CRISPR-Cas13b-mediated suppression of hepatitis B virus replication and protein expression.

BACKGROUND & AIMS: New antiviral approaches are urgently required that target multiple aspects of the hepatitis B virus (HBV) replication cycle to improve rates of functional cure. HBV RNA represents a novel therapeutic target. Here, we programmed Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-Cas13b endonuclease, to specifically target the HBV pregenomic RNA (pgRNA) and viral mRNAs in a novel approach to reduce HBV replication and protein expression. METHODS: Cas13b CRISPR RNAs (crRNAs) were designed to target multiple regions of HBV pgRNA. Mammalian cells with replication competent wildtype HBV DNA of different genotypes, a HBV stable cell line, a HBV infection model and a hepatitis B surface antigen (HBsAg)-expressing stable cell line were transfected with PspCas13b-blue fluorescent protein (BFP) and crRNAs plasmids and the impact on HBV replication and protein expression was measured. WT HBV DNA, PspCas13b-BFP and crRNA plasmids were simultaneously hydrodynamically injected into mice, and sera HBsAg was measured. PspCas13b mRNA and crRNA were also delivered by lipid nanoparticles (LNP) in a HBsAg-expressing stable cell line and the impact on secreted HBsAg determined. RESULTS: Our HBV targeting crRNAs strongly suppressed HBV replication and protein expression in mammalian cells by up to 96% (p<0.0001). HBV protein expression was also reduced in an HBV stable cell line and in the HBV infection model. CRISPR-Cas13b crRNAs reduced HBsAg expression by 50% (p<0.0001) in vivo. LNP-encapsulated PspCas13b mRNA reduced secreted HBsAg by 87% (p=0.0168) in a HBsAg-expressing stable cell line. CONCLUSIONS: Together, these results show that CRISPR-Cas13b can be programmed to specifically target and degrade HBV RNAs to reduce HBV replication and protein expression, demonstrating its potential as a novel therapeutic option for chronic HBV infection. IMPACT AND IMPLICATIONS: There is an urgent need for new treatments that target multiple aspects of the HBV replication cycle. Here, we present CRISPR-Cas13b as a novel strategy to target HBV replication and protein expression paving the way for its development as a potential new treatment option for patients living with chronic hepatitis B.

Interim results from a phase I randomized, placebo-controlled trial of novel SARS-CoV-2 beta variant receptor-binding domain recombinant protein and mRNA vaccines as a 4th dose booster.

BACKGROUND: SARS-CoV-2 booster vaccination should ideally enhance protection against variants and minimise immune imprinting. This Phase I trial evaluated two vaccines targeting SARS-CoV-2 beta-variant receptor-binding domain (RBD): a recombinant dimeric RBD-human IgG1 Fc-fusion protein, and an mRNA encoding a membrane-anchored RBD. METHODS: 76 healthy adults aged 18-64 y, previously triple vaccinated with licensed SARS-CoV-2 vaccines, were randomised to receive a 4th dose of either an adjuvanted (MF59®, CSL Seqirus) protein vaccine (5, 15 or 45 µg, N = 32), mRNA vaccine (10, 20, or 50 µg, N = 32), or placebo (saline, N = 12) at least 90 days after a 3rd boost vaccination or SARS-CoV-2 infection. Bleeds occurred on days 1 (prior to vaccination), 8, and 29. CLINICALTRIALS: govNCT05272605. FINDINGS: No vaccine-related serious or medically-attended adverse events occurred. The protein vaccine reactogenicity was mild, whereas the mRNA vaccine was moderately reactogenic at higher dose levels. Best anti-RBD antibody responses resulted from the higher doses of each vaccine. A similar pattern was seen with live virus neutralisation and surrogate, and pseudovirus neutralisation assays. Breadth of immune response was demonstrated against BA.5 and more recent omicron subvariants (XBB, XBB.1.5 and BQ.1.1). Binding antibody titres for both vaccines were comparable to those of a licensed bivalent mRNA vaccine. Both vaccines enhanced CD4+ and CD8+ T cell activation. INTERPRETATION: There were no safety concerns and the reactogenicity profile was mild and similar to licensed SARS-CoV-2 vaccines. Both vaccines showed strong immune boosting against beta, ancestral and omicron strains. FUNDING: Australian Government Medical Research Future Fund, and philanthropies Jack Ma Foundation and IFM investors.

Perceptions of electronic cigarettes among ethno-culturally diverse Latino adults in four US urban centers.

OBJECTIVE: The aim of this study was to examine perceptions including knowledge, attitudes, and beliefs about e-cigarettes among ethno-culturally diverse Latino adults living in the US, a rapidly growing minority group for which we know little about their e-cigarette perceptions. DESIGN: A total of 25 focus groups with Latinos (n = 180; ages 18-64 years) were conducted in 2014. E-cigarettes users and non-users were recruited via purposive sampling techniques. Participants completed brief questionnaires on sociodemographic factors and tobacco use. Focus group discussions were conducted in English and Spanish, audio-recorded, and transcribed. Data were analyzed using thematic analysis procedures. RESULTS: Participants were of diverse Latino backgrounds. Over one-third (35%) reported current cigarette smoking and 8% reported current e-cigarette or hookah use. Nonsmokers reported experimenting with e-cigarettes and hookah during social occasions. Participants' perceptions towards e-cigarettes were generally formed in comparison to conventional cigarettes. Perceived benefits of using e-cigarettes included their utility as a smoking cessation aid, higher social acceptability, and lower harm compared to conventional cigarettes. Negative perceptions of e-cigarettes included lower overall satisfaction compared to conventional cigarettes and high content of toxins. Socio-cultural factors (e.g. gender roles, familismo, and simpatía) also influenced perceptions of e-cigarette of study participants. CONCLUSIONS: Overall, Latino adults knew relatively little about the potential health risks associated with e-cigarette use. The limited knowledge about and misinformation of e-cigarettes among this rapidly growing minority group have important public health implications. Findings may inform culturally tailored health communication campaigns, which are much needed among underserved US Latino populations in light of low effectiveness of tobacco control and regulatory efforts.

The Influence of Friends on Teen Vaping: A Mixed-Methods Approach.

Vaping is popular among adolescents. Previous research has explored sources of information and influence on youth vaping, including marketing, ads, family, peers, social media, and the internet. This research endeavors to expand understanding of peer influence. Our hypothesis is that friends' influence on teen vapers' first electronic nicotine delivery systems (ENDS) use varies by demographic variables and awareness of ENDS advertising. In August-October 2017, youth (n = 3174) aged 13-18 completed an online survey to quantify ENDS behaviors and attitudes and were invited to participate in follow-up online research in November-December 2017 to probe qualitative context around perceptions and motivations (n = 76). This analysis focused on the ENDS users, defined as having ever tried any ENDS product, from the survey (n = 1549) and the follow-up research (n = 39). Among survey respondents, friends were the most common source of vapers' first ENDS product (60%). Most survey respondents tried their first ENDS product while "hanging out with friends" (54%). Among follow-up research participants, the theme of socializing was also prominent. ENDS advertising and marketing through social media had a strong association with friend networks; in fact, the odds of friends as source of the first vaping experience were 2 times higher for those who had seen ENDS ads on social media compared with other types of media. The influence of friends is particularly evident among non-Hispanic Whites, Hispanics/Latinos, those living in urban areas, those living in high-income households, those with higher self-esteem, and those who experiment with vaping. These findings support the premise that peer influence is a primary social influencer and reinforcer for vaping. Being included in a popular activity appears to be a strong driving force.

Tobacco Use Prevalence and Transitions From 2013 to 2018 Among Adults With a History of Cardiovascular Disease.

Background Although tobacco product use and transitions have been characterized in the general population, few studies have focused on individuals with established cardiovascular disease (CVD) in a population-based sample. Methods and Results We examined tobacco use prevalence and longitudinal patterns of tobacco product transitions in adults (≥18 years) of the nationally representative PATH (Population Assessment of Tobacco and Health) study, from 2013 to 2014 (Wave 1) through 2016 to 2018 (Wave 4). Prevalent CVD was classified through self-report of having had a heart attack, heart failure, stroke, or other heart condition. Factors associated with tobacco product use and transitions were investigated using survey logistic regression. We examined 2615 participants with self-reported CVD at Wave 1. Overall, 28.9% reported current tobacco use, equating to ≈6.2 million adults in the United States with prevalent CVD and current tobacco use. Among adults with CVD who are current tobacco users, the most commonly used product was cigarettes (82.8%), followed by any type of cigar (23.7%), and e-cigarette use (23.3%). E-cigarette use without concurrent cigarette use among participants with prevalent CVD was uncommon (1.1%). Factors associated with tobacco use were younger age, male sex, had lower education level, and lack of knowledge about the association between smoking and CVD. Men with prevalent CVD were less likely to use e-cigarettes compared with women (odds ratio [OR], 0.7; 95% CI, 0.5-0.9). Among cigarette users with CVD, transition rates between Waves 1 and 4 demonstrated <5% decrease in cigarette, with a 0.5% increase in e-cigarette use. Only ≈10% were in formal tobacco cessation programs. Conclusions Despite known harmful cardiovascular effects, over one fourth of adults with prevalent CVD use tobacco products and few quit smoking over the 4 waves of the PATH data set.

Association between electronic nicotine delivery systems (ENDS) device and E-liquid alterations and flavor use with clinical and EVALI-like symptoms.

Studies reporting clinical symptoms related to electronic nicotine delivery systems (ENDS) usage, especially types of devices and e-liquids, are sparse. The sample included 1,432 current ENDS users, ages 18-64, from a nationwide online survey conducted in 2016. ENDS use included device types, nicotine content, flavors, and e-liquid used. Outcomes included any e-cigarette, or vaping, product use-associated lung injury (EVALI)-like symptoms (e.g., cough, shortness of breath, nausea) as well as any clinical symptoms. Of the sample, 50% were female, 23% non-Hispanic (NH) White, 23% NH Black, 54% Hispanic, 18% aged 18-24, 17% LGBTQ, 41% with <$50 K income, 55% 1 + any symptoms, and 33% 1 + any EVALI-like symptoms. Cough and nausea were most prevalent among EVALI-like symptoms (27% and 7.3%, respectively). The proportion having any EVALI-like symptoms was higher in the following groups: younger, Hispanic, current smokers, and current other product users. With multiple adjustments, participants who used refillable devices, varied nicotine content, used flavored products, or made their own e-liquids were more likely to have clinical symptoms than their counterparts. For example, the odds (95% CI) of having 1 + EVALI-like symptoms in participants who used refillable devices with e-liquid pour or e-liquid cartridge replacement were 1.70 (1.13, 2.56) and 1.95 (1.27, 2.99), respectively, compared to the non-refillable group. Use of products (devices and e-liquids) that can be altered and flavored products are associated with higher odds of having clinical symptoms, including EVALI-like symptoms.

Gene-based association analysis reveals involvement of LAMA5 and cell adhesion pathways in nicotine dependence in African- and European-American samples.

Nicotine dependence (ND) is a chronic brain disorder that causes heavy social and economic burdens. Although many susceptibility genetic loci have been reported, they can explain only approximately 5%-10% of the genetic variance for the disease. To further explore the genetic etiology of ND, we genotyped 242 764 SNPs using an exome chip from both European-American (N = 1572) and African-American (N = 3371) samples. Gene-based association analysis revealed 29 genes associated significantly with ND. Of the genes in the AA sample, six (i.e., PKD1L2, LAMA5, MUC16, MROH5, ATP8B1, and FREM1) were replicated in the EA sample with p values ranging from 0.0031 to 0.0346. Subsequently, gene enrichment analysis revealed that cell adhesion-related pathways were significantly associated with ND in both the AA and EA samples. Considering that LAMA5 is the most significant gene in cell adhesion-related pathways, we did in vitro functional analysis of this gene, which showed that nicotine significantly suppressed its mRNA expression in HEK293T cells (p < 0.001). Further, our cell migration experiment showed that the migration rate was significantly different in wild-type and LAMA5-knockout (LAMA5-KO)-HEK293T cells. Importantly, nicotine-induced cell migration was abolished in LAMA5-KO cells. Taken together, these findings indicate that LAMA5, as well as cell adhesion-related pathways, play an important role in the etiology of smoking addiction, which warrants further investigation.

Determination of shared genetic etiology and possible causal relations between tobacco smoking and depression.

BACKGROUNDS: Cigarette smoking is strongly associated with major depressive disorder (MDD). However, any genetic etiology of such comorbidity and causal relations is poorly understood, especially at the genome-wide level. METHODS: In the present in silico research, we analyzed summary data from the genome-wide association study of the Psychiatric Genetic Consortium for MDD (n = 191 005) and UK Biobank for smoking (n = 337 030) by using various biostatistical methods including Bayesian colocalization analysis, LD score regression, variant effect size correlation analysis, and Mendelian randomization (MR). RESULTS: By adopting a gene prioritization approach, we identified 43 genes shared by MDD and smoking, which were significantly enriched in membrane potential, gamma-aminobutyric acid receptor activity, and retrograde endocannabinoid signaling pathways, indicating that the comorbid mechanisms are involved in the neurotransmitter system. According to linkage disequilibrium score regression, we found a strong positive correlation between MDD and current smoking (rg = 0.365; p = 7.23 × 10-25) and a negative correlation between MDD and former smoking (rg = -0.298; p = 1.59 × 10-24). MR analysis suggested that genetic liability for depression increased smoking. CONCLUSIONS: These findings inform the concomitant conditions of MDD and smoking and support the use of self-medication with smoking to counteract depression.

Associations between tobacco use patterns and demographic characteristics of sexual minority and heterosexual youth: Results from a nationwide online survey.

INTRODUCTION: Youth are at risk for tobacco use, and previous research has pointed to increased vulnerabilities associated with sexual minority identity. For example, LGB youth have increased odds for using tobacco than their heterosexual peers, and bisexual youth have higher odds of smoking than other sexual identity groups. As new tobacco products proliferate and health risks from dual/poly use grow, increased understanding of tobacco use patterns by sexual minority youth is needed. METHODS: For 3117 youth, aged 13-18 years, who completed an online questionnaire in 2017 and identified their sexual orientation [minority (e.g. lesbian/gay, bisexual, or pansexual) vs majority (heterosexual)] and gender, we classified current tobacco use into four categories: e-cigarette only, other product only (such as cigarette, cigar, or smokeless tobacco; not an e-cigarette), dual/poly use, and no use. Analyses were conducted separately for male and female participants. Multinomial logistic regression was employed. RESULTS: Female sexual minority youth had nearly twofold odds of dual/ poly tobacco use (OR=1.95; 95% CI: 1.12-3.40), compared to their heterosexual counterparts. For male youth, sexual minority identification was not significantly associated with dual/poly use. No significant differences were found in sexual minority and heterosexual youth e-cigarette only or other tobacco only use groups. Tobacco use patterns also significantly differed by age, race, place of residence, and parental education level. CONCLUSIONS: Study findings reveal greater odds of dual/poly tobacco use for female sexual minority youth. Tailored tobacco prevention and cessation programs or interventions are needed for sexual minority youth most at risk of tobacco use, especially multiple product use.

Relationship between population characteristics, e-cigarette and tobacco-related perceptions, and likelihood of ever using e-cigarettes.

INTRODUCTION: Electronic nicotine delivery systems (ENDS) are a relatively new type of nicotine-containing product that has risen greatly in use within the past decade, displacing conventional tobacco products as the dominant source of nicotine exposure by many groups. Among those impacted are large sections of US youth. Though health outcomes associated with ENDS use are still being assessed, several potential harms have been noted in the extant literature. The purpose of this study is to examine which US youth subpopulations are at greatest risk for ENDS ever use and how perceptions pertaining to nicotine-containing products relate to this risk. METHODS: A nationwide online survey was administered to US youth ENDS users and non-users aged 13-18 years. A total weighted sample of 2501 participants was obtained. Statistical analyses included binomial logistic regression and a likelihood ratio test. RESULTS: Of these youth, 1346 (53.8%) reported having ever used an ENDS product. Those most likely to have used ENDS were White males in their late teens. Those who reported ever using a conventional tobacco product were much more likely to have reported ever using ENDS (AOR= 19.96; 95% CI: 15.30-26.05). A number of perceptions related to nicotine-containing products, including product safety and health effects, were significantly associated with an increased likelihood of ENDS use. CONCLUSIONS: Certain sections of the US youth population have elevated odds of being ENDS ever users. As increasing evidence supports the need to combat ENDS use by youth, effectively targeted education and prevention campaigns will be necessary.

Prediction of Smoking Behavior From Single Nucleotide Polymorphisms With Machine Learning Approaches.

Smoking is a complex behavior with a heritability as high as 50%. Given such a large genetic contribution, it provides an opportunity to prevent those individuals who are susceptible to smoking dependence from ever starting to smoke by predicting their inherited predisposition with their genomic profiles. Although previous studies have identified many susceptibility variants for smoking, they have limited power to predict smoking behavior. We applied the support vector machine (SVM) and random forest (RF) methods to build prediction models for smoking behavior. We first used 1,431 smokers and 1,503 non-smokers of African origin for model building with a 10-fold cross-validation and then tested the prediction models on an independent dataset consisting of 213 smokers and 224 non-smokers. The SVM model with 500 top single nucleotide polymorphisms (SNPs) selected using logistic regression (p<0.01) as the feature selection method achieved an area under the curve (AUC) of 0.691, 0.721, and 0.720 for the training, test, and independent test samples, respectively. The RF model with 500 top SNPs selected using logistic regression (p<0.01) achieved AUCs of 0.671, 0.665, and 0.667 for the training, test, and independent test samples, respectively. Finally, we used the combined logistic (p<0.01) and LASSO (λ=10-3) regression to select features and the SVM algorithm for model building. The SVM model with 500 top SNPs achieved AUCs of 0.756, 0.776, and 0.897 for the training, test, and independent test samples, respectively. We conclude that machine learning methods are promising means to build predictive models for smoking.

Genome-wide DNA methylation analysis reveals significant impact of long-term ambient air pollution exposure on biological functions related to mitochondria and immune response.

Exposure to long-term ambient air pollution is believed to have adverse effects on human health. However, the mechanisms underlying these impacts are poorly understood. DNA methylation, a crucial epigenetic modification, is susceptible to environmental factors and likely involved in these processes. We conducted a whole-genome bisulfite sequencing study on 120 participants from a highly polluted region (HPR) and a less polluted region (LPR) in China, where the HPR had much higher concentrations of five air pollutants (PM2.5, PM10, SO2, NO2, and CO) (fold difference 1.6 to 6.6 times; P value 1.80E-07 to 3.19E-23). Genome-wide methylation analysis revealed 371 DMRs in subjects from the two areas and these DMRs were located primarily in gene regulatory elements such as promoters and enhancers. Gene enrichment analysis showed that DMR-related genes were significantly enriched in diseases related to pulmonary disorders and cancers and in biological processes related to mitochondrial assembly and cytokine production. Further, HPR participants showed a higher mtDNA copy number. Of those identified DMRs, 15 were significantly correlated with mtDNA copy number. Finally, cytokine assay indicated that an increased plasma interleukin-5 level was associated with greater air pollution. Taken together, our findings suggest that exposure to long-term ambient air pollution can lead to alterations in DNA methylation whose functions relate to mitochondria and immune responses.

Correlates of youth vaping flavor preferences.

Among youth who use electronic nicotine delivery systems (ENDS), e-cigarettes are often the first tobacco product tried. Flavor is a common reason for experimentation with e-cigarettes. This study assessed flavor preferences and the choice of ENDS as an initial product among youth by selected demographic characteristics. The analysis sample included 1549 participants who had ever tried ENDS, drawn from a national online survey of youth aged 13-18 in 2017. Fruit was the most common favorite flavor among ENDS users, followed by menthol/mint/wintergreen. Preference for flavor varied by age, sex and racial/ethnic background. ENDS were the tobacco products most likely to be tried first, particularly among participants under age 17. Those who preferred fruit flavor were twice as likely to have tried ENDS first, compared to those with other flavor preferences, while those who preferred menthol/mint/wintergreen flavor were half as likely to have tried ENDS first. Our findings support an association between flavor and ENDS use. Our research supports previous findings indicating that: 1) flavor is one of the primary reasons for experimentation with ENDS among youth; 2) fruit flavor is strongly associated with use of ENDS as the first tobacco product; and 3) preference of fruit flavor varies by age, sex and racial/ethnic background. These findings have relevance for developing targeted messages for specific youth audiences and implications for tobacco regulatory policies. In addition to January 2020 federal regulations, the authors recommend tighter restrictions, specifically that the marketing and sale of all e-cigarette flavors other than tobacco be eliminated.

Identification of 34 genes conferring genetic and pharmacological risk for the comorbidity of schizophrenia and smoking behaviors.

The prevalence of smoking is significantly higher in persons with schizophrenia (SCZ) than in the general population. However, the biological mechanisms of the comorbidity of smoking and SCZ are largely unknown. This study aimed to reveal shared biological pathways for the two diseases by analyzing data from two genome-wide association studies with a total sample size of 153,898. With pathway-based analysis, we first discovered 18 significantly enriched pathways shared by SCZ and smoking, which were classified into five groups: postsynaptic density, cadherin binding, dendritic spine, long-term depression, and axon guidance. Then, by using an integrative analysis of genetic, epigenetic, and expression data, we found not only 34 critical genes (e.g., PRKCZ, ARHGEF3, and CDKN1A) but also various risk-associated SNPs in these genes, which convey susceptibility to the comorbidity of the two disorders. Finally, using both in vivo and in vitro data, we demonstrated that the expression profiles of the 34 genes were significantly altered by multiple psychotropic drugs. Together, this multi-omics study not only reveals target genes for new drugs to treat SCZ but also reveals new insights into the shared genetic vulnerabilities of SCZ and smoking behaviors.

Socioeconomic and Demographic Status and Perceived Health Risks of E-Cigarette Product Contents Among Youth: Results From a National Survey.

Background. The prevalence of e-cigarette use among youth is rising and may be associated with perceptions of health risks for these products. We examined how demographic factors and socioeconomic status (SES) are correlated with the perceived health risks of e-cigarette product contents among youth. Method. Data were from a national online survey of youth aged 13 to 18 between August and October 2017, weighted to be representative of the overall U.S. population in age, sex, race/ethnicity, and region. Survey analysis procedures were used. Results. Of 1,549 e-cigarette users and 1,451 never-e-cigarette users, 20.9% were Hispanic, 13.7% Black, 21.7% LGBTQ (lesbian/gay/bisexual/transgender/queer), and 49.3% in low-income families. With adjustment for e-cigarette use status, perceived health risks of nicotine and toxins/chemicals in e-cigarettes significantly differed by gender, race, sexual orientation, and SES (ps < .05). For example, adjusted odds of perceiving harm from nicotine were 60% higher in girls versus boys, 34% lower in non-Hispanic Blacks versus non-Hispanic Whites, 33% lower in urban versus suburban residents, 40% higher in LGBTQ versus straight-identifying individuals, and 28% lower in low-income versus high-income families. Lower parental education level also was associated with children's lower health risk perception of e-cigarette product contents. Conclusions. For youth, the perceived health risks of e-cigarette product contents were associated with demographics, sexual orientation, and SES. The findings may have relevance for developing communication and education strategies addressing specific youth audiences, especially those in vulnerable groups. These strategies could improve awareness among youth concerning the health risks of e-cigarettes, helping to prevent or reduce e-cigarette uptake and continued use.

Tobacco perceptions and practices: User groups and demographic characteristics, Mississippi, USA.

INTRODUCTION: Despite decreases in the overall US smoking rate, tobacco use remains more common in some areas and by some groups. Deeper understanding of group differences is needed in order to tailor public health campaigns to the interests, perceptions and experiences of targeted audiences. Although some differences have been identified across African American and Caucasian smokers in the United States, additional insight is needed regarding factors that differentiate these groups. This study examined tobacco-related perceptions and practices, with an emphasis on identifying differences across African American and Caucasian smokers. Toward this goal, we examined key demographic variables of race and age, and tobacco use characteristics. METHODS: The sample consisted of 284 people from the Jackson, Mississippi area who participated in focus groups and completed surveys addressing a variety of tobacco-related topics, including knowledge and perceptions of products as well as use and health information seeking behavior. The selection criteria and recruitment approach ensured a balance across race (black, white), age (18-34, >35 years), sex, and cigarette smoking status (current, former, never). Statistical analyses were performed using SAS (v.9.4). RESULTS: Differences were observed across demographic subgroups regarding type and pattern of tobacco products used (e.g. mentholated, markers of nicotine dependence, hookah). Differences in preferred sources of health information based on age as well as perceptions of risk as a function of age, smoking status and race were also noted. Exposure to secondhand smoke and perceptions of its risks, quitting efforts and cessation methods differed by race. CONCLUSIONS: Study findings suggest key differences across important subgroups. Knowledge of such differences has the potential to improve strategic public health messaging, allowing health campaigns to more effectively prevent tobacco product uptake as well as promote interest in quitting tobacco.

Genetic and Epigenetic Analysis Revealing Variants in the NCAM1-TTC12-ANKK1-DRD2 Cluster Associated Significantly With Nicotine Dependence in Chinese Han Smokers.

BACKGROUNDS: Although studies have demonstrated that the NCAM1-TTC12-ANKK1-DRD2 gene cluster plays essential roles in addictions in subjects of European and African origin, study of Chinese Han subjects is limited. Further, the underlying biological mechanisms of detected associations are largely unknown. METHODS: Sixty-four single-nucleotide polymorphisms (SNPs) in this cluster were analyzed for association with Fagerstrom Test for Nicotine Dependence score (FTND) and cigarettes per day (CPD) in male Chinese Han smokers (N = 2616). Next-generation bisulfite sequencing was used to discover smoking-associated differentially methylated regions (DMRs). Both cis-eQTL and cis-mQTL analyses were applied to assess the cis-regulatory effects of these risk SNPs. RESULTS: Association analysis revealed that rs4648317 was significantly associated with FTND and CPD (p = .00018; p = .00072). Moreover, 14 additional SNPs were marginally significantly associated with FTND or CPD (p = .05-.01). Haplotype-based association analysis showed that one haplotype in DRD2, C-T-A-G, formed by rs4245148, rs4581480, rs4648317, and rs11214613, was significantly associated with CPD (p = .0005) and marginally associated with FTND (p = .003). Further, we identified four significant smoking-associated DMRs, three of which are located in the DRD2/ANKK1 region (p = .0012-.00005). Finally, we found five significant CpG-SNP pairs (p = 7.9 × 10-9-6.6 × 10-6) formed by risk SNPs rs4648317, rs11604671, and rs2734849 and three methylation loci. CONCLUSIONS: We found two missense variants (rs11604671; rs2734849) and an intronic variant (rs4648317) with significant effects on ND and further explored their mechanisms of action through expression and methylation analysis. We found the majority of smoking-related DMRs are located in the ANKK1/DRD2 region, indicating a likely causative relation between non-synonymous SNPs and DMRs. IMPLICATIONS: This study shows that there exist significant association of variants and haplotypes in ANKK1/DRD2 region with ND in Chinese male smokers. Further, this study also shows that DNA methylation plays an important role in mediating such associations.

The role of flavors in vaping initiation and satisfaction among U.S. adults.

BACKGROUND: The prevalence of electronic cigarette use has grown over the past decade, with some users reportedly initiating e-cigarette use primarily due to flavors. This study examined the role of flavors in initiation among adult e-cigarette users, as well as the association of flavors with satisfaction and perceived addiction to vaping. METHODS: The analysis sample consisted of 1492 current e-cigarette users aged 18 or older, drawn from an online quantitative survey conducted in 2016. Multivariable logistic regression and general linear models were used. RESULTS: Most current e-cigarette users (62.9%) typically used flavors other than tobacco (including fruit, mint/menthol, sweet, candy, coffee and other), 24.2% typically used tobacco flavors, and 12.9% typically used non-flavored e-cigarettes. Flavor was a common reason for vaping initiation, selected by 29.5% of the sample. Flavor, particularly fruit flavor, was more likely to motivate young adults 18-24 to initiate vaping compared adults 35-44. Those who used flavors, particularly mint/menthol and flavors other than tobacco flavor, had higher odds of reporting high satisfaction with vaping and had higher odds of perceived addiction to vaping than respondents who did not use flavored e-cigarettes. CONCLUSIONS: Users of flavored e-cigarettes reported greater satisfaction and self-perceived addiction than users of non-flavored e-cigarettes. The appeal of flavors, particularly among young adults, has implications for regulatory policy regarding the marketing and promotion of flavored products. These findings may provide direction for the Food and Drug Administration's plans to restrict flavors other than menthol, mint, and tobacco.

Age differences in electronic nicotine delivery systems (ENDS) usage motivations and behaviors, perceived health benefit, and intention to quit.

INTRODUCTION: Data from comprehensive studies are sparse regarding age differences in issues related to electronic nicotine delivery systems (ENDS) usage. This study examined age differences in usage motivations and behaviors, perceived health benefit, and quit intentions in a large and diverse sample recruited online. METHODS: The sample included 1,432 current ENDS users, ages 18-64, drawn from a national online survey conducted in 2016. Descriptive and multivariable analyses were used. RESULTS: The sample included participants in the following age groups: 18-24 (17.5%), 25-34 (38.6%), 35-44 (23.3%), and 45-64 (20.7%). With multiple adjustments, the 18-24 age group was more likely to vape for reasons such as flavors or friends' use, and to use multiple flavors and products with varying nicotine content. For example, the odds (95% CI) of vaping initiation due to flavor attraction vs. other reasons in the 18-24 age group were 1.40 (1.02-1.92), 2.73 (1.85-3.99), and 2.12 (1.41-3.18) compared to the 25-34, 35-44, and 45-64 age groups, respectively. In contrast, compared to older age groups, the 18-24 age group was less likely to use ENDS as an alternative to cigarettes or as a quitting device; they also used ENDS less frequently and perceived less health benefit of ENDS use. The 18-24 age group, especially those who had only used ENDS, had the lowest odds of likely quitting use of tobacco/nicotine products compared to other groups (lower by 44-73%). CONCLUSION: There were significant age differences in ENDS usage motivations and behaviors, perceived health benefit, and quit intentions.