Comparison of raw accelerometry data from ActiGraph, Apple Watch, Garmin, and Fitbit using a mechanical shaker table

The purpose of this study was to evaluate the reliability and validity of the raw accelerometry output from research-grade and consumer wearable devices compared to accelerations produced by a mechanical shaker table. Raw accelerometry data from a total of 40 devices (i.e., n = 10 ActiGraph wGT3X-BT, n = 10 Apple Watch Series 7, n = 10 Garmin Vivoactive 4S, and n = 10 Fitbit Sense) were compared to reference accelerations produced by an orbital shaker table at speeds ranging from 0.6 Hz (4.4 milligravity-mg) to 3.2 Hz (124.7mg). Two-way random effects absolute intraclass correlation coefficients (ICC) tested inter-device reliability. Pearson product moment, Lin's concordance correlation coefficient (CCC), absolute error, mean bias, and equivalence testing were calculated to assess the validity between the raw estimates from the devices and the reference metric. Estimates from Apple, ActiGraph, Garmin, and Fitbit were reliable, with ICCs = 0.99, 0.97, 0.88, and 0.88, respectively. Estimates from ActiGraph, Apple, and Fitbit devices exhibited excellent concordance with the reference CCCs = 0.88, 0.83, and 0.85, respectively, while estimates from Garmin exhibited moderate concordance CCC = 0.59 based on the mean aggregation method. ActiGraph, Apple, and Fitbit produced similar absolute errors = 16.9mg, 21.6mg, and 22.0mg, respectively, while Garmin produced higher absolute error = 32.5mg compared to the reference. ActiGraph produced the lowest mean bias 0.0mg (95%CI = -40.0, 41.0). Equivalence testing revealed raw accelerometry data from all devices were not statistically significantly within the equivalence bounds of the shaker speed. Findings from this study provide evidence that raw accelerometry data from Apple, Garmin, and Fitbit devices can be used to reliably estimate movement; however, no estimates were statistically significantly equivalent to the reference. Future studies could explore device-agnostic and harmonization methods for estimating physical activity using the raw accelerometry signals from the consumer wearables studied herein.

Determinants of Change in Physical Activity in Children During the Transition from Elementary to High School

INTRODUCTION

Effective public health interventions targeting factors that influence physical activity are urgently needed to reduce the age-related decline in physical activity in youth. The purpose of this study was to identify associations between physical activity and a set of potential influences on physical activity in children as they transition from elementary to high school.

METHODS

Participants were 951 children from South Carolina school districts who completed outcome and independent variable measures on at least two time points from the 5th through 11th grades in 2010 - 2017. The primary outcome variable was physical activity, measured by accelerometry. Independent variables included a comprehensive set of variables in the child, parent/home, school, and community domains. Children, parents and school administrators, and staff completed questionnaires to assess psychosocial and home, school, and neighborhood environmental influences. Growth curve analyses identified independent variables associated with physical activity over time, either as a main effect or as an interaction with age.

RESULTS

As main effects, self-efficacy, self-schema, sport participation, weekday outdoor hours, importance of child participating in sports and physical activity, safe to play outside, and Physical Activity Resource Assessment weighted score were positively associated with physical activity. The associations between physical activity and enjoyment motivation, appearance motivation, weekend outdoor time, and home equipment exhibited significant interactions with age. Enjoyment motivation influenced physical activity during the earlier years, whereas the remaining three variables influenced physical activity in the later years.

CONCLUSIONS

Interventions should target multiple domains of influences that may vary by age.

Clustering Patterns of 24-Hour Physical Activity in Children 6-36 Months Old

PURPOSE

To determine 24-hour physical activity (PA) clusters in children 6-36 months of age, factors associated with the clusters, and their agreement across time.

METHOD

A longitudinal study followed 150 infants from South Carolina up to 36 months of age. Measures included 24-hour PA and demographic data. Functional clustering was used to obtain the clusters. The association between cluster membership and infant/parent characteristics was examined by Kruskal-Wallis and chi-squared tests. Concordance was measured with the kappa coefficient and percent agreement.

RESULTS

At each follow-up, 3 clusters were optimal, identified as late activity (cluster 1), high activity (cluster 2), and medium activity (cluster 3). The defining feature of the late activity cluster was that their physical activity (PA) activity was shifted to later in the day versus children in clusters 2 and 3. At 6 months, the clusters were associated with race (<0.001), crawling (0.043), other children in the household (0.043), and mother's education (0.004); at 12 months with race (0.029), childcare (<0.001), and education (<0.001); and at 36 months with other children in the household (0.019). Clusters showed moderate agreement (kappa = .41 [.25 to .57], agreement = 61% [49% to 72%]) between 6 and 12 months and, at 36 months, showed no agreement with either 6 or 12 months.

CONCLUSION

Twenty-four-hour PA can be clustered into medium, high, and late PA. Further research is needed into the consequences of late sleeping in children at this age. Clusters are associated with household and childcare factors, and cluster membership is dynamic across time.

Association of physical activity, sedentary behavior, diet quality with adiposity: a longitudinal analysis in children categorized by baseline weight status

BACKGROUND/OBJECTIVES

Childhood obesity rates have increased in recent years. The effectiveness of future public health interventions to reduce childhood obesity will be enhanced by a better understanding of behavioral factors that influence adiposity in children as they transition from childhood to adolescence. The purpose of this study was to examine whether initial weight status modifies the longitudinal associations of physical activity, sedentary behavior, and diet quality with changes in adiposity over time.

SUBJECTS/METHODS

A total of 658 children (45% boys) were stratified into 3 groups based on 5th grade BMI percentiles ( < 85th, 85-95th, > 95th) and followed from 5th grade to 6th and/or 7th grade. Study variables, including fat-mass-index (FMI), moderate-to-vigorous physical activity (MVPA), diet quality, and sedentary behavior, were measured at 5th, 6th, and/or 7th grades. Separate growth curve models were conducted within each weight status group to examine the associations between MVPA, sedentary behavior, diet quality and adiposity, operationalized as FMI. All models controlled for sex, maturity offset, race, and parent education.

RESULTS

Of the 658 children, 53% were classified with normal weight at baseline, 18% with overweight, and 29% with obesity. Associations between MVPA, sedentary behavior, diet quality and FMI varied within each weight status group. MVPA was negatively associated with adiposity (FMI) for all weight status groups. Diet quality and sedentary behavior were associated with adiposity only in children with obesity at baseline; neither diet quality nor sedentary behavior was associated with FMI for those with overweight.

CONCLUSIONS

MVPA was negatively associated with adiposity (FMI) in all weight status groups, suggesting that MVPA may protect against higher adiposity. Sedentary behavior and diet quality were associated with adiposity only in children with obesity at baseline; neither sedentary behavior nor diet quality was associated with FMI for children with overweight.

Policies, Practices, and Environmental Characteristics Among Family Child Care Homes in South Carolina

Background: Child care program requirements have adopted nutrition and physical activity standards to address childhood obesity, but few studies have examined the effects of these standards in family child care homes (FCCHs). Methods: In a cross-sectional study (2017-2019), the Childcare Home Eating and Exercise study examined self-reported provider characteristics and observed policies and practices related to physical activity and nutrition in FCCHs in South Carolina. Two-sample t-tests were used to compare observed nutrition and physical activity policy, practice, and environment scores in child care homes that participated in versus did not participate in the state's ABC Quality program, which is designed to improve child care and includes policies and practices intended to increase physical activity levels and improve diet quality. Results: Environment and Policy Assessment and Observation results for nutrition and physical activity were 7.5 out of 21 and 11.8 out of 30, respectively, indicating much room for improvement in nutrition and physical activity policies, practices, and environment in South Carolina FCCHs. The study found one difference between FCCHs that did and did not participate in the ABC Quality program; non-ABC homes provided more time for physical activity. Conclusions: Future research should develop ways to strengthen the guidelines and improve the implementation of obesity prevention standards in FCCHs.

Household Food Insecurity Is Associated With Physical Activity in Youth and Young Adults With Diabetes: A Cross-Sectional Study

BACKGROUND

Physical activity (PA) is essential for optimal diabetes management. Household food insecurity (HFI) may negatively affect diabetes management behaviors. The purpose of this study was to cross-sectionally examine the association between HFI and PA in youth and young adults (YYA) with type 1 (N = 1998) and type 2 (N = 391) diabetes from the SEARCH for Diabetes in Youth Study.

METHODS

HFI was measured with the US Household Food Security Survey Module. PA was measured with the International Physical Activity Questionnaire Short Form. Walking, moderate-intensity PA (excluding walking), vigorous-intensity PA, moderate- to vigorous-intensity PA, and total PA were estimated as minutes per week, while time spent sitting was assessed in minutes per day. All were modeled with median regression. Meeting PA guidelines or not was modeled using logistic regression.

RESULTS

YYA with type 1 diabetes who experienced HFI spent more time walking than those who were food secure. YYA with type 2 diabetes who experienced HFI spent more time sitting than those who were food secure.

CONCLUSIONS

Future research should examine walking for leisure versus other domains of walking in relation to HFI and use objective PA measures to corroborate associations between HFI and PA in YYA with diabetes.

Young Children's Dietary Quality in Family Child Care and in Their Own Home

BACKGROUND

Some evidence suggests that children may have higher quality dietary intake in early care and education settings, compared with their respective homes, but no studies have explored these differences among children in less formal family child care.

OBJECTIVE

The purpose of this study was to compare dietary quality via the Healthy Eating Index 2015 among children in family child care and in their own home.

DESIGN

This was a cross-sectional analysis of baseline dietary intake data from the Childcare Home Eating and Exercise Research study, a natural experiment, using directly observed dietary data in child care and 24-hour recall data in homes among children in South Carolina.

PARTICIPANTS/SETTING

Participants were 123 children in 52 family child-care homes between 2018 and 2019.

MAIN OUTCOME MEASURE

The main outcome was total and component Healthy Eating Index 2015 scores.

STATISTICAL ANALYSIS

The analysis was a hierarchical linear regression of children nested within family child care homes adjusting for child, provider, facility, and parent characteristics, including sex, age, race, ethnicity, and income, with parameters and SEs estimated via bootstrap sampling.

RESULTS

Children had a mean ± SD Healthy Eating Index 2015 score of 60.3 ± 12.1 in family child-care homes and 54.3 ± 12.9 in their own home (P < 0.001). In adjusted analysis and after accounting for clustering of children in family child care homes, total HEI-2015 scores were lower at home than in care (β = -5.18 ± 1.47; 95% CI -8.05 to -2.30; P = 0.003).

CONCLUSIONS

Children had healthier dietary intake in family child-care homes vs their respective homes.

Longitudinal associations between sleep and weight status in infants and toddlers

BACKGROUND

The limited research assessing relationships between sleep duration and weight status in infants and toddlers relies primarily on parent-reported sleep and cross-sectional studies.

OBJECTIVES

Examine whether average sleep duration and changes in sleep duration among 6-24-month-old children were associated with weight-for-length z-scores, and whether these associations varied by race/ethnicity, socioeconomic status and sex.

METHODS

Data were collected when children were approximately 6, 12, 18 and 24 months old (N = 116). Sleep duration was measured using actigraphy. Weight-for-length z-scores were calculated using children's height and weight. Physical activity was assessed using accelerometry. Diet was assessed using a feeding frequency questionnaire. Demographic characteristics included sex, race/ethnicity and socioeconomic status. Separate associations of between- and within-person changes in sleep duration were estimated with weight-for-length z-score treated as the outcome variable in linear mixed model analyses. Additional models were assessed that included interactions between sleep and demographic characteristics.

RESULTS

At time points where children slept longer at night compared to their own average, their weight-for-length z-score was lower. This relationship was attenuated by physical activity levels.

CONCLUSIONS

Increasing sleep duration can improve weight status outcomes in very young children who have low physical activity levels.

Factors Associated with Children's Physical Activity During Youth Soccer Practices

Purpose: To identify practice and social contextual factors that associate with physical activity (PA) levels of children during their participation in a youth soccer program. Methods: Twenty-seven youth soccer teams serving children ages 6-11 years participated. Research staff directly observed and recorded PA intensity and practice and social contextual factors using momentary time-sampling procedures. Each team was observed for 1 practice, during which approximately 6 children were each observed for twenty 30-s observation blocks (10-s observation, 20-s recording). In total, children were observed for 3,102 intervals. Multilevel logistic regression analyses were conducted to describe associations between PA intensity and practice and social contexts. Interaction terms were introduced into the models to determine if the associations differed across girls-only, boys-only, and coed teams. Results: A total of 158 children were observed across the 27 teams. Children were more likely to engage in moderate or vigorous PA while performing fitness (Odds Ratio [OR], 9.9, 95% CI = 5.34-18.04), game (OR, 4.0, 95% CI = 2.88-5.66), warm-up (OR, 2.8, 95% CI = 1.85-4.11), and drill (OR, 1.9, 95% CI = 1.41-2.67) activities compared to tactic/instructional activities. The associations between PA intensity levels and practice and social contexts did not differ across girls-only, boys-only, and coed teams. Conclusions: Fitness activities and full-team game play were associated with higher PA intensity levels during children's participation in youth soccer practices. Youth sport practice protocols can be modified to increase children's physical activity.

Physical activity in infancy and early childhood: a narrative review of interventions for prevention of obesity and associated health outcomes

In the context of the childhood obesity epidemic, this narrative review aims to explore opportunities to promote physical activity (PA) between birth and age 5 years as well as the health outcomes associated with PA in early childhood. Although early childhood is an ideal time to promote healthy habits, guidelines for PA have often ignored early childhood given the limited evidence for children <5 years old. Herein we discuss and highlight infant, toddler and preschool age interventions to promote PA and prevent obesity both in the short and long-term. We describe novel and modified interventions to promote improved early childhood health outcomes, encompassing cardiorespiratory, muscle, and bone strengthening components necessary for short-term motor development and long-term health. We call for new research aimed at developing and testing innovative early childhood interventions that may be performed in home or childcare settings, monitored by parents or caregivers.

An Assessment of State-Level Planning for Physical Activity Promotion in the United States

The prevalence and attributable risk of disease due to physical inactivity require it to be made a public health priority. Public health planning allows for prioritization and resource allocation, particularly at the state and local levels. The extent to which state planning efforts for physical activity exist in the United States is unknown. The purpose of this paper is to describe the scope in which physical activity is incorporated in state-level public health plans in the United States, with an emphasis on alignment with the national guidelines and the National Physical Activity Plan. A standardized internet search audit was developed and conducted for each of 50 US states and the District of Columbia between May 2017 and January 2018 to determine the prevalence and characteristics of health planning documents that include physical activity. Data abstracted for analysis used a standardized search protocol that included the components of the Physical Activity Guidelines for Americans and the US National Physical Activity Plan. Results found that most states had between 4 and 6 chronic disease prevention and control plans that mention physical activity; however, it was inconsistently aligned with recommendations from both the Guidelines and the National Plan. Only 2 states had stand-alone public health planning documents explicitly dedicated to physical activity promotion. No state planning documents addressed children and adolescents, adults, and older adults simultaneously. To be maximally effective, state public health planning for physical activity should be made a priority and these efforts should align as much as possible with current guidance from the Physical Activity Guidelines for Americans and the US National Physical Activity Plan.

Longitudinal changes in domains of physical activity during the transition from elementary school to high school in the U.S

OBJECTIVES

To describe patterns of age-related change in self-reported physical activity domains within a heterogeneous sample of boys and girls in the U.S. transitioning from elementary to high school.

DESIGN

Prospective cohort study.

METHODS

Participants included n = 644 children recruited in 5th grade (10.5 ± 0.5 years old, 45 % female) who completed the Physical Activity Choices survey at least twice over 5 time points (5th, 6th, 7th, 9th and 11th grade). Participants' self-reported physical activities were categorized into organized and non-organized activities, and a comprehensive variable was created as the product of the total number of physical activities reported in the past 5 days, the number of days spent in each activity, and the total time spent in each activity. Descriptive statistics and growth curve models (controlling for covariates) for the total sample and by sex were examined for total, organized, and non-organized physical activities from ages 10 to 17.

RESULTS

There was a significant age by gender interaction (p < 0.05) for time spent in non-organized physical activities. Specifically, both sexes had similar patterns of decline before age 13, while boys increased after age 13 and girls declined and then maintained. In contrast, boys and girls declined in organized physical activities from ages 10 to 17 (p < 0.001).

CONCLUSIONS

We observed stark differences in the age-related change between organized and non-organized physical activities and marked differences in the patterns of non-organized physical activities between boys and girls. Future research should examine physical activity interventions that consider age-, sex-, and domain-specific physical activity options for youth.

Longitudinal Associations of Cardiorespiratory Fitness and Poverty With Academic Performance Among Youth

BACKGROUND

Cardiorespiratory fitness (CRF) plays a significant role in health and academic performance in youth. The purpose of this study was to examine the longitudinal relationship between CRF and academic performance from fifth to eighth grade among a large, diverse, and state-wide cohort of students, and to determine the extent to which the relationship between change in CRF and academic performance is moderated by poverty status.

METHODS

CRF and academic performance data were obtained for a retrospective state-wide cohort of 11,013 students with baseline (fifth grade, school year 2015-2016) and follow-up (eighth grade, school year 2018-2019) data. Analysis of covariance was used to examine the association between changes in CRF over a 3-year follow-up period and eighth grade academic performance.

RESULTS

After adjusting for covariates, change in CRF and poverty status were positively and significantly associated with eighth grade academic performance. Poverty status did not significantly moderate the association between changes in CRF and academic performance.

CONCLUSIONS

Schools should prioritize evidence-based policies and programs that optimize students' access to high quantity and quality physical activity throughout the school day. Such efforts can improve and maintain student CRF and thus academic performance outcomes.

Factors Related to High-School Students’ Odds of Having Overweight or Obesity

This study used data the Youth Risk Behavior Surveillance System ( N = 7,088) to examine factors associated with the odds of overweight/obesity. Overweight/obese was defined as a body mass index ≥85th percentile, based on age- and sex-specific growth charts. Participants were categorized into meeting/not meeting guidelines for: sleep, moderate-to-vigorous PA (MVPA), muscle strengthening PA, screen time, breakfast eating, fruit and vegetable consumption, and soda and milk consumption. Logistic regression analyses determined whether meeting guidelines for each health behavior was associated with the odds of students having overweight/obesity in the total group and stratified by sex. Meeting MVPA guidelines was the only behavior associated with having a lower odds of overweight/obesity in both sexes. For females, meeting recommendations for breakfast eating and strength training were also associated with lower odds of having overweight/obesity, whereas for boys, getting the recommended amount of sleep was associated with having lower odds of overweight/obesity. Interventions to reduce the prevalence of overweight/obesity in youth should be implemented inside and outside of the school environment and should include components addressing physical activity, diet, and sleep. Such interventions should address barriers to healthy behaviors that are unique to adolescents already affected by overweight/obesity.

The association of physical activity to oral glucose tolerance test outcomes in multiple autoantibody positive children: The TEDDY Study

OBJECTIVE

To examine the association of physical activity (PA), measured by accelerometry, to hemoglobin AIC (HbA1c) and oral glucose tolerance test (OGTT) outcomes in children who were multiple persistent confirmed autoantibody positive for type 1 diabetes (T1D).

METHODS

The Environmental Determinants of Diabetes in the Young (TEDDY) multinational study followed children from birth. Children ≥3 years of age who were multiple persistent confirmed autoantibody positive were monitored by OGTTs every 6 months. TEDDY children's PA was measured by accelerometry beginning at 5 years of age. We examined the relationship between moderate plus vigorous (mod + vig) PA, HbA1c, and OGTT in 209 multiple autoantibody children who had both OGTT and PA measurements.

RESULTS

Mod + vig PA was associated with both glucose and C-peptide measures (fasting, 120-min, and AUC); higher mod + vig PA was associated with a better OGTT response primarily in children with longer duration of multiple autoantibody positivity. Mod + vig PA also interacted with child age; lower mod + vig PA was associated with a greater increase in C-peptide response across age. Mod + vig PA was not related to fasting insulin, HOMA-IR or HbA1c.

CONCLUSIONS

The OGTT is the gold standard for diabetes diagnosis and is used to monitor those at high risk for T1D. We found higher levels of mod + vig PA were associated with better OGTT outcomes in children ≥5 years of age who have been multiple autoantibody positive for longer periods of time. Physical activity should be the focus of future efforts to better understand the determinants of disease progression in high-risk children.

Acculturation and leisure-time physical activity among Asian American adults in the United States

ABSTRACTObjectives: To examine the association between acculturation and leisure-time physical activity among Asian Americans.Design: Data came from the 2011-2016 National Health and Nutrition Examination Survey, restricting to non-Hispanic Asian adults aged 20 years and older (n = 1989). Acculturation was assessed by language preference at home, birth locations, and length of residency in the United States (US). Self-reported physical activity was used to estimate leisure-time moderate-to-vigorous physical activity (MVPA) in MET-minutes/week and meeting the World Health Organization's physical activity guidelines. Multiple linear and logistic regression models were used to model MVPA as continuous and categorical variables, respectively.Results: A quarter of Asian Americans spoke only English and 47.8% spoke only non-English at home; 13.0% were born in the US. Asians who spoke only English (adjusted prevalence ratio [aPR]:1.5) and Asians who spoke both English and non-English at home (aPR: 1.4) had greater proportions of meeting physical activity guidelines compared to those who spoke only non-English at home. The US-born Asians had higher a proportion of meeting the physical activity guidelines (aPR:1.4) and performed 547.6 more MET-minutes of MVPA each week than foreign-born Asians; they also had a higher proportion of meeting the physical activity guidelines than foreign-born Asians who stayed in US for ≤10 years (aPR:1.5). Length of time staying in the US was associated with a higher proportion of meeting physical activity guidelines. Among foreign-born Asian Americans, higher acculturation measures were also positively associated with meeting physical activity guidelines.Conclusions: Acculturation was positively associated with physical activity levels among Asian Americans. More acculturated Asian Americans such as those who spoke more English at home and US-born Asians, performed more MVPA than less acculturated Asian Americans. Interventions are needed to promote physical activity among non-English speaking Asian immigrants and recent immigrants.

A Summary of One Research Team's Contributions to Understanding Physical Activity Behavior in Children and Youth

Schools are well-positioned to provide physical activity opportunities to help youth achieve the recommended 60 or more daily minutes of moderate-to-vigorous physical activity. The Children's Physical Activity Research Group (CPARG) at the University of South Carolina has focused on understanding physical activity in school-aged youth for 30+ years. The purpose of this article was to critically review (CPARG) contributions to the field in school settings and school-age youth. We reviewed 127 published CPARG articles from six research projects conducted between 1993-2019. The review was guided by questions in five categories: measurement of physical activity and its determinants, characteristics of physical activity behavior, correlates/determinants of physical activity, physical activity interventions, and race/ethnicity and physical activity. Results were summarized by question and synthesized across categories. CPARG contributions included assessing physical activity levels, patterns, forms, and contexts; identifying and measuring physical activity correlates/determinants; and conducting school-based physical activity interventions. Identifying multiple domains of physical activity determinants enables researchers and practitioners to select/design age-appropriate, valid, and reliable instruments to assess determinants. Focusing on determinants enables them to create effective physical activity interventions, environments, programs, and policies in schools. These efforts must address race/ethnicity differences, ensuring that measurement instruments and intervention strategies are culturally appropriate.

Buffering effects of protective factors on light and moderate-to-vigorous physical activity among african american women

Physical activity (PA) plays an integral role in reducing risk for the leading causes of death and has also been shown to buffer stress. Based on the stress-buffering hypothesis, the present study examined whether protective factors (self-efficacy and informal social control) buffered the effects of perceived stress on PA over time. Secondary data analyses of female African American caregivers (N = 143) were conducted using data from the Families Improving Together (FIT) trial. Validated measures of stressors and protective factors were assessed at baseline. Light PA and moderate-to-vigorous PA were assessed using seven-day accelerometry estimates over sixteen weeks. Multilevel growth modeling was used to assess whether protective factors moderated the effects of perceived stress on PA outcomes across 16 weeks. There was a significant two-way interaction between informal social control and time (B = 0.40, SE = 0.17, p = .019) such that higher informal social control was positively associated with MVPA over time. There was a marginal three-way interaction (B = -18.90, SE = 10.31, p = .067) such that stress was associated with greater LPA at baseline under conditions of high but not low self-efficacy. This study provides preliminary support that social factors may be important for maintaining MVPA regardless of stress levels, while cognitive resources may be more important to target for influencing LPA engagement under conditions of high stress.

Behavioral, Environmental, and Demographic Factors Associated with Objectively Measured Physical Activity in Infants

Background: To describe objectively measured physical activity (PA) in infants, and to identify demographic, behavioral, and environmental factors associated with infants' PA. Methods: Participants were 6-7-month-old infants and their mothers (N = 143 dyads) from two Southeastern US counties. Infant measures included PA assessed by accelerometers at ankle and waist sites, motor developmental status (i.e., stationary and locomotion), and anthropometric characteristics (i.e., height and weight). Mothers provided information on home environment, child care settings, and family demographic factors. PA levels were compared across demographic subgroups. Correlation coefficients described associations between PA and continuous variables, including motor developmental status and anthropometric characteristics. Multiple linear regression analyses examined factors found to be independently associated with PA. Results: Infants' PA counts were greater at the ankle (77,700 counts/hr) vs. the waist site (32,500 counts/hr). In univariate analyses, a diverse set of environmental, behavioral, and infant-level demographic factors were found to be significantly associated with PA at the ankle site. Multivariate analyses indicated that more advanced motor development status (B = 666.3 ± 329.8, p < 0.05), attendance at home child care settings (B = -13,724.4 ± 5083.9, p < 0.05), greater exposure to tummy time (B = 213.5 ± 79.9, p < 0.05), and white racial/ethnic composition (B = -19,953.4 ± 5888.5, p < 0.01) were independently, associated with infants' PA. Conclusions: In 6-7-month-old infants, objectively measured PA was found to be associated with motor developmental status and physical and social environmental factors, including both demographic moderators and factors that are influenced by parents and caregivers. Longitudinal studies are needed to determine if these relationships persist or change as infants develop.

Exercise and Cardiovascular Disease Risk Factors in Children and Adolescents With Obesity: A Systematic Review With Meta-Analysis of Randomized Controlled Trials

The purpose of this study was to examine the effects of exercise on cardiovascular disease (CVD) risk factors in children and adolescents with obesity. Randomized controlled trials (RCTs) of exercise ≥4 weeks in children and adolescents with obesity were included if one or more CVD risk factors were included as an outcome. Studies were retrieved by searching 7 electronic databases, cross-referencing, and expert review. Data were pooled using the inverse-variance heterogeneity (IVhet) model and strength of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) instrument. Thirty-nine studies representing 1548 participants (847 exercise, 701 control) met the inclusion criteria. Aerobic exercise improved 10 of 12 (83.3%) outcomes (P < .05 for all) while combined aerobic and strength training improved 5 of 8 (62.5%) outcomes (P < .05 for all). The strength of evidence ranged from "very low" to "moderate." It was concluded that aerobic exercise, as well as combined aerobic and strength training, is associated with improvements in multiple CVD risk factors among children and adolescents with obesity. However, the generally low strength of evidence suggests a need for future well-designed and conducted RCTs on the effects of exercise, especially strength training, in children and adolescents with obesity.

Patterns of age-related change in physical activity during the transition from elementary to high school

This study was designed: 1) to describe patterns of age-related change in total and moderate-to-vigorous physical activity (MVPA) in children as they transitioned from elementary school to high school, and 2) to determine if those patterns differed across demographic sub-groups formed on the basis of gender, race/ethnicity, parent education (socioeconomic status), and urbanicity. A cohort of children (analysis sample, N = 951) was comprised of students drawn from two public school districts in South Carolina. Physical activity was measured by accelerometry on at least two and up to five occasions between 2010 and 2017. Growth curve analyses were performed to describe the pattern of age-related change in the physical activity variables for the full sample and for demographic sub-groups. A relatively steep age-related decline in total physical activity was observed in children before age 14, with a slower rate after that age. Physical activity was lower in girls than boys, and the age-related rate of decline was steeper in girls. Physical activity patterns did not differ across race/ethnicity groups, but children of parents with less education were more active than children of parents with more education. Children living in rural areas participated in less MVPA than children living in urban settings, and this difference increased with increasing age. These findings indicate that children experience a particularly steep decrease in physical activity as they transition from elementary to middle school, and this trend is particularly prominent in girls, children living in rural areas, and children of parents with college education.

Longitudinal association of biological maturation with physical activity behaviors in girls transitioning from 5th to 7th grade

Introduction

This longitudinal study determined if social cognitive variables influence physical activity in girls stratified on the basis of maturity status.

Methods

Participants attended South Carolina public schools (Mage in 5th grade = 11.1 years) and included a cohort of 529 girls who provided physical activity data in the 5th grade and in 6th and/or 7th grade. The measure of maturity status was age at peak height velocity (APHV) estimated from maturity offset when the children were in the 5th grade. The Earlier Maturity (EM) group included girls whose APHV was one standard deviation or more below the mean APHV for the full sample. All other girls were placed in the Later Maturity (LM) group. Physical activity was assessed at each time point via accelerometry. Social‐cognitive variables were assessed at each time point by a questionnaire measuring self‐efficacy, enjoyment, competence, appearance, fitness, and social motives for physical activity. Growth curves for the total, Earlier Maturing, and Later Maturing groups assessed relationships between physical activity over time and time‐varying social cognitive variables.

Results

Physical activity was lower in the Earlier Maturing group and was positively associated with self‐efficacy and enjoyment motivation in the total group. These relationships were observed in the 5th grade and maintained through 7th grade. In the Later Maturing group, we observed positive relationships between physical activity and self‐efficacy, enjoyment and competence motivation.

Conclusions

Strategies to increase confidence, skills, and enjoyment of physical activity may only be effective for promoting activity among later maturing girls.

Supporting Physical Activity in Patients and Populations During Life Events and Transitions: A Scientific Statement From the American Heart Association

Achieving recommended levels of physical activity is important for optimal cardiovascular health and can help reduce cardiovascular disease risk. Emerging evidence suggests that physical activity fluctuates throughout the life course. Some life events and transitions are associated with reductions in physical activity and, potentially, increases in sedentary behavior. The aim of this scientific statement is to first provide an overview of the evidence suggesting changes in physical activity and sedentary behavior across life events and transitions. A second aim is to provide guidance for health care professionals or public health workers to identify changes and promote physical activity during life events and transitions. We offer a novel synthesis of existing data, including evidence suggesting that some subgroups are more likely to change physical activity behaviors in response to life events and transitions. We also review the evidence that sedentary behavior changes across life events and transitions. Tools for health care professionals to assess physical activity using simple questions or wearable devices are described. We provide strategies for health care professionals to express compassion as they ask about life transitions and initiate conversations about physical activity. Last, resources for life phase-specific, tailored physical activity support are included. Future research needs include a better characterization of physical activity and sedentary behavior across life events and transitions in higher-risk subgroups. Development and testing of interventions designed specifically to combat declines in physical activity or increases in sedentary behavior during life events and transitions is needed to establish or maintain healthy levels of these cardiovascular health-promoting behaviors.

Nighttime sleep and physical activity in 6-7 month-old infants

This study examined associations between objectively-measured nighttime sleep duration and physical activity in a sample of 6-7 month-old infants (N=93). The study also investigated relationships between infant sleep and demographic and environmental characteristics. Cross-sectional relationships were assessed using linear regression analyses. Nighttime sleep duration was positively associated with physical activity levels. Nighttime sleep duration was greater when infants had a consistent bedtime, slept in a separate room, were male, and had mothers who reported having a college education or greater. These findings can inform the development of interventions that aim to improve infant sleep.

Impact of a year-round school calendar on children's BMI and fitness: Final outcomes from a natural experiment

BACKGROUND

Structure may mitigate children's accelerated summer BMI gain and cardiorespiratory-fitness (CRF) loss.

OBJECTIVES

Examine BMI and CRF change during school and summer for year-round and traditional calendar school children.

METHODS

Three schools (N = 2279, 1 year-round) participated in this natural experiment. Children's BMI z-score (zBMI) and CRF (PACER laps) were measured from 2017 to 2019 each May/August. Mixed effects regression estimated monthly zBMI and CRF change during school/summer. Secondary analyses examined differences by weight status and race. Spline regression models estimated zBMI and CRF growth from kindergarten-sixth grade.

RESULTS

Compared to traditional school, children attending a year-round school gained more zBMI (difference = 0.015; 95CI = 0.002, 0.028) during school, and less zBMI (difference = -0.029; 95CI = -0.041, -0.018), and more CRF (difference = 0.834; 95CI = 0.575, 1.093) monthly during summer. Differences by weight status and race were observed during summer and school. Growth models demonstrated that the magnitude of overall zBMI and CRF change from kindergarten-sixth grade was similar for year-round or traditional school children.

CONCLUSIONS

Contrary to traditional school children zBMI increased during the traditional 9-month school calendar and zBMI decreased during the traditional summer vacation for year-round school children. Structured summer programming may mitigate accelerated summer BMI gain and CRF loss especially for overweight or obese, and/or Black children.

COVID-19 Leads to Accelerated Increases in Children's BMI z-Score Gain: An Interrupted Time-Series Study

INTRODUCTION

The COVID-19 pandemic may have negatively impacted children's weight status owing to the closure of schools, increased food insecurity and reliance on ultraprocessed foods, and reduced opportunities for outdoor activity.

METHODS

In this interrupted time-series study, height and weight were collected from children (n=1,770 children, mean age=8.7 years, 55.3% male, 64.6% Black) and were transformed into BMI z-score in each August/September from 2017 to 2020. Mixed-effects linear regression estimated yearly BMI z-score change before the COVID-19 pandemic year (i.e., 2017-2019) and during the COVID-19 pandemic year (i.e., 2019-2020). Subgroup analyses by sex, race (i.e., Black, White, other race), weight status (overweight or obese and normal weight), and grade (i.e., lower=kindergarten-2nd grade and upper=3rd-6th grade) were conducted.

RESULTS

Before the COVID-19 pandemic, children's yearly BMI z-score change was +0.03 (95% CI= -0.10, 0.15). Change during the COVID-19 pandemic was +0.34 (95% CI=0.21, 0.47), an acceleration in BMI z-score change of +0.31 (95% CI=0.19, 0.44). For girls and boys, BMI z-score change accelerated by +0.33 (95% CI=0.16, 0.50) and +0.29 (95% CI=0.12, 0.46), respectively, during the pandemic year. Acceleration in BMI z-score change during the pandemic year was observed for children who were Black (+0.41, 95% CI=0.21, 0.61) and White (+0.22, 95% CI=0.06, 0.39). For children classified as normal weight, BMI z-score change accelerated by +0.58 (95% CI=0.40, 0.76). Yearly BMI z-score change accelerated for lower elementary/primary (+0.23, 95% CI=0.08, 0.37) and upper elementary/primary (+0.42, 95% CI=0.42, 0.63) children.

CONCLUSIONS

If similar BMI z-score accelerations occurred for children across the world, public health interventions to address this rapid unhealthy BMI gain will be urgently needed.

Implementation Monitoring of a Promotora-Led, Home-Based Obesity Prevention Pilot Study With Latino Preschool Children and Their Mothers

BACKGROUND

Latino preschool children have higher rates of obesity than children from other racial/ethnic backgrounds. Few effective, culturally-tailored obesity prevention interventions exist that have focused on Latino preschool children, and even fewer have published results of the process evaluation. The purpose of this paper was to monitor reach, fidelity, and completeness of implementation to determine whether ANDALE, a promising promotora-led, home-based pilot study to prevent obesity in Latino preschool children, was implemented as planned.

METHODS

Guided by a logic model, we assessed reach, implementation fidelity and completeness through descriptive analyses of multiple data sources. Reach was assessed through attendance records. Fidelity was assessed via observation checklist and completeness was assessed via survey with both parents and promotoras in a subsample of 12 families.

RESULTS

Promotoras recruited participants primarily through their own social networks and delivered the intervention to 50 families (mother-child dyads); the majority were of Mexican-origin, low-acculturation, dual-parent households. Nearly all (98%) families completed the whole 10-week intervention. Results demonstrated completeness and fidelity of implementation were acceptable in a subsample of 12 families. In sum, 75% of families in the subsample met the criteria (≥75%) for overall implementation of essential program elements (i.e., reach, completeness, and fidelity).

CONCLUSION

Evidence suggests that ANDALE was delivered with high levels of completeness and fidelity in this sample of Latino families with preschool-aged children. These results support implementation of ANDALE in a large, randomized trial.

Dynamics of sleep, sedentary behavior, and moderate-to-vigorous physical activity on school versus nonschool days

STUDY OBJECTIVES

Studies examining time-use activity behaviors (sleep, sedentary behavior, and physical activity) on school days compared with nonschool days have examined these behaviors independently, ignoring their interrelated nature, limiting our ability to optimize the health benefits of these behaviors. This study examines the associations of school-day (vs. nonschool day) with time-use activity behaviors.

METHODS

Time series data (6,642 days) from Fitbits (Charge-2) were collected (n = 196, 53% female, 5-10 years). We used a variable-centered dynamic structural equation modeling approach to estimate day-to-day associations of time-use activity behaviors on school days for each child. We then used person-centered cluster analyses to group individuals based on these estimates.

RESULTS

Within-participant analysis showed that on school days (vs. nonschool days), children (1) slept less (β = -0.17, 95% CI = -0.21, -0.13), (2) were less sedentary (β = -0.05, 95% CI = -0.09, -0.02), and (3) had comparable moderate-to-vigorous physical activity (MVPA; β = -0.05, 95% CI = -0.11, 0.00). Between-participant analysis showed that, on school days, children with higher sleep carryover experienced greater decreases in sleep (β = 0.44, 95% CI = 0.08, 0.71), children with higher body mass index z-score decreased sedentary behavior more (β = -0.41, 95% CI = -0.64, -0.13), and children with lower MVPA increased MVPA more (β = -0.41, 95% CI -0.64, -0.13). Cluster analysis demonstrated four distinct patterns of connections between time-use activity behaviors and school (High Activity, Sleep Resilient, High Sedentary, and Dysregulated Sleep).

CONCLUSIONS

Using a combination of person-centered and more traditional variable-centered approaches, we identified patterns of interrelated behaviors that differed on school, and nonschool days. Findings can inform targeted intervention strategies tailored to children's specific behavior patterns.

Associations between three measures of physical activity and selected influences on physical activity in youth transitioning from elementary to middle school

Measurement of physical activity is challenging, and objective and subjective methods can be used. The purposes of this study were to apply structural equation modeling in: 1) examining the associations between three distinct measures of physical activity and three factors that are often found to be correlated to physical activity in children, and 2) examining the associations of the combination of three measures with the same correlates in a cohort of youth followed from 5th to 7th grade. A total of 409 children (45% boys) had complete physical activity data derived from accelerometers, self-report by youth, and proxy-report by parents. The potential correlates of physical activity included self-efficacy, physical activity support, and facilities for physical activity. Structural equation models were used to assess the relationship between physical activity and the correlates. The structural equation models examining associations between individual measures of physical activity and selected correlates showed that parent-reported and child self-reported physical activity were associated with parental support for physical activity and self-efficacy. Objectively measured physical activity was associated only with facilities for physical activity. A structural equation model showed that a composite expression of physical activity, based on the inclusion of all three individual measures, was associated with all three correlates of physical activity. In conclusion, combining measures of physical activity from different sources may improve the identification of correlates of physical activity. This information could be used to plan more effective physical activity interventions in children and youth.

How Many US Children and Adolescents with Overweight and Obesity Could Improve Their Percent Body Fat by Exercising?: Meta-Analytic Based Estimates

Background: Provide national estimates of the number of US children and adolescents with overweight and obesity who could improve their percent body fat by exercising. Methods: Data were derived from (1) a previous meta-analysis, (2) 2015-2016 prevalence data from the National Health and Nutrition Examination Survey (NHANES), and (3) 2017 US Census population data. Multiplicative calculations were based on (1) number-needed-to treat data from a previous meta-analysis of the number of children with overweight and obesity who could reduce their percent body fat by participating in either aerobic, strength, or combined aerobic and strength training, (2) 2015-2016 NHANES data on the prevalence of children and adolescents with overweight or obesity, and (3) 2017 US Census population data on children and adolescents 2-19 years of age. Results: For both children and adolescents with overweight or obesity, the number who could improve their percent body fat was estimated at 4,388,273 [95% confidence interval (CI) 3,831,523-4,845,023] for either aerobic or strength exercise and 6,507,410 (95% CI 5,744,285-7,267,534) for combined aerobic and strength exercise. Conclusions: A large number of US children and adolescents with overweight and obesity could improve their percent body fat by exercising.

Children's moderate-to-vigorous physical activity on weekdays versus weekend days: a multi-country analysis

Purpose

The Structured Days Hypothesis (SDH) posits that children’s behaviors associated with obesity – such as physical activity – are more favorable on days that contain more ‘structure’ (i.e., a pre-planned, segmented, and adult-supervised environment) such as school weekdays, compared to days with less structure, such as weekend days. The purpose of this study was to compare children’s moderate-to-vigorous physical activity (MVPA) levels on weekdays versus weekend days using a large, multi-country, accelerometer-measured physical activity dataset.

Methods

Data were received from the International Children’s Accelerometer Database (ICAD) July 2019. The ICAD inclusion criteria for a valid day of wear, only non-intervention data (e.g., baseline intervention data), children with at least 1 weekday and 1 weekend day, and ICAD studies with data collected exclusively during school months, were included for analyses. Mixed effects models accounting for the nested nature of the data (i.e., days within children) assessed MVPA minutes per day (min/day MVPA) differences between weekdays and weekend days by region/country, adjusted for age, sex, and total wear time. Separate meta-analytical models explored differences by age and country/region for sex and child weight-status.

Results/findings

Valid data from 15 studies representing 5794 children (61% female, 10.7 ± 2.1 yrs., 24% with overweight/obesity) and 35,263 days of valid accelerometer data from 5 distinct countries/regions were used. Boys and girls accumulated 12.6 min/day (95% CI: 9.0, 16.2) and 9.4 min/day (95% CI: 7.2, 11.6) more MVPA on weekdays versus weekend days, respectively. Children from mainland Europe had the largest differences (17.1 min/day more MVPA on weekdays versus weekend days, 95% CI: 15.3, 19.0) compared to the other countries/regions. Children who were classified as overweight/obese or normal weight/underweight accumulated 9.5 min/day (95% CI: 6.9, 12.2) and 10.9 min/day (95% CI: 8.3, 13.5) of additional MVPA on weekdays versus weekend days, respectively.

Conclusions

Children from multiple countries/regions accumulated significantly more MVPA on weekdays versus weekend days during school months. This finding aligns with the SDH and warrants future intervention studies to prioritize less-structured days, such as weekend days, and to consider providing opportunities for all children to access additional opportunities to be active.

Inter-individual differences in body mass index were not observed as a result of aerobic exercise in children and adolescents with overweight and obesity

BACKGROUND

Exercise has been recommended as an important intervention for reducing adiposity in children and adolescents with overweight and obesity.

OBJECTIVE

Determine whether inter-individual differences exist in relation to exercise-induced changes in adiposity among children and adolescents with overweight and obesity.

METHODS

Meta-analysis of randomized controlled aerobic exercise trials and body mass index (BMI) in kg · m^-2 . Change outcome standard deviations were pooled using the inverse-variance heterogeneity model.

RESULTS

Twenty-eight studies (1185 participants) were included. Inter-individual differences in BMI were -0.1 (95% compatibility interval, -0.7 to 0.7). The 95% prediction interval for inter-individual responses in a future study was -2.9 to 2.9. The probability of a clinically meaningful difference in variability was 29% (possibly clinically important) in favour of controls vs exercisers.

CONCLUSIONS

Inter-individual differences for BMI in kg · m^-2 were not observed as a result of aerobic exercise in children and adolescents with overweight and obesity.

The impact of summer vacation on children's obesogenic behaviors and body mass index: a natural experiment

BACKGROUND

Children's BMI gain accelerates during summer. The Structured Days Hypothesis posits that the lack of the school day during summer vacation negatively impacts children's obesogenic behaviors (i.e., physical activity, screen time, diet, sleep). This natural experiment examined the impact of summer vacation on children's obesogenic behaviors and body mass index (BMI).

METHODS

Elementary-aged children (n = 285, 5-12 years, 48.7% male, 57.4% African American) attending a year-round (n = 97) and two match-paired traditional schools (n = 188) in the United States participated in this study. Rather than taking a long break from school during the summer like traditional schools, year-round schools take shorter and more frequent breaks from school. This difference in school calendars allowed for obesogenic behaviors to be collected during three conditions: Condition 1) all children attend school, Condition 2) year-round children attend school while traditional children were on summer vacation, and Condition 3) summer vacation for all children. Changes in BMI z-score were collected for the corresponding school years and summers. Multi-level mixed effects regressions estimated obesogenic behaviors and monthly zBMI changes. It was hypothesized that children would experience unhealthy changes in obesogenic behaviors when entering summer vacation because the absence of the school day (i.e., Condition 1 vs. 2 for traditional school children and 2 vs. 3 for year-round school children).

RESULTS

From Condition 1 to 2 traditional school children experienced greater unhealthy changes in daily minutes sedentary (∆ = 24.2, 95CI = 10.2, 38.2), screen time minutes (∆ = 33.7, 95CI = 17.2, 50.3), sleep midpoint time (∆ = 73:43, 95CI = 65:33, 81:53), and sleep efficiency percentage (-∆ = 0.7, 95CI = -1.1, - 0.3) when compared to year-round school children. Alternatively, from Condition 2 to 3 year-round school children experienced greater unhealthy changes in daily minutes sedentary (∆ = 54.5, 95CI = 38.0, 70.9), light physical activity minutes (∆ = - 42.2, 95CI = -56.2, - 28.3) MVPA minutes (∆ = - 11.4, 95CI = -3.7, - 19.1), screen time minutes (∆ = 46.5, 95CI = 30.0, 63.0), and sleep midpoint time (∆ = 95:54, 95CI = 85:26, 106:22) when compared to traditional school children. Monthly zBMI gain accelerated during summer for traditional (∆ = 0.033 95CI = 0.019, 0.047) but not year-round school children (∆ = 0.004, 95CI = -0.014, 0.023).

CONCLUSIONS

This study suggests that the lack of the school day during summer vacation negatively impacts sedentary behaviors, sleep timing, and screen time. Changes in sedentary behaviors, screen time, and sleep midpoint may contribute to accelerated summer BMI gain. Providing structured programming during summer vacation may positively impact these behaviors, and in turn, mitigate accelerated summer BMI gain.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03397940 . Registered January 12th 2018.

Preschool Healthy Food Policy Did Not Increase Percent of Food Wasted: Evidence from the Carolinas

This research evaluates the effects of a South Carolina (SC) policy, which changed the nutrition standards for foods served in early care and education (ECE) settings, on wasted food. A two-group pre-test/post-test evaluation was performed in ECE centers serving children age 3-5 from households with lower incomes in SC (n = 102 children from 34 centers, intervention) and North Carolina (NC; n = 99 children from 30 centers, comparison). Direct observation was performed to assess the quantity and kcal of food served and quantity and percent of food discarded, by food group and nutrient, enabling assessment of waste in the absence of intervention. Mixed-effects linear models were fit to estimate, by state, differences in change from baseline to post-implementation at the center level. Covariates were selected a priori, including center enrollment, racial composition, director educational attainment, years in operation, for-profit status, and Child and Adult Care Food Program (CACFP) participation. Waste of food was high across states and time points. The policy was not associated with a change in percent of food discarded in SC compared to NC in adjusted analyses.

Changes in Diet Quality in Youth Living in South Carolina From Fifth to 11th Grade

OBJECTIVE

To examine diet quality levels and changes in a diverse sample of youth from fifth to 11th grade, and interactions by race/ethnicity and socioeconomic status.

DESIGN

Transitions and Activity Changes in Kids prospective cohort study.

SETTING

Elementary, middle, and high schools in South Carolina.

PARTICIPANTS

A sample of 260 fifth-graders (106 boys and 154 girls) with complete data at baseline and at least 1 time point each in middle school and in high school.

MAIN OUTCOME MEASURE

Dietary intake assessed with the Block Food Screener for Kids (last week). Diet quality was assessed using energy-adjusted intakes of 5 food groups.

ANALYSIS

Descriptive statistics and growth curve models for the total group and by gender for diet quality from fifth to 11th grade (P < 0.05).

RESULTS

Both boys and girls had low levels of diet quality, which continued to decline through 11th grade. Significant main effects by race and poverty as well as a race by poverty interaction were observed.

CONCLUSIONS AND IMPLICATIONS

Programs and policies that support healthy dietary patterns in children transitioning from elementary to middle and high school are needed. Specific efforts that focus on nutrition disparities in children from low-income and minority backgrounds are warranted.

An observation system to assess physical activity of children with developmental disabilities and delays in preschool

BACKGROUND

Physical activity (PA) behaviors during preschool settings can influence the health and development of children with developmental disabilities (DD). There is a need for a direct observation system that simultaneously assesses PA and preschool environmental contexts.

OBJECTIVE

The purpose of this study was to develop an observation instrument for measuring PA and related contextual factors of preschoolers with DD, and to establish content validity and reliability.

METHODS

Content validity was established through consultation with experts, informal observations in inclusive and special education preschools, and literature reviews. Categories and codes were identified and modified from existing observational systems for young children. Reliability was assessed in a convenience sample of preschool children with DD using a cross-sectional design. Data were collected using a momentary time sampling system (5-sec observe, 25-sec record) following a focal child. Inter-rater reliability was assessed during 20% of the observation sessions.

RESULTS

The instrument development process resulted in ten coding categories that accounted for PA levels, types, and social and physical environmental contexts relevant to preschoolers with disabilities. Observers completed 137.5 observation sessions, yielding 5498 30-s observation intervals. Interval-by-interval percent agreement was excellent (91%-100%) and kappa values were high (0.82-0.99).

CONCLUSIONS

The instrument was found to be a reliable measure of PA of preschoolers with DD and provided important contextual information about PA behaviors in early childhood special education settings. Additionally, it allowed for the simultaneous measurement of specific types and contexts of PA behaviors of preschoolers with DD and will be useful for describing PA and informing future interventions.

Neighborhood Socioeconomic Deprivation Associated with Fat Mass and Weight Status in Youth

(1) Background: Few studies have examined the relationship between neighborhood socioeconomic deprivation (SED) and weight-related outcomes in youth, controlling for weight-related behaviors. Hence, the purpose of this study was to examine the association between neighborhood SED, weight status, and fat mass in a diverse sample of youth, before and after controlling for physical activity and diet. (2) Methods: The sample included 828 youth from the Transitions and Activity Changes in Kids study. Neighborhood SED was expressed as an index score at the census tract of residence. Height, weight, and body composition were measured and used to calculate fat mass index (FMI) and weight status. Moderate-to-vigorous physical activity (MVPA) and sedentary behavior (min/h) were measured via accelerometry. Diet quality was assessed via the Block Food Screener for Kids. Multilevel regression models were employed to examine these relationships. (3) Results: Neighborhood SED was significantly associated with FMI and weight status before and after controlling for MVPA, sedentary behavior, and diet. Notably, youth residing in the most deprived neighborhoods had significantly higher FMI and were 30% more likely to be overweight/obese (OR = 1.30; 95% CI = 1.03-1.65). (4) Conclusions: Greater neighborhood SED was consistently and significantly associated with higher fat mass index and increased likelihood of overweight/obesity among youth.

The translation of an evidence-based preschool physical activity intervention from in-person to online delivery of professional development to preschool teachers

Study of Health and Activity in Preschool Environments (SHAPES) aimed to increase preschoolers' physical activity by engaging preschool teachers in professional development designed to modify instructional practices. SHAPES originated as a randomized controlled trial, tested in 16 preschools and disseminated to 4 control schools, and was shown to be effective in increasing preschool children's physical activity (Phase I, 2008-2012). This article describes the steps taken to translate an evidence-based physical activity intervention, SHAPES, from in-person delivery to online delivery of professional development to preschool teachers. In Phase II (2013-2016), professional development delivery was modified from an in-person to an online program for preschool teachers. Teacher implementation completeness and fidelity were examined in 10 pilot preschools and then replicated in 30 preschools. Large-scale dissemination of SHAPES began in Phase III (2017-2019), reaching 818 teachers from 228 unique centers after 2 years. The final SHAPES program consisted of six online modules, an accompanying guidebook, over 90 activities, self-assessment techniques, a video library, and an electronic community forum. The SHAPES core elements, defined in Phase I, were retained throughout all three phases. The Phase II change to online delivery was characterized by high levels of implementation completeness and fidelity. Results of Phase III statewide dissemination revealed comparable implementation completeness and fidelity. An intervention shown to be effective in a randomized controlled trial can be translated into an online professional development program and disseminated on a large scale in a timely manner.

Poverty Status Moderates the Relationship between Cardiorespiratory Fitness and Academic Achievement

BACKGROUND

The purpose of the study was to examine the associations among cardiorespiratory fitness (CRF), weight status and academic achievement in youth, and to determine if these relationships are moderated by poverty status.

METHODS

The sample included 5th (N = 27,791) and 8th grade (N = 16,047) South Carolina students. Academic achievement was assessed using a state-wide assessment and classified into 2 categories (ie, does not meet/approaches standards vs meets/exceeds standards). CRF was assessed and expressed as Healthy Fitness Zone (HFZ) or Needs Improvement/Needs-Improvement-Health Risk. Students' demographics and poverty status were reported. Multilevel logistic regression analyses were used to examine the association between CRF, weight status and academic achievement. Interaction terms were introduced into the final models. Analyses were performed separately by grade level and academic subject.

RESULTS

The CRF was significantly associated with the odds of meeting/exceeding academic standards after controlling for covariates and adjusting for weight status. The relationship between CRF and academic achievement varied significantly by poverty status. After adjustment for CRF, weight status was not significantly associated with academic achievement.

CONCLUSIONS

The odds of achieving academic standards were significantly higher among students achieving CRF HFZ regardless of poverty status. CRF may partially mitigate the adverse effect of poverty on academic achievement.

Are There Inter-Individual Differences in Fat Mass and Percent Body Fat as a Result of Aerobic Exercise Training in Overweight and Obese Children and Adolescents? A Meta-Analytic Perspective

Background: Determine whether inter-individual response differences exist with respect to changes in fat mass and percent body fat as a result of aerobic exercise training in overweight and obese children and adolescents. Methods: Using the meta-analytic approach, randomized controlled trials that examined the effects of aerobic exercise training on fat mass and percent body fat in overweight and obese children and adolescents were included. Change outcome standard deviations for fat mass and percent body fat were used to calculate true inter-individual differences from each study. The inverse variance heterogeneity model was used to pool results. Results: Pooled changes for inter-individual response differences in fat mass (16 studies, 575 participants) were 0.9 kg (95% confidence interval [CI], -1.4 to 1.8 kg) while tau ([Formula: see text]) was 2.9. For percent body fat, inter-individual differences (27 studies, 1035 participants) were 0.6% (95% CI, -0.6% to 1.0%, [Formula: see text] = 0.7). The 95% prediction interval for true inter-individual responses in a future study was -4.9 to 5.5 kg for fat mass and -0.7% to 1.7% for percent body fat. The percent chance, that is, probability, of a clinically meaningful difference in variability was 47% for fat mass and 26% for percent body fat, both of which were considered as only possibly clinically important. Conclusions: There is a lack of convincing evidence to suggest that true inter-individual response differences exist with respect to aerobic exercise training and changes in fat mass and percent body fat in overweight and obese children and adolescents.

Association between change in maternal physical activity during pregnancy and infant size, in a sample overweight or obese women

Physical activity (PA) naturally declines during pregnancy and its effects on infant size are unclear, especially in overweight or obese pregnancies, a low-active subpopulation that tends deliver heavier infants. The objective of this study was to evaluate changes in prenatal PA and infant birthweight in a group of overweight or obese pregnant women. We employed a prospective analysis using data from a randomized controlled exercise trial (2001 to 2006) in sedentary, overweight or obese pregnant women in Michigan. Women with complete data on peak oxygen consumption, daily PA (via pedometers) and birthweight were included in the analyses. Change in PA was estimated via repeated measures analyses, and then its influence on infant birthweight was assessed via linear regression. Eighty-nine pregnant women were included and considered low-active (6,579.91 ± 2379.17 steps/day). PA declined from months 4 to 8 (-399.73 ± 371.38 steps∙day^-1∙month^-1). Analyses showed that the decline in PA (β = -0.28 g, 95%CI: -0.70, 0.25 g, p = .35) was not associated with birthweight. The findings of this study demonstrated that the decline in maternal PA during mid- to late-pregnancy, in overweight or obese women, was unrelated to infant birthweight. Future investigations should employ rigorous measurements of PA and infant anthropometry in this subpopulation.

Linking Activity, Nutrition, and Child Health (LAUNCH): protocol for a longitudinal cohort study of children as they develop from infancy to preschool age

BACKGROUND

Physical activity is known to provide important health benefits in children ages 3 years and above, but little is known about the effects of physical activity on health in very young children under age 3. LAUNCH (Linking Activity, Nutrition, and Child Health) is a study designed to expand the body of knowledge on development of physical activity behavior and associations between physical activity and other health characteristics as children transition from infancy to preschool age.

METHODS

Physical activity and sedentary behavior will be measured objectively in young children over a period of 30 months. Each child will complete a measurement protocol at 6, 12, 18, 24, 30 and 36 months of age. The following factors will be measured at each time point: physical activity, sedentary behavior, anthropometric characteristics, and motor developmental status. Objectively-measured sleep behavior will be included as an optional component of the protocol. Parents will provide information on demographic factors, parenting behaviors, home and childcare characteristics, and the child's dietary and sleep behaviors.

DISCUSSION

LAUNCH will employ a longitudinal study design and objective measures of physical activity, sedentary behavior and sleep in examining developmental trends for those characteristics in children between the ages of 6 and 36 months. Associations among physical activity, sedentary behavior, sleep, and weight status will be examined. Findings will inform public health guidance and intervention strategies for very young children.

Healthy Eating Policy Improves Children's Diet Quality in Early Care and Education in South Carolina

Policies to promote healthy foods in early care and education (ECE) in the United States exist, but few have been prospectively evaluated. In South Carolina, a statewide program serving low-income children in ECE enacted new policies promoting healthy foods. We conducted an evaluation to measure changes in dietary intake among children in ECE exposed and not exposed to the new policy. Using direct observation, we assessed dietary intake in 112 children from 34 ECE centers in South Carolina and 90 children from 30 ECE centers in North Carolina (a state with no policy). We calculated Healthy Eating Index-2015 (HEI) scores to measure diet quality consumed before and after the policy was enacted. We fit mixed-effects linear models to estimate differences in HEI scores by state from baseline to post-policy, adjusting for child race, number of children enrolled, director education, center years in operation, participation in the Child and Adult Care Food Program (CACFP), and center profit status. The policy increased HEI scores for whole fruits, total fruits, and lean proteins, but decreased scores for dairy. Thus, the policy was associated with some enhancements in dietary intake, but additional support may help improve other components of diet.

Participation in the Child and Adult Care Food Program is associated with fewer barriers to serving healthier foods in early care and education

BACKGROUND

Early care and education (ECE) is an important setting for influencing young children's dietary intake. There are several factors associated with barriers to healthy eating in ECE, and recent evidence suggests that participation in the Child and Adult Care Food Program (CACFP), the primary national food assistance program in ECE, may be associated with fewer barriers to serving healthier foods. However, no prior studies have examined differences between CACFP participants and non-participants across a large, multi-state sample. This is the first study to examine the association between CACFP participation and barriers to serving healthier foods in ECE using a random sample of directors from two regions across the country.

METHODS

We conducted a cross-sectional survey among a random sample of child care center directors from four states (Massachusetts, North Carolina, Rhode Island, and South Carolina). We conducted logistic and Poisson regression to calculate the odds and incidence rate ratios of reporting 1) no barriers, 2) specific barriers (e.g., cost), and 3) the total number of barriers, by CACFP status, adjusting for covariates of interest.

RESULTS

We received 713 surveys (36% response rate). About half (55%) of centers participated in CACFP. The most prevalent reported barriers to serving healthier foods were cost (42%) and children's food preferences (19%). Directors from CACFP centers were twice as likely to report no barriers, compared to directors from non-CACFP centers (OR 2.03; 95% CI [1.36, 3.04]; p < 0.01). Directors from CACFP centers were less likely to report cost as a barrier (OR = 0.46; 95% [CI 0.31, 0.67]; p < 0.001), and reported fewer barriers overall (IRR = 0.77; 95% CI [0.64, 0.92]; p < 0.01), compared to directors from non-CACFP centers.

CONCLUSIONS

CACFP directors reported fewer barriers to serving healthier foods in child care centers. Still, cost and children's food preferences are persistent barriers to serving healthier foods in ECE. Future research should evaluate characteristics of CACFP participation that may alleviate these barriers, and whether barriers emerge or persist following 2017 rule changes to CACFP nutrition standards.

Cross-Country Comparisons of Physical Activity and Sedentary Behavior among 5-Year-Old Children

PURPOSE

Previous studies have observed that physical activity (PA) levels tend to be lower in the U.S. population than in many other countries. Within the U.S., PA levels in children are lower in the South than in other regions. Cross-country and interregional differences in PA have not been studied in young children.

METHODS

In an ongoing study of children at genetic risk for Type 1 diabetes, PA was measured by accelerometry in samples of 5-year-old children (n = 2008) from Finland (n = 370), Germany (n = 85), Sweden (n = 706), and the U.S. (n = 847). The U.S. sample was drawn from centers in Washington State, Colorado, and Georgia/Florida. Children wore accelerometers for 7 days, and the data were reduced to daily minutes of light-, moderate- (MPA), vigorous- (VPA), and moderate-to-vigorous- (MVPA) intensity PA and sedentary behavior. Multiple regression was used to compare children across countries and across regions in the U.S, adjusting for wear time, body mass index, and demographic characteristics.

RESULTS

After adjusting for previously mentioned factors, MVPA and MPA were lower in U.S. children than those in Finland and Sweden. Estimates of physical activity were higher in Finland than in other countries, although not all comparisons were significantly different. U.S children spent significantly more time in sedentary behavior than children in Finland (p < 0.0001). Within the U.S., children's PA was consistently lowest in Georgia/Florida and highest in Washington.

CONCLUSIONS

Cross-country differences in PA, previously reported for adults and adolescents, are evident in 5-year-old children. In general, PA levels are lower in U.S. children than their European counterparts, and within the U.S., are lower in Georgia/Florida and Colorado than in Washington. Future studies should be designed to identify the factors that explain these differences.