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

Prediction of adult height in girls: the Beunen-MalinaFreitas method

The purpose of this study was to validate and cross-validate the Beunen-Malina-Freitas method for non-invasive prediction of adult height in girls. A sample of 420 girls aged 10–15 years from the Madeira Growth Study were measured at yearly intervals and then 8 years later. Anthropometric dimensions (lengths, breadths, circumferences, and skinfolds) were measured; skeletal age was assessed using the Tanner-Whitehouse 3 method and menarcheal status (present or absent) was recorded. Adult height was measured and predicted using stepwise, forward, and maximum R2 regression techniques. Multiple correlations, mean differences, standard errors of prediction, and error boundaries were calculated. A sample of the Leuven Longitudinal Twin Study was used to cross-validate the regressions. Age-specific coefficients of determination (R2) between predicted and measured adult height varied between 0.57 and 0.96, while standard errors of prediction varied between 1.1 and 3.9 cm. The cross-validation confirmed the validity of the Beunen-Malina-Freitas method in girls aged 12–15 years, but at lower ages the cross-validation was less consistent. We conclude that the Beunen-Malina-Freitas method is valid for the prediction of adult height in girls aged 12–15 years. It is applicable to European populations or populations of European ancestry.info:eu-repo/semantics/publishedVersio

Genetic and Environmental Influences on Smoking Behavior across Adolescence and Young Adulthood in the Virginia Twin Study of Adolescent Behavioral Development and the Transitions to Substance Abuse Follow-Up

Little is known regarding the underlying relationship between smoking initiation and current quantity smoked during adolescence into young adulthood. It is possible that the influences of genetic and environmental factors on this relationship vary across sex and age. To investigate this further, the current study applied a common causal contingency model to data from a Virginia-based twin study to determine: (1) if the same genetic and environmental factors are contributing to smoking initiation and current quantity smoked; (2) whether the magnitude of genetic and environmental factor contributions are the same across adolescence and young adulthood; and (3) if qualitative and quantitative differences in the sources of variance between males and females exist. Study results found no qualitative or quantitative sex differences in the relationship between smoking initiation and current quantity smoked, though relative contributions of genetic and environmental factors changed across adolescence and young adulthood. More specifically, smoking initiation and current quantity smoked remain separate constructs until young adulthood, when liabilities are correlated. Smoking initiation is explained by genetic, shared, and unique environmental factors in early adolescence and by genetic and unique environmental factors in young adulthood; while current quantity smoked is explained by shared environmental and unique environmental factors until young adulthood, when genetic and unique environmental factors play a larger role

An investigation of weight suppression in a population-based sample of female twins

Weight suppression (WS), maintaining a body weight below one’s maximum adult weight, is associated with bingeing, purging and weight gain in clinical samples