Kirsten K. Davison

Childhood overweight: a contextual model and recommendations for future research

The prevalence of overweight among children has doubled within the past two decades. Increases in the rate of childhood overweight are of particular concern due to the negative health and psychological effects noted among overweight children. As shown by previous research, the development of childhood overweight involves a complex set of factors from multiple contexts that interact with each other to place a child at risk of overweight. This multifaceted system can be conceptualized using Ecological Systems Theory (EST). EST highlights the importance of considering the context(s), or ecological niche, in which a person is located in order to understand the emergence of a particular characteristic. In the case of a child, the ecological niche includes the family and the school, which are in turn embedded in larger social contexts including the community and society at large. In this review, EST is used as a framework with which to summarize research assessing predictors of childhood overweight. Specifically, child characteristics that place children at risk of the development of overweight (including dietary intake, physical activity, and sedentary behaviour) will be reviewed while taking into consideration the influence of the familial environment, the school environment, and the community and larger social environments. It is concluded that future research needs to adopt a broader contextual approach in order to understand and intervene against the processes leading to the development of overweight among children and that the use of theories or paradigms such as EST will facilitate developing and testing models of causal processes.

Do attributes in the physical environment influence children's physical activity? A review of the literature

BackgroundMany youth today are physically inactive. Recent attention linking the physical or built environment to physical activity in adults suggests an investigation into the relationship between the built environment and physical activity in children could guide appropriate intervention strategies.MethodThirty three quantitative studies that assessed associations between the physical environment (perceived or objectively measured) and physical activity among children (ages 3 to 18-years) and fulfilled selection criteria were reviewed. Findings were categorized and discussed according to three dimensions of the physical environment including recreational infrastructure, transport infrastructure, and local conditions.ResultsResults across the various studies showed that childrens participation in physical activity is positively associated with publicly provided recreational infrastructure (access to recreational facilities and schools) and transport infrastructure (presence of sidewalks and controlled intersections, access to destinations and public transportation). At the same time, transport infrastructure (number of roads to cross and traffic density/speed) and local conditions (crime, area deprivation) are negatively associated with childrens participation in physical activity.ConclusionResults highlight links between the physical environment and childrens physical activity. Additional research using a transdisciplinary approach and assessing moderating and mediating variables is necessary to appropriately inform policy efforts.

Percentage of Body Fat and Body Mass Index Are Associated with Mobility Limitations in People Aged 70 and Older from NHANES III

OBJECTIVES: To assess the association between functional limitations and body composition indices, including percentage of body fat, muscle mass, and body mass index (BMI).

Effect of cocoa flavanols and exercise on cardiometabolic risk factors in overweight and obese subjects

Objective:Impaired endothelial function in obesity may reduce blood flow to sites of metabolism, contributing to impaired fat oxidation and insulin resistance. This study investigated the effects of cocoa flavanols and regular exercise, interventions known to improve endothelial function, on cardiometabolic function and body composition in obese individuals.Design:Overweight and obese adults were randomly assigned to high-flavanol cocoa (HF, 902 mg flavanols), HF and exercise, low-flavanol cocoa (LF, 36 mg flavanols), or LF and exercise for 12 weeks (exercise duration was 3 × 45 min per week at 75% of age-predicted maximum heart rate). Body composition was assessed by dual-energy X-ray absorptiometry at 0 and 12 weeks. Brachial artery flow-mediated dilatation (FMD), supine blood pressure (BP) and fasting plasma insulin, and glucose levels were assessed at 0, 6 and 12 weeks, respectively. Insulin sensitivity/resistance was determined using the modified homeostasis model assessment of insulin resistance (HOMA2).Results:A total of 49 subjects (M=18; F=31) completed the intervention. Baseline averages were as follows: body mass index=33.5 kg/m2; BP=123/76 mm Hg; HOMA2=2.4; FMD=4.3%; rate of fat oxidation during exercise=0.34 g min−1; abdominal fat=45.7% of total abdominal mass. Compared to LF, HF increased FMD acutely (2 h post-dose) by 2.4% (P<0.01) and chronically (over 12 weeks; P<0.01) by 1.6% and reduced insulin resistance by 0.31% (P<0.05), diastolic BP by 1.6 mm Hg and mean arterial BP by 1.2 mm Hg (P<0.05), independent of exercise. Regular exercise increased fat oxidation during exercise by 0.10 g min−1 (P<0.01) and reduced abdominal fat by 0.92% (P<0.05).Conclusion:Although HF consumption was shown to improve endothelial function, it did not enhance the effects of exercise on body fat and fat metabolism in obese subjects. However, it may be useful for reducing cardiometabolic risk factors in this population.

A childhood obesity intervention developed by families for families: results from a pilot study

BackgroundIneffective family interventions for the prevention of childhood obesity have, in part, been attributed to the challenges of reaching and engaging parents. With a particular focus on parent engagement, this study utilized community-based participatory research to develop and pilot test a family-centered intervention for low-income families with preschool-aged children enrolled in Head Start.MethodsDuring year 1 (2009–2010), parents played an active and equal role with the research team in planning and conducting a community assessment and using the results to design a family-centered childhood obesity intervention. During year 2 (2010–2011), parents played a leading role in implementing the intervention and worked with the research team to evaluate its results using a pre-post cohort design. Intervention components included: (1) revisions to letters sent home to families reporting child body mass index (BMI); (2) a communication campaign to raise parents’ awareness of their child’s weight status; (3) the integration of nutrition counseling into Head Start family engagement activities; and (4) a 6-week parent-led program to strengthen parents’ communication skills, conflict resolution, resource-related empowerment for healthy lifestyles, social networks, and media literacy. A total of 423 children ages 2–5 years, from five Head Start centers in upstate New York, and their families were exposed to the intervention and 154 families participated in its evaluation. Child outcome measures included BMI z-score, accelerometer-assessed physical activity, and dietary intake assessed using 24-hour recall. Parent outcomes included food-, physical activity- and media-related parenting practices and attitudes.ResultsCompared with pre intervention, children at post intervention exhibited significant improvements in their rate of obesity, light physical activity, daily TV viewing, and dietary intake (energy and macronutrient intake). Trends were observed for BMI z-score, sedentary activity and moderate activity. Parents at post intervention reported significantly greater self-efficacy to promote healthy eating in children and increased support for children’s physical activity. Dose effects were observed for most outcomes.ConclusionsEmpowering parents to play an equal role in intervention design and implementation is a promising approach to family-centered obesity prevention and merits further testing in a larger trial with a rigorous research design.

A Meta-analysis of Interventions That Target Children's Screen Time for Reduction

BACKGROUND: Screen time, especially television viewing, is associated with risk of overweight and obesity in children. Although several interventions have been developed to reduce childrens screen time, no systematic review of these interventions exists to date. OBJECTIVE: This is a systematic review and meta-analysis of interventions targeting a reduction in childrens screen time. METHODS: Effect sizes and associated 95% confidence intervals (CIs) were calculated by using a random-effects model. Heterogeneity tests, moderator analyses, assessment of bias, and sensitivity analyses were conducted. Reliability was assessed with Cohens κ. RESULTS: The systematic search identified 3002 documents; 33 were eligible for inclusion, and 29 were included in analyses. Most reported preintervention and postintervention data and were published in peer-reviewed journals. Although heterogeneity was present, no moderators were identified. Overall Hedges g (−0.144 [95% CI: −0.217 to −0.072]) and standard mean difference (SMD) (−0.148 [95% CI: −0.224 to −0.071]) indicated that interventions were linked with small but statistically significant reductions in screen time in children. The results were robust; the failsafe N was large, and the funnel plot and trim-and-fill methods identified few missing studies. CONCLUSIONS: Results show that interventions to reduce childrens screen time have a small but statistically significant effect. As the evidence base expands, and the number of screen-time interventions increases, future research can expand on these findings by examining the clinical relevance and sustainability of effects, conducting a more thorough analysis of effect modifiers, and identifying critical components of effective interventions.

Parental Sedentary Restriction, Maternal Parenting Style, and Television Viewing Among 10- to 11-Year-Olds

OBJECTIVE: To examine whether parenting styles or practices were associated with childrens television (TV) viewing. METHODS: A total of 431 parent-child dyads (10- to 11-year-old children) from Bristol, United Kingdom, were included. Child and parent TV viewing were self-reported and categorized as <2, 2 to 4, or >4 hours/day. Children reported maternal parenting style (authoritarian, authoritative, or permissive). Child-reported maternal and paternal sedentary restriction scores were combined to create a family-level restriction score. Multinomial logistic regression was used to examine whether child TV viewing was predicted by parenting style or family restriction. RESULTS: A greater proportion of children with permissive mothers watched >4 hours of TV per day, compared with children with authoritarian or authoritative mothers (P = .033). A greater proportion of children for whom both parents demonstrated high restriction watched <2 hours of TV per day (P < .001). The risk of watching 2 to 4 hours (vs <2 hours) of TV per day was 2.2 times higher for children from low-restriction families (P = .010). The risk of watching >4 hours (vs <2 hours) of TV per day was 3.3 times higher for children from low-restriction families (P = .013). The risk of watching >4 hours of TV per day was 5.2 times higher for children with permissive (versus authoritative) mothers (P = .010). CONCLUSIONS: Clinicians need to talk directly with parents about the need to place limitations on childrens screen time and to encourage both parents to reinforce restriction messages.

Sleep Duration, Restfulness, and Screens in the Sleep Environment

BACKGROUND AND OBJECTIVE: Associations of inadequate sleep with numerous health outcomes among youth necessitate identifying its modifiable determinants. Television (TV) has been associated with sleep curtailment, but little is known about small screens (eg, smartphones), which can be used in bed and emit notifications. Therefore, we examined associations of different screens in sleep environments with sleep duration and perceived insufficient rest or sleep. METHODS: Participants included 2048 fourth- and seventh-graders participating in the Massachusetts Childhood Obesity Research Demonstration Study in 2012 to 2013. Using linear and log binomial regression, we examined cross-sectional associations of small screens and TVs in sleep environments and screen time with weekday sleep duration and perceived insufficient rest or sleep in the past week. RESULTS: Children who slept near a small screen (compared with never) reported 20.6 fewer minutes of sleep (95% confidence interval [CI], −29.7 to −11.4) and had a higher prevalence of perceived insufficient rest or sleep (prevalence ratio, 1.39; 95% CI, 1.21 to 1.60). Children who slept in a room with a TV (compared with no TV) reported 18.0 fewer minutes of sleep (95% CI, −27.9 to −8.1). TV or DVD viewing and video or computer game playing were associated with both sleep outcomes (P < .01). Some associations were stronger among Hispanic, non-Hispanic black, and older children (P < .05 for heterogeneity). CONCLUSIONS: Sleeping near a small screen, sleeping with a TV in the room, and more screen time were associated with shorter sleep durations. Presence of a small screen, but not a TV, in the sleep environment and screen time were associated with perceived insufficient rest or sleep. These findings caution against unrestricted screen access in children’s bedrooms.

Measuring parental support for children's physical activity in white and African American parents: the Activity Support Scale for Multiple Groups (ACTS-MG).

OBJECTIVES The Activity Support Scale (ACTS) was expanded for use with African American families. Its factorial invariance and internal reliability were examined for non-Hispanic white and African American parents. METHODS The ACTS was modified to improve its applicability to African American families based on information from five focus groups with 27 African American parents of elementary school-aged children. Between 2006 and 2008, the revised scale was administered to 119 African American and 117 non-Hispanic white parents in northeastern NY and Alabama. Its factorial invariance across race/ethnicity and internal consistency were examined. RESULTS Factor analysis of the revised scale, the Activity Support Scale for Multiple Groups (ACTS-MG), identified four parenting factors in white and African American parents including logistic support, modeling, use of community resources to promote physical activity (PA), and restriction of sedentary behaviors. Results supported the scales internal reliability and factorial invariance across race/ethnicity. CONCLUSION The ACTS-MG is appropriate for use with non-Hispanic white and African American families and will enable the extension of current research with white families to the examination of strategies supporting PA in African American families. Additional psychometric work with the ACTS-MG is encouraged.

The Family-Centered Action Model of Intervention Layout and Implementation (FAMILI): The Example of Childhood Obesity

Parents play a fundamental role in shaping children’s development, including their dietary and physical activity behaviors. Yet family-centered interventions are rarely used in obesity prevention research. Less than half of childhood obesity prevention programs include parents, and those that do include parents or a family component seldom focus on sustainable change at the level of the family. The general absence of a family-centered approach may be explained by persistent challenges in engaging parents and families and the absence of an intervention framework explicitly designed to foster family-centered programs. The Family-centered Action Model of Intervention Layout and Implementation, or FAMILI, was developed to address these needs. FAMILI draws on theories of family development to frame research and intervention design, uses a mixed-methods approach to conduct ecologically valid research, and positions family members as active participants in the development, implementation, and evaluation of family-centered obesity prevention programs. FAMILI is intended to facilitate the development of culturally responsive and sustainable prevention programs with the potential to improve outcomes. Although childhood obesity was used to illustrate the application of FAMILI, this model can be used to address a range of child health problems.