The temporal relationship between marriage and risk for suicidal ideation.

BACKGROUND: Marriage is consistently identified as a protective factor for suicidality, but it remains unclear whether this relationship varies by time elapsed since the transition to marriage. METHODS: Participants were 15,870 individuals (52 % female, mean age = 44.63 years, age range = 18-99 years) from the Collaborative Psychiatric Epidemiology Surveys. Cox proportional hazards models were used to test the relationship between marriage, as well as time elapsed since the transition to marriage (0-5 years, 6-10 years, or 11+ years), and suicidal ideation. Years of education and race and ethnicity were included as covariates, and analyses were stratified by sex. Separate hazard ratios were estimated for individuals aged <30 years and 30+ years to address violations of the proportionality assumption. RESULTS: Being married was associated with lower risk for suicidal ideation across age and sex. Among individuals aged <30 years, marriage was reliably associated with lower risk for suicidal ideation, regardless of the time elapsed since marriage. For individuals aged 30+ years, being married for 0-5 years or 6-10 years was associated with increased risk for suicidal ideation, particularly in females. Being married for 11+ years was associated with decreased risk across sex. LIMITATIONS: Analyses focused on participants' first marriage and did not examine mediators of the association between marriage and suicidal ideation. CONCLUSIONS: Overall, being married protects against suicidal ideation. However, among individuals aged 30 years or older, the first 10 years of marriage are associated with elevated risk for suicidal thoughts, and clinical outreach may be warranted.

A scoping review of smoking cessation pharmacogenetic studies to advance future research across racial, ethnic, and ancestral populations.

Abstinence rates among smokers attempting to quit remain low despite the wide availability and accessibility of pharmacological smoking cessation treatments. In addition, the prevalence of cessation attempts and abstinence differs by individual-level social factors such as race and ethnicity. Clinical treatment of nicotine dependence also continues to be challenged by individual-level variability in effectiveness to promote abstinence. The use of tailored smoking cessation strategies that incorporate information on individual-level social and genetic factors hold promise, although additional pharmacogenomic knowledge is still needed. In particular, genetic variants associated with pharmacological responses to smoking cessation treatment have generally been conducted in populations with participants that self-identify as White race or who are determined to be of European genetic ancestry. These results may not adequately capture the variability across all smokers as a result of understudied differences in allele frequencies across genetic ancestry populations. This suggests that much of the current pharmacogenetic study results for smoking cessation may not apply to all populations. Therefore, clinical application of pharmacogenetic results may exacerbate health inequities by racial and ethnic groups. This scoping review examines the extent to which racial, ethnic, and ancestral groups that experience differences in smoking rates and smoking cessation are represented in the existing body of published pharmacogenetic studies of smoking cessation. We will summarize results by race, ethnicity, and ancestry across pharmacological treatments and study designs. We will also explore current opportunities and challenges in conducting pharmacogenomic research on smoking cessation that encourages greater participant diversity, including practical barriers to clinical utilization of pharmacological smoking cessation treatment and clinical implementation of pharmacogenetic knowledge.

The Concept of Resistance to Substance Use and a Research Approach: The Resist! Project.

Illicit substance use is dangerous in both acute and chronic forms, frequently resulting in lethal poisoning, addiction, and other negative consequences. Similar to research in other psychiatric conditions, whose ultimate goal is to enable effective prevention and treatment, studies in substance use are focused on factors elevating the risk for the disorder. The rapid growth of the substance use problem despite the effort invested in fighting it, however, suggests the need in changing the research approach. Instead of attempting to identify risk factors, whose neutralization is often infeasible if not impossible, it may be more promising to systematically reverse the perspective to the factors enhancing the aspect of liability to disorder that shares the same dimension but is opposite to risk, that is, resistance to substance use. Resistance factors, which enable the majority of the population to remain unaffected despite the ubiquity of psychoactive substances, may be more amenable to translation. While the resistance aspect of liability is symmetric to risk, the resistance approach requires substantial changes in sampling (high-resistance rather than high-risk) and using quantitative indices of liability. This article provides an overview and a practical approach to research in resistance to substance use/addiction, currently implemented in a NIH-funded project. The project benefits from unique opportunities afforded by the data originating from two longitudinal twin studies, the Virginia Twin Study of Adolescent and Behavioral Development and the Minnesota Twin Family Study. The methodology described is also applicable to other psychiatric disorders.

Creating structural community cohesion: Addressing racial equity in older adult homelessness.

Older adults and racial minorities are overrepresented in homeless populations. Shelter and housing options for homeless older adults who have complex health and social needs are necessary, but not readily available. Older homeless adults that require, but do not receive, health-sensitive, age-sensitive, and racial equity housing, remain vulnerable to poor outcomes and premature mortality. Accordingly, this study examines the development of a coalition to better address older adult homelessness within a racial equity framework. A community coalition was established to better address older adult homelessness within the lens of age-sensitivity and racial equity, due to a disconnect between healthcare and senior housing placement programs, creating unaddressed multifaceted health issues/complications. The community coalition development is described, including the coalition process, activities, and outcomes. Local rehoused older adults are also interviewed and described to better understand their central life circumstances.

Understanding the preference for receiving mental health and substance use support in African Americans 50 and older.

OBJECTIVE: This study aims to determine whether current tobacco and/or alcohol use is associated with setting preferences for seeking support for substance use (SU) and mental health (MH) services to African Americans ages 50 and older. METHODS: Data from 368 African American individuals (aged 50+) who participated in a community-based needs assessment survey were used. Preferences included community-based (e.g., health centers) and traditional settings (e.g., doctor's office). SU was measured as a categorical variable detailing past-month use of conventional cigarettes and alcohol graded by risk levels. Logistic regression models tested the associations between SU and setting preference before and after adjusting for the influence of self-reported MH diagnoses. RESULTS: Prior to adjustment for the influence of MH outcomes, high-risk use of tobacco and alcohol in the past month was associated with a lower odds of preferring MH/SU support in traditional settings (OR = 0.23, 95% CI = 0.06-0.85) compared to participants engaged in no-/low- risk substance use. This association was no longer significant after accounting for the influence of mental health symptoms and covariates. DISCUSSION: These results provide preliminary evidence that mental health outcomes mediate the association between substance use and setting preference for seeking MH/SU support in traditional settings. TRANSLATIONAL SIGNIFICANCE: This exploratory study encourages additional investigation of the association between substance use, setting preferences, and the likelihood of seeking treatment in community health centers using larger sample sizes. Additional opportunities to offer mental health/substance use support to African American older adults within clinical settings should be explored.

Examining interactions between polygenic scores and interpersonal trauma exposure on alcohol consumption and use disorder in an ancestrally diverse college cohort.

Introduction: Genetic factors impact alcohol consumption and use disorder (AUD), with large-scale genome-wide association studies (GWAS) identifying numerous associated variants. Aggregate genetic methods in combination with important environmental factors (e.g., interpersonal trauma [IPT]) can be applied to expand our understanding of the ways by which genetic and environmental variables work together to influence alcohol consumption and disordered use. The present study aimed to detail the relationships between genome-wide polygenic scores (PGS) for alcohol phenotypes (i.e., alcohol consumption and AUD status) and IPT exposure as well as the interaction between them across ancestry. Methods: Data were drawn from the Spit for Science (S4S) study, a US college student population, where participants reported on IPT exposure prior to college and alcohol consumption and problems during college (N = 9,006; ancestry: 21.3% African [AFR], 12.5% Admixed Americas [AMR], 9.6% East Asian [EAS], 48.1% European [EUR], 8.6% South Asian [SAS]). Two trans-ancestry PGS were constructed, one for alcohol consumption and another for AUD, using large-scale GWAS summary statistics from multiple ancestries weighted using PRS-CSx. Regression models were applied to test for the presence of associations between alcohol-PGS and IPT main and interaction effects. Results: In the meta-analysis across ancestry groups, IPT exposure and PGS were significantly associated with alcohol consumption (ßIPT = 0.31, P IPT = 0.0002; ßPGS = 0.09, P PGS = 0.004) and AUD (ORIPT = 1.12, P IPT = 3.5 × 10-8; ORPGS = 1.02, P PGS = 0.002). No statistically significant interactions were detected between IPT and sex nor between IPT and PGS. When inspecting ancestry specific results, the alcohol consumption-PGS and AUD-PGS were only statistically significant in the EUR ancestry group (ßPGS = 0.09, P PGS = 0.04; ORPGS = 1.02, P PGS = 0.022, respectively). Discussion: IPT exposure prior to college was strongly associated with alcohol outcomes in this college-age sample, which could be used as a preventative measure to identify students at high risk for problematic alcohol use. Additionally, results add to developing evidence of polygenic score association in meta-analyzed samples, highlighting the importance of continued efforts to increase ancestral representation in genetic studies and inclusive analytic approaches to increase the generalizability of results from genetic association studies.

A network approach to substance use, internalizing, and externalizing comorbidity in U.S. adults.

INTRODUCTION: Use of conventional cigarettes (CIG), alcohol, marijuana, and sedatives [i.e., benzodiazepines and barbiturates]) commonly co-occur with internalizing and externalizing disorders. It is unclear how these relationships extend to electronic cigarettes (ECIGs) and prescription drugs not prescribed (i.e., sedatives, tranquilizers, and painkillers [PDNP]), and whether they differ by gender. METHODS: Adult data (N = 30,211) from Wave 1 (2013-2014) of the Population Assessment of Tobacco and Health Study were used to estimate a network of current or past-month use for six substances, experiencing four internalizing symptoms in the past month, and experiencing seven externalizing symptoms in the past month. Visual comparisons, global strength invariance, network structure invariance, and edge strength invariance were tested to detail substance use and internalizing/externalizing symptom networks. RESULTS: Overall, networks were consistent between men and women. The strongest substance use/mental health symptom connections estimated as edge-weights (EW) were between marijuana with lying (EW = 0.60, 95% CI = 0.49; 0.70), marijuana with engaging in fights (EW = 0.54, 95% CI = 0.27; 0.81), PDNP with having trouble sleeping (EW = 0.53, 95% CI = 0.40; 0.66), and alcohol and impulsivity (EW = 0.48, 95% CI = 0.42; 0.53). DISCUSSION: There were many weak connections throughout the substance use and internalizing/externalizing network. A few important connections were identified and encourage future study. In particular, PDNP was most strongly associated with internalizing symptoms. Marijuana, alcohol and PDNP use were most strongly associated with externalizing symptoms.

Effects of family history of alcohol problems on alcohol consumption: Stronger for medically underserved men.

Family history (FH), informed by genetics and family environment, can be used by practitioners for risk prediction. This study compares the associations of FH with alcohol outcomes for medically underserved (MUS) men and women with the associations for non-underserved individuals to assess the utility of FH as a screening tool for this high-priority group. Data were from 29,993 adult lifetime drinkers in the Wave 1 (2001-2002) and Wave 2 (2004-2005) National Epidemiologic Survey on Alcohol and Related Conditions. All variables except FH were measured at Wave 2. Dependent variables were 12-month alcohol consumption and alcohol use disorder (AUD). FH scores (FH-SCORE) measured the proportion of first- and second-degree biological relatives with alcohol problems. MUS status was defined by household income at or below 100% of the federal poverty line and participants reporting no usual source of health care. Multivariate linear and logistic regression models tested main and interaction effects. Models showed a significant interaction of FH-SCORE with MUS status (p < .01), with a stronger effect of FH on alcohol consumption for the MUS group. This moderating effect was weaker for women than for men (FH-SCORE x MUS x Sex three-way interaction: p < .01). AUD models showed a significant positive association with FH-SCORE (p < .001) but no association with MUS status and no significant interaction effects. In this sample of lifetime drinkers, FH was associated with higher alcohol consumption, especially for MUS men. These results encourage additional validation of FH scores to prioritize MUS adults at high risk for alcohol problems to receive preventive interventions.

The Association Between Health Literacy and Tobacco Use: Results from a Nationally Representative Survey.

Dual use of conventional cigarettes and electronic cigarettes presents an emerging public health issue. Previous research has demonstrated a negative relationship between health literacy and conventional cigarette (CIG) use. However, the relationship between health literacy and e-cigarette (ECIG) use remains unclear. This studies examines the possible association of health literacy and CIG, ECIG, or dual use. A multinomial regression was used to model the association between health literacy and current CIG use, current ECIG use, or dual tobacco use status using state-optional data from the 2016 Behavioral Risk Factor Surveillance System (BRFSS; N = 40,404). One-third of the sample (N = 13,478; 33.3%) had initiated tobacco use. Approximately 36.6% of participants exclusively used cigarettes. A smaller proportion of participants were dual users of ECIG and CIGs (7.0%) and e-cigarette exclusive users (4.5%). After adjusting for covariates, higher levels of oral health literacy was associated with lower odds of current dual use. However, there was no significant association between written HL and either conventional cigarette use or electronic cigarette use or after adjusting for covariates. Oral messaging around the dangers of CIG use may be effective at lowering odds of CIG or dual use, especially for those with higher levels of HL. Further research is needed to examine how to best disseminate information regarding the health risks of ECIGs.

Bringing Transdisciplinary Aging Research From Theory to Practice.

There is a growing emphasis to use a transdisciplinary team approach to accelerate innovations in science to solve complex conditions associated with aging. However, the optimal organizational structure and process for how to accomplish transdisciplinary team science is unclear. In this forum, we illustrate our team's experience using transdisciplinary approaches to solve challenging and persistent problems for older adults living in urban communities. We describe our challenges and successes using the National Institutes of Health four-phase model of transdisciplinary team-based research. Using a de-identified survey, the team conducted an internal evaluation to identify features that created challenges including structural incongruities, interprofessional blind spots, group function, and group dynamics. This work resulted in the creation of the team's Transdisciplinary Conceptual Model. This model became essential to understanding the complex interplay between societal factors, community partners, and academic partners. Conducting internal evaluations of transdisciplinary team processes is integral for teams to move beyond the multi- and interdisciplinary niche and to reach true transdisciplinary success. More research is needed to develop measures that assess team transdisciplinary integration. Once the process of transdisciplinary integration can be reliably assessed, the next step would be to determine the impact of transdisciplinary team science initiatives on aging communities.

Polygenic score for cigarette smoking is associated with ever electronic-cigarette use in a college-aged sample.

BACKGROUND AND AIMS: Electronic cigarette use has escalated rapidly in recent years, particularly among youth. Little is known about the genetic influences on e-cigarette use. This study aimed to determine whether genetic risk for regular use of combustible cigarettes or for number of cigarettes smoked per day confers risk for ever e-cigarette use or frequency of e-cigarette use. DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS: We used data from 9541 young adults from the Spit for Science longitudinal cohort study (2011-2019). Polygenic scores (PGS) of regular combustible cigarette use (PGS-RCU) and cigarettes per day (PGS-CPD) were constructed using summary statistics from the two largest available genome-wide association study (GWAS) meta-analysis of European ancestry and East Asian ancestry of combustible cigarette use and used to test whether the PGS of RCU or CPD predicted lifetime e-cigarette use and frequency of past 30-day e-cigarette use in a diverse sample of young adults of African (AFR), Admixed American (AMR), East Asian (EAS), European (EUR), and South Asian (SAS) ancestry. FINDINGS: The PGS-RCU was associated with lifetime e-cigarette use in the EUR sample (OR = 1.27, 95% CI = 1.19-1.36, P = 7.53 × 10-12 ), but not in the other subsamples (ps > 0.12). This association remained significant after excluding regular combustible cigarette smokers (OR = 1.21, 95% CI = 1.12-1.31, P = 3.36 × 10-6 ). There was no statistically significant association between PGS-CPD and lifetime e-cigarette use and neither the PGS-RCU nor the PGS-CPD were associated with frequency of e-cigarette use in the past 30 days in any of the subsamples. CONCLUSIONS: Genetic factors associated with regular combustible cigarette use appear to be associated with ever e-cigarette use in young adults. We did not find evidence for shared genetic factors influencing heaviness of use of combustible cigarettes and current e-cigarette use frequency.

Vaginal microbiome Lactobacillus crispatus is heritable among European American women.

The diversity and dominant bacterial taxa in the vagina are reported to be influenced by multiple intrinsic and extrinsic factors, including but not limited to pregnancy, contraceptive use, pathogenic states, socioeconomic status, and ancestry. However, the extent to which host genetic factors influence variation in the vaginal microbiota is unclear. We used a biometrical genetic approach to determine whether host genetic factors contribute to inter-individual differences in taxa from a sample of 332 twins who self-identified as being of African (44 pairs) or European ancestry (122 pairs). Lactobacillus crispatus, a major determinant of vaginal health, was identified as heritable among European American women (narrow-sense heritability = 34.7%, P-value = 0.018). Heritability of L. crispatus is consistent with the reduced prevalence of adverse reproductive disorders, including bacterial vaginosis and preterm birth, among women of European ancestry.

Association between caregiver depression and child after-school program participation.

Depressive symptoms in parents and caregivers to children are associated with adverse biopsychosocial outcomes for caregivers themselves and the children in their custody. Higher overall and parenting-related stress, including stress over children's unsupervised after-school time, is associated with increased caregiver depression risk. Child after-school program participation is a form of social support that may mitigate parenting-related stress and reduce caregiver depression risk. This study tested for the association between child after-school program participation and caregiver depression in a sample of 486 caregivers in Richmond, Virginia. Child after-school program participation was associated with a significant reduction in the likelihood of a past caregiver depression diagnosis (OR = 0.58, 95% CI = 0.39 - 0.86, p = 0.007). This relationship remained significant after adjusting for the influence of caregiver anxiety, stress, financial hardship, and sociodemographic characteristics (OR = 0.49, 95% CI = 0.27 - 0.86, p = 0.015). Child after-school program participation may function as a protective factor that reduces caregiver depression risk. More research is needed to determine whether the observed association is causal in nature and dosage dependent. Findings from this and future studies may be used to inform evaluation of the impact of after-school programs at the family-level.

The association between internalizing and externalizing severity with current use of cigarettes, e-cigarettes, and alcohol in adults: Wave 1 of the Population Assessment of Tobacco and Health (PATH) study.

INTRODUCTION: Concurrent tobacco/alcohol use is common in adults, and associated with the severity of symptoms experienced by those with mental health disorders. However, few studies have explored this relationship across different combinations of tobacco products [i.e., conventional cigarette (CC) and electronic cigarette (EC)] and alcohol. METHODS: Data from the Wave 1 (2013-2014) Population Assessment of Tobacco and Health study were used. A total of 15,947 adults aged 18 years or older with complete study information were included. Multinomial logistic regression analyses were performed to determine the relationship between lifetime internalizing/externalizing severity and past 30-day use of tobacco and alcohol, adjusting for nicotine dependence (ND), sex, age, race, education, and income. RESULTS: Internalizing severity was more strongly associated with CC and alcohol use (moderate AOR = 1.47, 95% CI = 1.22-1.77; high AOR = 1.29, 95% CI = 1.03-1.61) as well as alcohol-exclusive use (moderate AOR = 1.58, 95% CI = 1.27-1.96; high AOR = 1.31, 95% CI = 1.05-1.64) while externalizing severity was more strongly associated with EC and alcohol use (high AOR = 2.97, 95% CI = 1.84-4.81, moderate AOR = 2.29, 95% CI = 1.53-3.43) when accounting for ND compared to none. The relationship between externalizing severity with EC use was dependent on alcohol being used with EC. CONCLUSIONS: The associations between psychopathology (internalizing vs. externalizing severity) varies by different combinations of alcohol, CC, and EC. Further, these relationships may be mediated through ND. Future investigations into the comorbidity between mental disorder symptoms with tobacco and alcohol use should consider use of specific substances as well as their combination.

Using Genetic Marginal Effects to Study Gene-Environment Interactions with GWAS Data.

Gene-environment interactions (GxE) play a central role in the theoretical relationship between genetic factors and complex traits. While genome wide GxE studies of human behaviors remain underutilized, in part due to methodological limitations, existing GxE research in model organisms emphasizes the importance of interpreting genetic associations within environmental contexts. In this paper, we present a framework for conducting an analysis of GxE using raw data from genome wide association studies (GWAS) and applying the techniques to analyze gene-by-age interactions for alcohol use frequency. To illustrate the effectiveness of this procedure, we calculate genetic marginal effects from a GxE GWAS analysis for an ordinal measure of alcohol use frequency from the UK Biobank dataset, treating the respondent's age as the continuous moderating environment. The genetic marginal effects clarify the interpretation of the GxE associations and provide a direct and clear understanding of how the genetic associations vary across age (the environment). To highlight the advantages of our proposed methods for presenting GxE GWAS results, we compare the interpretation of marginal genetic effects with an interpretation that focuses narrowly on the significance of the interaction coefficients. The results imply that the genetic associations with alcohol use frequency vary considerably across ages, a conclusion that may not be obvious from the raw regression or interaction coefficients. GxE GWAS is less powerful than the standard "main effect" GWAS approach, and therefore require larger samples to detect significant moderated associations. Fortunately, the necessary sample sizes for a successful application of GxE GWAS can rely on the existing and on-going development of consortia and large-scale population-based studies.

GW-SEM 2.0: Efficient, Flexible, and Accessible Multivariate GWAS.

Most genome-wide association study (GWAS) analyses test the association between single-nucleotide polymorphisms (SNPs) and a single trait or outcome. While valuable second-step analyses of these associations (e.g., calculating genetic correlations between traits) are common, single-step multivariate analyses of GWAS data are rarely performed. This is unfortunate because multivariate analyses can reveal information which is irrevocably obscured in multi-step analysis. One simple example is the distinction between variance common to a set of measures, and variance specific to each. Neither GWAS of sum- or factor-scores, nor GWAS of the individual measures will deliver a clean picture of loci associated with each measure's specific variance. While multivariate GWAS opens up a broad new landscape of feasible and informative analyses, its adoption has been slow, likely due to the heavy computational demands and difficulties specifying models it requires. Here we describe GW-SEM 2.0, which is designed to simplify model specification and overcome the inherent computational challenges associated with multivariate GWAS. In addition, GW-SEM 2.0 allows users to accurately model ordinal items, which are common in behavioral and psychological research, within a GWAS context. This new release enhances computational efficiency, allows users to select the fit function that is appropriate for their analyses, expands compatibility with standard genomic data formats, and outputs results for seamless reading into other standard post-GWAS processing software. To demonstrate GW-SEM's utility, we conducted (1) a series of GWAS using three substance use frequency items from data in the UK Biobank, (2) a timing study for several predefined GWAS functions, and (3) a Type I Error rate study. Our multivariate GWAS analyses emphasize the utility of GW-SEM for identifying novel patterns of associations that vary considerably between genomic loci for specific substances, highlighting the importance of differentiating between substance-specific use behaviors and polysubstance use. The timing studies demonstrate that the analyses take a reasonable amount of time and show the cost of including additional items. The Type I Error rate study demonstrates that hypothesis tests for genetic associations with latent variable models follow the hypothesized uniform distribution. Taken together, we suggest that GW-SEM may provide substantially deeper insights into the underlying genomic architecture for multivariate behavioral and psychological systems than is currently possible with standard GWAS methods. The current release of GW-SEM 2.0 is available on CRAN (stable release) and GitHub (beta release), and tutorials are available on our github wiki ( https://jpritikin.github.io/gwsem/ ).

Assessing Stakeholder Perceptions of the Utility of Genetic Information for the Clinical Care of Mental Health Disorders: We Have a Will but Need to See the Way.

Academic stakeholders' (primarily mental health researchers and clinicians) practices and attitudes related to the translation of genetic information into mental health care were assessed. A three-part survey was administered at two large, urban universities. Response frequencies were calculated. Participants (N = 64) reported moderate levels of translational practice, adequate levels of genetic knowledge, and variable levels of genetic competence. They held positive attitudes toward translating genetic information about mental health broadly but negative attitudes about the impact that such information would have on specific aspects of care. The current study lays the groundwork for further inquiry into translating genetic information to mental health care.

The Genetic and Environmental Influences Contributing to the Association between Electronic and Conventional Cigarette Initiation.

INTRODUCTION: As the use of electronic cigarette (EC) continues to rise in the United States, especially among adolescents and young adults, it is necessary to better understand the factors associated with EC initiation. Specifically, it is unclear how genetic and environmental contributions influence the initiation of EC. Furthermore, the degree to which genetic and environmental influences are shared between EC initiation and conventional cigarette (CC) initiation is unknown. METHODS: A sample of young adult twins ages 15-20 (N = 858 individuals; 421 complete twin pairs) was used to estimate the genetic and environmental influences on the liability of initiation unique to EC and CC as well as the degree to which these factors are shared between the two. Approximately 24% of participants initiated the use of EC, 19% initiated the use of CC, and 11% initiated the dual use. RESULTS: Combined contributions of additive genetic and shared environmental influences were significant for CC (ACC = 0.19 [95% confidence interval {CI} = 0-0.79], p = 0.57; CCC = 0.42 [95% CI = 0-0.70], p = 0.13) and EC (AEC = 0.25 [95% CI = 0-0.83, p = 0.44; CEC = 0.42 [95% CI = 0-0.73], p = 0.12), whereas unique environmental influences were significant (ECC = 0.39 [95% CI = 0.18-0.57], p < 0.001; EEC = 0.32 [95% CI = 0.14-0.56], p < 0.001). Results also demonstrated a significant overlap of the unique environmental (rE = 0.87, p < 0.001) and familial influences contributing to correlation between the two phenotypes in the bivariate analysis. CONCLUSIONS: These preliminary results suggest that both genes and environmental influences are potential drivers of EC initiation among adolescents and young adults. IMPLICATIONS: This article is the first to use a sample of twin to estimate the contributions of genetic and environmental influences toward EC initiation and estimate the potential for overlapping influences with CC initiation. This study has implications for future debate about the etiology of EC and CC use with respect to potential overlapping genetic and environmental influences.