Heewon Lee Gray

Intraclass Correlation Coefficients for Obesity Indicators and Energy Balance–Related Behaviors Among New York City Public Elementary Schools

Objective. Sample size and statistical power calculation should consider clustering effects when schools are the unit of randomization in intervention studies. The objective of the current study was to investigate how student outcomes are clustered within schools in an obesity prevention trial. Method. Baseline data from the Food, Health & Choices project were used. Participants were 9- to 13-year-old students enrolled in 20 New York City public schools (n = 1,387). Body mass index (BMI) was calculated based on measures of height and weight, and body fat percentage was measured with a Tanita® body composition analyzer (Model SC-331s). Energy balance–related behaviors were self-reported with a frequency questionnaire. To examine the cluster effects, intraclass correlation coefficients (ICCs) were calculated as school variance over total variance for outcome variables. School-level covariates, percentage students eligible for free and reduced-price lunch, percentage Black or Hispanic, and English language learners were added in the model to examine ICC changes. Results. The ICCs for obesity indicators are: .026 for BMI-percentile, .031 for BMI z-score, .035 for percentage of overweight students, .037 for body fat percentage, and .041 for absolute BMI. The ICC range for the six energy balance–related behaviors are .008 to .044 for fruit and vegetables, .013 to .055 for physical activity, .031 to .052 for recreational screen time, .013 to .091 for sweetened beverages, .033 to .121 for processed packaged snacks, and .020 to .083 for fast food. When school-level covariates were included in the model, ICC changes varied from −95% to 85%. Conclusions. This is the first study reporting ICCs for obesity-related anthropometric and behavioral outcomes among New York City public schools. The results of the study may aid sample size estimation for future school-based cluster randomized controlled trials in similar urban setting and population. Additionally, identifying school-level covariates that can reduce cluster effects is important when analyzing data.

Cost-effectiveness of a Nutrition Education Curriculum Intervention in Elementary Schools

Objective To estimate the long‐term cost‐effectiveness of an obesity prevention nutrition education curriculum (Food, Health, & Choices) as delivered to all New York City fifth‐grade public school students over 1 year. Methods This study is a standard cost‐effectiveness analysis from a societal perspective, with a 3% discount rate and a no‐intervention comparator, as recommended by the US Panel on Cost‐effectiveness in Health and Medicine. Costs of implementation, administration, and future obesity‐related medical costs were included. Effectiveness was based on a cluster‐randomized, controlled trial in 20 public schools during the 2012–2013 school year and linked to published estimates of childhood‐to‐adulthood body mass index trajectories using a decision analytic model. Results The Food, Health, & Choices intervention was estimated to cost

Mediating Mechanisms of Theory-Based Psychosocial Determinants on Behavioral Changes in a Middle School Obesity Risk Reduction Curriculum Intervention, Choice, Control, and Change

8,537,900 and result in 289 fewer males and 350 fewer females becoming obese (0.8% of New York City fifth‐grade public school students), saving 1,599 quality‐adjusted life‐years (QALYs) and

Testing an Integrated Model of Program Implementation: the Food , Health & Choices School-Based Childhood Obesity Prevention Intervention Process Evaluation

8,098,600 in direct medical costs. Food, Health, & Choices is predicted to be cost‐effective at

A Mixed-Methods Comparison of Classroom Context During Food, Health & Choices, a Childhood Obesity Prevention Intervention

275/QALY (95% confidence interval, –

Association Between the Built Environment in School Neighborhoods With Physical Activity Among New York City Children, 2012

2,576/QALY to

Nutrition Science and Behavioral Theories Integrated in a Serious Game for Adolescents

2,084/QALY) with estimates up to

Does the Mexican sugar-sweetened beverage tax have a signaling effect? ENSANUT 2016

6,029/QALY in sensitivity analyses. Conclusions and Implications This cost‐effectiveness model suggests that a nutrition education curriculum in public schools is effective and cost‐effective in reducing childhood obesity, consistent with the authors’ hypothesis and previous literature. Future research should assess the feasibility and sustainability of scale‐up.

School Lunch Environmental Factors Impacting Fruit and Vegetable Consumption

BACKGROUND A limited number of school-based intervention studies have explored mediating mechanisms of theory-based psychosocial variables on obesity risk behavior changes. The current study investigated how theory-based psychosocial determinants mediated changes in energy balance-related behaviors (EBRBs) among urban youth. METHODS A secondary analysis study was conducted using data from a cluster randomized controlled trial. Data from students at 10 middle schools in New York City (n = 1136) were used. The intervention, Choice, Control, and Change curriculum, was based on social cognitive and self-determination theories. Theory-based psychosocial determinants (goal intention, cognitive outcome expectations, affective outcome expectations, self-efficacy, perceived barriers, and autonomous motivation) and EBRBs were measured with self-report questionnaires. Mediation mechanisms were examined using structural equation modeling, Results: Mediating mechanisms for daily sugar-sweetened beverage (SSB) consumption and purposeful stair climbing were identified. Models with best fit indices (root mean square error of approximation = 0.039/0.045, normed fit index = 0.916/0.882; comparative fit index = 0.945/0.932; Tucker-Lewis index = 0.896/0.882, respectively) suggested that goal intention and reduced perceived barriers were significant proximal mediators for reducing SSB consumption among both boys and girls or increasing physical activity by stair climbing among boys. Cognitive outcome expectations, affective outcome expectations, self-efficacy, and autonomous motivation indirectly mediated behavioral changes through goal intention or perceived barriers (p < 0.05 to p < 0.001). The final models explained 25%-27% of behavioral outcome variances. CONCLUSIONS Theory-based psychosocial determinants targeted in Choice, Control, and Change in fact mediated behavior changes in middle school students. Strategies targeting these mediators might benefit future success of behavioral interventions. Further studies are needed to determine other potential mediators of EBRBs in youth.

Brief Report: Mealtime Behaviors of Chinese American Children with Autism Spectrum Disorder.

Childhood obesity is a complex, worldwide problem. Significant resources are invested in its prevention, and high-quality evaluations of these efforts are important. Conducting trials in school settings is complicated, making process evaluations useful for explaining results. Intervention fidelity has been demonstrated to influence outcomes, but others have suggested that other aspects of implementation, including participant responsiveness, should be examined more systematically. During Food, Health & Choices (FHC), a school-based childhood obesity prevention trial designed to test a curriculum and wellness policy taught by trained FHC instructors to fifth grade students in 20 schools during 2012–2013, we assessed relationships among facilitator behaviors (i.e., fidelity and teacher interest); participant behaviors (i.e., student satisfaction and recall); and program outcomes (i.e., energy balance-related behaviors) using hierarchical linear models, controlling for student, class, and school characteristics. We found positive relationships between student satisfaction and recall and program outcomes, but not fidelity and program outcomes. We also found relationships between teacher interest and fidelity when teachers participated in implementation. Finally, we found a significant interaction between fidelity and satisfaction on behavioral outcomes. These findings suggest that individual students in the same class responded differently to the same intervention. They also suggest the importance of teacher buy-in for successful intervention implementation. Future studies should examine how facilitator and participant behaviors together are related to both outcomes and implementation. Assessing multiple aspects of implementation using models that account for contextual influences on behavioral outcomes is an important step forward for prevention intervention process evaluations.