A comparison of peer influence measures as predictors of smoking among predominately hispanic/latino high school adolescents

Dying to Fit In: How Interpersonal Networks Shape COVID-19 Health Outcomes Through Discussion and Social Norms

Research has repeatedly demonstrated the ability of social networks, interpersonal discussion, and perceived social norms to shape health-related outcomes. There are still substantial gaps, however, in understanding the theoretical mechanism that holds these components together, as well as the boundary conditions of their effects. Employing ego-network analysis with a representative sample of Illinois residents (N = 711) and focusing on the context of COVID-19 vaccine adherence, this study constructs a comprehensive framework to examine the direct, indirect, and conditional relationships linking social capital within networks, factual knowledge, and vaccination. Overall, the results point to the ability of tight-knit networks to influence knowledge and behavior for better or worse, depending on the composition of the network and its conversational valence. Theoretical and practical implications are discussed.

Impact of social networks and norms on e-cigarette use among adolescents in Southern California: a prospective cohort study

Objective

Using social network analysis, we assessed the mechanisms of social influence that promote e-cigarette use in adolescent networks.

Methods

Data on health behaviours and friendship networks from a cohort of 10 high schools in Southern California (N=1599) were collected in grade 9 Spring 2021 (W1), grade 10 Fall 2021 (W2) and Spring 2022 (W3). Two mixed effects logistic regression models were estimated (full sample and subsample of non-vapers only) to evaluate the associations of W1 and W2 pro-vaping norms, peer e-cigarette use exposure and prior e-cigarette use (full sample) on past 6-month vaping at W3, adjusting for demographic covariates and school clustering.

Results

Previous vaping was the strongest predictor of past 6-month vaping at W3 among the full sample. Greater exposure to friend e-cigarette use at W2 (adjusted OR (AOR)=12.2, 95% CI 4.04 to 36.5) and greater pro-vaping norms at W2 (AOR=2.63, 95% CI 1.24 to 5.55) were significantly and positively associated with increased odds of initiating e-cigarette use at W3 among students with no lifetime e-cigarette use.

Conclusion

Peer network exposure and pro-vaping norms are significant predictors of vaping initiation even when network vaping prevalence is low.

Latent Profile Patterns of Network-Level Norms and Associations with Individual-Level Sexual Behaviors: The N2 Cohort Study in Chicago

Individual-level behavior can be influenced by injunctive and descriptive social network norms surrounding that behavior. There is a need to understand how the influence of social norms within an individual's social networks may influence individual-level sexual behavior. We aimed to typologize the network-level norms of sexual behaviors within the social networks of Black sexual and gender minoritized groups (SGM) assigned male at birth. Survey data were collected in Chicago, Illinois, USA, between 2018 and 2019 from Black SGM. A total of 371 participants provided individual-level information about sociodemographic characteristics and HIV vulnerability from sex (i.e., condomless sex, group sex, use of alcohol/drugs to enhance sex) and completed an egocentric network inventory assessing perceptions of their social network members' (alters') injunctive and descriptive norms surrounding sexual behaviors with increased HIV vulnerability. We used Latent Profile Analysis (LPA) to identify network-level norms based on the proportion of alters' approval of the participant engaging in condomless sex, group sex, and use of drugs to enhance sex (i.e., injunctive norms) and alters' engagement in these behaviors (i.e., descriptive norms). We then used binomial regression analyses to examine associations between network-level norm profiles and individual-level HIV vulnerability from sex. The results of our LPA indicated that our sample experienced five distinct latent profiles of network-level norms: (1) low HIV vulnerability network norm, (2) moderately high HIV vulnerability network norm, (3) high HIV vulnerability network norm, (4) condomless sex dominant network norm, and (5) approval of drug use during sex dominant network norm. Condomless anal sex, group sex, and using drugs to enhance sex were positively and significantly associated with higher HIV vulnerability social network norm profiles, relative to low HIV vulnerability norm profiles. To mitigate Black SGM's HIV vulnerability, future HIV risk reduction strategies can consider using network-level intervention approaches such as opinion leaders, segmentation, induction, or alteration, through an intersectionality framework.

Social Network Influences on Adolescent E-cigarette Use

Background: Determine if individual adolescent vaping is associated with the vaping behavior of their school-based friendships; whether that association stems from peer influence or peer selection; and whether it varies by age. Methods: Two wave longitudinal survey of 1,208 students in one Midwestern US school district. Students were asked if they ever vaped and to name their seven closest friends within the school district. A roster of all eligible students was pre-loaded into the survey to facilitate network data collection. Terms for network exposure, the proportion of vaping friends; and selection, the number of new friends who vape, were created. Logistic regression and Stochastic Actor Oriented Models were used to test both influence and selection effects. Results: A cross-sectional logistic regression model indicated that friend vaping was associated with individual vaping (AOR = 4.96, p < 0.01); and lagged logistic models indicated that increased friend vaping was associated with individual vaping initiation (AOR = 1.72, p < 0.05). Selecting new friends who vape was also associated with becoming a vaper (AOR = 1.25, p < 0.01). Both influence and selection were present for those less than 14 years old. Conclusions: This is the first study to use social network analysis to show that adolescents who vape or initiate vaping are more likely to do so if their friends vape, and/or they make new friends who vape. Prevention and cessation programs should address the role of friend influence and selection on e-cigarette use; particularly at younger ages.

The State of Norm-Based Antismoking Research: Conceptual Frameworks, Research Designs, and Implications for Interventions

This synthesis review examined 189 qualified studies on norms and smoking in terms of conceptual frameworks, types of social norms, research designs, dependent variables, independent variables and covariates, and findings related to norms. Results show that 7.9% were experimental, and the remaining were cross-sectional. By far, the reasoned action approach (RAA) was the most-cited theory, but RAA was not used to guide experimental designs. The social norms approach, norm focus theory, social cognitive theory guided the intervention experiments. Harmful norms were more frequently examined than healthful norms. Pro-smoking norms positively predicted smoking intentions and behaviors, whereas antismoking norms positively predicted antismoking intentions and behaviors. The over-application of RAA in cross-sectional antismoking research has yielded repetitive findings. Norm-based experiments can adopt other theoretical perspectives to offer insights into antismoking interventions. The RAA constructs are still applicable and can be integrated into intervention designs.

Social network analysis to study health behaviours in adolescents: A systematic review of methods

PURPOSE

Our objectives were (i) to systematically review how SNA is used in studies investigating adolescent health behaviours (i.e., the purpose of using SNA, methods used for network data collection and analysis), and (ii) to develop methodological guidelines to help researchers use SNA in studies on adolescent health behaviours.

METHODS

Five databases were searched using keywords related to "social network analysis" and "adolescents". We extracted data from included articles pertaining to the choice of methods for network data collection and analysis. We used these data to develop a 5-step decision tree to help researchers make methodological decisions most appropriate to their research objectives.

RESULTS

A total of 201 articles were included. Most investigated tobacco (50%) or alcohol use (48%). SNA was used most often to examine processes related to peer selection or influence (37%) and/or to examine the effect of sociometric position on health behaviours (34%). 181 studies (90%) used a sociocentric approach for SNA, 16 studies (8%) used an egocentric approach, and 4 studies (2%) used both. We identified five decision-making steps in SNA including the choice of: (i) network boundary, (ii) SNA approach, (iii) methods for name generators, (iv) methods for name interpreters, and (iv) SNA indicators.

CONCLUSION

This study provides insights and guidance in a 5-step decision tree on practical and methodological considerations in using SNA to explore adolescent health behaviours.

Adolescent Body Mass Index and Exposure to Peers with Overweight and Obesity: A Structural Equation Model Approach to Longitudinal Network Data

Purpose: Considerable evidence has shown that social networks influence a wide variety of health behaviors. This study investigates whether having friends with overweight/obesity in one's social network (network exposure) can predict changes in body mass index (BMI) throughout high school in a diverse urban population of students. Methods: Racially and ethnically diverse students from five high schools in Los Angeles County were surveyed at four time points throughout high school from 2010 to 2013 (N = 2091). Surveys included questions on students' social networks, demographics, and health-related information. BMI and weight categories were calculated for all students who provided height and weight information (∼50%). A latent growth curve model was used to assess the growth trajectory of BMI and the time-varying effect of network exposure to friends with overweight/obesity while controlling for demographic covariates. Results: Hispanic students had a significantly higher initial BMI compared with non-Hispanic students (p < 0.01). There was a significant positive slope for time on BMI growth (p < 0.01). Greater personal network exposure to friends with overweight/obesity was associated with a significant 0.65-point average increase in BMI (p < 0.05) at the first follow-up time point (T2) and a significant 0.62-point average increase in BMI (p < 0.01) at the last follow-up (T4) while controlling for covariates. Conclusions: Using structural equation modeling to understand the relationship between BMI and social networks, we found that increased network exposure to peers with overweight/obesity is associated with higher individual BMI, demonstrating that friendships may influence adolescents' weight status over time.

Assessing Social Network Influences on Adult Physical Activity Using Social Network Analysis: A Systematic Review

OBJECTIVE

Social network analysis (SNA) can measure social connectedness and assess impact of interpersonal connections on health behaviors, including physical activity (PA). This paper aims to systematically review adult PA studies using SNA to understand important social network concepts relative to PA.

DATA SOURCE

A search was performed using PsycINFO, MEDLINE, PubMed, and Web of Science.

STUDY INCLUSION AND EXCLUSION CRITERIA

To be included in the search, articles needed to 1) include a measure of PA, 2) conduct an SNA in which specific relationships were measured, and 3) conduct an analysis between social network measures and PA.

DATA EXTRACTION

Key study elements including network design and results were extracted.

DATA SYNTHESIS

Data were synthesized to answer 2 questions: 1) how has adult PA been investigated using SNA approaches and 2) how is an adult's social network associated with PA behaviors?

RESULTS

A final sample of 28 articles remained from an initial 11 085 articles. Network size, homophily, network composition, and network exposure to PA were all associated with individual level PA across studies. Lastly, longitudinal and intervention studies showed a more complex picture of social influence and diffusion of PA behavior.

CONCLUSIONS

Adults' PA behaviors are influenced by their networks. Capitalizing on this influence, researchers should engage not just individual behavior change but also the social influences present within the person's life.

Social norms as a predictor of smoking uptake among youth: a systematic review, meta-analysis and meta-regression of prospective cohort studies

BACKGROUND AND AIMS

Social norms towards smoking are a key concept in tobacco control policy and research. However, the influence and strength of different types of social norms on youth smoking uptake is unclear. This study aimed to examine, quantify and compare evidence of the longitudinal associations between different types of social norms towards smoking and youth smoking uptake (initiation and escalation).

METHODS

Systematic review searching four databases (MEDLINE, EMBASE, PsycInfo, CINAHL) from January 1998 to October 2020. Evidence synthesis via narrative review, meta-analysis pooling unadjusted associations (initiation only, due to heterogeneity in escalation outcomes) and meta-regression comparing effect sizes by norm type and study characteristics. Studies included observational prospective cohort studies using survey methodology with youth aged ≤24 years. Measurements included longitudinal associations between descriptive norms (perceived smoking behaviour) and injunctive norms (perceived approval/disapproval of smoking) among social network(s) and subsequent smoking initiation or escalation.

RESULTS

Thirty articles were identified. In the narrative review, smoking initiation (but not escalation) was consistently predicted by two norms: parental and close friend smoking. Associations between smoking uptake and other descriptive norms (smoking among siblings, family/household, partner, peers, adults) and all injunctive norms (perceived approval of smoking among parents, siblings, close friends/peers, partner, teachers, people important to you, the public) were less consistent or inconclusive. In the meta-analysis pooling unadjusted associations, 17 articles were included (n = 27 767). Smoking initiation was predicted by the following descriptive norms: smoking among parents [Odds Ratio (OR) = 1.88, 95% Confidence Interval (CI) = 1.56-2.28], close friends (OR = 2.53, 95% CI = 1.99-3.23), siblings (OR = 2.44, 95% CI = 1.93-3.08), family/household (OR = 1.55, 95% CI = 1.36-1.76) and adults (OR = 1.34, 95% CI = 1.02-1.75), but not peers (OR = 1.14, 95% CI = 0.92-1.42). Smoking initiation was also predicted by two injunctive norms, perceived approval of smoking among parents (OR = 1.74, 95% CI = 1.27-2.38) and the public (OR = 4.57, 95% CI = 3.21-6.49), but not close friends/peers (OR = 2.36, 95% CI = 0.86-6.53) or people important to the individual (OR = 1.24, 95% CI = 0.98-1.58).

CONCLUSIONS

In this systematic review (narrative and meta-analysis), descriptive norms of parents' and close friends' smoking behaviour appeared to be consistent predictors of youth smoking initiation, more so than the descriptive norms of more distal social networks and injunctive norms.

Peer effects in smoking cessation: An instrumental variables analysis of a worksite intervention in Thailand

While smoking is widely acknowledged to be a social activity, limited evidence exists on the extent to which friends influence each other during worksite-based tobacco cessation interventions. Drawing on data from adult smokers (N = 1823) in a large, cluster randomized controlled trial in worksites in Thailand, this study examines the presence of social spillovers in the decision to abstain from smoking. We leverage a unique aspect of social network structure in these data-the existence of non-overlapping friendship networks-to address the challenge of isolating the effects of peers on smoking behavior from the confounding effects of endogenous friend selection and bidirectional peer influence. We find that individuals with workplace friends who have abstained from smoking during the trial are significantly more likely to abstain themselves. Instrumental variables estimates suggest that abstinence after 3 and 12 months increases 26 and 32 percentage points, respectively, for each additional workplace friend who abstains. These findings highlight the potential for workplace interventions to use existing social networks to magnify the effect of individual-level behavior change, particularly in low- and middle-income countries where tobacco cessation support tends to be limited.

Adolescent Depression and Substance Use: the Protective Role of Prosocial Peer Behavior

Adolescents with depression disorders have higher rates of substance use. In order to advance contextually relevant mental health interventions, basic research is needed to test social ecological mechanisms hypothesized to influence adolescent depression and substance use. Accordingly, we conducted growth curve modeling with a sample of 248 urban adolescents to determine if depression's effect on substance use was dependent upon peer network health (sum of peer risk and protective behaviors) and activity space risk (likelihood of high-risk behaviors at routine locations). Results showed that peer network health moderated the effects of depression on substance use, but this effect was not altered by activity space risk. These findings suggest the importance of peer network health relative to depression and substance use, particularly for young adolescents.

Egocentric social network correlates of physical activity

BACKGROUND

The social environment might play an important role in explaining people's physical activity (PA) behavior. However, little is known regarding whether personal networks differ between physically active and physically inactive people. This study aimed to examine the relationship between personal network characteristics and adults' physical (in)activity.

METHODS

An egocentric social network study was conducted in a random sample in Switzerland (n = 529, mean age of 53 years, 54% females). Individual and personal network measures were compared between regular exercisers and non-exercisers. The extent of these factors' association with PA levels was also examined.

RESULTS

Non-exercisers (n = 183) had 70% non-exercising individuals in their personal networks, indicating homogeneity, whereas regular exercisers (n = 346) had 57% regularly exercising individuals in their networks, meaning more heterogeneous personal networks. Additionally, having more regular exercisers in personal networks was associated with higher PA levels, over and above individual factors. Respondents with an entirely active personal network reported, on average, 1 day of PA more per week than respondents who had a completely inactive personal network. Other personal network characteristics, such as network size or gender composition, were not associated with PA.

CONCLUSION

Non-exercisers seem to be clustered in inactive networks that provide fewer opportunities and resources, as well as less social support, for PA. To effectively promote PA, both individuals and personal networks need to be addressed, particularly the networks of inactive people (e.g., by promoting group activities).

Perceived Social Acceptability and Longitudinal Trends in Adolescent Cigarette Smoking

The current study uses methods from social network analysis to predict longitudinal trends in adolescent cigarette smoking based on perceived social acceptability from friends, in addition to typical measures of peer influence (e.g., self-reported cigarette use of friends). By concurrently investigating the role of perceived social acceptability of smoking and peer influence, the current study offers new insight into the mechanisms through which peers influence adolescent smoking. Two waves of data from five high schools within one US school district (n = 1563) were used. Stochastic actor-based models simultaneously estimated changes in smoking predicted by perceived social acceptability and peer influence. Findings demonstrate that adolescents with higher perceived social acceptability of cigarette use increased cigarette smoking over time. Conversely, support for peer influence on smoking was not found after controlling for the effects of perceived social acceptability. The results suggest that perceived social acceptability regarding cigarette smoking rather than self-report of cigarette use among friends is predictive of future smoking behavior. Consequently, the findings highlight the need for prevention efforts to take into account the multifaceted dynamics between adolescent smoking and friendships. Programs that address peer influence alone, without considering peer mechanisms such as perceived social acceptability, are at risk of ignoring critical avenues for prevention.

How the Structure of Egocentric Facebook Networks is Associated With Exposure to Risky Content for Maltreated versus Comparison Youth

The current study examined the size and connectedness of egocentric Facebook networks as predictors of exposure to risky content among a sample of maltreated and comparison youth (n=118). Social network measures (i.e., size, density, average degree, percent of isolates) were computed from the mutual friend list. A content analysis of posts by friends captured references to alcohol use, marijuana use, partying, and sexual content. Multiple-group path models showed that the larger size of the Facebook network and higher average degree predicted references to marijuana use only for comparison youth, whereas for maltreated youth a higher percent of isolates predicted more references to sexual content by Facebook friends. Structural measures of online networks may have potential utility for identifying those at risk.

Peer social network processes and adolescent health behaviors: A systematic review

Research has highlighted the importance of peers for determining health behaviors in adolescents, yet these behaviors have typically been investigated in isolation. We need to understand common network processes operating across health behaviors collectively, in order to discern how social network processes impact health behaviors. Thus, this systematic review of studies investigated adolescent peer social networks and health behaviors. A search of six databases (CINAHL, Education Resources Information Centre, Embase, International Bibliography of the Social Sciences, Medline and PsycINFO) identified 55 eligible studies. The mean age of the participants was 15.1 years (range 13-18; 51.1% female). Study samples ranged from 143 to 20,745 participants. Studies investigated drinking (31%), smoking (22%), both drinking and smoking (13%) substance use (18%), physical activity (9%) and diet or weight management (7%). Study design was largely longitudinal (n = 41, 73%) and cross-sectional (n = 14, 25%). All studies were set in school and all but one study focused on school-based friendship networks. The Newcastle-Ottawa Scale was used to assess risk of bias: studies were assessed as good (51%), fair (16%) or poor (33%). The synthesis of results revolved around two network behavior patterns: 1) health behavior similarity within a social network, driven by homophilic social selection and/or social influence, and 2) popularity: health behavior engagement in relation to changes in social status; or network popularity predicting health behaviors. Adolescents in denser networks had statistically significant lower levels of harmful behavior (n = 2/2, 100%). Findings suggest that social network processes are important factors in adolescent health behaviors.

Smoking Diffusion through Networks of Diverse, Urban American Adolescents over the High School Period

This study uses recent data to investigate if smoking initiation diffuses through friendship networks over the high school period and explores if diffusion processes differ across schools. One thousand four hundred and twenty-five racially and ethnically diverse youth from four high schools in Los Angeles were surveyed four times over the high school period from 2010 to 2013. Probit regression models and stochastic actor-based models for network dynamics tested for peer effects on smoking initiation. Friend smoking was found to predict adolescent smoking, and smoking initiation diffused through friendship networks in some but not all of the schools. School differences in smoking rates and the popularity of smokers may be linked to differences in the diffusion of smoking through peer networks. We conclude that there are differences in peer effects on smoking initiation across schools that will be important to account for in network-based smoking interventions.

The accuracy of young adult cannabis users' perceptions of friends' cannabis and alcohol use

OBJECTIVE

Understanding the complex influence of peers on young adult substance use is an important component of intervention research and is challenging methodologically. The false consensus theory suggests that individuals falsely attribute their own substance use behaviors onto others, producing biased data.

METHODS

We tested this theory with 39 young adults who had a cannabis use disorder and a mean age of 20. Participants (egos) recruited three of their close friends (alters). Egos reported their past 30-day cannabis and alcohol use and their perceptions of alters' use. Alters also reported their actual past 30-day cannabis and alcohol use.

RESULTS

Results demonstrated that egos were very accurate in their perceptions of the frequency of alters' cannabis (ρ = 0.82, p < 0.001) and alcohol (ρ = 0.74, p < 0.001) use. Linear regression models predicted alters' actual cannabis and alcohol use based on egos' perceptions of alters' use, controlling for egos' own substance use. Egos' perceptions of alters' cannabis use strongly predicted alters' actual use (β = 0.80, p < 0.001, adj-R² = 0.67), and egos' perceptions of alters' alcohol use also predicted alters' actual use (β = 0.66, p < 0.001, adj-R² = 0.62). Egos' own substance use did not predict alters' use in either model.

CONCLUSIONS

Results provide evidence that the false consensus theory may be limited when applied to young adults with cannabis use disorder within a close-friend research framework. The results support the hypothesis that young adults are very accurate in their perceptions of the frequency of close friends' substance use and that these perceptions are independent of egos' own use. These findings support the continued use of ego-centric reported close peer substance use for understanding peer effects.

The Influence of Online-Only Friends on the Substance Use of Young Adults with a History of Childhood Maltreatment

BACKGROUND

Existing research shows that having offline friends that use substances increases risk for individual substance use in adolescence. However, there is little research examining the influence of online social networks on substance use in young adulthood.

OBJECTIVES

This study examined the number of online-only Facebook friends (i.e. those with no in-person contact) that were substance users in relation to the participants' alcohol and marijuana use in the past year.

METHODS

The sample (n = 114) were selected from participants enrolled in a longitudinal study on childhood maltreatment in an urban city within the United States. The mean age of the sample was 21.84 (SD = 1.43), 61% female. With participant permission, data were downloaded from Facebook to obtain the list of online friends. A self-report questionnaire recorded the substance use of each participant. Path analysis and logistic regression were used to examine (a) the number of online-only friends who drink as a predictor of participants' problem drinking, (b) the number of online-only friends who smoke marijuana as a predictor of participants' marijuana use, and (c) moderation by maltreatment status.

RESULTS

The results showed a significant effect of the number of online-only friends who smoke marijuana on the participant's marijuana use. However, after including offline friends this significant effect was no longer present, but offline friends predicted individual marijuana use. Conclusions/Importance: These findings demonstrate that substance use in online social networks may be associated with individual use in young adulthood, but that offline influence is stronger.

Assessment of Exposure to High-Performing Schools and Risk of Adolescent Substance Use: A Natural Experiment

IMPORTANCE

Although school environments are thought to influence health behaviors, experimental data assessing causality are lacking, and which aspects of school environments may be most important for adolescent health are unknown.

OBJECTIVE

To test whether exposure to high-performing schools is associated with risky adolescent health behaviors.

DESIGN, SETTING, AND PARTICIPANTS

This natural experiment used admission lotteries, which mimic random assignment, to estimate the association of school environments and adolescent health. A survey of 1270 students who applied to at least 1 of 5 high-performing public charter schools in low-income minority communities in Los Angeles, California. Schools had an academic performance ranked in the top tertile of Los Angeles County public high schools, applicants outnumbered available seats by at least 50, and an admissions lottery was used. Participants included lottery winners (intervention group [n = 694]) and lottery losers (control group [n = 576]) from the end of 8th grade and beginning of 9th grade through the end of 11th grade. Intention-to-treat (ITT) and instrumental variable techniques estimated the association of winning the lottery and attending high-performing schools with health behaviors and whether the association varied by sex. Data were collected from March 11, 2013, through February 22, 2017, and analyzed from October 1, 2017, through July 1, 2018.

EXPOSURES

Schools were considered high performing if they placed in the top tercile of public high schools in LA County on 2012 state standardized tests. Most students attended that same school for 3 years (9th-11th grades).

MAIN OUTCOMES AND MEASURES

Primary self-reported outcomes were 30-day and high-risk self-reported marijuana use. Additional health outcomes included 30-day alcohol use, alcohol misuse, ever being in a fight, ever having sex, and past-year delinquency. Potential intermediate factors (time studying, truancy, school mobility, school culture, school order, teacher support for college, and proportion of substance-using peers in students' social networks) were also examined.

RESULTS

Among the 1270 participating students (52.6% female; mean [SD] age at enrollment, 14.3 [0.5] years), ITT analysis showed that the intervention group reported less marijuana misuse than the control group (mean marijuana misuse score, 0.46 vs 0.71), as well as fewer substance-using peers (9.6% vs 12.7%), more time studying (mean, 2.63 vs 2.49 hours), less truancy (84.3% vs 77.3% with no truancy), greater teacher support for college (mean scores, 7.20 vs 7.02), more orderly schools (mean order score, 7.06 vs 6.83), and less school mobility (21.4% vs 28.4%) (all P < .05). Stratified analyses suggest that among boys, intervention participants had significantly lower marijuana use (mean misuse score, 0.43 vs 0.88; difference, -0.45; 95% CI, -0.78 to -0.13) and alcohol misuse (mean misuse score, 0.52 vs 0.97; difference, -0.44; 95% CI, -0.80 to -0.09) scores compared with control participants, whereas no significant health outcomes were noted for girls.

CONCLUSIONS AND RELEVANCE

This natural experiment provides evidence that school environments can improve risky behaviors for low-income minority adolescents.

Structural characteristics of the online social networks of maltreated youth and offline sexual risk behavior

Maltreated youth are at risk for exposure to online sexual content and high-risk sexual behavior, yet characteristics of their online social networks have not been examined as a potential source of vulnerability. The aims of the current study were: 1) to test indicators of size (number of friends) and fragmentation (number of connections between friends) of maltreated young adults' online networks as predictors of intentional and unintentional exposure to sexual content and offline high-risk sexual behavior and 2) to test maltreatment as a moderator of these associations. Participants were selected from a longitudinal study on the effects of child maltreatment (n = 152; Mean age 21.84 years). Data downloaded from Facebook were used to calculate network variables of size (number of friends), density (connections between friends), average degree (average number of connections for each friend), and percent isolates (those not connected to others in the network). Self-reports of intentional and unintentional exposure to online sexual content and offline high-risk sexual behavior were the outcome variables. Multiple-group path modeling showed that only for the maltreated group having a higher percent of isolates in the network predicted intentional exposure to online sexual content and offline high-risk sexual behavior. An implication of this finding is that the composition of the Facebook network may be used as a risk indicator for individuals with child-welfare documented maltreatment experiences.

Egocentric networks and physical activity outcomes in Latinas

OBJECTIVE

Despite data linking the social environment to physical inactivity in Latinas, research on social network predictors of physical activity (PA) is limited. This study examined social network predictors of PA change in Latinas.

METHODS

Egocentric network data were collected from 102 adult Latinas (egos) participating in a randomized controlled PA intervention trial for underactive women. Moderate-to-vigorous PA (MVPA) was measured in minutes per week using the 7-Day PA Recall Interview and accelerometers at baseline and 12 months. Analyses characterized social network structure, composition, tie strength, homogeneity, and support for PA and determined the relationship between network characteristics and PA outcomes.

RESULTS

Networks had an average of four social ties (alters). Networks were high in density and transitivity and low in components, indicating high cohesion. Networks were primarily composed of females, Latinos, Spanish-speakers, and family members. Relationship ties were strong as evidenced by close living proximity, in-person contact, high emotional closeness, and long relationship duration. There was high homogeneity in demographics and PA behaviors. Multivariate analyses revealed that network size, familial ties, contact frequency, and ego-alter dissimilarities in age and running but similarities in walking, were associated with increased MVPA. Networks high in support for PA in the form of complimenting ego on exercise, taking over chores to allow ego to exercise, and co-participating with ego in exercise were also associated with greater MVPA.

CONCLUSION

These findings contribute to better understanding interpersonal processes that may influence behavior change in a group with especially low levels of PA.

Network analysis of the NetHealth data: exploring co-evolution of individuals' social network positions and physical activities

Understanding the relationship between individuals' social networks and health could help devise public health interventions for reducing incidence of unhealthy behaviors or increasing prevalence of healthy ones. In this context, we explore the co-evolution of individuals' social network positions and physical activities. We are able to do so because the NetHealth study at the University of Notre Dame has generated both high-resolution longitudinal social network (e.g., SMS) data and high-resolution longitudinal health-related behavioral (e.g., Fitbit physical activity) data. We examine trait differences between (i) users whose social network positions (i.e., centralities) change over time versus those whose centralities remain stable, (ii) users whose Fitbit physical activities change over time versus those whose physical activities remain stable, and (iii) users whose centralities and their physical activities co-evolve, i.e., correlate with each other over time. We find that centralities of a majority of all nodes change with time. These users do not show any trait difference compared to time-stable users. However, if out of all users whose centralities change with time we focus on those whose physical activities also change with time, then the resulting users are more likely to be introverted than time-stable users. Moreover, users whose centralities and physical activities both change with time and whose evolving centralities are significantly correlated (i.e., co-evolve) with evolving physical activities are more likely to be introverted as well as anxious compared to those users who are time-stable and do not have a co-evolution relationship. Our network analysis framework reveals several links between individuals' social network structure, health-related behaviors, and the other (e.g., personality) traits. In the future, our study could lead to development of a predictive model of social network structure from behavioral/trait information and vice versa.

Associations between friendship characteristics and HIV and HSV-2 status amongst young South African women in HPTN-068

INTRODUCTION

Prevalence of HIV among young women in South Africa remains extremely high. Adolescent peer groups have been found to be an important influence on a range of health behaviours. The characteristics of young women's friendships might influence their sexual health and HIV risk via connections to sexual partners, norms around sexual initiation and condom use, or provision of social support. We investigated associations between young women's friendships and their Herpes Simplex Virus Type 2 (HSV-2) and HIV infection status in rural South Africa.

METHODS

Our study is a cross-sectional, egocentric network analysis. In 2011 to 2012, we tested 13- to 20-year-old young women for HIV and HSV-2, and collected descriptions of five friendships for each. We generated summary measures describing friend socio-demographic characteristics and the number of friends perceived to have had sex. We used logistic regression to analyse associations between friend characteristics and participant HIV and HSV-2 infection, excluding likely perinatal HIV infections.

RESULTS

There were 2326 participants included in the study sample, among whom HIV and HSV-2 prevalence were 3.3% and 4.6% respectively. Adjusted for participant and friend socio-demographic characteristics, each additional friend at least one year older than the participant was associated with raised odds of HIV (odds ratio (OR) = 1.37, 95% CI 1.03 to 1.82) and HSV-2 (adjusted OR=1.41, 95% CI 1.18 to 1.69). Each additional friend perceived to have ever had sex also raised the odds of HIV (OR = 1.29, 95% CI 1.03 to 1.63) and HSV-2 (OR=1.18, 95% CI 1.03 to 1.35).

DISCUSSION

We found good evidence that a greater number of older friends and friends perceived to have had sex were associated with increased risk for HSV-2 and HIV infection among young women.

CONCLUSIONS

The characteristics of young women's friendships could contribute to their risk of HIV infection. The extent to which policies or programmes influence age-mixing and young women's normative environments should be considered.

National substance use patterns on Twitter

Purpose

We examined openly shared substance-related tweets to estimate prevalent sentiment around substance use and identify popular substance use activities. Additionally, we investigated associations between substance-related tweets and business characteristics and demographics at the zip code level.

Methods

A total of 79,848,992 tweets were collected from 48 states in the continental United States from April 2015-March 2016 through the Twitter API, of which 688,757 were identified as being related to substance use. We implemented a machine learning algorithm (maximum entropy text classifier) to estimate sentiment score for each tweet. Zip code level summaries of substance use tweets were created and merged with the 2013 Zip Code Business Patterns and 2010 US Census Data.

Results

Quality control analyses with a random subset of tweets yielded excellent agreement rates between computer generated and manually generated labels: 97%, 88%, 86%, 75% for underage engagement in substance use, alcohol, drug, and smoking tweets, respectively. Overall, 34.1% of all substance-related tweets were classified as happy. Alcohol was the most frequently tweeted substance, followed by marijuana. Regression results suggested more convenience stores in a zip code were associated with higher percentages of tweets about alcohol. Larger zip code population size and higher percentages of African Americans and Hispanics were associated with fewer tweets about substance use and underage engagement. Zip code economic disadvantage was associated with fewer alcohol tweets but more drug tweets.

Conclusions

The patterns in substance use mentions on Twitter differ by zip code economic and demographic characteristics. Online discussions have great potential to glorify and normalize risky behaviors. Health promotion and underage substance prevention efforts may include interactive social media campaigns to counter the social modeling of risky behaviors.

An exploration of the Facebook social networks of smokers and non-smokers

BACKGROUND

Social networks influence health behavior, including tobacco use and cessation. To date, little is known about whether and how the networks of online smokers and non-smokers may differ, or the potential implications of such differences with regards to intervention efforts. Understanding how social networks vary by smoking status could inform public health efforts to accelerate cessation or slow the adoption of tobacco use.

OBJECTIVES

These secondary analyses explore the structure of ego networks of both smokers and non-smokers collected as part of a randomized control trial conducted within Facebook.

METHODS

During the trial, a total of 14,010 individuals installed a Facebook smoking cessation app: 9,042 smokers who were randomized in the trial, an additional 2,881 smokers who did not meet full eligibility criteria, and 2,087 non-smokers. The ego network for all individuals was constructed out to second-degree connections. Four kinds of networks were constructed: friendship, family, photo, and group networks. From these networks we measured edges, isolates, density, mean betweenness, transitivity, and mean closeness. We also measured diameter, clustering, and modularity without ego and isolates. Logistic regressions were performed with smoking status as the response and network metrics as the primary independent variables and demographics and Facebook utilization metrics as covariates.

RESULTS

The four networks had different characteristics, indicated by different multicollinearity issues and by logistic regression output. Among Friendship networks, the odds of smoking were higher in networks with lower betweenness (p = 0.00), lower transitivity (p = 0.00), and larger diameter (p = 0.00). Among Family networks, the odds of smoking were higher in networks with more vertices (p = .01), less transitivity (p = .04), and fewer isolates (p = .01). Among Photo networks, none of the network metrics were predictive of smoking status. Among Group networks, the odds of smoking were higher when diameter was smaller (p = .04). Together, these findings suggested that compared to non-smokers, smokers in this sample had less connected, more dispersed Facebook Friendship networks; larger but more fractured Family networks with fewer isolates; more compact Group networks; and Photo networks that were similar in network structure to those of non-smokers.

CONCLUSIONS

This study illustrates the importance of examining structural differences in online social networks as a critical component for network-based interventions and lays the foundation for future research that examines the ways that social networks differ based on individual health behavior. Interventions that seek to target the behavior of individuals in the context of their social environment would be well served to understand social network structures of participants.

The influence of peer behavior as a function of social and cultural closeness: A meta-analysis of normative influence on adolescent smoking initiation and continuation

Although the influence of peers on adolescent smoking should vary depending on social dynamics, there is a lack of understanding of which elements are most crucial and how this dynamic unfolds for smoking initiation and continuation across areas of the world. The present meta-analysis included 75 studies yielding 237 effect sizes that examined associations between peers' smoking and adolescents' smoking initiation and continuation with longitudinal designs across 16 countries. Mixed-effects models with robust variance estimates were used to calculate weighted-mean Odds ratios. This work showed that having peers who smoke is associated with about twice the odds of adolescents beginning (OR ¯ = 1.96, 95% confidence interval [CI] [1.76, 2.19]) and continuing to smoke (OR ¯ = 1.78, 95% CI [1.55, 2.05]). Moderator analyses revealed that (a) smoking initiation was more positively correlated with peers' smoking when the interpersonal closeness between adolescents and their peers was higher (vs. lower); and (b) both smoking initiation and continuation were more positively correlated with peers' smoking when samples were from collectivistic (vs. individualistic) cultures. Thus, both individual as well as population level dynamics play a critical role in the strength of peer influence. Accounting for cultural variables may be especially important given effects on both initiation and continuation. Implications for theory, research, and antismoking intervention strategies are discussed. (PsycINFO Database Record

Developmental pathways from maltreatment to risk behavior: Sexual behavior as a catalyst

Although delinquency, substance use, and sexual activity are established to be highly intercorrelated, the extant research provides minimal evidence in support of one particular sequence of risk behavior or on the cascade effects from maltreatment. The present study tested a longitudinal model incorporating maltreatment, deviant peers, sexual behavior, delinquency, and substance use to elucidate the sequential pathway(s) from maltreatment to each specific risk behavior throughout adolescence. Data came from a longitudinal study on the effects of maltreatment on adolescent development (N = 454) with four study assessments from early (Time 1 M age = 10.98) to late adolescence (Time 4 M age = 18.22). Results from the cross-lagged model showed a sequence from maltreatment to sexual behavior (Time 1), to delinquency (Time 2), to sexual behavior (Time 3), to substance use and delinquency (Time 4). These findings support sexual behavior as the initial risk behavior that is the catalyst for engagement in more advanced risk behaviors across adolescence.

The role of smoking in social networks on smoking cessation and relapse among adults: A longitudinal study

Understanding the spread of smoking cessation and relapse within social networks may offer new approaches to further curb the smoking epidemic. Whether smoking behavior among social network members determines smoking cessation and relapse of adults however, is less known. For this study, longitudinal data of 4623 adults participating in the Dutch Longitudinal Internet Studies for the Social sciences (LISS) panel were collected in March 2013 with a follow-up in 2014. Logistic regression was used to examine the association between the proportion of smokers in social networks, and (1) smoking cessation (n=762) and (2) smoking relapse (n=1905). Analyses were adjusted for the size of the network, age, sex, and education. Respondents with the largest proportion of smokers in their social network were less likely to quit smoking (OR=0.25; 95% CI=0.11-0.66) and more likely to experience a relapse (6.08; 3.01-12.00). Smoking cessation and relapse were most strongly associated with the proportion of smokers among household members and friends. The proportion of smokers in family outside the household was not related to smoking cessation and smoking relapse. In conclusion, smoking behavior in social networks, especially among household members and friends, is strongly associated with smoking cessation and relapse. These findings further support the spread of smoking within social networks, and provide evidence for network-based interventions, particularly including household members and friends.

Lessons from a peer-led obesity prevention programme in English schools

Obesity in young people is a major public health concern. Energy balance, the interrelationship between diet and physical activity, is known to be a key determinant. Evidence supports the development of school-based approaches to obesity prevention. ASSIST (A Stop Smoking in Schools Trial) is an effective school-based, peer-led smoking prevention programme for 12-13-year-old students, based on diffusion of innovations theory. The AHEAD (Activity and Healthy Eating in ADolescence) study tested the feasibility of adapting ASSIST to an obesity prevention intervention. The AHEAD intervention was tested and refined during a pilot study in one school, followed by an exploratory trial in six schools. Quantitative (self-report behavioural questionnaires and evaluation forms) and qualitative (structured observations, focus groups and interviews) research methods were used to examine the implementation and acceptability of the intervention. The potential effectiveness of the intervention in increasing healthy eating was measured using self-report behavioural questionnaires. Activity monitors (accelerometers) were used to measure physical activity. Results show it was feasible to implement the AHEAD intervention, which was well received. However, implementation was resource and labour intensive and relatively expensive. Furthermore, there was no evidence of promise that the intervention would increase physical activity or healthy eating in adolescents. Although diet and physical activity are both relevant for obesity prevention, the focus on two behaviours appeared too complex for informal diffusion through peer networks. This identifies a tension, particularly for adolescent peer-led health promotion, between the desire not to isolate or oversimplify health behaviours and the need to present clear, succinct health promotion messages.

Adolescent Social Networks and Alcohol Use: Variability by Gender and Type

BACKGROUND

Scientists have established that social networks influence adolescents' substance use behavior, an influence that varies by gender. However, the role of gender in this mechanism of influence remains poorly understood. Particularly, the role an adolescent's gender, alongside the gender composition of his/her network, plays in facilitating or constraining alcohol use is still unclear.

OBJECTIVES

This study examined the associations among the gender composition of adolescents' networks, select network characteristics, intrapersonal and interpersonal factors, and alcohol use among a sample of adolescents in the United States.

METHODS

We assessed cross-sectional data from a 2010 study of 1,523 high school students from a school district in Los Angeles. Analyses of adolescents' network characteristics were conducted using UCINET 6; and logistic regression analyses testing the associations between gender composition of the network and alcohol use were conducted using SPSS 20.

RESULTS

Our results indicate that the gender composition of adolescents' networks in our sample is associated with alcohol use. Adolescents in predominantly female or predominantly male friendship networks were less likely to report alcohol use compared to adolescents in an equal/balanced network. In addition, depending upon the context/type of network, intrapersonal and interpersonal factors varied in their association with alcohol use. Conclusions/Importance: Based on these findings, we make several recommendations for the future research. We call for researchers to further examine gender as a risk factor for alcohol abuse, particularly within the complex interplay between gender and network contexts.

An Appraisal of Social Network Theory and Analysis as Applied to Public Health: Challenges and Opportunities

The use of social network theory and analysis methods as applied to public health has expanded greatly in the past decade, yielding a significant academic literature that spans almost every conceivable health issue. This review identifies several important theoretical challenges that confront the field but also provides opportunities for new research. These challenges include (a) measuring network influences, (b) identifying appropriate influence mechanisms, (c) the impact of social media and computerized communications, (d) the role of networks in evaluating public health interventions, and (e) ethics. Next steps for the field are outlined and the need for funding is emphasized. Recently developed network analysis techniques, technological innovations in communication, and changes in theoretical perspectives to include a focus on social and environmental behavioral influences have created opportunities for new theory and ever broader application of social networks to public health topics.

Identifying Well-Connected Opinion Leaders for Informal Health Promotion: The Example of the ASSIST Smoking Prevention Program

Methods used to select opinion leaders for informal behavior change interventions vary, affecting the role they adopt and the outcomes of interventions. The development of successful identification methods requires evidence that these methods achieve their aims. This study explored whether the "whole community" nomination process used in the ASSIST smoking prevention program successfully identified "peer supporters" who were well placed within their school social networks to diffuse an antismoking message to their peers. Data were collected in the United Kingdom during A Stop Smoking in Schools Trial. Behavioral data were provided at baseline and post intervention by all students. Social network data were provided post intervention by students in four control and six intervention schools. Centrality measures calculated using UCINET demonstrate that the ASSIST nomination process successfully identified peer supporters who were more socially connected than others in their year and who had social connections across the entire year group including the program's target group. The results indicate that three simple questions can identify individuals who are held in high esteem by their year group and who also have the interpersonal networks required of opinion leaders to successfully disseminate smoke-free messages through their social networks. This approach could be used in other informal health promotion initiatives.

A youth-led social marketing intervention to encourage healthy lifestyles, the EYTO (European Youth Tackling Obesity) project: a cluster randomised controlled0 trial in Catalonia, Spain

Background

The encouragement of healthy lifestyles for obesity prevention in young people is a public health priority. The European Youth Tackling Obesity (EYTO) project is a multicentric intervention project with participation from the United Kingdom, Portugal, the Czech Republic and Spain. The general aim of the EYTO project is to improve lifestyles, including nutritional habits and physical activity practice, and to prevent obesity in socioeconomically disadvantaged and vulnerable adolescents. The EYTO project works through a peer-led social marketing intervention that is designed and implemented by the adolescents of each participating country. Each country involved in the project acts independently. This paper describes the “Som la Pera” intervention Spanish study that is part of the EYTO project.

Methods/Design

In Spain, the research team performed a cluster randomised controlled intervention over 2 academic years (2013–2015) in which 2 high-schools were designated as the control group and 2 high-schools were designated as the intervention group, with a minimum of 121 schoolchildren per group.

From the intervention group, 5 adolescents with leadership characteristics, called “Adolescent Challenge Creators” (ACCs), were recruited. These 5 ACCs received an initial 4 h training session about social marketing principles and healthy lifestyle theory, followed by 24 sessions (1.30 h/session) divided in two academic years to design and implement activities presented as challenges to encourage healthy lifestyles among their peers, the approximately 180–200 high-school students in the intervention group. During the design of the intervention, it was essential that the ACCs used the 8 social marketing criteria (customer orientation, behaviour, theory, insight, exchange, competition, segmentation and methods mix). The expected primary outcomes from the Spanish intervention will be as follows: increases in the consumption of fruits and vegetables and physical activity practice along with reductions in TV/computer/game console use. The secondary outcomes will be as follows: increased breakfast consumption, engagement with local recreation and reduced obesity prevalence. The outcomes will be measured by the Health Behaviour in School-aged Children Study (HBSC) survey at baseline and at the end of the intervention.

In the control group, no intervention was implemented, but the outcome measurements were collected in parallel with the intervention group.

Discussion

This study described a new methodology to improve lifestyles and to address adolescent obesity.

Trial registration

ClinicalTrials.gov: NCT02157402. Registered 03 June 2014.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-015-1920-1) contains supplementary material, which is available to authorized users.

Elucidating the mechanisms linking early pubertal timing, sexual activity, and substance use for maltreated versus nonmaltreated adolescents

PURPOSE

To test models linking pubertal timing, peer substance use, sexual behavior, and substance use for maltreated versus comparison adolescents. Three theoretical mechanisms were tested: (1) peer influence links early pubertal timing to later sexual behavior and substance use; (2) early maturers engage in substance use on their own and then select substance-using friends; or (3) early maturers initiate sexual behaviors which lead them to substance-using peers.

METHODS

The data came from a longitudinal study of the effects of child maltreatment on adolescent development (303 maltreated and 151 comparison adolescents; age, 9-13 years at initial wave). Multiple-group structural equation models tested the hypotheses across three time points including variables of pubertal timing, perception of peer substance use, sexual behavior, and self-reported substance use.

RESULTS

Early pubertal timing was associated with substance-using peers only for maltreated adolescents, indicating the mediation path from early pubertal timing through substance-using peers to subsequent adolescent substance use and sexual behavior only holds for maltreated adolescents. Mediation via sexual behavior was significant for both maltreated and comparison adolescents. This indicates that sexual behavior may be a more universal mechanism linking early maturation with risky friends regardless of adverse life experiences.

CONCLUSIONS

The findings are a step toward elucidating the developmental pathways from early puberty to risk behavior and identifying early experiences that may alter mediation effects.

Social network influences on initiation and maintenance of reduced drinking among college students

OBJECTIVE

To determine whether (a) social networks influence the extent to which college students initiate and/or maintain reductions in drinking following an alcohol intervention and (b) students with riskier networks respond better to a counselor-delivered, vs. a computer-delivered, intervention.

METHOD

Mandated students (N = 316; 63% male) provided their perceptions of peer network members' drinking statuses (e.g., heavy drinker) and how accepting each friend would be if the participant reduced his or her drinking. Next, they were randomized to receive a brief motivational intervention (BMI) or Alcohol Edu for Sanctions (EDU). In latent growth models controlling for baseline levels on outcomes, influences of social networks on 2 phases of intervention response were examined: initiation of reductions in drinks per heaviest week, peak blood alcohol content (BAC), and consequences at 1 month (model intercepts) and maintenance of reductions between 1 and 12 months (model slopes).

RESULTS

Peer drinking status predicted initiation of reductions in drinks per heaviest week and peak BAC; peer acceptability predicted initial reductions in consequences. Peer Acceptability × Condition interactions were significant or marginal for all outcomes in the maintenance phase. In networks with higher perceived acceptability of decreasing use, BMI and EDU exhibited similar growth rates. In less accepting networks, growth rates were significantly steeper among EDU than BMI participants. For consumption outcomes, lower perceived peer acceptability predicted steeper rates of growth in drinking among EDU but not BMI participants.

CONCLUSIONS

Understanding how social networks influence behavior change and how interventions mitigate their influence is important for optimizing efficacy of alcohol interventions.

The interaction of social networks and child obesity prevention program effects: the pathways trial

OBJECTIVE

Social network analysis was used to examine whether peer influence from one's social networks moderates obesity prevention program effects on obesity-related behaviors: healthful and unhealthful.

METHODS

Participants included 557 children residing in Southern California. The survey assessed health-promoting behaviors (i.e., physical activity at school, physical activity outside of school, and fruit and vegetable intake), as well as unhealthful behaviors (high-calorie, low-nutrient intake and sedentary activity), and peer exposure calculated from social network nominations as indicators of peer influence. Multilevel models were conducted separately on outcomes predicted by program participation, peer exposure, and program participation by peer exposure.

RESULTS

Results indicated that peer exposure was positively associated with one's own healthful and unhealthful behaviors. Program participation effects were moderated by peer influence, but only when unhealthful peer influence was present. Results suggest that peer influence can diminish or amplify prevention programs

CONCLUSION

Future interventions should consider peer-led components to promote healthful influence of peers on healthful and unhealthful behaviors, and programs should be mindful that their effects are moderated by social networks.

Multiplex congruity: friendship networks and perceived popularity as correlates of adolescent alcohol use

Adolescents interact with their peers in multiple social settings and form various types of peer relationships that affect drinking behavior. Friendship and popularity perceptions constitute critical relationships during adolescence. These two relations are commonly measured by asking students to name their friends, and this network is used to construct drinking exposure and peer status variables. This study takes a multiplex network approach by examining the congruity between friendships and popularity as correlates of adolescent drinking. Using data on friendship and popularity nominations among high school adolescents in Los Angeles, California (N = 1707; five schools), we examined the associations between an adolescent's drinking and drinking by (a) their friends only; (b) multiplexed friendships, friends also perceived as popular; and (c) congruent, multiplexed-friends, close friends perceived as popular. Logistic regression results indicated that friend-only drinking, but not multiplexed-friend drinking, was significantly associated with self-drinking (AOR = 3.51, p < 0.05). However, congruent, multiplexed-friend drinking also was associated with self-drinking (AOR = 3.10, p < 0.05). This study provides insight into how adolescent health behavior is predicated on the multiplexed nature of peer relationships. The results have implications for the design of health promotion interventions for adolescent drinking.

Peer influences: the impact of online and offline friendship networks on adolescent smoking and alcohol use

PURPOSE

Online social networking sites (SNSs) have become a popular mode of communication among adolescents. However, little is known about the effects of social online activity on health behaviors. The authors examined the use of SNSs among friends and the degree to which SNS activities relate to face-to-face peer influences and adolescent risk behaviors.

METHODS

Longitudinal egocentric friendship network data along with adolescent social media use and risk behaviors were collected from 1,563 10th-grade students across five Southern California high schools. Measures of online and offline peer influences were computed and assessed using fixed-effects models.

RESULTS

The frequency of adolescent SNS use and the number of their closest friends on the same SNSs were not significantly associated with risk behaviors. However, exposure to friends' online pictures of partying or drinking was significantly associated with both smoking (β = .11, p < .001) and alcohol use (β = .06, p < .05). Whereas adolescents with drinking friends had higher risk levels for drinking, adolescents without drinking friends were more likely to be affected by higher exposure to risky online pictures (β = -.10, p < .05). Myspace and Facebook had demographically distinct user characteristics and differential effects on risk behaviors.

CONCLUSIONS

Exposure to risky online content had a direct impact on adolescents' risk behaviors and significantly interacted with risk behaviors of their friends. These results provide evidence that friends' online behaviors should be considered a viable source of peer influence and that increased efforts should focus on educating adolescents on the negative effects of risky online displays.