addiction. However, previous studies are limited, generally small, and have largely targeted a priori metabolites.

METHODS

We examined associations between cigarette smoking and metabolites using an untargeted metabolomics approach in 892 men and women from four studies including participants from Italy, USA, China and Finland. We examined associations between individual log-transformed metabolites and two key smoking phenotypes (current smoking status and cigarettes per day [cig/day]) using linear regression. Fixed-effect meta-analysis was used to combine results across studies. Strict Bonferroni thresholds were used as our significance criteria. We further examined associated metabolites with other metrics of smoking behaviuor (current versus former, former versus never, smoking duration and years since quitting) in the US study.

RESULTS

We identified a total of 25 metabolites associated with smoking behaviours; 24 were associated with current smoking status and eight with cig/day. In addition to three well-established nicotine metabolites (cotinine, hydroxycotinine, cotinine N-oxide), we found an additional 12 xenobiotic metabolites involved in benzoatic (e.g. 3-ethylphenylsulphate) or xanthine metabolism (e.g. 1-methylurate), three amino acids (o-cresol sulphate, serotonin, indolepropionate), two lipids (scyllo-inositol, pregnenolone sulphate), four vitamins or cofactors [e.g. bilirubin (Z,Z)], and one carbohydrate (oxalate).

CONCLUSIONS

We identified associations between cigarette smoking and a diverse range of metabolites. Our findings, with further validation in future studies, have implications regarding aetiology and study design of smoking-related diseases.

Molecular epidemiology of acute leukemia in children: causal model, interaction of three factors-susceptibility, environmental exposure and vulnerability period

Acute leukemias have a huge morphological, cytogenetic and molecular heterogeneity and genetic polymorphisms associated with susceptibility. Every leukemia presents causal factors associated with the development of the disease. Particularly, when three factors are present, they result in the development of acute leukemia. These phenomena are susceptibility, environmental exposure and a period that, for this model, has been called the period of vulnerability. This framework shows how the concepts of molecular epidemiology have established a reference from which it is more feasible to identify the environmental factors associated with the development of leukemia in children. Subsequently, the arguments show that only susceptible children are likely to develop leukemia once exposed to an environmental factor. For additional exposure, if the child is not susceptible to leukemia, the disease does not develop. In addition, this exposure should occur during a time window when hematopoietic cells and their environment are more vulnerable to such interaction, causing the development of leukemia. This model seeks to predict the time when the leukemia develops and attempts to give a context in which the causality of childhood leukemia should be studied. This information can influence and reduce the risk of a child developing leukemia.

Epidemiology, attitudes and perceptions toward cigarettes and hookah smoking amongst adults in Jordan

OBJECTIVES

The aims of this study are to assess cigarette and hookah smoking rates amongst adult population in Jordan and to determine predictors of smoking status. Selected beliefs, perceptions and attitudes toward cigarettes and hookah smoking were also assessed.

METHODS

This cross-sectional study was conducted in five regional governorates of Jordan through face-to-face interviews on a random sample of adult population aged 18-79 years. Data was collected using a piloted questionnaire based on the Global Adult Tobacco Questionnaire.

RESULTS

The overall prevalence of cigarette smoking in our sample (869) was 59.1 % amongst males and 23.3 % amongst females, while the overall prevalence of hookah smoking was 18.9 % amongst males and 23.1 % amongst females. Leisure and imitation were the most commonly reported reasons for smoking. Regardless of smoking status, people were aware of health risks associated smoking and also had negative perceptions toward smoking.

CONCLUSIONS

Smoking rates for both genders have reached alarmingly high rates in Jordan. There is an urgent need for a comprehensive national programme to target the country's growing burden of smoking. Suggestions on leisure time activities should be included in such programmes.

Beneficial effects of nicotine, cotinine and its metabolites as potential agents for Parkinson's disease

Parkinson’s disease (PD) is a progressive neurodegenerative disorder, which is characterized by neuroinflammation, dopaminergic neuronal cell death and motor dysfunction, and for which there are no proven effective treatments. The negative correlation between tobacco consumption and PD suggests that tobacco-derived compounds can be beneficial against PD. Nicotine, the more studied alkaloid derived from tobacco, is considered to be responsible for the beneficial behavioral and neurological effects of tobacco use in PD. However, several metabolites of nicotine, such as cotinine, also increase in the brain after nicotine administration. The effect of nicotine and some of its derivatives on dopaminergic neurons viability, neuroinflammation, and motor and memory functions, have been investigated using cellular and rodent models of PD. Current evidence shows that nicotine, and some of its derivatives diminish oxidative stress and neuroinflammation in the brain and improve synaptic plasticity and neuronal survival of dopaminergic neurons. In vivo these effects resulted in improvements in mood, motor skills and memory in subjects suffering from PD pathology. In this review, we discuss the potential benefits of nicotine and its derivatives for treating PD.

Reference interval determination for anabasine: a biomarker of active tobacco use

Laboratory detection of nicotine exposure is important for establishing eligibility for organ transplant and elective surgery. Nicotine testing is also used to verify compliance with nicotine replacement therapies (NRT), smoking cessation programs and for life insurance purposes. Nicotine metabolites, such as cotinine and trans-3'-hydroxycotinine, are used as biomarkers of nicotine exposure. For some clinical applications, it is important to distinguish between active use of tobacco products versus NRT. Anabasine is a tobacco alkaloid that has been used as a biomarker of active tobacco use. However, the use of anabasine as an insecticide, and its presence in consumables other than nicotine products, suggests that anabasine may not be specific to tobacco use/exposure. Here, we determine the reference interval for anabasine in the urine of nonsmokers and compare it to the range of anabasine concentrations observed in the presence or absence of nicotine metabolites.

Smoking Behaviour of Asthmatic Patients in Primary Care: A Cross-Sectional Study

Introduction:

One-third of adult asthma patients smoke cigarettes despite smoking being a known trigger of asthma exacerbation. This study aims to describe the behaviour of asthmatic patients who smoke and explore the reasons why they continue to smoke cigarettes even when unwell.

Methods:

A cross-sectional questionnaire survey was conducted on adult asthma patients at primary care clinics in Singapore. One hundred and seventy-four asthmatic smokers (AS) of four ethnic groups, both genders, aged 21–50 years were recruited. Demographic data and smoking characteristics, reasons for smoking, and experiences during their attempts to quit were collected and analysed using the statistical software STATA version 12.

Results:

The median age of AS was 30 years. Seventy-five percent were males and mostly Malays (58%). Seventy-one percent had at least secondary education. Eighty-six percent started smoking before 20 years old. Ninety-eight percent smoked less than 10 sticks per day and 51% smoked ≤5 pack-years. Thirty-eight percent smoked within 5 minutes of awakening. AS cited reasons such as stress relief (79%), peer pressure (36%), influence from family members who smoke (40%), think better (35%), staying alert (57%), and relaxed (53%). Although 77% believed smoking worsened their asthma, they continued to smoke. Restlessness (43%), mood swings (27%), difficulties in concentration (25%) and irritability (24%) were common symptoms encountered in those who attempted to quit. About 44% did not refrain from smoking even when they were ill.

Conclusion:

Adult asthmatic smokers continued cigarette smoking to relieve stress, maintain mental alertness and avoid withdrawal symptoms. Implementing a programme to address smoking behaviour and withdrawal symptoms is paramount towards successful smoking cessation.

Differential Effect of Active Smoking on Gene Expression in Male and Female Smokers

Smoking is the second leading cause of preventable death in the United States. Cohort epidemiological studies have demonstrated that women are more vulnerable to cigarette-smoking induced diseases than their male counterparts, however, the molecular basis of these differences has remained unknown. In this study, we explored if there were differences in the gene expression patterns between male and female smokers, and how these patterns might reflect different sex-specific responses to the stress of smoking. Using whole genome microarray gene expression profiling, we found that a substantial number of oxidant related genes were expressed in both male and female smokers, however, smoking-responsive genes did indeed differ greatly between male and female smokers. Gene set enrichment analysis (GSEA) against reference oncogenic signature gene sets identified a large number of oncogenic pathway gene-sets that were significantly altered in female smokers compared to male smokers. In addition, functional annotation with Ingenuity Pathway Analysis (IPA) identified smoking-correlated genes associated with biological functions in male and female smokers that are directly relevant to well-known smoking related pathologies. However, these relevant biological functions were strikingly overrepresented in female smokers compared to male smokers. IPA network analysis with the functional categories of immune and inflammatory response gene products suggested potential interactions between smoking response and female hormones. Our results demonstrate a striking dichotomy between male and female gene expression responses to smoking. This is the first genome-wide expression study to compare the sex-specific impacts of smoking at a molecular level and suggests a novel potential connection between sex hormone signaling and smoking-induced diseases in female smokers.

Smoking and psychopathology increasingly associated in recent birth cohorts

BACKGROUND

In recent decades, smoking has become an increasingly non-normative behavior. Because deviant behaviors are associated with greater clinical and genetic risks, current-generation smokers may have greater concentrations of psychiatric comorbidity than previous generations. We examined this question empirically by testing whether associations between measures of smoking, psychiatric diagnoses, and risk-associated personality traits, increased across seven birth-cohorts of the 20th century.

METHOD

4326 subjects from a cross-sectional NIMH control sample were categorized into one of seven groups based on birth (born before 1930, and 1930s-80s) and one of three smoking levels (lifetime dependent smoker, never dependent smoker, never smoker). Smoking and ND were assessed using the Fagerstrom Test for Nicotine Dependence; psychiatric diagnoses (drug and alcohol dependence, major depression, and generalized anxiety disorder) using the Composite International Diagnostic Interview-Short Form, and personality traits (neuroticism and extraversion) with the Eysenck Personality Questionnaire.

RESULT

Lifetime prevalence of smoking decreased across the seven cohorts. Associations between smoking and drug dependence, generalized anxiety, and neuroticism, as well as total psychiatric comorbidity, were greater in more recent cohorts [smoking-by-cohort interaction: p<0.01], with greatest increases contributed by nicotine-dependent smokers. Smoking was also independently associated with alcohol dependence and depression, but these associations did not significantly vary across cohorts.

CONCLUSIONS

More recent generations included fewer persons who smoked, but their smoking was associated with greater psychiatric morbidity. Failure to account for systematic variation in comorbidity across smoking cohorts may lead to unwanted heterogeneity in clinical, and possibly genetic, studies of nicotine dependence.

LGBT community, social network characteristics, and smoking behaviors in young sexual minority women

Smoking rates among young sexual minority women (YSMW) are disproportionately high as compared to heterosexual populations. While this disparity has commonly been attributed to the sexual minority stress process, little empirical work has explored what may protect YSMW from high rates of smoking. Using data (N = 471) from a cross-sectional study designed to investigate YSMW's (age 18-24) smoking behaviors and correlates; we explore the relationship of LGBT community connections, YSMW's social network characteristics, and stress to smoking behaviors (i.e., status, frequency, amount). Through this analysis, we find support for LGBT community connection as well as friendships with other sexual minorities as protective in relation to YSMW's smoking behaviors. We discuss the implications of our results, highlighting the need for future longitudinal research and interventions designed to bolster YSMW's connections to the LGBT community and their social networks.

The contribution of smoking to black-white differences in U.S. mortality

Smoking has significantly impacted American mortality and remains a major cause of morbidity and mortality. No previous study has systematically examined the contribution of smoking-attributable deaths to mortality trends among blacks or to black-white mortality differences at older ages over time in the United States. In this article, we employ multiple methods and data sources to provide a comprehensive assessment of this contribution. We find that smoking has contributed to the black-white gap in life expectancy at age 50 for males, accounting for 20 % to 48 % of the gap between 1980 and 2005, but not for females. The fraction of deaths attributable to smoking at ages above 50 is greater for black males than for white males; and among men, current smoking status explains about 20 % of the black excess relative risk in all-cause mortality at ages above 50 without adjustment for socioeconomic characteristics. These findings advance our understanding of the contribution of smoking to contemporary mortality trends and differences and reinforce the need for interventions that better address the needs of all groups.

Detection of epidermal growth factor receptor intensity in asymptomatic fully impacted lower third molar follicles of smoking and nonsmoking patients

OBJECTIVE

The objective of this study was to determine whether smoking causes pathological changes, comparing intensity of epidermal growth factor receptor (EGFR) expression in smokers' and nonsmokers' pericoronal follicles located around asymptomatic impacted lower third molars.

STUDY DESIGN

Eighty-two dental follicles were collected from asymptomatic mandibular third molars of 41 smoker and 41 nonsmoker patients. Specimens were examined immunohistochemically using antibody against EGFR.

RESULTS

The expression of EGFR in smokers' pericoronal follicles was higher as compared with nonsmokers (P = 0.036). Also, high EGFR expression was detected in female smokers than in female nonsmokers (P = 0.01). There was a statistically significant correlation between pack-years and EGFR expression intensity in male patients.

CONCLUSIONS

The risk of pathological differentiation in pericoronal tissues of smoking patients is higher than in the nonsmoking patients. This factor may be taken into account when deciding whether to remove an asymptomatic impacted lower third molar.

The physical health of the seriously mentally ill: an overview of the literature

Despite the wealth of literature which attests to the relationship between serious mental illness (SMI) and physical ill health, the provision of optimum physical health care for mental health service users remains a challenge. In England the Department of Health has identified the evident health inequalities for people with SMI as a priority area for health improvement, publishing numerous policy directives aimed at addressing these inequalities. However, this is a highly complex process and little is known about why the rhetoric of holistic health care has proved unattainable thus far. In this paper we present an informed commentary of the contemporary literature with the aim of offering a more comprehensive understanding of the health inequalities faced by people with SMI. We searched relevant databases for publications related to: the causes of poor physical health among the mentally ill, strategies to address these health needs and the impact which professional education, culture and services structure has on this facet of service delivery. This enabled us to identify potential strategies that can be adopted by health care practitioners wishing to improve the health of this vulnerable group, and by educationalists to advance professionals' knowledge of this important and ostensibly neglected area.

Simultaneous quantification of nicotine, cotinine, trans-3'-hydroxycotinine, norcotinine and mecamylamine in human urine by liquid chromatography-tandem mass spectrometry

BACKGROUND

Mecamylamine is a nicotine antagonist under investigation in combination with nicotine replacement for smoking treatment.

METHODS

A simple, rapid and reliable liquid chromatography tandem mass spectrometry (LCMSMS) method was developed and validated for quantifying nicotine, cotinine, trans-3'-hydroxycotinine, norcotinine and mecamylamine in human urine. Chromatography was performed on a Synergi PolarRP column with a gradient of 0.1% formic acid and 0.1% formic acid in acetonitrile at 0.25 ml/min with an 8-min total runtime. Analytes were monitored by positive mode electrospray ionization and multiple reaction monitoring mass spectrometry.

RESULTS

Linear dynamic ranges were 1-500 ng/ml for nicotine and norcotinine, 0.5-500 ng/ml for trans-3'-hydroxycotinine, 0.2-500 ng/ml for cotinine, and 0.1-100 ng/ml for mecamylamine; correlation coefficients were consistently greater than 0.99, and all calibrator concentrations were within 20% of target. Extensive endogenous and exogenous interferences were evaluated. At 3 concentrations spanning the linear dynamic range of the assay, mean extraction efficiencies from urine were 55.1-109.1% with analytical recovery (bias) 82.0-118.7% and total imprecision of 0.7-9.1%. Analytes were stable for 24h at room temperature, 72 h at 4 °C, 72 h in autosampler at 15 °C and after three freeze/thaw cycles.

CONCLUSION

This method is useful for monitoring mecamylamine, nicotine and nicotine metabolites in smoking cessation and other clinical nicotine research.

Gene-centric analysis of serum cotinine levels in African and European American populations

To date, most genetic association studies of tobacco use have been conducted in European American subjects using the phenotype of smoking quantity (cigarettes per day). However, smoking quantity is a very imprecise measure of exposure to tobacco smoke constituents. Analyses of alternate phenotypes and populations may improve our understanding of tobacco addiction genetics. Cotinine is the major metabolite of nicotine, and measuring serum cotinine levels in smokers provides a more objective measure of nicotine dose than smoking quantity. Previous genetic association studies of serum cotinine have focused on individual genes. We conducted a genetic association study of the biomarker in African American (N=365) and European American (N=315) subjects from the Coronary Artery Risk Development in Young Adults study using a chip containing densely-spaced tag SNPs in ∼2100 genes. We found that rs11187065, located in the non-coding region (intron 1) of insulin-degrading enzyme (IDE), was the most strongly associated SNP (p=8.91 × 10(-6)) in the African American cohort, whereas rs11763963, located on chromosome 7 outside of a gene transcript, was the most strongly associated SNP in European Americans (p=1.53 × 10(-6)). We then evaluated how the top variant association in each population performed in the other group. We found that the association of rs11187065 in IDE was also associated with the phenotype in European Americans (p=0.044). Our top SNP association in European Americans, rs11763963 was non-polymorphic in our African American sample. It has been previously shown that psychostimulant self-administration is reduced in animals with lower insulin because of interference with dopamine transmission in the brain reward centers. Our finding provides a platform for further investigation of this, or additional mechanisms, involving the relationship between insulin and self-administered nicotine dose.

Lack of an association between three tagging SNPs within the FTO gene and smoking behavior

INTRODUCTION

Using genome-wide screening, a polymorphism within the second intron of the FTO gene (rs2302673) was found to be associated with smoking habits in females. In a population-based, cross-sectional study, we analyzed three tagging FTO single-nucleotide polymorphisms (SNPs) for their association with smoking behavior.

METHODS

Subjects from the Czech post-MONICA study, including 1,191 adult males (32.1% smokers) and 1,368 adult females (22.5% smokers) were included in this study. Smoking habits were obtained through questionnaire data analysis, and three FTO tagging SNPs were genotyped (rs17817449: intron 1, rs2302673: intron 2, and rs17818902: intron 3).

RESULTS

We detected slightly lower frequencies (p = .043) of the GG genotype of the rs17818902 SNP in males who quit smoking compared with others. However, the significance disappeared after adjusting for multiple testing. Within the entire population, or in either males or females alone, we failed to detect a significant difference between other FTO genotypes and smoking status. Also, the number of cigarettes smoked per day was independent of individual FTO genotypes in both genders.

CONCLUSIONS

We did not find an association between the FTO gene tagging variants and smoking status. FTO is unlikely to be a major genetic determinant of smoking status.

Income and the midlife peak in common mental disorder prevalence

BACKGROUND

The prevalence of psychological distress and common mental disorders has been shown to peak in midlife but analyses have ignored the association of poor material circumstances with prevalence. This study aimed to test the hypothesis that the midlife prevalence peak occurs only in lower-income households.

METHOD

Pooled data were used from the annual Health Survey for England, a nationally representative cross-sectional study, on community-dwelling individuals aged ≥ 16 years from years 1997 to 2006 (n=100 457). 12-item General Health Questionnaire scores, reported mental illness diagnoses and receipt of relevant medication were assessed in relation to household income and age. Analyses were separated by gender and adjusted for age, ethnicity, smoking, social class, education and co-morbidities.

RESULTS

Prevalence of psychological distress, diagnoses and treatments rose with age until early middle age and declined subsequently. In analyses conducted separately by income categories, this pattern was marked in low-income groups but absent in high-income groups. Income-related inequalities in the prevalence of psychological distress were greatest in midlife; for example, in men aged 45-54 years the odds ratio of receiving psychiatric medication in the lowest income group compared with the highest was 7.50 [95% confidence interval (CI) 4.24-13.27] and in women aged 45-54 years the odds ratio of reporting mental illness was 10.25 (95% CI 6.16-17.05).

CONCLUSIONS

An increased prevalence of psychological distress, common mental disorder diagnoses and treatment in midlife is not a universal phenomenon but is found only in those in low-income households. This implies the phenomenon is not inevitable but is potentially manageable or preventable.

No smoke without fire: The impact of future friends on adolescent smoking behaviour

OBJECTIVE

This study examined the impact of future friends and the contribution of different social influence and selection processes in predicting adolescents' smoking behaviour by extending the theory of planned behaviour (TPB). We investigated the impact of previous smoking, direct pressure from friends, descriptive norms of present and future friends, smoking-based selection of future friends, and distinguished between reciprocal and desired friends.

DESIGN

A longitudinal design with three measurements was used. METHODSL: The sample consisted of 1,475 Dutch high school students (mean age = 12.7 years) that participated as a control group in the European Smoking prevention Framework Approach study at three measurements.

RESULTS

Structural equation modelling revealed that adolescent smoking was influenced by intention, previous smoking, descriptive norms of parents and siblings, and that desired as well as reciprocal friends were selected based on similar smoking behaviour. Future friends indirectly influenced adolescent smoking through intention, as did attitude, subjective norms of parents and siblings, previous smoking, and descriptive norms of reciprocal friends and siblings.

CONCLUSIONS

The present results suggest that descriptive norms and selection of friends need to be considered as major factors explaining smoking behaviour among adolescents besides the TPB components. These insights contribute to the further refinement of smoking prevention strategies.

Mutagenicity of 11 cigarette smoke condensates in two versions of the mouse lymphoma assay

Cigarette smoke condensate (CSC) is genotoxic in nearly all assays in which it has been tested. In this study, we investigated the mutagenicity of 11 CSCs using the microwell and soft-agar versions of the mouse lymphoma assay (MLA). These CSCs were prepared from commercial or experimental cigarettes, 10 of them were produced using International Organisation for Standardisation (ISO) conditions and one CSC was generated using intense Massachusetts Department of Public Health (MDPH) conditions. In the presence of rat liver S9, the L5178Y/Tk(+/-) mouse lymphoma cells were treated with 11 CSCs at different concentrations (25-200 μg/ml) for 4 h. All CSCs resulted in dose-dependent increases of both cytotoxicity and mutagenicity in both versions of the MLA. The mutagenic potencies of the CSCs were calculated as mutant frequency per microgram CSC from the slope of the linear regression of the dose-response curves and showed no correlations with the tar yield of the cigarette or nicotine concentrations of the CSCs. Comparing two CSCs produced from the same commercial cigarettes using two different smoking conditions, the one generated under ISO conditions was more mutagenic than the other generated under intense conditions on a per microgram CSC basis. We also examined the loss of heterozygosity (LOH) at four microsatellite loci spanning the entire chromosome 11 for the mutants induced by 11 CSCs. The most common type of mutation observed was LOH with chromosome damage spanning less than ∼34 Mbp. These results indicate that the MLA identifies different genotoxic potencies among a variety of CSCs and that the results from both versions of the assay are comparable.

The smoking culture in psychiatry: time for change

Smoking is closely linked to severe mental illness and has a major detrimental impact on individuals' lives. Despite this and the recent societal 'de-normalisation' of smoking, the historic 'smoking culture' still prevails within mental health settings. Change is urgently required to prevent a widening of existing health gaps.

Resequencing of nicotinic acetylcholine receptor genes and association of common and rare variants with the Fagerström test for nicotine dependence

Common single-nucleotide polymorphisms (SNPs) at nicotinic acetylcholine receptor (nAChR) subunit genes have previously been associated with measures of nicotine dependence. We investigated the contribution of common SNPs and rare single-nucleotide variants (SNVs) in nAChR genes to Fagerström test for nicotine dependence (FTND) scores in treatment-seeking smokers. Exons of 10 genes were resequenced with next-generation sequencing technology in 448 European-American participants of a smoking cessation trial, and CHRNB2 and CHRNA4 were resequenced by Sanger technology to improve sequence coverage. A total of 214 SNP/SNVs were identified, of which 19.2% were excluded from analyses because of reduced completion rate, 73.9% had minor allele frequencies <5%, and 48.1% were novel relative to dbSNP build 129. We tested associations of 173 SNP/SNVs with the FTND score using data obtained from 430 individuals (18 were excluded because of reduced completion rate) using linear regression for common, the cohort allelic sum test and the weighted sum statistic for rare, and the multivariate distance matrix regression method for both common and rare SNP/SNVs. Association testing with common SNPs with adjustment for correlated tests within each gene identified a significant association with two CHRNB2 SNPs, eg, the minor allele of rs2072660 increased the mean FTND score by 0.6 Units (P=0.01). We observed a significant evidence for association with the FTND score of common and rare SNP/SNVs at CHRNA5 and CHRNB2, and of rare SNVs at CHRNA4. Both common and/or rare SNP/SNVs from multiple nAChR subunit genes are associated with the FTND score in this sample of treatment-seeking smokers.

Personality traits and cancer risk and survival based on Finnish and Swedish registry data

Personality traits have been studied extensively as risk and prognostic factors for cancer; however, the association remains unclear. This prospective, population-based cohort study comprised 59,548 Swedish (1974-1999) and Finnish (1976-2004) participants who completed a questionnaire eliciting information for the Eysenck Personality Inventory and on health behavior at baseline. To analyze the association of personality traits extraversion and neuroticism with risk of cancer, the authors identified 4,631 cancer cases for a maximum 30 years of follow-up. To assess the association with cancer survival among the Finnish participants, they identified 2,733 cancer cases and, later, 1,548 deaths for a maximum 29 years of follow-up. Hazard ratios were estimated by treating the personality scales as continuous variables and are presented per one increase in score on each scale. In multivariate analyses, extraversion and neuroticism were not significantly associated with risk of cancers at all sites (extraversion: hazard ratio = 0.99, 95% confidence interval: 0.98, 1.01; neuroticism: hazard ratio = 1.00, 95% confidence interval: 0.99, 1.02). Results showed no significant association between these traits and the hazard ratio for death after cancers at all sites, and they do not support the hypothesis that extraversion and neuroticism are direct risk factors for cancer or survival after cancer.

Subjective well-being, personality, demographic variables, and American state differences in smoking prevalence

INTRODUCTION

The present study was conducted to determine relations between smoking prevalence, subjective well-being, and the Big Five personality variables at the American state level.

METHOD

State smoking prevalence was based on the responses of more than 350,000 adults interviewed in the Behavioral Risk Factor Surveillance System in 2008. Subjective well-being was based on the state-aggregated responses of 353,039 adults to the Gallup-Healthways Well-Being Index phone interviews during 2008. Big Five variables were based on the state-aggregated responses of 619,397 persons to an Internet survey between 1999 and 2005, which included the 44-item Big Five Inventory.

RESULTS

Well-being and smoking prevalence were negatively correlated and remained so when state Big Five, socioeconomic status (SES), White population percent, urban population percent, and median age were controlled in a partial correlation. Hierarchical and stepwise multiple regressions showed (a) that SES and neuroticism were the prime predictors of well-being, (b) that well-being was the prime predictor of smoking prevalence, and (c) that openness to experience was the sole personality or demographic variable to account for differences in smoking prevalence when well-being was controlled, and it explained very little of the remaining variance.

DISCUSSION

Applied implications for state-tailored attempts to reduce smoking are briefly discussed, and suggestions for future research directions are put forward.

Impact of female cigarette smoking on circulating B cells in vivo: the suppressed ICOSLG, TCF3, and VCAM1 gene functional network may inhibit normal cell function

As pivotal immune guardians, B cells were found to be directly associated with the onset and development of many smoking-induced diseases. However, the in vivo molecular response of B cells underlying the female cigarette smoking remains unknown. Using the genome-wide Affymetrix HG-133A GeneChip microarray, we firstly compared the gene expression profiles of peripheral circulating B cells between 39 smoking and 40 non-smoking healthy US white women. A total of 125 differential expressed genes were identified in our study, and 75.2% of them were down-regulated in smokers. We further obtained genotypes of 702 single nucleotide polymorphisms in those promising genes and assessed their associations with smoking status. Using a novel multicriteria evaluation model integrating information from microarray and the association studies, several genes were further revealed to play important roles in the response of smoking, including ICOSLG (CD275, inducible T-cell co-stimulator ligand), TCF3 (E2A immunoglobulin enhancer binding factors E12/E47), VCAM1 (CD106, vascular cell adhesion molecule 1), CCR1 (CD191, chemokine C-C motif receptor 1) and IL13 (interleukin 13). The differential expression of ICOSLG (p = 0.0130) and TCF3 (p = 0.0125) genes between the two groups were confirmed by real-time reverse transcription PCR experiment. Our findings support the functional importance of the identified genes in response to the smoking stimulus. This is the first in vivo genome-wide expression study on B cells at today's context of high prevalence rate of smoking for women. Our results highlight the potential usage of integrated analyses for unveiling the novel pathogenesis mechanism and emphasized the significance of B cells in the etiology of smoking-induced disease.

Currents in contemporary ethics. Should health care providers get treatment priority in an influenza pandemic?

The 2009 pandemic of influenza A (H1N1) was relatively mild, but a subsequent outbreak of pandemic influenza could be much worse. According to projections from the Department of Health and Human Services, the potential health consequences of a severe (1918-like) influenza pandemic in the United States could be literally overwhelming: up to 1.9 million deaths; 90 million people sick; 45 million people needing outpatient care; 9.9 million people hospitalized, of whom 1.485 million would need treatment in an intensive care unit (ICU); and 742,500 patients needing mechanical ventilators. Even a less cataclysmic, moderate pandemic (like 1958 or 1968) would result in 209,000 deaths; 90 million people sick; 45 million people needing outpatient care; 865,000 people hospitalized, of whom 128,750 would need treatment in an ICU; and 64,875 patients needing mechanical ventilators.

A Two-Latent-Class Model for Smoking Cessation Data with Informative Dropouts

Non ignorable missing data is a common problem in longitudinal studies. Latent class models are attractive for simplifying the modeling of missing data when the data are subject to either a monotone or intermittent missing data pattern. In our study, we propose a new two-latent-class model for categorical data with informative dropouts, dividing the observed data into two latent classes; one class in which the outcomes are deterministic and a second one in which the outcomes can be modeled using logistic regression. In the model, the latent classes connect the longitudinal responses and the missingness process under the assumption of conditional independence. Parameters are estimated by the method of maximum likelihood estimation based on the above assumptions and the tetrachoric correlation between responses within the same subject. We compare the proposed method with the shared parameter model and the weighted GEE model using the areas under the ROC curves in the simulations and the application to the smoking cessation data set. The simulation results indicate that the proposed two-latent-class model performs well under different missing procedures. The application results show that our proposed method is better than the shared parameter model and the weighted GEE model.

Nicotine enhances skin necrosis and expression of inflammatory mediators in a rat pressure ulcer model

BACKGROUND

Many bedridden patients develop pressure ulcers, not only in hospital but also at home. Clinical studies have indicated cigarette smoking to be a risk factor for pressure ulcers. However, the contribution of nicotine to pressure ulcer formation has not been identified.

OBJECTIVES

We aimed to clarify the effect of nicotine on pressure ulcer formation, and its mechanism.

METHODS

Ischaemia-reperfusion (I/R) was performed in rat dorsal skin to induce pressure ulcers. The extent of the resulting necrotic area was determined. To clarify the mechanism of the effect of nicotine, mRNA levels of cyclooxygenase-2 (COX-2), interleukin (IL)-1beta, IL-6 and inducible nitric oxide synthase (iNOS) and protein expression of COX-2 and iNOS in the necrotic area were investigated by real-time reverse transcription-polymerase chain reaction and Western blotting, respectively. Furthermore, the effects of the COX-2 inhibitor NS-398 and the iNOS inhibitor aminoguanidine on necrosis were examined.

RESULTS

Skin necrosis in the I/R-treated area was significantly increased by intraperitoneal administration of nicotine (0.175 mg kg(-1) daily). Repeated nicotine administration had little effect on systolic and diastolic blood pressure. I/R treatment increased mRNA levels of COX-2, IL-1beta, IL-6 and iNOS, which were further augmented by nicotine in a dose-dependent manner. Correspondingly, nicotine (0.35 mg kg(-1) daily) markedly enhanced the protein expression of COX-2 and iNOS. Moreover, NS-398 and aminoguanidine showed a tendency to abrogate the increase of I/R-induced skin necrosis caused by nicotine.

CONCLUSIONS

These results suggest that the increased risk of pressure ulcers due to cigarette smoking is mediated, in part, by nicotine. They also indicated that the effect of nicotine is not mediated by a change in blood pressure, but is elicited via an increase of inflammatory mediators in the I/R-treated skin.

Genome-wide linkage of cotinine pharmacokinetics suggests candidate regions on chromosomes 9 and 11

Characterizing cotinine pharmacokinetics is a useful way to study nicotine metabolism because the same liver enzyme is primarily responsible for the metabolism of both, and the clearances of nicotine and cotinine are highly correlated. We conducted a whole-genome linkage analysis to search for candidate regions influencing quantitative variation in cotinine pharmacokinetics in a large-scale pharmacokinetic study with 61 families containing 224 healthy adult participants. The strongest linkage signal was identified at 135 cM of chromosome 9 with LOD = 2.81 and P = 0.0002; two other suggestive linkage peaks appear at 31.4 and 73.5 cM of chromosome 11 with LOD = 1.96 (P = 0.0013) and 1.94 (P = 0.0014). The confidence level of the linkage between the three genome regions and cotinine pharmacokinetics is statistically significant with a genome-wide empirical probability of P = 0.029.

Genome-wide and candidate gene association study of cigarette smoking behaviors

The contribution of common genetic variation to one or more established smoking behaviors was investigated in a joint analysis of two genome wide association studies (GWAS) performed as part of the Cancer Genetic Markers of Susceptibility (CGEMS) project in 2,329 men from the Prostate, Lung, Colon and Ovarian (PLCO) Trial, and 2,282 women from the Nurses' Health Study (NHS). We analyzed seven measures of smoking behavior, four continuous (cigarettes per day [CPD], age at initiation of smoking, duration of smoking, and pack years), and three binary (ever versus never smoking, < or = 10 versus > 10 cigarettes per day [CPDBI], and current versus former smoking). Association testing for each single nucleotide polymorphism (SNP) was conducted by study and adjusted for age, cohabitation/marital status, education, site, and principal components of population substructure. None of the SNPs achieved genome-wide significance (p<10(-7)) in any combined analysis pooling evidence for association across the two studies; we observed between two and seven SNPs with p<10(-5) for each of the seven measures. In the chr15q25.1 region spanning the nicotinic receptors CHRNA3 and CHRNA5, we identified multiple SNPs associated with CPD (p<10(-3)), including rs1051730, which has been associated with nicotine dependence, smoking intensity and lung cancer risk. In parallel, we selected 11,199 SNPs drawn from 359 a priori candidate genes and performed individual-gene and gene-group analyses. After adjusting for multiple tests conducted within each gene, we identified between two and five genes associated with each measure of smoking behavior. Besides CHRNA3 and CHRNA5, MAOA was associated with CPDBI (gene-level p<5.4x10(-5)), our analysis provides independent replication of the association between the chr15q25.1 region and smoking intensity and data for multiple other loci associated with smoking behavior that merit further follow-up.

Work-place social capital and smoking cessation: the Finnish Public Sector Study

AIMS

To examine whether high social capital at work is associated with an increased likelihood of smoking cessation in baseline smokers.

DESIGN

Prospective cohort study.

SETTING

Finland.

PARTICIPANTS

A total of 4853 employees who reported to be smokers in the baseline survey in 2000-2002 (response rate 68%) and responded to a follow-up survey on smoking status in 2004-2005 (response rate 77%).

MEASUREMENTS

Work-place social capital was assessed using a validated and psychometrically tested eight-item measure. Control variables included sex, age, socio-economic position, marital status, place of work, heavy drinking, physical activity, body mass index and physician-diagnosed depression.

FINDINGS

In multi-level logistic regression models adjusted for all the covariates, the odds for being a non-smoker at follow-up were 1.26 [95% confidence interval (CI)=1.03-1.55] times higher for baseline smokers who reported high individual-level social capital than for their counterparts with low social capital. In an analysis stratified by socio-economic position, a significant association between individual-level social capital and smoking cessation was observed in the high socio-economic group [odds ratio (OR) (95% CI)=1.63 (1.01-2.63)], but not in intermediate [(OR=1.10 (0.83-1.47)] or low socio-economic groups [(OR=1.28 (0.86-1.91)]. Work unit-level social capital was not associated with smoking cessation.

CONCLUSIONS

If the observed associations are causal, these findings suggest that high perceived social capital at work may facilitate smoking cessation among smokers in higher-status jobs.

Comparison of cigarette and water-pipe smoking by Arab and non-Arab-American youth

BACKGROUND

Water-pipe smoking is a rapidly growing form of tobacco use worldwide. Building on an earlier report of experimentation with cigarette and water-pipe smoking in a U.S. community sample of Arab-American youth aged 14-18 years, this article examines water-pipe smoking in more detail (e.g., smoking history, belief in harmfulness compared to cigarettes, family members in home who smoke water pipes) and compares the water-pipe-smoking behaviors of Arab-American youth with non-Arab-American youth in the same community.

METHODS

A convenience sample of 1872 Arab-American and non-Arab-American high school students from the Midwest completed a 24-item tobacco survey. Data were collected in 2004-2005 and analyzed in 2007-2008.

RESULTS

Arab-American youth reported lower percentages of ever cigarette smoking (20% vs 39%); current cigarette smoking (7% vs 22%); and regular cigarette smoking (3% vs 15%) than non-Arab-American youth. In contrast, Arab-American youth reported significantly higher percentages of ever water-pipe smoking (38% vs 21%) and current water-pipe smoking (17% vs 11%) than non-Arab-American youth. Seventy-seven percent perceived water-pipe smoking to be as harmful as or more harmful than cigarette smoking. Logistic regression showed that youth were 11.0 times more likely to be currently smoking cigarettes if they currently smoked water pipes. Youth were also 11.0 times more likely to be current water-pipe smokers if they currently smoked cigarettes. If one or more family members smoked water pipes in the home, youth were 6.3 times more likely to be current water-pipe smokers. The effects of ethnicity were reduced as a result of the explanatory value of family smoking.

CONCLUSIONS

Further research is needed to determine the percentages, patterns, and health risks of water-pipe smoking and its relationship to cigarette smoking among all youth. Additionally, youth tobacco prevention/cessation programs need to focus attention on water-pipe smoking in order to further dispel the myth that water-pipe smoking is a safe alternative to cigarette smoking.

Factors related to smoking in college women

Cigarette smoking among American women attending college has increased dramatically since the 1980's. To develop effective smoking prevention and cessation programs, a better understanding of factors associated with smoking in college women is needed. Therefore, the purpose of this study was to examine if selected factors (stress, stress management, nutrition, physical activity, alcohol consumption, and race) were related to smoking in college women. A sample of 354 college women in a southeastern state, 18-22 years of age, participated in the study. Logistic regression analysis indicated that White race (p = < .001), alcohol consumption (p = .0013), and limited physical activity (p = .0078) were significantly associated with smoking. Physically active college women were 2 times less likely to be smokers. However, physical activity mediated the effect of stress and stress management on smoking. Additionally, stress management confounded the effect of stress on smoking. Therefore, in addition to alcohol avoidance, exercise (as a stress management strategy) may be an important component of primary prevention and smoking cessation programs for college women.