Effect of the Smart Moms intervention on targeted mediators of change in child sugar-sweetened beverage intake.

OBJECTIVE: Few parent-targeted interventions have examined the mechanisms of action by which the intervention changes child behavior. The purpose of this study was to test the theoretical and behavioral mediators of the Smart Moms intervention on changes in child sugar-sweetened beverage and juice (SSB/juice) consumption. STUDY DESIGN: This is a secondary mediation analysis of data from a 6-month randomized controlled trial (N = 51 mother-child dyads) of a mobile phone-based program to reduce child SSB/juice intake compared with a waitlist control group. METHODS: Linear mixed models compared changes in intervention targets from baseline to 3 months between treatment groups. Intervention targets that changed significantly between groups were tested in a multiple mediation model to evaluate their significance as mediators of change in child SSB/juice at 6 months. RESULTS: Maternal beverage consumption but no other behavioral or theoretical intervention targets mediated the effect of the intervention on the reduction in child SSB/juice at 6 months. There were few mediators of the intervention on child SSB/juice change. CONCLUSION: Greater longitudinal research is needed to understand predictors of child dietary changes to inform future intervention efforts. In addition, a greater focus on the measurement of theoretical constructs in family-based child obesity prevention research is needed.

Evidence-based practice in school substance use prevention: fidelity of implementation under real-world conditions.

Fidelity of program implementation under real-world conditions is a critical issue in the dissemination of evidence-based school substance use prevention curricula. Program effects are diminished when programs are implemented with poor fidelity. We assessed five domains of fidelity--adherence, exposure (dosage), quality of delivery, participant responsiveness and program differentiation (lack of contamination from other programs)--in a subset of respondents (N = 342) from a national random sample of public schools with middle school grades (N = 1721). Respondents taught 1 of 10 evidence-based universal substance use prevention programs as their primary program during the 2004-05 school year. Their responses to survey questions about their recent implementation practices indicated that fidelity was high for quality of delivery and participant responsiveness, low for program differentiation and modest for adherence and exposure--the two core domains of fidelity. Results suggest the need for continued emphasis on fidelity in program materials, trainings and on-going technical support. Particular attention should be paid to supporting use of interactive delivery strategies.

A mHealth randomized controlled trial to reduce sugar-sweetened beverage intake in preschool-aged children.

BACKGROUND: Sugar-sweetened beverages and maternal weight are strong drivers of child obesity, but few studies have targeted these risk factors as an obesity prevention strategy in children. OBJECTIVE: The objective of this study was to test the efficacy of a smartphone-delivered intervention to reduce parent-provided sugar-sweetened beverage and juice (SSB/juice) consumption among children ages 3-5 and maternal weight. METHODS: Mothers with overweight or obesity, who had a child ages 3-5 that consumed at least 12 fl. oz./day of SSB/juice (N = 51 dyads) were randomized to the Smart Moms group that received one group session, lessons on a mobile website, and text messages, or to a waitlist control group. Mothers self-monitored their children's beverages in addition to their own beverages, high-calorie foods, and weight. Assessments at baseline, 3, and 6 months included dietary recalls to measure SSB/juice intake and objectively measured maternal weight. RESULTS: Using linear mixed models controlling for baseline values, child age and race, there was a greater reduction in child SSB/juice in Smart Moms compared with control at 6 months (-9.7 oz./day vs. 1.7 oz./day, p < .01). Mothers in Smart Moms lost 2.4 kg at 6 months compared with a 0.9-kg gain in the control group (p < .01). CONCLUSIONS: An intervention delivered using mHealth technologies can target mothers to change child dietary behaviours and improve maternal weight, which suggests a novel approach to family-based obesity prevention.

On the importance of peer influence for adolescent drug use: commonly neglected considerations.

Peer influence is generally believed to be a major cause of adolescent drug behavior. This paper reviews research findings on friend selection and projection to suggest that the magnitude of friend influence may be overestimated. This paper also observes that, although adolescent drug use is assumed to begin in response to peer group influence, peer groups have rarely been measured in studies of drug behavior. Social network analysis is identified as a promising method for measuring peer groups. The implications of this review for research and programs are considered.

Analysis of prevention program effectiveness with clustered data using generalized estimating equations.

Experimental studies of prevention programs often randomize clusters of individuals rather than individuals to treatment conditions. When the correlation among individuals within clusters is not accounted for in statistical analysis, the standard errors are biased, potentially resulting in misleading conclusions about the significance of treatment effects. This study demonstrates the generalized estimating equations (GEE) method, focusing specifically on the GEE-independent method, to control for within-cluster correlation in regression models with either continuous or binary outcomes. The GEE-independent method yields consistent and robust variance estimates. Data from project DARE, a youth substance abuse prevention program, are used for illustration.

The contribution of influence and selection to adolescent peer group homogeneity: the case of adolescent cigarette smoking.

Understanding the homogeneity of peer groups requires identification of peer groups and consideration of influence and selection processes. Few studies have identified adolescent peer groups, however, or examined how they become homogeneous. This study used social network analysis to identify peer groups (cliques), clique liaisons, and isolates among adolescents in 5 schools at 2 data collection rounds (N = 926). Cigarette smoking was the behavior of interest. Influence and selection contributed about equally to peer group smoking homogeneity. Most smokers were not peer group members, however, and selection provided more of an explanation than influence for why isolates smoke. The results suggest the importance of using social network analysis in studies of peer group influence and selection.

Substance use and risky sexual behavior among homeless and runaway youth.

PURPOSE: To (a) characterize human immunodeficiency virus (HIV)-related risk behaviors of homeless youth; (b) determine whether substance use is associated with risky sexual behavior in this population; and, if so, (c) explore explanations for this relationship. METHODS: A purposive sample of 327 homeless youth (ages 14-21 years) in Washington, DC, were surveyed in 1995 and 1996. Survey items were adapted from items used in a national study of adult substance use and sexual behavior and measured global (lifetime) and event-specific (most recent sexual encounter) behaviors. RESULTS: Sexual activity with many partners, "survival" sex, and substance use were common. However, needle use was rare, and consistent condom use was evident in half the sample. Nearly all correlations between global measures of substance use and risky sex were statistically significant, but only a few of the event-specific correlations were significant. Marijuana use during the most recent sexual encounter was associated with nonuse of condoms, but this relationship disappeared in the multivariate model. However, crack use during the last encounter was associated with condom use; this relationship remained significant in the multivariate model. Lack of motivation to use condoms, longer histories of sexual activity and homelessness, symptoms of drug dependency, not discussing HIV risks with partner, and being female were also associated with nonuse of condoms. CONCLUSIONS: Homeless youth do use condoms, even within the context of substance use and casual sex. Results suggest that prevention and targeted intervention efforts have had some positive effect on this population, but young homeless women are in need of targeted prevention. Finally, additional research is needed to investigate the observed relationship between crack use and condom use in this sample.

HIV-risk behaviors associated with homelessness characteristics in youth.

PURPOSE: To examine characteristics of youth homelessness associated with engaging in risk behaviors for human immunodeficiency virus (HIV). METHODS: The sample included 288 currently homeless or runaway Washington, DC youth aged 14-21 years. Measures were self-reported homelessness characteristics, unsafe sexual behavior, injection drug use, and background characteristics. Bivariate and multivariable analyses of the relationships between homelessness characteristics and HIV risk behaviors were conducted. RESULTS: Both male (n = 140) and female (n = 148) participants reported high rates of unsafe sexual behaviors, but low rates of injection drug use. HIV risk was significantly associated in bivariate analyses with severity of homelessness circumstances (i.e., spending the night in public place or with strangers, going hungry, and participating in the street economy), the duration of homelessness (i.e., greater number of episodes of homelessness, longer time length of current episode), and specific reasons for being homeless (i.e., thrown out). In addition, sexual victimization and older age were associated with increased HIV risk. In multivariable models, a smaller set of these homelessness characteristics remained significant independent correlates and explained a substantial amount of the variation in the HIV risk indices for both males and females. CONCLUSIONS: The results contribute to greater theoretical understanding of the characteristics of homelessness associated with increased risk of HIV infection within this vulnerable population of youth. The associations between homelessness characteristics and HIV risk suggest the need for HIV prevention efforts to focus directly on ameliorating the homelessness circumstances of youth.

Correlates of participation in a family-directed tobacco and alcohol prevention program for adolescents.

This study examined correlates of program initiation and completion in a family-directed program that involved families of adolescents throughout the United States. Correlates varied by whether program initiation, program completion, or the number of activities completed was the indicator of participation. In final regression models, participation was relatively likely by non-Hispanic whites when compared with persons of race/ethnicity other than white, black, and Hispanic; by families with a female adolescent as the program recipient; by families with mothers who had many years of education; and by families with both parents living in the household. There was more participation if parents thought their child would smoke in the future and if the parent thought the adolescent did not smoke currently. Participation was higher if the adolescent felt strongly attached to the parent and if parents did not smoke. The findings are considered in the context of similar programs and future research on family-directed programs to prevent adolescent tobacco and alcohol use.

Peer group structure and adolescent cigarette smoking: a social network analysis.

Social network theory and analysis are applied to examine whether adolescents who fill various social positions that characterize peer group structure differ in prevalence of current smoking. One thousand and ninety-two (1,092) ninth graders in one school system named their three best friends, allowing the identification of each adolescent as clique member, clique liaison, or isolate. At four of five schools, the odds of being a current smoker were significantly higher for isolates than for clique members and liaisons. The relationship was not explained by demographic variables or by the number of friends who smoke.

Social network characteristics associated with risky behaviors among runaway and homeless youth.

Runaway and homeless youth are at high risk for substance abuse and unsafe sexual behavior. Our study describes the personal social networks of these youth and examines network characteristics associated with risky behaviors. In 1995 and 1996, we interviewed a purposive sample of youth aged 14 through 21 who were living in Washington, DC and were identified on the streets or through shelters or other service agencies (N = 327). Although we found that most youth reported current social relationships, a significant minority (26%) did not. Youth without a social network were significantly more likely to report current illicit drug use, multiple sex partners, and survival sex than youth with a network. For youth with a network, the networks were small, strong in affective and supportive qualities, comprised primarily of friends, typically included an alcohol or illicit drug user, and usually were not a source of pressure for risky behaviors. Our results indicate that networks had risk-enhancing and risk-decreasing properties in that network characteristics were associated in both positive and negative directions with risky behaviors.

School and neighborhood characteristics associated with school rates of alcohol, cigarette, and marijuana use.

Previous research has noted that schools vary in substance use prevalence rates, but explanations for school differences have received little empirical attention. We assess variability across elementary schools (N = 36) in rates of early adolescent alcohol, cigarette, and marijuana use. Characteristics of neighborhoods and schools potentially related to school prevalence rates are examined, as well as whether these characteristics have independent effects or whether neighborhood characteristics are mediated by school characteristics. Neighborhood and school characteristics were measured using student, parent, and archival data. The findings show substantial variation across schools in substance use. Attributes of neighborhoods and schools are statistically significantly related to school rates of lifetime alcohol use, lifetime cigarette use, and current cigarette use. Contrary to expectations, lifetime alcohol and cigarette use rates are higher in schools located in neighborhoods having greater social advantages as indicated by the perceptions of residents and archival data. Neighborhood effects are expressed both directly and indirectly through school characteristics. The findings are discussed in light of contagion and social disorganization theories.

Potential mediators, moderators, or independent effects in the relationship between parents' former and current cigarette use and their children's cigarette use.

Research consistently has shown that cigarette use by adolescents is related to their parents' use and to particular characteristics of the family environment, but few studies have examined the linkages between parents' smoking behavior and other family characteristics to explain adolescents' smoking. In this study, we tested mediator, moderator, and independent models for their ability to characterize the relationship between parents' and their children's smoking. A sample of 719 matched pairs of parent (usually mother) and child was used. Respondents were part of an ongoing randomized evaluation of the Drug Abuse Resistance Education (DARE) Project in Illinois, and the subset of data used in these analyses was collected in 1991, when the youths were in the sixth or seventh grades. Results of logistic regression provided the greatest support for the independent model, which suggests that the effects of parents' smoking and familial characteristics on adolescents' smoking are not linked. Results also supported those found by other researchers by showing that parents' former smoking is associated with adolescents' current smoking. Significant family characteristics were family disunion and parents' awareness of their child's activities. These results suggest, in part, that children at any age may have the capability of storing memories of their parents' smoking, memories that influence their own smoking; also, characteristics of the family environment, independent of parents' smoking behavior, have an effect on adolescents' smoking. Prevention implications and recommendations are also discussed.

Variability in cigarette smoking within and between adolescent friendship cliques.

Research has consistently shown that adolescent smoking is related to friends' smoking, yet smoking in the context of adolescent peer groups (friendship cliques) has been little studied. Formal network analysis was used to identify 87 adolescent friendship cliques in a sample of 1,092 ninth graders at five schools. There was intraclique homogeneity and interclique heterogeneity in current cigarette smoking, confirming that smokers tend to be in cliques with smokers and nonsmokers tend to be with nonsmokers. Most cliques were comprised entirely or mostly of nonsmokers, suggesting that friendship cliques may contribute more to the maintenance of nonsmoking than to the onset and maintenance of smoking. Prevention and research implications are discussed.

Long-term evaluation of drug abuse resistance education.

Project DARE (Drug Abuse Resistance Education) is the most prevalent school-based drug-use prevention program in the United States, but there is little evidence of its effectiveness. Results from a longitudinal evaluation of the program in 36 schools in Illinois provide only limited support for DARE's impact on student's drug use immediately following the intervention, and no support for either continued or emerging impact on drug use 1 or 2 years after receiving DARE instruction. In addition, DARE had only limited positive effects on psychological variables (i.e., self-esteem) and no effect on social variables (e.g., peer resistance skills). Possible substantive and methodological explanations for the relative lack of DARE's effectiveness observed in this study are discussed.

Conceptual models for health education research and practice.

Although conceptual models are frequently used to illustrate research questions under investigation, there is a paucity of articles about how to develop conceptual models or their importance to health education research and practice. A number of uses of the term model exist. Therefore, we describe a conceptual model developed to guide health education research or practice as a diagram of proposed causal linkages among a set of concepts believed to be related to a specific public health problem. Although informed by the multicausal models of public health, the conceptual models we describe differ from those models in that they do not incorporate all factors correlated with an endpoint of interest. Rather they show only the small part of the causal web selected for study. Conceptual models differ from theory in that they are not usually concerned with global classes of behavior but with specific types of behavior in specific contexts. They often are informed by more than one theory, as well as by empirical findings. Because of the usefulness of conceptual models in narrowing both research questions and the targets of intervention, we advocate the inclusion of the model development process in public health education research methods courses.

Substance use among runaway and homeless youth in three national samples.

OBJECTIVES: Standardized estimates of the prevalence of substance use by runaway and homeless youth between the ages of 12 and 21 in various settings were compared with each other and with estimates for youth in the general population. METHODS: Four surveys were used: (1) a nationally representative survey of runaway and homeless youth residing in federally and non-federally funded shelters; (2) a multicity survey of street youth; (3) a nationally representative household survey of youth with and without recent runaway and homeless experiences; and (4) a nationally representative household survey of youth whose previous runaway/homeless status was unknown. RESULTS: For almost every substance, substance use prevalence was highest among street youth. Shelter youth and household youth with recent runaway/homeless experiences reported similar rates. In the household surveys, substance use rates were lowest and were generally comparable. CONCLUSIONS: Many homeless and runaway youth use tobacco, alcohol, and other drugs at rates substantially higher than nonrunaway and nonhomeless youth, indicating a need for comprehensive and intensive substance abuse prevention and treatment services for these youth.

Controlling for the endogeneity of peer substance use on adolescent alcohol and tobacco use.

This study examines whether the effects of peer substance use on adolescent alcohol and tobacco use are due to endogeneity of adolescents selecting their peer group. We analyzed data collected for a longitudinal analysis of a drug-use prevention programme for upper elementary school students. We used a two-step probit regression to control for the potentially endogenous explanatory variable peer substance use. Rigorous tests of endogeneity and the validity of the instrumental variables showed that controlling for the endogeneity of peer substance use to reduce bias is not worth the reduction in mean squared error in these data. Peer substance use has a positive and significant effect on adolescent substance use for both drinking and smoking. These results imply that peer influence is empirically more important than peer selection (endogeneity) in our sample of adolescents in grades 6-9. Living in a single-parent family was by far the strongest predictor of adolescent drinking and smoking.

Prevalence and correlates of survival sex among runaway and homeless youth.

OBJECTIVE: This study examined the prevalence and correlates of survival sex among runaway and homeless youths. METHODS: A nationally representative sample of shelter youths and a multicity sample of street youths were interviewed. RESULTS: Approximately 28% of street youths and 10% of shelter youths reported having participated in survival sex, which was associated with age, days away from home, victimization, criminal behaviors, substance use, suicide attempts, sexually transmitted disease, and pregnancy. CONCLUSIONS: Intensive and ongoing services are needed to provide resources and residential assistance to enable runaway and homeless youths to avoid survival sex, which is associated with many problem behaviors.