Background: Peer drinking is one of the most robust predictors of college students' alcohol use and can moderate students' genetic risk for alcohol use. Peer effect research generally suffers from 2 problems: selection into peer groups and relying more on perceptions of peer alcohol use than peers' selfreport. The goal of the present study was to overcome those limitations by capitalizing on a genetically informed sample of randomly assigned college roommates to examine multiple dimensions of peer influence and the interplay between peer effects and genetic predisposition on alcohol use, in the form of polygenic scores.Methods: We used a subsample (n = 755) of participants from a university-wide, longitudinal study at a large, diverse, urban university. Participants reported their own alcohol use during fall and spring and their perceptions of college peers' alcohol use in spring. We matched individuals into their rooms and residence halls to create a composite score of peer-reported alcohol use for each of those levels. We examined multiple dimensions of peer influence and whether peer influence moderated genetic predisposition to predict college students' alcohol use using multilevel models to account for clustering at the room and residence hall level.Results: We found that polygenic scores (b = 0.12), perceptions of peer drinking (b = 0.37), and roommates' self-reported drinking (b = 0.10) predicted alcohol use (all ps < 0.001), while average alcohol use across residence hall did not (b = À0.01, p = 0.86). We found no evidence for interactions between peer influence and genome-wide polygenic scores for alcohol use.Conclusions: Our findings underscore the importance of genetic predisposition on individual alcohol use and support the potentially causal nature of the association between peer influence and alcohol use.

IMPORTANCE Incidental findings (IFs) are unexpected abnormalities discovered during imaging and can range from normal anatomic variants to findings requiring urgent medical intervention. In the case of brain magnetic resonance imaging (MRI), reliable data about the prevalence and significance of IFs in the general population are limited, making it difficult to anticipate, communicate, and manage these findings.OBJECTIVES To determine the overall prevalence of IFs in brain MRI in the nonclinical pediatric population as well as the rates of specific findings and findings for which clinical referral is recommended. DESIGN, SETTING, AND PARTICIPANTS This cohort study was based on the April 2019 release of baseline data from 11 810 children aged 9 to 10 years who were enrolled and completed baseline neuroimaging in the Adolescent Brain Cognitive Development (ABCD) study, the largest US population-based longitudinal observational study of brain development and child health, between September 1, 2016, and November 15, 2018. Participants were enrolled at 21 sites across the US designed to mirror the demographic characteristics of the US population.Baseline structural MRIs were centrally reviewed for IFs by board-certified neuroradiologists and findings were described and categorized (category 1, no abnormal findings; 2, no referral recommended; 3; consider referral; and 4, consider immediate referral). Children were enrolled through a broad school-based recruitment process in which all children of eligible age at selected schools were invited to participate. Exclusion criteria were severe sensory, intellectual, medical, or neurologic disorders that would preclude or interfere with study participation. During the enrollment process, demographic data were monitored to ensure that the study met targets for sex, socioeconomic, ethnic, and racial diversity. Data were analyzed from March 15, 2018, to November 20, 2020. MAIN OUTCOMES AND MEASURES Percentage of children with IFs in each category and prevalence of specific IFs.RESULTS A total of 11 679 children (52.1% boys, mean [SD] age, 9.9 [0.62] years) had interpretable baseline structural MRI results. Of these, 2464 participants (21.1%) had IFs, including 2013 children (17.2%) assigned to category 2, 431 (3.7%) assigned to category 3, and 20 (0.2%) assigned to category 4. Overall rates of IFs did not differ significantly between singleton and twin gestations or between monozygotic and dizygotic twins, but heritability analysis showed heritability for the presence or absence of IFs (h 2 = 0.260; 95% CI, 0.135-0.387). CONCLUSIONS AND RELEVANCEIncidental findings in brain MRI and findings with potential clinical significance are both common in the general pediatric population. By assessing IFs and concurrent developmental and health measures and following these findings over the longitudinal study course, the ABCD study has the potential to determine the significance of many common IFs.

Neighborhood-level socioeconomic variables, such as the proportion of minority and low-income residents, have been associated with a greater density of tobacco retail outlets (TROs), though less is known about the degree to which these neighborhood indicators are related to vape shop outlet (VSO) density. Many studies of TROs and neighborhood characteristics include only a small set of variables and also fail to take into account the correlation among these variables. Using a carefully curated database of all TROs and VSOs in Virginia (2016–2018), we developed a Bayesian model to estimate a neighborhood disadvantage index and examine its association with rates of outlets across census tracts while also accounting for correlations among variables. Models included 12 census tract variables from the American Community Survey. Results showed that increasing neighborhood disadvantage was associated with a 63% and 64% increase in TRO and VSO risk, respectively. Important variables associated with TRO rates included % renter occupied housing, inverse median gross rent, inverse median monthly housing costs, inverse median monthly housing costs, and % vacant housing units. Important variables associated with VSO rates were % renter occupied housing and % Hispanic population. There were several spatial clusters of significantly elevated risk for TROs and VSOs in western and eastern Virginia.

Background Research on cannabis use among those with a history of cancer is limited. Methods Prevalence of past‐year cannabis use among individuals with and without a cancer history and predictors of use within these 2 groups were determined using data from the Population Assessment of Tobacco and Health study, a nationally representative, longitudinal survey conducted in the United States (waves 1‐4; 2013‐2018). Discrete time survival analyses were used to estimate baseline (wave 1) predictors (physical health status, mental health status, pain, and demographic variables) on past‐year engagement with cannabis within individuals who reported a cancer diagnosis at wave 1 (n = 1022) and individuals who reported never having cancer at any wave (n = 19,702). Results At the most recent survey, 8% of cancer survivors reported past‐year cannabis use, compared with 15% of those without a cancer history. Across 4 time points, an estimated 3.8% of cancer survivors engaged with cannabis, as compared to 6.5% of those without a cancer history. Across both groups, older age and having health insurance were associated with lower likelihood of engaging in cannabis use, whereas greater levels of pain were associated with higher likelihood of engaging in cannabis use. Among those without a cancer history, being female, White, and having better mental health status were associated with lower likelihood of engaging in cannabis use. Conclusions Although cannabis use prevalence is lower among cancer survivors, the reasons for use are not markedly different from those without a cancer history. Continued monitoring of use, reasons for use, and harms or benefits is warranted. Lay Summary Results from this study, which uses data from the Population Assessment of Tobacco and Health Study, indicate that cannabis use is generally increasing across cancer survivors and those without a history of cancer. Cancer survivors are using cannabis at slightly lower rates than those without a history of cancer. Factors related to pain seem to be more prevalent in cancer populations relative to the general population, and could be contributing to cannabis use within cancer survivor populations.

Background: Attention-deficit/hyperactivity disorder (ADHD) symptoms have been linked with eating behaviors and obesity adolescence and young adulthood. Yet, little is known about whether these associations occur during early childhood and few studies have examined these associations prospectively.Objectives: To assess magnitude and direction of associations between childhood ADHD symptoms and eating behaviors. Methods: Participants were from the Newborn Epigenetics Study (N = 470, M age = 4 years). Multivariable linear regression models were used to examine crosssectional associations between ADHD symptoms and eating behaviors. Latent Change Score (LCS) modeling was performed to examine prospective association among a subset of children with available follow-up data. (N = 100, M age = 7 years). Results:The cross-sectional results showed that attention problem (AP) and hyperactivity (HY) were positively associated with food responsiveness, emotional overeating, desire to drink, and slowness in eating. AP, but not HY, was inversely associated with enjoyment of food. Results of the LCS models revealed AP and HY were both positively associated with prospective changes in emotional overeating and satiety responsiveness. AP was further positively associated with prospective changes in food responsiveness. The reverse relationship predicting changes in ADHD symptoms from earlier assessments of eating behaviors was not significant. Conclusion:Results suggest a link between ADHD symptoms and obesity-related eating behaviors in early childhood, highlighting the need to address self-regulation and healthy eating behaviors in the prevention of childhood obesity. K E Y W O R D S