Developmental changes in genetic and shared environmental contributions to smoking initiation and subsequent smoking quantity in adolescence and young adulthood

Background Few studies examining the genetic architecture of cigarette smoking have focused on adolescents or examined developmental changes in additive genetic, shared environment and unique environmental influences on liability to initiate cigarette smoking and quantity of cigarettes smoked. The aim of this study is to add to the literature on liability to initiate and use cigarettes during adolescence using a nationally representative sample. Method Data for this study came from adolescent and young adult twin pairs (ages 14-33) from the National Longitudinal Study of Adolescent to Adult Health. We ran a series of developmental causal-contingent-common pathway models to examine whether additive genetic, shared and unique environmental influences on liability to the initiation of cigarette use are shared with those on smoking quantity, and whether their contributions change across development. Results We found evidence for a developmental shift in genetic and shared environmental contributions to cigarette use. Early in adolescence genetic and environmental influences work independently on liability to cigarette smoking initiation and quantity of cigarettes smoked, but liability to these behaviors becomes correlated as individuals age into young adulthood. Conclusions These findings provide insight into the causal processes underlying the liability to smoke cigarettes. With age, there is greater overlap in the genetic and environmental factors that influence the initiation of cigarette smoking and quantity of cigarettes smoked

Extended twin study of alcohol use in Virginia and Australia

Drinking alcohol is a normal behavior in many societies, and prior studies have demonstrated it has both genetic and environmental sources of variation. Using two very large samples of twins and their first-degree relatives (Australia ≈ 20,000 individuals from 8,019 families; Virginia ≈ 23,000 from 6,042 families), we examine whether there are differences: (1) in the genetic and environmental factors that influence four interrelated drinking behaviors (quantity, frequency, age of initiation, and number of drinks in the last week), (2) between the twin-only design and the extended twin design, and (3) the Australian and Virginia samples. We find that while drinking behaviors are interrelated, there are substantial differences in the genetic and environmental architectures across phenotypes. Specifically, drinking quantity, frequency, and number of drinks in the past week have large broad genetic variance components, and smaller but significant environmental variance components, while age of onset is driven exclusively by environmental factors. Further, the twin-only design and the extended twin design come to similar conclusions regarding broad-sense heritability and environmental transmission, but the extended twin models provide a more nuanced perspective. Finally, we find a high level of similarity between the Australian and Virginian samples, especially for the genetic factors. The observed differences, when present, tend to be at the environmental level. Implications for the extended twin model and future directions are discussed

Cross-cultural comparison of genetic and cultural transmission of smoking initiation using an extended twin kinship model

Background: Considerable evidence from twin and adoption studies indicates that genetic and shared environmental factors play a role in the initiation of smoking behavior. Although twin and adoption designs are powerful to detect genetic and environmental influences, they do not provide information on the processes of assortative mating and parent–offspring transmission and their contribution to the variability explained by genetic and/or environmental factors. Methods: We examined the role of genetic and environmental factors in individual differences for smoking initiation (SI) using an extended kinship design. This design allows the simultaneous testing of additive and non-additive genetic, shared and individual-specific environmental factors, as well as sex differences in the expression of genes and environment in the presence of assortative mating and combined genetic and cultural transmission, while also estimating the regression of the prevalence of SI on age. A dichotomous lifetime ‘ever’ smoking measure was obtained from twins and relatives in the ‘Virginia 30,000’ sample and the ‘Australian 25,000’. Results: Results demonstrate that both genetic and environmental factors play a significant role in the liability to SI. Major influences on individual differences appeared to be additive genetic and unique environmental effects, with smaller contributions from assortative mating, shared sibling environment, twin environment, cultural transmission, and resulting genotype-environment covariance. Age regression of the prevalence of SI was significant. The finding of negative cultural transmission without dominance led us to investigate more closely two possible mechanisms for the lower parent–offspring correlations compared to the sibling and DZ twin correlations in subsets of the data: (1) age × gene interaction, and (2) social homogamy. Neither of the mechanism provided a significantly better explanation of the data. Conclusions: This study showed significant heritability, partly due to assortment, and significant effects of primarily non-parental shared environment on liability to SI

Prevalence of Nicotine Delivery Systems by Biological Sex in the Spit for Science Study

Nicotine intake usage trends have changed over recent decades given the wide variety of nicotine delivery systems including cigarettes, vaping, hookah, and snubs/chewables. These trends also vary by demographic factors, such as race/ethnicity, sex, and socioeconomic status (SES). For example, studies in rat populations, as well as humans, have found that females tend to be more dependent on nicotine products and have a more difficult time quitting than male rats and humans (Pogun et al., 2017). Also, race/ethnicity may impact the frequency of nicotine usage in different populations; in that non-white Hispanics were more susceptible to smoking through adolescence with a peak at ages 12 and 16; whereas non-Hispanic Asian Americans were less susceptible to smoking at ages 11 and 15 (El-Toukhy et al., 2016). Certain nicotine delivery methods may be more available or perhaps more socially accepted by certain groups of people. While lower SES is associated with more prevalent cigarette advertisements and usage, individuals with a higher SES were associated with an increased prevalence of e-cigarette advertisements, leading to an increased frequency of e-cigarette usage among adolescents (Simon et al., 2018). This project aims to document rates of nicotine use across different nicotine delivery systems in college students by demographic factors. We use the Spit for Science (S4S) database to investigate prevalence rates and study if they differ by sex, race/ethnicity, or SES. It is hypothesized that higher SES individuals will have an increased frequency of use with nicotine products that are non-cigarette based, non-white Hispanics will have greater frequency with nicotine usage, and females within the study sample will display a higher dependency on nicotine products than males. Preliminary analyses reveal that there are more female participants than males throughout the S4S cohorts collected between 2020 and 2022. Across cohorts, prevalence of all nicotine delivery systems differs in female and male participants across all products. Larger differences in prevalence between females and males are observed for cigarettes, smokeless tobacco, and cigars than for products that have been introduced more recently, such as hookah, vaping, and heat-not-burn products. Further analyses will focus on patterns of use in relation to race/ethnicity and SES. Understanding nicotine usage trends within our sample could pave the way for additional research (i.e., genetic studies) and allow for the development of prevention/intervention models tailored to our sample populations.https://scholarscompass.vcu.edu/uresposters/1436/thumbnail.jp

VCU Brew

VCU Brew is an innovative proposal to create a VCU branded signature beer. The Campus Connectors will present a rationale showing how this proposal will i) potentially generate revenue to benefit VCU scholarships and academic programs, ii) create opportunities for experiential learning by engaging VCU students in product development, branding, labeling, marketing, business, and awareness of responsible drinking, iii) and guide the process of partnering with local breweries to provide practical expertise and stimulate entrepreneurship initiatives that lead to distribution at VCU athletic, community and Alumni events, while increasing ties with the community and national prominence

On the association of common and rare genetic variation influencing body mass index: a combined SNP and CNV analysis

Background As the architecture of complex traits incorporates a widening spectrum of genetic variation, analyses integrating common and rare variation are needed. Body mass index (BMI) represents a model trait, since common variation shows robust association but accounts for a fraction of the heritability. A combined analysis of single nucleotide polymorphisms (SNP) and copy number variation (CNV) was performed using 1850 European and 498 African-Americans from the Study of Addiction: Genetics and Environment. Genetic risk sum scores (GRSS) were constructed using 32 BMI-validated SNPs and aggregate-risk methods were compared: count versus weighted and proxy versus imputation. Results The weighted SNP-GRSS constructed from imputed probabilities of risk alleles performed best and was highly associated with BMI (p = 4.3×10−16) accounting for 3% of the phenotypic variance. In addition to BMI-validated SNPs, common and rare BMI/obesity-associated CNVs were identified from the literature. Of the 84 CNVs previously reported, only 21-kilobase deletions on 16p12.3 showed evidence for association with BMI (p = 0.003, frequency = 16.9%), with two CNVs nominally associated with class II obesity, 1p36.1 duplications (OR = 3.1, p = 0.009, frequency 1.2%) and 5q13.2 deletions (OR = 1.5, p = 0.048, frequency 7.7%). All other CNVs, individually and in aggregate, were not associated with BMI or obesity. The combined model, including covariates, SNP-GRSS, and 16p12.3 deletion accounted for 11.5% of phenotypic variance in BMI (3.2% from genetic effects). Models significantly predicted obesity classification with maximum discriminative ability for morbid-obesity (p = 3.15×10−18). Conclusion Results show that incorporating validated effect sizes and allelic probabilities improve prediction algorithms. Although rare-CNVs did not account for significant phenotypic variation, results provide a framework for integrated analyses