Kayla de la Haye

Obesity-related behaviors in adolescent friendship networks

This study examines obesity-related behaviors within adolescent friendship networks, because adolescent peers have been identified as being important determinants of many health behaviors. We applied ERGM selection models for single network observations to determine if close adolescent friends engage in similar behaviors and to explore associations between behavior and popularity. Same-sex friends were found to be similar on measures of organized physical activity in two out of three school-based friendship networks. Female friends were found to engage in similar screen-based behaviors, and male friends tended to be similar in their consumption of high-calorie foods. Popularity (receiving ties) was also associated with some behaviors, although these effects were gender specific and differed across networks.

Selection and Influence Mechanisms Associated With Marijuana Initiation and Use in Adolescent Friendship Networks

Friends are thought to influence adolescent drug use. However, few studies have examined the role of drugs in friendship selection, which is necessary to draw sound conclusions about influence. This study applied statistical models for social networks to test the contribution of selection and influence to associations in marijuana use among friends in two large high schools (N = 1,612; M age = 16.4). There was evidence for friend selection based on similar lifetime and current marijuana use at both schools, but friends were found to influence the initiation and frequency of adolescent marijuana use in just one of these schools. There was minimal evidence that peer effects were moderated by personal, school, or family risk factors.

Neighborhood characteristics and the initiation of marijuana use and binge drinking

BACKGROUND This study examines whether residential neighborhood characteristics influence the initiation of marijuana use and binge drinking, and if these neighborhood factors heighten or dampen peer influences on substance use. METHODS Predictors of marijuana (N=6516) and binge drinking (N=6630) initiation over a 1-year period were identified using data from the National Longitudinal Study of Adolescent Health. Participants were of ages 12-19 years at baseline. The main predictor variables were neighborhood characteristics, using both objective (proportion of households below the poverty line and female-headed, unemployment rate, residential stability) and subjective (perceived cohesion and safety) measures. Binge drinking was defined as 5 or more drinks in a row. RESULTS Initiation occurred for 12.9% of adolescents in the case of marijuana and 16.4% for binge drinking. Marijuana initiation was more likely among adolescents who lived in neighborhoods with a higher unemployment rate, and binge drinking initiation was more likely among those who perceived greater safety in their neighborhood, after adjusting for other neighborhood characteristics, demographics, friend characteristics, and behavioral and family risk factors. There was no evidence that neighborhood context moderates the associations of peer factors on initiation. CONCLUSIONS Select neighborhood characteristics appear relevant to the initiation of marijuana use and binge drinking, although the mechanisms appear to be distinct for each substance. If these results are found to be robust, future research should aim to better understand how neighborhood context influences the initiation of adolescent substance use in order to inform prevention efforts.

Friendship network characteristics are associated with physical activity and sedentary behavior in early adolescence

Introduction There is limited understanding of the association between peer social networks and physical activity (PA), sedentary and screen-related behaviors. This study reports on associations between personal network characteristics and these important health behaviors for early adolescents. Methods Participants were 310 students, aged 11–13 years, from fifteen randomly selected Victorian primary schools (43% response rate). PA and sedentary behaviors were collected via accelerometer and self-report questionnaire, and anthropometric measures via trained researchers. Participants nominated up to fifteen friends, and described the frequency of interaction and perceived activity intensity of these friends. Personal network predictors were examined using regression modelling for PA and sedentary/screen behavior. Results Perceived activity levels of friends, and friendships with very frequent interaction were associated with outside-of-school PA and/or sedentary/screen time. Differences according to sex were also observed in the association between network characteristics and PA and sedentary time. A higher number of friends and greater proportion of same sex friends were associated with boys engaging in more moderate-to-vigorous PA outside of school hours. PA intensity during school-day breaks was positively associated with having a greater proportion of friends who played sports for girls, and a greater proportion of male friends for boys. Conclusion Friendship network characteristics are associated with PA and sedentary/screen time in late childhood/early adolescence, and these associations differ by sex. The positive influence of very active peers may be a promising avenue to strengthen traditional interventions for the promotion of PA and reduction in screen time.

Shared Risk: Who Engages in Substance Use with American Homeless Youth?

AIMS To identify characteristics of social network members with whom homeless youth engage in drinking and drug use. DESIGN A multi-stage probability sample of homeless youth completed a social network survey. SETTING Forty-one shelters, drop-in centers and known street hangouts in Los Angeles County. PARTICIPANTS A total of 419 homeless youth, aged 13-24 years (mean age = 20.09, standard deviation = 2.80). MEASUREMENTS Respondents described 20 individuals in their networks, including their substance use and demographics, and the characteristics of the relationships they shared, including with whom they drank and used drugs. Dyadic, multi-level regressions identified predictors of shared substance use. FINDINGS Shared drinking was more likely to occur with recent sex partners [odds ratio (OR) = 2.64, confidence interval (CI): 1.67, 4.18], drug users (OR = 4.57, CI: 3.21, 6.49), sexual risk takers (OR = 1.71, CI: 1.25, 2.33), opinion leaders (OR = 1.69, CI: 1.42, 2.00), support providers (OR = 1.41, CI: 1.03, 1.93) and popular people (those with high degree scores in the network) (OR = 1.07, CI: 1.01, 1.14). Shared drug use was more likely to occur with recent sex partners (OR = 2.44, CI: 1.57, 3.80), drinkers (OR = 4.53, CI: 3.05, 6.74), sexual risk takers (OR = 1.51, CI: 1.06, 2.17), opinion leaders (OR = 1.24, CI: 1.03, 1.50), support providers (OR = 1.83, CI: 1.29, 2.60) and popular people (OR = 1.16, CI: 1.08, 1.24). CONCLUSIONS Homeless youth in the United States are more likely to drink or use drugs with those who engage in multiple risk behaviors and who occupy influential social roles (popular, opinion leaders, support providers, sex partners). Understanding these social networks may be helpful in designing interventions to combat substance misuse.

Longitudinal associations of homophobic name-calling victimization with psychological distress and alcohol use during adolescence

PURPOSE Homophobic victimization, and specifically name-calling, has been associated with greater psychological distress and alcohol use in adolescents. This longitudinal study examines whether sexual orientation moderates these associations and also differentiates between the effects of name-calling from friends and nonfriends. METHODS Results are based on 1,325 students from three Midwestern high schools who completed in-school surveys in 2012 and 2013. Linear regression analysis was used to examine the associations among homophobic name-calling victimization and changes in anxiety symptoms, depressive symptoms, and alcohol use one year later, controlling for other forms of victimization and demographics. RESULTS Homophobic name-calling victimization by friends was not associated with changes in psychological distress or alcohol use among either students who self-identified as heterosexual or those who self-identified as lesbian, gay, or bisexual (LGB). In contrast, homophobic name-calling by nonfriends was associated with increased psychological distress over a one-year period among LGB students and increased drinking among heterosexual students. CONCLUSIONS Homophobic name-calling victimization, specifically from nonfriends, can adversely affect adolescent well-being over time and, thus, is important to address in school-based bullying prevention programs. School staff and parents should be aware that both LGB and heterosexual adolescents are targets of homophobic name-calling but may tend to react to this type of victimization in different ways. Further research is needed to understand the mechanisms through which homophobic victimization increases the risk of psychological distress and alcohol use over time.

Covariance among Multiple Health Risk Behaviors in Adolescents

Purpose In a diverse group of early adolescents, this study explores the co-occurrence of a broad range of health risk behaviors: alcohol, cigarette, and marijuana use; physical inactivity; sedentary computing/gaming; and the consumption of low-nutrient energy-dense food. We tested differences in the associations of unhealthy behaviors over time, and by gender, race/ethnicity, and socioeconomic status. Methods Participants were 8360 students from 16 middle schools in California (50% female; 52% Hispanic, 17% Asian, 16% White, and 15% Black/multiethnic/other). Behaviors were measured with surveys in Spring 2010 and Spring 2011. Confirmatory factor analysis was used to assess if an underlying factor accounted for the covariance of multiple behaviors, and composite reliability methods were used to determine the degree to which behaviors were related. Results The measured behaviors were explained by two moderately correlated factors: a ‘substance use risk factor’ and an ‘unhealthy eating and sedentary factor’. Physical inactivity did not reflect the latent factors as expected. There were few differences in the associations among these behaviors over time or by demographic characteristics. Conclusions Two distinct, yet related groups of health compromising behaviors were identified that could be jointly targeted in multiple health behavior change interventions among early adolescents of diverse backgrounds.

A prospective study of marijuana use change and cessation among adolescents

BACKGROUND With marijuana use increasing among American adolescents, better understanding of the factors associated with decreasing use and quitting can help inform cessation efforts. This study evaluates a range of neighborhood, family, peer network, and individual factors as predictors of marijuana use, change, and non-use over one year, and cessation over six years. METHODS Data come from adolescents in Waves I and II of the National Longitudinal Study of Adolescent Health (N=458, one-year sample), or Waves I and III (N=358, six-year sample), and reported using marijuana at least four times in the past month at Wave I. RESULTS Eighteen percent of adolescents stopped using marijuana after six years. Results suggest neighborhood context affects overall use level, whereas neighborhood context and friends were critical to cessation vs. continuation of use. Decrease in use were more likely among adolescents in disadvantaged or less cohesive neighborhoods, or who moved between waves. Non-use after one year was more likely among adolescents who did not move, had fewer marijuana-using friends, and did not exclusively have outside-of-school friends. Cessation at six years was more likely among adolescents in less disadvantaged and more cohesive neighborhoods, and for those with within-school friends. CONCLUSIONS Results highlight the importance of both objective and subjective neighborhood characteristics, as well as peer networks, on adolescent marijuana use. Factors associated with decreases in use appear distinct from those that predict quitting, suggesting that continuation vs. cessation is linked to peers as well as neighborhood context. Relocated and isolated individuals may face challenges with cessation.

Whole of Systems Trial of Prevention Strategies for Childhood Obesity: WHO STOPS Childhood Obesity

Background: Community-based initiatives show promise for preventing childhood obesity. They are characterized by community leaders and members working together to address complex local drivers of energy balance. Objectives: To present a protocol for a stepped wedge cluster randomized trial in ten communities in the Great South Coast Region of Victoria, Australia to test whether it is possible to: (1) strengthen community action for childhood obesity prevention, and (2) measure the impact of increased action on risk factors for childhood obesity. Methods: The WHO STOPS intervention involves a facilitated community engagement process that: creates an agreed systems map of childhood obesity causes for a community; identifies intervention opportunities through leveraging the dynamic aspects of the system; and, converts these understandings into community-built, systems-oriented action plans. Ten communities will be randomized (1:1) to intervention or control in year one and all communities will be included by year three. The primary outcome is childhood obesity prevalence among grade two (ages 7–8 y), grade four (9–10 y) and grade six (11–12 y) students measured using our established community-led monitoring system (69% school and 93% student participation rate in government and independent schools). An additional group of 13 external communities from other regions of Victoria with no specific interventions will provide an external comparison. These communities will also allow us to assess diffusion of the intervention to control communities during the first three years of the trial. Conclusion: This trial will test effectiveness, over a five-year period, of community-owned, -supported and -led strategies designed to address complex and dynamic causes of childhood obesity.

Quantifying a Systems Map: Network Analysis of a Childhood Obesity Causal Loop Diagram

Causal loop diagrams developed by groups capture a shared understanding of complex problems and provide a visual tool to guide interventions. This paper explores the application of network analytic methods as a new way to gain quantitative insight into the structure of an obesity causal loop diagram to inform intervention design. Identification of the structural features of causal loop diagrams is likely to provide new insights into the emergent properties of complex systems and analysing central drivers has the potential to identify leverage points. The results found the structure of the obesity causal loop diagram to resemble commonly observed empirical networks known for efficient spread of information. Known drivers of obesity were found to be the most central variables along with others unique to obesity prevention in the community. While causal loop diagrams are often specific to single communities, the analytic methods provide means to contrast and compare multiple causal loop diagrams for complex problems.