Meghan M. JaKa

Reporting of treatment fidelity in behavioural paediatric obesity intervention trials: a systematic review

Behavioural interventions for paediatric obesity are promising, but detailed information on treatment fidelity (i.e. design, training, delivery, receipt and enactment) is needed to optimize the implementation of more effective interventions. Little is known about current practices for reporting treatment fidelity in paediatric obesity studies. This systematic review, in accordance with Preferred Reporting Items for Systematic Reviews and Meta‐Analyses guidelines, describes the methods used to report treatment fidelity in randomized controlled trials. Treatment fidelity was double‐coded using the National Institutes of Health Fidelity Framework checklist. Three hundred articles (N = 193 studies) were included. Mean inter‐coder reliability across items was 0.83 (SD = 0.09). Reporting of treatment design elements within the field was high (e.g. 77% of studies reported designed length of treatment session), but reporting of other domains was low (e.g. only 7% of studies reported length of treatment sessions delivered). Few reported gold standard methods to evaluate treatment fidelity (e.g. coding treatment content delivered). General study quality was associated with reporting of treatment fidelity (p < 0.01) as was the number of articles published for a given study (p < 0.01). The frequency of reporting treatment fidelity components has not improved over time (p = 0.26). Specific recommendations are made to support paediatric obesity researchers in leading health behaviour disciplines towards more rigorous measurement and reporting of treatment fidelity.

Describing the relationship between occupational and non-occupational physical activity using objective measurement

Objective Physical inactivity is a major health risk for working adults, yet the interplay between physical activity levels in work and non-work settings is not well understood. The association between occupational physical activity (OPA) and non-occupational physical activity (non-OPA), and associations by sex, were examined in a group of 233 working adults in the Minneapolis, MN metro area between 2010 and 2012. Methods Accelerometry-measured activity was split into OPA and non-OPA via participant-reported typical work start and end times. Regression models were used to estimate associations. Results Average weekly OPA was positively associated with non-OPA (B = 0.18, 95% CI: 0.08 to 0.28) and associations were stronger among women than men (Binteraction = − 0.39, 95% CI: − 0.61 to − 0.17). Conclusions Results suggest that individuals with less physical activity during work also have less physical activity outside of work. Understanding the complexities of the OPA/non-OPA relationship will enable researchers to explore the underlying mechanisms.

Physical changes in the home environment to reduce television viewing and sugar-sweetened beverage consumption among 5- to 12-year-old children: a randomized pilot study

This study evaluated the feasibility of a home‐based intervention to reduce sugar‐sweetened beverage intake and television viewing among children. Lower income parents of overweight children aged 5–12 years (n = 40) were randomized to a home environment intervention to reduce television viewing with locking devices and displace availability of sugar‐sweetened beverages with home delivery of non‐caloric beverages (n = 25), or to a no‐intervention control group (n = 15) for 6 months. Data were collected at baseline and 6 months. After 6 months, television viewing hours per day was significantly lower in the intervention group compared with the control group (1.7 [SE = .02] vs. 2.6 [SE = .25] hours/day, respectively, P < .01). Sugar‐sweetened beverage intake was marginally significantly lower among intervention group compared to control group children (0.21 [SE = .09] vs. 0.45 [SE = .10], respectively, P < .09). Body mass index (BMI) z‐score was not significantly lower among intervention compared to control children. Among a lower income sample of children, a home‐based intervention reduced television viewing, but not sugar‐sweetened beverage intake or BMI z‐score.

Mediation of weight loss and weight loss maintenance through dietary disinhibition and restraint.

Understanding the degree to which eating behaviors, such as disinhibition and restraint, are associated with weight loss and weight loss maintenance could contribute to further refinement of effective weight management intervention strategies. The purpose of this analysis was to examine if these factors mediate weight loss or weight loss maintenance using data from a randomized controlled trial testing a commercial weight loss program that delivered behavioral counseling and structured meal plans including prepackaged foods. Mediation analyses were used to examine whether changes in disinhibition and restraint mediated the relationship between intervention and weight change during initial weight loss (0-6 months), continued weight loss (6-12 months), or weight loss maintenance (12-24 months) phases. Only decreases in disinhibition between baseline and 6 months mediated the intervention effect on initial weight loss. Our results suggest the mediation effects of these eating behaviors are modest and other factors contribute to a larger, more complex long-term weight loss prognosis.

Decision trees in epidemiological research

BackgroundIn many studies, it is of interest to identify population subgroups that are relatively homogeneous with respect to an outcome. The nature of these subgroups can provide insight into effect mechanisms and suggest targets for tailored interventions. However, identifying relevant subgroups can be challenging with standard statistical methods.Main textWe review the literature on decision trees, a family of techniques for partitioning the population, on the basis of covariates, into distinct subgroups who share similar values of an outcome variable. We compare two decision tree methods, the popular Classification and Regression tree (CART) technique and the newer Conditional Inference tree (CTree) technique, assessing their performance in a simulation study and using data from the Box Lunch Study, a randomized controlled trial of a portion size intervention. Both CART and CTree identify homogeneous population subgroups and offer improved prediction accuracy relative to regression-based approaches when subgroups are truly present in the data. An important distinction between CART and CTree is that the latter uses a formal statistical hypothesis testing framework in building decision trees, which simplifies the process of identifying and interpreting the final tree model. We also introduce a novel way to visualize the subgroups defined by decision trees. Our novel graphical visualization provides a more scientifically meaningful characterization of the subgroups identified by decision trees.ConclusionsDecision trees are a useful tool for identifying homogeneous subgroups defined by combinations of individual characteristics. While all decision tree techniques generate subgroups, we advocate the use of the newer CTree technique due to its simplicity and ease of interpretation.

Parent’s Physical Activity Associated With Preschooler Activity in Underserved Populations

INTRODUCTION In the U.S., children from low-income families are more likely to be obese. The impact of parent modeling of physical activity (PA) and sedentary behaviors in low-income American ethnic minorities is unclear, and studies examining objective measures of preschooler and parent PA are sparse. METHODS This cross-sectional study examined 1,003 parent-child pairs who were of low income, largely Latino and African American, and living in one of two geographically disparate metropolitan areas in the U.S. Parents and children wore GT3X/GT3X+ accelerometers for an average of >12 hours/day (7:00am-9:00pm) for 1 week (September 2012 to May 2014). Analysis occurred in 2015-2016. RESULTS About 75% of children were Latino and >10% were African American. Mean child age was 3.9 years. The majority of children (60%) were normal weight (BMI ≥50th and <85th percentiles), and more than a third were overweight/obese. Childrens total PA was 6.03 hours/day, with 1.5 hours spent in moderate to vigorous PA (MVPA). Covariate-adjusted models showed a monotonic, positive association between parent and child minutes of sedentary behavior (β=0.10, 95% CI=0.06, 0.15) and light PA (β=0.06; 95% CI=0.03, 0.09). Child and parent MVPA were positively associated up to 40 minutes/day of parent MVPA, but an inverse association was observed when parental MVPA was beyond 40 minutes/day (p=0.002). CONCLUSIONS Increasing parental PA and reducing sedentary behavior correlate with increased PA-related behaviors in children. However, more work is needed to understand the impact of high levels of parental MVPA on the MVPA levels of their children.

Objectively coding intervention fidelity during a phone-based obesity prevention study.

BACKGROUND Childhood obesity prevention studies have yielded disappointing results. Understanding intervention fidelity is necessary in explaining why interventions are (or are not) successful and ultimately improving future intervention. In spite of this, intervention fidelity it is not consistently reported in the obesity prevention literature. The purpose of the current study was to develop and utilize a coding protocol to objectively assess intervention fidelity in a phone-based obesity prevention study for parents of preschool-aged children. FINDINGS Both interventionists and independent coders completed session fidelity measures including time spent on target areas (media use, physical activity, etc.) and components of goal setting quality. Coders also rated participant engagement. Agreement between ratings by interventionists and coders, fidelity levels and changes in fidelity components over time are presented. Coders and interventionists showed high agreement when reporting time spent discussing different target areas. Interventionists consistently rated themselves higher than independent coders on measures of goal quality. Coder ratings of session quality were initially high, but some components declined slightly across the eight sessions. CONCLUSIONS Future directions for intervention fidelity measurement and analysis are discussed, including utilizing changes in fidelity measures over time to predict study outcomes. Obtaining a more in-depth understanding of intervention fidelity has the potential to strengthen obesity interventions.

Understanding Outcomes in Behavior Change Interventions to Prevent Pediatric Obesity: The Role of Dose and Behavior Change Techniques

Background. Behavioral interventions to prevent pediatric obesity have shown inconsistent results across the field. Studying what happens within the “black box” of these interventions and how differences in implementation lead to different outcomes will help researchers develop more effective interventions. Aim. To compare the implementation of three features of a phone-based intervention for parents (time spent discussing weight-related behaviors, behavior change techniques used in sessions, and intervention activities implemented by parents between sessions) with study outcomes. Methods. A random selection of 100 parent–child dyads in the intervention arm of a phone-based obesity prevention trial was included in this analysis. Sessions were coded for overall session length, length of time spent discussing specific weight-related behaviors, number of behavior change techniques used during the sessions, and number of intervention-recommended activities implemented by the parents between sessions (e.g., parent-reported implementation of behavioral practice/rehearsal between sessions). The primary study outcome, prevention of unhealthy increase in child body mass index (BMI) percentile, was measured at baseline and 12 months. Results. Overall session length was associated with decreases in child BMI percentile (b = −0.02, p = .01). There was no association between the number of behavior change techniques used in the sessions and decreases in child BMI percentile (b = −0.29, p = .27). The number of activities the parents reported implementing between sessions was associated with decreases in child BMI percentile (b = −1.25, p = .02). Discussion. To improve future interventions, greater attention should be paid to the intended and delivered session length, and efforts should be made to facilitate parents’ implementation of intervention-recommended activities between sessions (ClinicalTrials.gov, No. NCT01084590).

Parent Choice in a Pediatric Obesity Prevention Intervention

Background There is value in having parents choose which behaviors to address in obesity interventions, but it is unknown whether they choose behaviors that will effectively impact healthy growth. This study assessed whether child behaviors or parent intention to change behaviors were associated with behaviors parents chose to discuss. Methods Parent intention to change specific behaviors and time spent discussing behaviors was coded during intervention sessions. Results Child activity, screen-time, energy intake, breakfast, and family meals were associated with time spent discussing these behaviors. Fewer associations were seen between parent intention and time spent discussing these behaviors. Conclusions Results suggest that in interventions allow choice, parents may choose to discuss the weight-related behaviors their children need to address.