Toddler physical activity study: laboratory and community studies to evaluate accelerometer validity and correlates

Modification of childcare's outdoor setting for toddler physical activity and nature-based play: A mixed methods study

BACKGROUND

Toddler physical activity is critical for child health, but little is known about its applications in early childhood education (ECE) centers. The aims of this study were 1) to determine if pragmatic and nature-based modifications to an ECE center's outdoor setting were feasible and acceptable, and 2) to identify barriers and facilitators of toddler physical activity at ECE centers.

METHODS

A multiphase mixed-methods study (QUANT+QUAL) was conducted. In the QUANT study, a stepped, sequential modification of the outdoor setting, using pragmatic and cost-effective nature-based elements, was conducted with a delayed control group over 10-weeks, with follow-up assessments 3-months later (week-20). Five elements (tree cookies, garden, teacher training, playground stencils, and nature table) were introduced individually. Feasibility was assessed using teacher surveys. Acceptability and engagement were assessed by direct observation of toddler use of outdoor elements. Accelerometers were used to assess toddlers' physical activity during outdoor sessions. The QUAL study included semi-structured interviews from ECE center directors (n = 27, 55.6% African American, 92.5% female) that were analyzed using content analysis for themes related to 1) toddler physical activity, 2) barriers and facilitators to toddler outdoor environment changes, 3) perspectives on nature-based elements, and 4) provider training. Member check focus groups (n = 2, 7-10/group) were conducted for additional interpretation. All three sources were reviewed for integration.

RESULTS

Toddlers engaged in physical activity for most of the outdoor sessions (>85%). This limited the effect of the intervention, but aligned with directors' and members' sentiments that toddlers were already quite active. Across directors, reported barriers to toddler outdoor environment changes were teacher turnover and finances. All nature-based elements, except the stencils, were feasible and acceptable, even at week-20. Directors and members identified additional age-appropriate elements, and desired pragmatic training with technical assistance and funding to implement these changes. Directors and members also desired a curriculum that could be used outdoors.

CONCLUSIONS

Nature-based elements were feasible and acceptable to toddlers. Directors were enthusiastic about nature-based elements, but barriers exist in linking directors with these elements. Opportunities to combine toddler-age curricula and pragmatic options for outdoor play may improve ECE centers' outdoor settings and ultimately toddler health.

Data Analytics in Physical Activity Studies With Accelerometers: Scoping Review

BACKGROUND

Monitoring free-living physical activity (PA) through wearable devices enables the real-time assessment of activity features associated with health outcomes and provision of treatment recommendations and adjustments. The conclusions of studies on PA and health depend crucially on reliable statistical analyses of digital data. Data analytics, however, are challenging due to the various metrics adopted for measuring PA, different aims of studies, and complex temporal variations within variables. The application, interpretation, and appropriateness of these analytical tools have yet to be summarized.

OBJECTIVE

This research aimed to review studies that used analytical methods for analyzing PA monitored by accelerometers. Specifically, this review addressed three questions: (1) What metrics are used to describe an individual's free-living daily PA? (2) What are the current analytical tools for analyzing PA data, particularly under the aims of classification, association with health outcomes, and prediction of health events? and (3) What challenges exist in the analyses, and what recommendations for future research are suggested regarding the use of statistical methods in various research tasks?

METHODS

This scoping review was conducted following an existing framework to map research studies by exploring the information about PA. Three databases, PubMed, IEEE Xplore, and the ACM Digital Library, were searched in February 2024 to identify related publications. Eligible articles were classification, association, or prediction studies involving human PA monitored through wearable accelerometers.

RESULTS

After screening 1312 articles, 428 (32.62%) eligible studies were identified and categorized into at least 1 of the following 3 thematic categories: classification (75/428, 17.5%), association (342/428, 79.9%), and prediction (32/428, 7.5%). Most articles (414/428, 96.7%) derived PA variables from 3D acceleration, rather than 1D acceleration. All eligible articles (428/428, 100%) considered PA metrics represented in the time domain, while a small fraction (16/428, 3.7%) also considered PA metrics in the frequency domain. The number of studies evaluating the influence of PA on health conditions has increased greatly. Among the studies in our review, regression-type models were the most prevalent (373/428, 87.1%). The machine learning approach for classification research is also gaining popularity (32/75, 43%). In addition to summary statistics of PA, several recent studies used tools to incorporate PA trajectories and account for temporal patterns, including longitudinal data analysis with repeated PA measurements and functional data analysis with PA as a continuum for time-varying association (68/428, 15.9%).

CONCLUSIONS

Summary metrics can quickly provide descriptions of the strength, frequency, and duration of individuals' overall PA. When the distribution and profile of PA need to be evaluated or detected, considering PA metrics as longitudinal or functional data can provide detailed information and improve the understanding of the role PA plays in health. Depending on the research goal, appropriate analytical tools can ensure the reliability of the scientific findings.

Sex differences in physical activity of US children at age 13 months: child and Mother Physical Activity Study (CAMPAS)

BACKGROUND

Lower physical activity (PA) has been observed in females compared to males among preschool-aged and older children. However, the timing of when the sex gap emerges is unclear. The purpose of this study was to investigate whether females have lower PA levels than males in the early toddler age and to explore whether gross motor competency and PA parenting practices might explain a sex difference in PA.

METHODS

The study design was cross-sectional. Participants were a community-based sample of 137 children aged 10-16 months residing in US Midwest urban/suburban area. Participants' mothers completed a survey that contained a demographic questionnaire, the Ages and Stages Questionnaire gross motor competency subscale, and a PA parenting practices questionnaire. Participating children wore an ActiGraph accelerometer on their hip for 7 days. Accelerometer-measured time spent in moderate- and vigorous intensity PA (MVPA; minutes/day) and in total PA (minutes/day) were calculated. Multivariable linear regression analysis was conducted to predict MVPA and total PA by sex, gross motor competency, PA parenting practices, and socioeconomic status.

RESULTS

Among 137 participants (54.0% female), average age was 13.6 months (SD = 1.7). MVPA was 72 ± 25 and 79 ± 26 min/day for females and males, respectively (p = 0.14). Total PA was 221 ± 48 and 238 ± 47 min/day for females and males, respectively (p = 0.04). Both gross motor competency and PA-encouraging parenting practices were positively associated MVPA (p = 0.01 and p = 0.02, respectively) and total PA (p = 0.02 and p = 0.01, respectively); however, these relationships did not differ by sex (p = 0.11 and p = 0.89, respectively). After accounting for gross motor competency and PA parenting practices, total PA was 15 min/day lower among females than males (p = 0.04).

CONCLUSIONS

This cross-sectional study of US children observed a sex gap in total PA at 10-16 months of age. Gross motor development and PA parenting practices did not differ by child sex nor explain the sex difference in PA. A longitudinal investigation should follow to further narrow down when sex differences in PA emerge and to determine the factors that lead to this difference.

Sex Differences in Physical Activity of US children at age 13 months: Child and Mother Physical Activity Study (CAMPAS)

Background

Lower physical activity (PA) has been observed in females compared to males among preschool-aged and older children. However, the timing of when the sex gap emerges is unclear. The purpose of this study was to investigate whether females have lower PA levels than males in the early toddler age and to explore whether gross motor competency and PA parenting practices might explain a sex difference in PA.

Methods

The study design was cross-sectional. Participants were a community-based sample of 137 children aged 10-16 months residing in US Midwest urban/suburban area. Participants' mothers completed a survey that contained a demographic questionnaire, the Ages and Stages Questionnaire gross motor competency subscale, and a PA parenting practices questionnaire. Participating children wore an ActiGraph accelerometer on their hip for 7 days. Accelerometer-measured time spent in moderate- and vigorous intensity PA (MVPA; minutes/day) and in total PA (minutes/day) were calculated. Multivariable linear regression analysis was conducted to predict MVPA and total PA by sex, gross motor competency, PA parenting practices, and socioeconomic status.

Results

Among 137 participants (54.0% female), average age was 13.6 months (SD = 1.7). MVPA was 72 ± 25 and 79 ± 26 minutes/day for females and males, respectively (p = 0.14). Total PA was 221 ± 48 and 238 ± 47 minutes/day for females and males, respectively (p = 0.04). Both gross motor competency and PA-encouraging parenting practices were positively associated MVPA (p = 0.01 and p = 0.02, respectively) and total PA (p = 0.02 and p = 0.01, respectively); however, these relationships did not differ by sex (p = 0.11 and p = 0.89, respectively). After accounting for gross motor competency and PA parenting practices, total PA was 15 minutes/day lower among females than males (p = 0.04).

Conclusions

This cross-sectional study of US children observed a sex gap in total PA at 10-16 months of age. Gross motor development and PA parenting practices did not differ by child sex nor explain the sex difference in PA. A longitudinal investigation should follow to further narrow down when sex differences in PA emerge and to determine the factors that lead to this difference.

Exploring Factors Associated With Accelerometer Validity Among Ethnically Diverse Toddlers

PURPOSE

Studying physical activity in toddlers using accelerometers is challenging due to noncompliance with wear time (WT) and activity log (AL) instructions. The aims of this study are to examine relationships between WT and AL completion and (1) demographic and socioeconomic variables, (2) parenting style, and (3) whether sedentary time differs by AL completion.

METHODS

Secondary analysis was performed using baseline data from a community wellness program randomized controlled trial for parents with toddlers (12-35 mo). Parents had toddlers wear ActiGraph wGT3x accelerometers and completed ALs. Valid days included ≥600-minute WT. Analysis of variance and chi-square analyses were used.

RESULTS

The sample (n = 50) comprised racial and ethnically diverse toddlers (mean age = 27 mo, 58% male) and parents (mean age = 31.7 y, 84% female). Twenty-eight families (56%) returned valid accelerometer data with ALs. Participants in relationships were more likely to complete ALs (P < .05). Toddler sedentary time did not differ between those with ALs and those without.

CONCLUSIONS

We found varied compliance with WT instructions and AL completion. Returned AL quality was poor, presenting challenges in correctly characterizing low-activity counts to improve internal validity of WT and physical activity measures. Support from marital partners may be important for adherence to study protocols.

Physical Activity, Confidence, and Social Norms Associated With Teachers' Classroom Physical Activity Break Implementation

Despite the benefits of classroom physical activity breaks on student health and academic outcomes, more research is needed to understand what factors may be associated with classroom physical activity break implementation, to bolster buy-in from school stakeholders and increase implementation. This quantitative study examined frequency of classroom physical activity break implementation in relation to (1) objectively measured teachers' physical activity and sedentary behaviors, (2) confidence for leading classroom physical activity breaks, (3) social norms (perceptions of other teachers' classroom physical activity break implementation), and (4) teacher- and school-level demographics. In total, 153 classroom teachers in 20 elementary and middle schools completed a survey including classroom physical activity break frequency, confidence, and social norms, one item each, dichotomized (1 = "most/all the time" OR "agree/strongly agree"). Accelerometry assessed total activity and daytime sedentary behavior. Analyses included multilevel binary logistic regression. Teachers were 90% female, 68% White, and 55% in elementary schools. Odds of implementing classroom physical activity breaks were lower among middle school teachers, 14 times greater among those with greater confidence, and over 17 times greater when teachers perceived others frequently implementing classroom physical activity breaks. Teacher activity was not associated with classroom physical activity break implementation. Future interventions to increase classroom physical activity break implementation should focus on increasing teachers' confidence to lead classroom physical activity breaks and creating more buy-in from classroom teachers to enhance each school's culture of health. By enhancing teacher confidence and social norms for implementing classroom physical activity breaks, we may increase school-based physical activity opportunities.

What can be done to protect toddlers from air pollution: Current evidence

PROBLEM

Toddlers are more prone to exposure to widely distributed air pollution and to health damage from it. However, systematic summaries of evidence on protective behaviors against air pollution for toddlers are lacking.

OBJECTIVE

To identify currently available evidence on protective behaviors against air pollution for toddlers.

METHODS

The literature retrieval was performed in selected databases, limited from 2002 to 2022. Studies meeting the following criteria were included and praised: 1) clinical practice guideline, systematic review, expert consensus, recommended practice, randomized control test (RCT) or cohort study published in Chinese or English; 2) studies reporting effects of protective behaviors against air pollution on toddlers' health outcomes or providing recommendation on these behaviors. The evidence in the included studies was extracted, synthesized and graded for evidence summary.

RESULTS

Studies (N = 19) were used for evidence summary development and 35 pieces of best evidence were synthesized, which were divided into three categories, including "avoiding or reducing air pollution generation", "removing existing air pollution", and "avoiding or reducing exposure to existing air pollution".

CONCLUSIONS

More evidence is needed to identify protective measures against outdoor air pollution and tobacco smoke. Research in the future should focus on the safety, effectiveness and feasibility of universal measures implemented in toddlers, and try to develop protective measures specific to toddlers which highlight their special nature.

IMPLICATIONS

The results of this study can help pediatric nurses provide individualized advice and assistance for toddlers and their families, and conduct research on the effectiveness of toddler-targeting protective behaviors more efficiently.

Offspring sex modifies the association between early-pregnancy adiposity and 2-year-old physical activity-The Glowing Study

BACKGROUND

Rodent models suggest that in utero exposure to under and overnutrition programs offspring physical activity (PA) behaviors. Such nexus has not been established in humans. This study evaluated the association of early pregnancy maternal adiposity with offspring PA at age 2 years (2-yo-PA) taking into consideration prenatal and postnatal factors.

METHODS

Women (n = 153) were enrolled early in pregnancy (<10 weeks). At enrollment, maternal adiposity [air displacement plethysmography, fat mass index (FMI, kg/m2)] and PA (accelerometers, activity counts) were measured, and age, race, and education self-reported. Gestational weight gain was measured at the research facility. Offspring birthweight and sex were self-reported. At age 2 years, parental feeding practices (child feeding questionnaire) were assessed, whereas anthropometrics (length and weight) and physical activity (accelerometers) were objectively measured. Offspring body mass index z-scores were calculated. Generalized linear regression analysis modeled the association of maternal FMI and 2-yo-PA [average activity counts (AC)4/day].

RESULTS

In bivariate associations, 2-yo-PA did not associate with maternal FMI (β = -0.22, CI = -0.73 to 0.29, p = 0.398). However, maternal FMI interacted with offspring sex in association with 2-yo-PA. Specifically, 2-yo-PA was lower in girls (β = -1.14, CI = -2.1 to -0.18, p = 0.02) compared to boys when maternal FMI was ≥7 kg/m2. When stratified by sex, 2-yo-PA of girls negatively associated with maternal FMI (β = -0.82, CI = -1.43 to 0.29, p = 0.009) while no association was found between maternal FMI and boy's PA (β = 0.32, CI = -0.38 to 1.01, p = 0.376).

CONCLUSIONS

The association of 2-yo-PA and early pregnancy maternal adiposity was modified by offspring sex. Offspring's physical activity decreased with increasing early pregnancy adiposity maternal in girls but not boys in second parity dyads.

Studying the impact of COVID-19 mitigation policies on childhood obesity, health behaviors, and disparities in an observational cohort: Protocol for the COVID-19 Family Study

BACKGROUND

COVID-19 pandemic control policies, including school closures, suspended extra-curricular activities, and social distancing, were introduced to prevent viral transmission, and disrupted children's daily routines, health behaviors, and wellness. This observational cohort study among 697 families with children or adolescents, based on the Family Stress Model, aims to: 1) evaluate pre- to during-pandemic changes in child health behaviors (diet, physical activity, sleep) and weight gain, 2) identify mechanisms explaining the changes, and 3) determine projected healthcare costs on weight gain and obesity. Each aim includes an examination by racial and ethnic, socioeconomic, and geographic disparities.

METHODS

The study employs a mixed methods design, recruiting children and their caregivers from two obesity prevention trials halted in 2020. Enrolled participants complete annual surveys to assess child health behaviors, family resources, routines, and demographics, and home environment in 2020-2022. Height and weight are measured annually in 2021-2022. Annual semi-structured interviews are conducted within a subsample to understand mechanisms of observed changes. Multilevel mixed models and mediation analyses are used to examine changes in child health behaviors and weight gain and mechanisms underlying the changes. Qualitative data are analyzed within and across time points and integrated with quantitative findings to further explain mechanisms. Markov models are used to determine healthcare costs for unhealthy child behaviors and weight gain.

CONCLUSION

Findings from this study will aid in understanding pandemic-related changes in child health behaviors and weight status and will provide insights for the implementation of future programs and policies to improve child and family wellness.

Determination of cut-off points for the Move4 accelerometer in children aged 8-13 years

BACKGROUND

To assess physical activity (PA) there is a need of objective, valid and reliable measurement methods like accelerometers. Before these devices can be used for research, they need to be calibrated and validated for specific age groups as the locomotion differs between children and adults, for instance. Therefore, the aim of the present study was the calibration and validation of the Move4 accelerometer for children aged 8-13 years.

METHODS

53 normal weighted children (52% boys, 48%girls) aged 8-13 years (mean age = 10.69 ± 1.46, mean BMI = 17.93 kg/m- 2, 60th percentile), wore the Move4 sensor at four different body positions (thigh, hip, wrist and the Move4ecg including heart rate measurement at the chest). They completed nine activities that considered the four activity levels (sedentary behavior (SB), light PA (LPA), moderate PA (MPA) and vigorous PA (VPA)) within a test-retest design. Intensity values were determined using the mean amplitude deviation (MAD) as well as the movement acceleration intensity (MAI) metrics. Determination of activities and energy expenditure was validated using heart rate. After that, cut-off points were determined in Matlab by using the Classification and Regression Trees (CART) method. The agreement for the cut-off points between T1 and T2 was analyzed.

RESULTS

MAD and MAI accelerometer values were lowest when children were lying on the floor and highest when running or doing jumping jacks. The mean correlation coefficient between acceleration values and heart rate was 0.595 (p = 0.01) for MAD metric and 0.611 (p = 0.01) for MAI metric, indicating strong correlations. Further, the MAD cut-off points for SB-LPA are 52.9 mg (hip), 62.4 mg (thigh), 86.4 mg (wrist) and 45.9 mg (chest), for LPA-MPA they are 173.3 mg (hip), 260.7 mg (thigh), 194.4 mg (wrist) and 155.7 mg (chest) and for MPA-VPA the cut-off points are 543.6 mg (hip), 674.5 mg (thigh), 623.4 mg (wrist) and 545.5 mg (chest). Test-retest comparison indicated good values (mean differences = 9.8%).

CONCLUSION

This is the first study investigating cut-off points for children for four different sensor positions using raw accelerometer metrics (MAD/MAI). Sensitivity and specificity revealed good values for all positions. Nevertheless, depending on the sensor position, metric values differ according to the different involvement of the body in various activities. Thus, the sensor position should be carefully chosen depending on the research question of the study.

Offspring-sex modifies the association between early-pregnancy adiposity and 2-year-old total physical activity - The Glowing Study

Background

Rodent models suggest that in utero exposure to under and overnutrition programs offspring physical activity (PA) behaviors. Such nexus has not been established in humans. This study evaluated the association of early pregnancy maternal adiposity with offspring PA at age 2 years (2-yo-PA) taking into consideration prenatal and postnatal factors.

Methods

Women (n=153) were enrolled early in pregnancy (<10 weeks). At enrollment, maternal adiposity [air displacement plethysmography, fat mass index (FMI, kg/m2)] and PA (accelerometers, activity counts) were measured, and age, race, and education self-reported. Gestational weight gain was measured at the research facility. Offspring birthweight and sex were self-reported. At age 2 years, parental feeding practices (child feeding questionnaire) were assessed, whereas anthropometrics (length and weight) and physical activity (accelerometers) were objectively measured. Offspring body mass index z-scores were calculated. Generalized linear regression analysis modeled the association of maternal FMI and 2-yo-PA [average activity counts (AC)4/day].

Results

There was an interaction between maternal FMI and offspring sex in association with 2-yo-PA (β= -1.03, p= 0.030). Specifically, 2-yo-PA was lower in girls compared to boys when maternal FMI was ≥7 kg/m2. Maternal PA early in pregnancy positively associated with 2-yo-PA (β= 0.21, p= 0.005). In addition, children born to women with college education tended to be more active compared to children born to women without college education (β= 3.46, p= 0.059).

Conclusions

Sexual dimorphism was observed in the associations of maternal adiposity with 2-yo-PA, with girls being less active compared to boys only when maternal FMI was ≥7 kg/m2.

Systematic review of accelerometer-based methods for 24-h physical behavior assessment in young children (0-5 years old)

BACKGROUND

Accurate accelerometer-based methods are required for assessment of 24-h physical behavior in young children. We aimed to summarize evidence on measurement properties of accelerometer-based methods for assessing 24-h physical behavior in young children.

METHODS

We searched PubMed (MEDLINE) up to June 2021 for studies evaluating reliability or validity of accelerometer-based methods for assessing physical activity (PA), sedentary behavior (SB), or sleep in 0-5-year-olds. Studies using a subjective comparison measure or an accelerometer-based device that did not directly output time series data were excluded. We developed a Checklist for Assessing the Methodological Quality of studies using Accelerometer-based Methods (CAMQAM) inspired by COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN).

RESULTS

Sixty-two studies were included, examining conventional cut-point-based methods or multi-parameter methods. For infants (0-12 months), several multi-parameter methods proved valid for classifying SB and PA. From three months of age, methods were valid for identifying sleep. In toddlers (1-3 years), cut-points appeared valid for distinguishing SB and light PA (LPA) from moderate-to-vigorous PA (MVPA). One multi-parameter method distinguished toddler specific SB. For sleep, no studies were found in toddlers. In preschoolers (3-5 years), valid hip and wrist cut-points for assessing SB, LPA, MVPA, and wrist cut-points for sleep were identified. Several multi-parameter methods proved valid for identifying SB, LPA, and MVPA, and sleep. Despite promising results of multi-parameter methods, few models were open-source. While most studies used a single device or axis to measure physical behavior, more promising results were found when combining data derived from different sensor placements or multiple axes.

CONCLUSIONS

Up to age three, valid cut-points to assess 24-h physical behavior were lacking, while multi-parameter methods proved valid for distinguishing some waking behaviors. For preschoolers, valid cut-points and algorithms were identified for all physical behaviors. Overall, we recommend more high-quality studies evaluating 24-h accelerometer data from multiple sensor placements and axes for physical behavior assessment. Standardized protocols focusing on including well-defined physical behaviors in different settings representative for children's developmental stage are required. Using our CAMQAM checklist may further improve methodological study quality.

PROSPERO REGISTRATION NUMBER

CRD42020184751.

Objectively Measured Physical Activity and Sedentary Time of Suburban Toddlers Aged 12-36 Months

Low levels of physical activity may predispose children to the development of obesity and related chronic diseases in later life. The aims of this study were as follows: (1) quantitatively describe the levels of habitual physical activity in a contemporary sample of suburban children aged 12 to 36 months; (2) assess for gender differences in physical activity and sedentary behavior; (3) examine the specific effects of ethnicity, gender and overweight status on the objectively measured physical activity; and (4) quantify the tracking of physical activity in a subset of children over 1 year. During year one, 142 participants wore the GT3X Actigraph for 3 days. At a 1-year follow-up, a subset of 25 participants wore the Actigraph for 7 consecutive days. GLM and t-tests as appropriate were carried out to assess the influence of gender on the physical activity level. Spearman rank correlations, percentage agreement and kappa statistics assessed the tracking of physical activity. The results showed no significant gender differences in any anthropometric measurements, sedentary behavior or MVPA (p > 0.05). There were also no significant gender, ethnicity or overweight interaction for sedentary behavior, time spent in light PA and time spent in MVPA (p > 0.05). For tracking, there was a moderate strength of agreement for MVPA. Considering the disproportionate effects of obesity in minority groups, culturally appropriate interventions targeting the reduction in sedentary behavior are urgently required.

Role of Spanish Toddlers' Education and Care Institutions in Achieving Physical Activity Recommendations in the COVID-19 Era: A Cross-Sectional Study

To our knowledge, there are no published studies that describe the physical activity (PA) levels and objectively measure them through accelerometry in toddlers (2-3 years old) attending early childhood education and care (ECEC) institutions during the COVID-19 pandemic. The aims of this study were two-fold: (a) to analyse toddlers' PA levels and sedentary behaviour (SB) during school hours in ECEC institutions, as well as the rate of adherence to specific recommendations on total PA (TPA) and moderate-vigorous PA (MVPA); and (b) to evaluate the characteristics correlates (age, gender, and body mass index -BMI) of young children and the school environment on toddlers' TPA, light PA (LPA), MVPA, and SB during school hours in ECEC institutions. PA was evaluated with ActiGraph accelerometers. The main findings were that: (a) toddlers engaged in very high amounts of TPA and MVPA during ECEC hours; (b) girls and boys displayed similar levels of LPA, TPA, and SB, while girls had lower levels of MVPA, compared to boys, and younger toddlers were less active than older ones; (c) BMI was not associated with PA of any intensity or SB; (d) playground and classroom density were not associated with higher levels of PA of any intensity, though classroom density was associated with SB. These ECEC institutions provide and challenge the new COVID-19 scenario, as well as supportive environments for toddlers' PA.

On the Move or Barely Moving? Age-Related Changes in Physical Activity, Sedentary, and Sleep Behaviors by Weekday/Weekend Following Pandemic Control Policies

This study examined pre-pandemic (2017-early March 2020) to early-pandemic (Spring 2020) changes in moderate-to-vigorous PA (MVPA), light PA (LPA), and sedentary behavior/sleep (SS), by weekday/weekend, and age (preschool, elementary, middle school). We re-enrolled children from two pre-pandemic obesity prevention trials and examined differences in accelerometer-measured PA from pre-pandemic to early-pandemic across age groups using linear mixed models. Children (n = 75) were 51% multiple race/ethnicities, 29% preschool, 28% elementary, 43% middle school, 65% suburban, 21% rural, and 13% urban. Pre-pandemic to early-pandemic changes in weekday MVPA (p = 0.006), LPA (p = 0.018), and SS (p = 0.003) differed by age. On weekdays, middle schoolers' MVPA decreased 15.36 min/day (p = 0.002) and SS increased 94.36 min/day (p < 0.001) with non-significant changes among preschoolers and elementary schoolers. Compared to elementary schoolers, middle schoolers' changes in weekday MVPA (b = -16.34, p = 0.036) and SS (b = 63.28, p = 0.039) significantly differed. Declines in weekday MVPA and increases in SS among middle schoolers suggest that, compared with younger children, middle schoolers are dependent on school and recreational facilities for PA, and in their absence engage in more sedentary activities and sleep.

Identifying Prenatal and Postnatal Determinants of Infant Growth: A Structural Equation Modelling Based Cohort Analysis

Background: The growth and maturation of infants reflect their overall health and nutritional status. The purpose of this study is to examine the associations of prenatal and early postnatal factors with infant growth (IG). Methods: A data-driven model was constructed by structural equation modelling to examine the relationships between pre- and early postnatal environmental factors and IG at age 12 months. The IG was a latent variable created from infant weight and waist circumference. Data were obtained on 274 mother–child pairs during pregnancy and the postnatal periods. Results: Maternal pre-pregnancy BMI emerged as an important predictor of IG with both direct and indirect (mediated through infant birth weight) effects. Infants who gained more weight from birth to 6 months and consumed starchy foods daily at age 12 months, were more likely to be larger by age 12 months. Infant physical activity (PA) levels also emerged as a determinant. The constructed model provided a reasonable fit (χ² (11) = 21.5, p < 0.05; RMSEA = 0.07; CFI = 0.94; SRMR = 0.05) to the data with significant pathways for all examined variables. Conclusion: Promoting healthy weight amongst women of child bearing age is important in preventing childhood obesity, and increasing daily infant PA is as important as a healthy infant diet.

Daily energy expenditure through the human life course

Total daily energy expenditure ("total expenditure") reflects daily energy needs and is a critical variable in human health and physiology, but its trajectory over the life course is poorly studied. We analyzed a large, diverse database of total expenditure measured by the doubly labeled water method for males and females aged 8 days to 95 years. Total expenditure increased with fat-free mass in a power-law manner, with four distinct life stages. Fat-free mass-adjusted expenditure accelerates rapidly in neonates to ~50% above adult values at ~1 year; declines slowly to adult levels by ~20 years; remains stable in adulthood (20 to 60 years), even during pregnancy; then declines in older adults. These changes shed light on human development and aging and should help shape nutrition and health strategies across the life span.

Exploring qualities of ethnically diverse parents related to the healthy home environment of toddlers

Parents serve as role models and household policy makers for their children's home social environment. Also, parents may influence the home physical environment through the provision of resources to support their children's dietary, activity, and sleep behaviors. Understanding the parental characteristics related to children's home environment may allow for tailoring obesity interventions to families' needs. This study aimed to explore parental qualities (general parenting styles, parent feeding practices, and parental BMI) related to healthy home food, physical activity, media and sleep environment of toddlers. A total of 50 multi-ethnic parents with toddler age children who were enrolled in a randomized pilot study of a wellness program completed the Structure and Control in Parent Feeding (SCPF) questionnaire and Comprehensive General Parenting Questionnaire (CGPQ). Parental BMI was calculated using self-reported weight and height data. The Healthy Home Survey, the Home Food Inventory, the Sleep Environment Questionnaire, and items developed for this study were standardized and summed to create home food, physical activity, screen media, and sleep environment scores; high scores reflected healthier environments. To examine the relationships between parental qualities and the home environment, Pearson's correlation test was performed. Parental BMI and overall healthy home environment were inversely associated (r = -0.306; p = 0.032). Structure in general parenting and parental feeding practice were positively correlated with the overall healthy home environment (r = 0.336; p = 0.026) and healthy home food environment (r = 0.415; p = 0.003), respectively. The coercive control general parenting was inversely related to overall healthy home environment score (r = -0.333; p = 0.022). Based on the findings from this study, parents who provide clear communication, set consistent rules, avoid pressure to control their child's behavior, and have lower BMI tend to live in a home environment that support children's health behaviors.

Associations between elementary and middle school teachers' physical activity promoting practices and teacher- and school-level factors

BACKGROUND

Few studies have evaluated teacher- and school-level characteristics associated with implementation of recommended physical activity (PA) promoting practices. The purpose of this study is to examine associations between teachers' PA practices and: [1] teacher-level factors, including their own PA, and [2] school-level factors.

METHODS

This cross-sectional study examined time spent daily in light PA (LPA) and moderate-vigorous PA (MVPA) in association with 7 teacher PA practices among 288 classroom/special area teachers and teaching assistants in 20 urban, suburban and rural schools (recruited through a school wellness trial) in 4 districts. LPA and MVPA was assessed using 24-h ankle accelerometry (up to seven consecutive days). A sum score for teacher PA practices was assessed via survey (7 items; sum score range: 7-35; Cronbach's alpha = 0.73; higher scores indicate more PA promoting practices). Teacher-level factors included gender, race, self-reported height/weight, years teaching, and education. School-level factors included school type, free-and-reduced-price meal eligibility, student racial/ethnic composition, and urbanicity. Analyses included multilevel regression models, accounting for clustering within schools and adjusting for demographic covariates and school district.

RESULTS

Teachers were 91% female, 63% elementary, 60% white, mean age 43.2 years (SD = 11.3), and 41% obese). Teachers wore accelerometers an average of 5.8 days, spent 399.6 min in LPA (SD = 85.0) per day, 24.1 min in MVPA (SD = 14.4) per day, and the mean teacher PA practices sum score was 22.4 (SD = 5.0). Every 15-min increase in MVPA was related to an increase in teacher PA practices sum score (coeff =1.07; SE = 0.28; p < 0.001). Female gender (versus males; coeff = - 1.95; SE = 0.92, p = 0.034), an obese weight status (versus non-obese; coeff = - 1.38; SE = 0.54, p = 0.010), and teaching in a middle school (versus elementary; coeff = - 3.86; SE = 0.54, p < 0.001) were associated with lower teacher PA practices scores. LPA was not associated with teacher PA promoting practices.

CONCLUSIONS

Teachers with higher MVPA, but not higher LPA, and those without obesity were more likely to implement PA promoting practices that could positively impact their students' PA. Similar to prior studies, these practices were more commonly implemented in elementary schools and by male teachers. Future studies in schools should explore whether improvement of teacher health behaviors subsequently impacts student health behaviors.

TRIAL REGISTRATION

Clinical Trials, NCT03432715 ; Registered on 02/2/2018.

An ecological momentary assessment study of physical activity behaviors among mothers of toddlers from low-income households

BACKGROUND

Mothers of young children from low-income communities may be vulnerable to barriers associated with low physical activity. The purpose of this study was to examine associations between home environment factors and maternal physical activity among mothers of toddlers.

METHODS

Mothers of toddlers (n = 200) recruited from low-income communities simultaneously wore an ankle-placed accelerometer and were given a personal digital assistant for ecological momentary assessment. Mothers received randomly prompted questions about their current environment, activity, and social setting several times a day over eight consecutive days. Data were analyzed using linear mixed-effects regression models with random intercepts; within-group and between-group relations between physical activity and environment factors were disaggregated.

RESULTS

Within-group relations included higher physical activity counts for specific mothers with television off versus on (95% CI = 130.45, 199.17), children absent versus present (95% CI = 82.00, 3.43), engaging with a child versus not (95% CI = 52.66, 127.63), and outside versus inside location (95% CI = 277.74, 392.67). Between-group relations included higher physical activity on average when other adults were absent versus present (95% CI = - 282.63, - 46.95). Recruitment site (urban vs. semi-urban) significantly moderated the within-group relation between being outside versus inside and activity count (β = - 243.12, 95% CI = - 358.74, - 127.47), and showed stronger relations among urban mothers (β = 440.33, 95% CI = 358.41, 522.25), than semi-urban (β = 190.37, 95% CI = 109.64, 271.11). Maternal body weight significantly moderated the within-group relation between being located outside versus inside the home and activity count (β for interaction = - 188.67, 95% CI = - 308.95, - 68.39), with a stronger relation among mothers with normal weight (β = 451.62, 95% CI = 345.51, 557.73), than mothers with overweight/obesity (β = 271.95, 95% CI = 204.26, 339.64).

CONCLUSIONS

This study highlights home environmental factors, including screen time, the presence of others (adults and children), and location (i.e., outside versus inside) that may relate to maternal physical activity behaviors. Understanding factors associated with physical activity could reduce physical activity disparities. Trial registry ClinicalTrials. NCT02615158, April 2006.

Association between Home Environment in Infancy and Child Movement Behaviors

Introduction: An adequate balance of movement behaviors, including physical activity (PA), sleep, and screen time, is important for preventing excess weight gain in children. This study examined the relationship between the infant home environment and movement behaviors later in life. Methods: Pregnant women were recruited for a cohort study related to maternal and child development. The home environment was assessed for developmental stimulation, organization, and toys by the Pediatric Review of Children's Environmental Support and Stimulation (PROCESS) questionnaire when the child was 6 months of age. At 2 years of age, mother-reported child screen time, and child PA and sleep duration were estimated by accelerometry. Child behaviors were compared with the 24-hour Movement Guidelines (≥180 minutes/day of total PA, 11-14 hours/day of sleep, and ≤1 hour/day of screen time). Logistic regression was used to assess the relationship between the home environment and movement behaviors, adjusting for maternal and child covariates. Results: Mother/child dyads (n = 141) were mainly white (84.4%), and middle (32.8%) or low income (48.9%). All children (100%) met the PA guideline, some met the sleep guideline (71.6%), fewer met the screen-time guideline (44.7%), and only one-third (34.0%) met all three guidelines. Children who met the screen-time guideline lived in homes with more developmental stimulation and toys (p < 0.05). Children who met all 3 guidelines lived in homes with more organization and toys (p < 0.05). Conclusion: The infant home environment was associated with appropriate amounts of movement behaviors at 2 years. Promoting organization (i.e., routines) and toys in infancy may help facilitate nonscreen-based habits and healthy development. The clinical trial registration number is NCT01131117.

The contributory role of the family context in early childhood sleep health: A systematic review

Sleep-wake regulation is established during early childhood and contributes to life-long health. The family context is critical to the development of child sleep-wake regulation. The primary aim of this systematic review was to elucidate family-level constructs (outside of bedtime parenting) that contribute to early childhood (age 0-5 years) sleep health. We identified empirical research articles that investigate these relationships through systematically searching PubMed, Web of Science, and PsycINFO databases. The transactional model of sleep-wake regulation guided the selection of family-level search terms, including socioeconomic status (SES), family structure, household chaos, marital, co-parenting, and social relationships. Sleep search terms included sleep problems, duration, timing, and variability. We searched sleep and family terms in combination with infant, toddler, or preschool developmental age. Sixteen studies satisfied criteria for inclusion. Results indicated that the presence of household chaos and poor quality marital relationships were directly associated with early childhood sleep problems and variable sleep timing. Higher marital satisfaction and the presence of household routines were positively associated with sleep duration. Several, but not all, studies showed an association between lower SES and poor child sleep health. There were no significant direct associations for family structure and limited findings for the role of perceived social support and co-parenting relationship quality. Overall, operationalization and measurement of family and sleep constructs varied across studies, decreasing our ability to make comparisons and draw robust conclusions. Future research should identify modifiable family-level factors that can be targeted, in addition to bedtime parenting, to improve sleep-wake regulation development.

Toddler obesity prevention: A two-generation randomized attention-controlled trial

Rapid weight gain increases risks of obesity and associated co-morbidities. The objective was to reduce the rate of body mass index (BMI) growth (BMI z score), relative to control. Secondary outcomes were toddler-mother physical activity, mealtime interactions and fruit/vegetable intake. The randomized three-arm, eight-session, 4-month trial, conducted 2009-2013, included two intervention arms (responsive parenting and maternal lifestyle) and an attention control (home safety). Baseline and 6- and 12-month follow-up evaluations included weight and length/height, ankle accelerometry, video-recorded mealtime interactions (Emotional Availability Scales) and 24-h diet recalls (Healthy Eating Index-2015 [HEI-2015]). Analyses used linear mixed-effects models with repeated measures comparing intervention versus control changes in BMI z score. We recruited 277 racially mixed (70% African American) toddler-mother dyads (mean ages 20.1 months and 27.3 years) from US WIC and primary care clinics and randomized them into intervention versus control; 31% toddlers and 73% mothers were overweight/obese. At follow-up, changes in the rate of toddler BMI z score and maternal BMI were non-significant. Maternal lifestyle group toddlers and mothers spent 24.43 and 11.01 more minutes in physical activity (95% confidence interval [CI]: 2.55, 46.32, and 95% CI: 1.48, 20.54, respectively). Fruit intake increased in both intervention groups. Hostile mealtime interactions increased in the maternal lifestyle group, and in supplementary analyses, mealtime interactions were significantly higher in the responsive parenting group than in the maternal lifestyles group, suggesting that toddler dietary interventions include responsive parenting. Intervention effects were stronger among older versus younger toddlers. Despite no impact on weight gain, additional research should examine integrated two-generation responsive parenting and maternal lifestyle interventions among toddler-mother dyads.

Motor Competence and Attainment of Global Physical Activity Guidelines among a Statewide Sample of Preschoolers

Global physical activity guidelines for preschoolers include 60 min of moderate-to-vigorous physical activity (MVPA) daily. This study, based on the developmental model of motor skill competence, examines how motor competence relates to preschoolers’ likelihood of meeting global guidelines using ankle accelerometry. We measured physical activity using 24-h ankle-placement accelerometry (Actical) for at least two consecutive days (87% with six-seven days), motor competence using the Test of Gross Motor Development-2 (TGMD-2), and BMI-for-age z-scores (BMIz) using anthropometry and age- and sex-specific CDC norms. Caregivers provided demographic characteristics of children’s age, sex, and race. We used multivariable logistic regression to examine how motor competence, BMIz weight status, and demographic characteristics related to meeting global physical activity guidelines. The sample included 588 preschoolers, age 3–5 years; 55% male; 60% white; and 28% overweight/obese; 75% attained the recommended 60 min of MVPA per day. The odds of meeting MVPA guidelines were associated with higher gross motor quotient, higher object control scores, sex (male), age (older), and race (white), but not with BMIz weight status. Findings support the use of 24-h ankle accelerometry among preschoolers and are consistent with the developmental model of motor competence applied to preschoolers, whereby object control competence relates positively to attaining global physical activity guidelines.

Longitudinal Associations Among Diet Quality, Physical Activity and Sleep Onset Consistency With Body Mass Index z-Score Among Toddlers in Low-income Families

BACKGROUND

Habits surrounding health behaviors (i.e., sleep, physical activity, diet) are developed in toddlerhood. Lack of consistent health habits may increase obesity risk among toddlers in low-income families.

PURPOSE

To compare the role of sleep onset consistency, physical activity and diet quality as mediators between household poverty and toddler weight.

METHODS

Two hundred and seven toddlers (mean age = 20.2 months, 46% female, 68.1% Black) participating in an obesity prevention trial were assessed at three time points over 12 months. Using Actical accelerometers, we assessed sleep and physical activity at each time point for up to 1 week. We defined sleep onset consistency as the standard deviation of sleep onset across all days. We calculated the Healthy Eating Index-2015 from a 24-hr dietary recall. We used WHO standards to calculate BMI-for-age z-scores from toddlers' weight/length, and calculated poverty ratio from parent-reported income and family size. Multilevel mediation models tested toddler sleep onset consistency, physical activity, and diet quality as mediators between household poverty and toddler BMI z-score.

RESULTS

Toddlers from households with higher poverty ratios had more inconsistent sleep onset times. Toddlers with more inconsistent sleep onset times had higher BMI z-scores across all timepoints, even when accounting for physical activity and diet quality. Sleep onset consistency indirectly explained the association between household poverty and BMI z-score.

CONCLUSIONS

Inconsistent sleep schedules could help explain the association between poverty and BMI. Future research should examine strategies to support low-income families to develop and maintain routines as a mechanism to prevent obesity and reduce disparities.

TRIAL REGISTRATION NUMBER

NCT02615158.

Featured Article: Bidirectional Effects of Sleep and Sedentary Behavior Among Toddlers: A Dynamic Multilevel Modeling Approach

OBJECTIVE

To examine the bidirectional effects of objectively measured nighttime sleep and sedentary activity among toddlers.

METHOD

Actical accelerometer data were analyzed for 195 toddlers participating in an obesity prevention trial (mean age = 27 months). Toddlers wore the accelerometers for up to 7 consecutive days. Nighttime sleep was defined as the number of minutes asleep between the hours of 8 pm and 8 am the following morning. Sedentary behavior (in minutes) was defined using previously established Actical cut points for toddlers. Variables were lagged and parsed into latent within- and between-person components, using dynamic structural equation modeling (DSEM).

RESULTS

Toddlers spent an average of 172 min (∼3 hr) in sedentary activity and slept an average of 460 min (∼8 hr) per night. An autoregressive cross-lagged multilevel model revealed significant autoregression for both sleep and sedentary activity. Cross-lagged values revealed that decreased sleep predicted increased next-day sedentary activity, and sedentary activity predicted that night's sleep. For 89% of the sample, the within-person standardized cross-lagged effects of sleep on sedentary were larger than the cross-lagged effects of sedentary on sleep.

CONCLUSIONS

Results suggest that, on average, nighttime sleep is a stronger predictor of subsequent sedentary behavior (compared with the reverse), and this is the case for the majority of toddlers. Findings highlight the importance of interindividual associations between sleep and sedentary activity. The present study is an example of how DSEM methods can be used to ask questions about Granger-causal cross-lagged relations between variables, both within and between individuals.

Infants' and toddlers' physical activity and sedentary time as measured by accelerometry: a systematic review and meta-analysis

BACKGROUND

Early experiences in physical activity (PA) are important to shape healthy movement behaviours long-term; as such, it is critical that PA is promoted from infancy, and that detrimental behaviours (e.g., prolonged sedentary time [ST]) are minimized. The purpose of this systematic review and meta-analysis was to examine infants' and toddlers' movement behaviours across daytime hours.

METHODS

Seven online databases were searched for terms related to infants (< 12 months), toddlers (12-35.9 months), PA, ST, and accelerometry. Two independent reviewers examined 4873 articles for peer-reviewed original research, published in English, that assessed infants' (counts/min) and/or toddlers' PA or ST (min/day) using accelerometry across daytime hours. Infants' mean PA level (counts/min) was averaged across studies, and ranges were produced. Estimates of toddlers' movement behaviours were aggregated meta-analytically to produce average daily rates, and accelerometer placement, cut-point validity, device type, and epoch length were tested as a moderating variables.

RESULTS

Twenty-four studies from 16 countries (published 2011-2019), representing 3699 participants, were included in the systematic review. Five studies reported on infants' PA, which ranged from 78.2 to 2580.5 cpm. Across 20 studies, toddlers' total PA, light PA, moderate-to vigorous-intensity PA, and ST ranged from 72.9 to 636.5, 48.5 to 582.4, 6.5 to 89.9, and 172.7 to 545.0 min/day, respectively. After taking into account accelerometer placement, cut-point validity, device type, and epoch length, we found that toddlers engaged in 246.19 min/day (SE = 28.50; 95% CI: 190.34, 302.04) of total PA, 194.10 min/day (SE = 28.76; 95% CI: 137.73, 250.47) of light PA, and 60.16 min/day (SE = 5.88; 95% CI: 48.64, 71.69) of moderate-to vigorous-intensity PA. Toddlers engaged in 337.04 min/day (SE = 32.67; 95% CI: 273.01, 401.07) of ST.

CONCLUSIONS

With limited studies conducted in infants (n = 5), PA estimates are inconclusive and largely heterogeneous. Overall, toddlers tend to exceed the total PA recommendation of 180 min/day; however, very little of this time is spent at higher movement intensities. Even with high PA rates, toddlers still engage in substantial ST. More consistent and valid measurement protocols are needed to improve comparability across studies.

Sleep duration associates with moderate-to-vigorous intensity physical activity and body fat in 1- to 3-year-old children

Sleep during early childhood is important for many developmental outcomes and shows promise as an important correlate of both obesity risk and physical activity behaviors. This was a cross-sectional study concerning the relationships between sleep and moderate- to - vigorous intensity physical activity and body fat percentage in a sample of 1- to 3-year-old children (N = 50; ages 27.512 ± 10.363 months). Sleep was measured with a caregiver questionnaire. Sedentary time, light, moderate, vigorous, and moderate- to - vigorous intensity physical activity were measured with Actigraph wT3x-BT accelerometers. Body fat was measured using Air Displacement Plethysmography with the BodPod Pediatric Option. Moderate- to - vigorous intensity physical activity and body fat percentage both associated with sleep duration, controlling for age and accelerometer wear time. These factors combined explained 54.3 % of the variance in sleep duration present in the sample. These results suggest the presence of relationships between sleep and physical activity and body composition constructs in this sample. Sleep may be an important variable in efforts to both promote early childhood physical activity and healthy body composition.

Daily Physical Activity Among Toddlers: Hip and Wrist Accelerometer Assessments

Physical activity (PA) habits seem to track over time from as young as early childhood. For children under age 3 years, wearable sensor-measured PA levels have begun to be investigated. The aims of this study were to evaluate the feasibility of using hip- vs. wrist-worn accelerometers, and to report accelerometer-derived PA metrics among toddlers. A convenience sample of 22 toddlers aged 13 to 35 months and their mothers were recruited for this study. ActiGraph wGT3X-BT accelerometers were attached to wrist bands and waist belts. The mothers were asked to affix a wrist band and a waist belt to their participating children during waking hours for four days. They also completed an acceptability survey. Of the 22 toddlers, 19 (86%) had ≥ 3 valid days of hip data, while only 14 (64%) did so for wrist data (p = 0.16). In terms of acceptability, 18 mothers (82%) responded that the 4-day hip wear was easy, while only 13 (59%) responded that the 4-day wrist wear was easy (p = 0.19). Daily light-intensity PA (LPA) was on average 161 min, and daily moderate- and vigorous-intensity PA (MVPA) was on average 47 min, as determined using published hip accelerometer cut-points. There were no significant differences in LPA or MVPA by age or by sex. In conclusion, this study suggests that hip placement of an ActiGraph accelerometer is more feasible than wrist placement among toddlers.

CHAMP: A cluster randomized-control trial to prevent obesity in child care centers

Foundational elements of lifelong health are formed during the preschool years. Child care attendance has nearly doubled in the past 5 years making child care centers an ideal setting to establish healthy habits that prevent pediatric obesity. Despite the promising evidence of efficacy of child care-based obesity prevention interventions, limited attention has been directed to criteria needed for implementation at scale. There is potential to improve children's dietary and physical activity behaviors in diverse communities through theory-based, culturally appropriate, manualized interventions, delivered by child care staff. CHAMP (Creating Healthy Habits Among Maryland Preschoolers) is a 3-arm cluster randomized controlled childhood obesity prevention trial, aiming to improve motor skills, physical activity and willingness to try new foods among 864 preschoolers (age 3-5 years) enrolled in 54 child care centers in 10 Maryland counties. CHAMP is informed by social-cognitive and bioecological theories and based on an evidence-based program, The Food Friends®. The two intervention arms include: 1) child care-center based lessons (18-week gross motor and 12-week nutrition) administered by trained child care staff, and 2) a web-based intervention for caregivers in addition to center-based lessons. Evaluations are conducted among children, caregivers, and child care staff at fall enrollment, midline, and spring, following intervention completion. Analyses include linear mixed-models, accounting for clustering and repeated measures, incorporating center-arms as moderators. CHAMP will provide evidence-based information to inform wellness guidelines and policies that can be disseminated broadly, to ensure that child care centers provide opportunities for children to develop healthy eating, and physical activity habits. Trial Registration: NCT03111264; https://clinicaltrials.gov/ct2/show/NCT03111264.

Hip and Wrist-Worn Accelerometer Data Analysis for Toddler Activities

Although accelerometry data are widely utilized to estimate physical activity and sedentary behavior among children age 3 years or older, for toddlers age 1 and 2 year(s), accelerometry data recorded during such behaviors have been far less examined. In particular, toddler’s unique behaviors, such as riding in a stroller or being carried by an adult, have not yet been examined. The objective of this study was to describe accelerometry signal outputs recorded during participation in nine types of behaviors (i.e., running, walking, climbing up/down, crawling, riding a ride-on toy, standing, sitting, riding in a stroller/wagon, and being carried by an adult) among toddlers. Twenty-four toddlers aged 13 to 35 months (50% girls) performed various prescribed behaviors during free play in a commercial indoor playroom while wearing ActiGraph wGT3X-BT accelerometers on a hip and a wrist. Participants’ performances were video-recorded. Based on the video data, accelerometer data were annotated with behavior labels to examine accelerometry signal outputs while performing the nine types of behaviors. Accelerometer data collected during 664 behavior assessments from the 21 participants were used for analysis. Hip vertical axis counts for walking were low (median = 49 counts/5 s). They were significantly lower than those recorded while a toddler was “carried” by an adult (median = 144 counts/5 s; p < 0.01). While standing, sitting, and riding in a stroller, very low hip vertical axis counts were registered (median ≤ 5 counts/5 s). Although wrist vertical axis and vector magnitude counts for “carried” were not higher than those for walking, they were higher than the cut-points for sedentary behaviors. Using various accelerometry signal features, machine learning techniques showed 89% accuracy to differentiate the “carried” behavior from ambulatory movements such as running, walking, crawling, and climbing. In conclusion, hip vertical axis counts alone may be unable to capture walking as physical activity and “carried” as sedentary behavior among toddlers. Machine learning techniques that utilize additional accelerometry signal features could help to recognize behavior types, especially to differentiate being “carried” from ambulatory movements.

Predictors of objectively measured physical activity in 12-month-old infants: A study of linked birth cohort data with electronic health records

BACKGROUND

Physical activity (PA) levels are associated with long-term health, and levels of PA when young are predictive of adult activity levels.

OBJECTIVES

This study examines factors associated with PA levels in 12-month infants.

METHOD

One hundred forty-one mother-infant pairs were recruited via a longitudinal birth cohort study (April 2010 to March 2013). The PA level was collected using accelerometers and linked to postnatal notes and electronic medical records via the Secure Anonymised Information Linkage databank. Univariable and multivariable linear regressions were used to examine the factors associated with PA levels.

RESULTS

Using univariable analysis, higher PA was associated with the following (P value less than 0.05): being male, larger infant size, healthy maternal blood pressure levels, full-term gestation period, higher consumption of vegetables (infant), lower consumption of juice (infant), low consumption of adult crisps (infant), longer breastfeeding duration, and more movement during sleep (infant) but fewer night wakings. Combined into a multivariable regression model (R2  = 0.654), all factors remained significant, showing lower PA levels were associated with female gender, smaller infant, preterm birth, higher maternal blood pressure, low vegetable consumption, high crisp consumption, and less night movement.

CONCLUSION

The PA levels of infants were strongly associated with both gestational and postnatal environmental factors. Healthy behaviours appear to cluster, and a healthy diet was associated with a more active infant. Boys were substantially more active than girls, even at age 12 months. These findings can help inform interventions to promote healthier lives for infants and to understand the determinants of their PA levels.

Objective sleep and physical activity using 24-hour ankle-worn accelerometry among toddlers from low-income families

OBJECTIVES

Poverty is a risk for short sleep duration and limited physical activity. This study describes sleep, physical activity, and sedentary behavior of Women, Infants, and Children-eligible toddlers and the proportion of toddlers meeting recommendations for sleep and physical activity, and examines associations with body mass index z scores and poverty.

PARTICIPANTS/MEASUREMENTS

A total of 101 toddlers (12-32 months) from low-income families (62% African American) wore 24-hour ankle accelerometers over 3-7 consecutive days. Concurrent validity for daytime napping was assessed using parent-reported toddler wake/sleep between 08:00 and 20:00 collected using Ecological Momentary Assessment. Logistic regressions predicted odds of meeting guidelines.

RESULTS

Toddlers averaged 10.56 hours of sleep in 24 hours. All toddlers averaged ≥180 minutes of total activity per day, 38% had ≥60 minutes of moderate/vigorous physical activity per day, 32% of toddlers slept between 11 and 14 hours over 24 hours, and 26% had a bedtime before 9:00 pm. Body mass index z score was not associated with meeting guidelines. Poverty was associated with less than 60 minutes of moderate/vigorous physical activity.

CONCLUSIONS

Most toddlers were not meeting sleep guidelines. This study provides objective data on sleep and activity among a diverse sample of low-income toddlers. Objective measures of sleep and physical activity facilitate surveillance of children meeting guidelines for sleep and physical activity. Such norms are needed to examine disparities among children from varying racial and economic backgrounds. Future research should examine if meeting guidelines is related to other health indicators.

International Comparison of the Levels and Potential Correlates of Objectively Measured Sedentary Time and Physical Activity among Three-to-Four-Year-Old Children

Physical activity (PA) patterns track from childhood through to adulthood. The study aimed to determine the levels and correlates of sedentary time (ST), total PA (TPA), and moderate-to-vigorous PA (MVPA) in preschool-aged children. We conducted cross-sectional analyses of 1052 children aged three-to-four-years-old from six studies included in the International Children’s Accelerometry Database. Multilevel linear regression models adjusting for age, gender, season, minutes of wear time, and study clustering effects were used to estimate associations between age, gender, country, season, ethnicity, parental education, day of the week, time of sunrise, time of sunset, and hours of daylight and the daily minutes spent in ST, TPA, and MVPA. Across the UK, Switzerland, Belgium, and the USA, children in our analysis sample spent 490 min in ST per day and 30.0% and 21.2% of children did not engage in recommended daily TPA (≥180 min) and MVPA (≥60 min) guidelines. There was evidence for an association between all 10 potential correlates analyzed and at least one of the outcome variables; average daily minutes spent in ST, TPA and/or MVPA. These correlates can inform the design of public health interventions internationally to decrease ST and increase PA in preschoolers.

Family Spirit Nurture (FSN) - a randomized controlled trial to prevent early childhood obesity in American Indian populations: trial rationale and study protocol

BACKGROUND

Childhood overweight and obesity is a persistent public health issue in the US. Risk for obesity and obesity-related morbidity throughout the life course begins in utero. Native Americans suffer the greatest disparities in the US in childhood overweight and obesity status of any racial or ethnic group. Existing early childhood home-visiting interventions provide an opportunity for addressing obesity during the first 1000 days. However, to date, no evidence-based model has been specifically designed to comprehensively target early childhood obesity prevention.

METHODS

This study is a randomized controlled trial to test the efficacy of home-visiting intervention, called Family Spirit Nurture, on reducing early childhood obesity in Native American children. Participants are expectant Native American mothers ages 14-24 and their child, enrolled from pregnancy to 24 months postpartum and randomized 1:1 to receive the Family Spirit Nurture intervention or a control condition. The intervention includes 36 lessons delivered one-on-one by locally-hired Native American Family Health Coaches to participating mothers from pregnancy until 18 months postpartum. A mixed methods assessment includes maternal self-reports, maternal and child observations, and physical and biological data collected at 11 time points from 32 weeks gestation to 2 years postpartum to measure the intervention's primary impact on maternal feeding behaviors; children's healthy diet and physical activity; children's weight status. Secondary measures include maternal psychosocial factors; household food and water security; infant sleep and temperament; and maternal and child metabolic status.

DISCUSSION

None of the 20 current federally-endorsed home-visiting models have demonstrated impacts on preventing early childhood obesity. The original Family Spirit program, upon which Family Spirit Nurture is based, demonstrated effect on maternal and child behavioral health, not including obesity related risk factors. This trial has potential to inform the effectiveness of home-visiting intervention to reduce obesity risk for tribal communities and other vulnerable populations and expand public health solutions for the world's obesity crisis.

TRIAL REGISTRATION

Clinicaltrials.gov (Identifier: NCT03334266 - Preventing Early Childhood Obesity, Part 2: Family Spirit Nurture, Prenatal - 18 Months; Retrospectively registered on 07 November 2017).

Objective measurement of tummy time in infants (0-6 months): A validation study

The 2017 Australian and Canadian 24-hour movement guidelines recommend infants receive 30 minutes of tummy time daily. Currently, there are no validated objective measurement tools or devices to assess tummy time. The purpose of this study was to: 1) test the practicality of using devices on infants as an objective measure of tummy time, and 2) test the accuracy of developed algorithms and cut-points for predicting prone posture. Thirty-two healthy infants aged 4 to 25 weeks completed a protocol of 12 positions. Infants were placed in each position for 3 minutes while wearing a MonBaby (chest), GENEActiv (right hip) and two ActiGraphs (right hip and ankle). Direct observation was the criterion measure. The accuracy of the algorithms or cut-points to predict prone on floor, non-prone and prone supported positions were analyzed. Parents also completed a practicality questionnaire. Algorithms and cut-points to classify posture using devices from MonBaby, GENEActiv and ActiGraph (hip and ankle) were 79%, 95%, 90% and 88% accurate at defining tummy time and 100%, 98%, 100% and 96% accurate at defining non-prone positions, respectively. GENEActiv had the smallest mean difference and limits of agreement (-8.4s, limits of agreement [LoA]: -78.2 to 61.3s) for the prone on floor positions and ActiGraph Hip had the smallest mean difference and LoA for the non-prone positions (-0.2s, LoA: -1.2 to 0.9s). The majority of parents agreed all devices were practical and feasible to use with MonBaby being the preferred device. The evaluated algorithms and cut-points for GENEActiv and ActiGraph (hip) are of acceptable accuracy to objectively measure tummy time (time spent prone on floor). Accurate measurement of infant positioning practices will be important in the observation of 24-hour movement guidelines in the early years.

Accelerometry to measure physical activity in toddlers: Determination of wear time requirements for a reliable estimate of physical activity

Accelerometry is widely used to evaluate physical activity in toddlers however recommendations regarding wear time are needed to understand physical activity behaviours in this age group. This study aimed to determine the minimum wear time to reliably evaluate physical activity in toddlers. Children from the 3D Birth Cohort (n = 255, 49.8% boys, 2.1 ± 0.2 years) were asked to wear an accelerometer (GT3X+, ActiGraph) for 7 days. Physical activity was expressed in active time (min/day) and counts per minute (CPM). Single day intraclass correlation coefficients (ICCs) were calculated to assess the effect of varying minimal wear time on reliability estimates. The Spearman-Brown formula was used to determine wear time required to achieve reliability levels of 70%, 80% and 90%. For active time, a reliability of 72.1% was achieved with wearing the accelerometer for ≥ 4 days of ≥ 6 h, which comprised 85.9% of the sample. For CPM, ≥ 4 days of ≥ 6 h provided a reliability of 74.7% and comprised 85.9% of the children. Results differed slightly when girls and boys were analysed separately, but restricting analyses to children with a weekend day did not. In summary, a minimum of 4 days with ≥ 6 h of accelerometry data provides a reliable estimate of physical activity in 2-year toddlers.

Describing the diurnal relationships between objectively measured mother and infant physical activity

BACKGROUND

Evidence for the importance of accumulating sufficient physical activity in the early years is mounting. This study aimed to determine the relationship between maternal and infant objectively measured physical activity, and to examine the diurnal interactions between these behaviours while accounting for potential covariates.

METHODS

Mothers and infants (n = 152 pairs; infants aged 3-24 months) were recruited from Soweto, South Africa, and physical activity was measured using a wrist worn accelerometer (Axivity AX3, Axivity Ltd., Newcastle-upon-Tyne, UK) for 3-7 days. Mothers completed sleep diaries recording night time-in-bed (used as a proxy for nocturnal sleep status) for themselves and their infant; and reported times during which their infant was in their personal care (caregiver status) for each day during the measurement period. Significant correlates of infant physical activity, as well as the interactions between mother's physical activity, day of the week, sleep status, and caregiver status, were included in panel regression analyses with infant physical activity as the outcome.

RESULTS

There was an equal distribution of boys and girls, and their age ranged from 2.6 to 24.5 months. The majority of mothers (73%) did not spend any time apart from their infant. During weekdays, the combined effect of mother's physical activity (β=0.11), the interactions between mother's physical activity and caregiver status (β=0.17), and sleep status (β= - 0.04) on infant physical activity was β=0.24; while during weekend days this association was β=0.21; and was largely moderated by the interaction between the mother being with the infant and her activity levels (β=0.23), but partly attenuated by mother's physical activity independent of other variables (β= - 0.04). For each hour of the day, for both mother and infant, peaks of physical activity were higher when the mother was not the primary caregiver.

CONCLUSIONS

Infant physical activity levels were strongly associated with their mother's activity levels particularly during the week; this relationship was stronger when mothers were more active while looking after their infant. Mothers should be encouraged to be active when looking after their children, particularly during the week, and to provide infants with as much opportunity to be active as possible.

Describing objectively measured physical activity levels, patterns, and correlates in a cross sectional sample of infants and toddlers from South Africa

BACKGROUND

Physical activity is considered to have health benefits across the lifespan but levels, patterns, and correlates have not been well described in infants and toddlers under the age of two years.

METHODS

This study aimed to describe objectively and subjectively measured physical activity in a group of South African infants aged 3- to 24-months (n = 140), and to investigate individual and maternal correlates of physical activity in this sample. Infants' physical activity was measured using an Axivity AX3 wrist-worn accelerometer for one week and the mean vector magnitude was calculated. In addition, mothers reported the average amount of time their infant spent in various types of activities (including in front of the TV), their beliefs about infants' physical activity, access to equipment in the home environment, and ages of motor development milestone attainment. Analysis of variance (ANOVA) and pair-wise correlations were used to test age and sex differences and associations with potential correlates.

RESULTS

There were significant age and sex effects on the distribution of time spent at different physical activity intensities (Wilks' lambda = 0.06, p < 0.01). In all cases, the trend was for boys to spend more time in higher intensity physical activity and less time in lower intensity activity than girls; and for time spent in higher intensity activities to be higher in older children. Time spent outside was higher in boys, and this reached significance at 18-months (F = 3.84, p = 0.02). Less concern around floor play was associated with higher physical activity at 12-months in females only (p = 0.03, r = 0.54), and no other maternal beliefs were correlated with physical activity. The majority (94%) of children were exceeding TV time recommendations. When controlling for age and sex, overall TV time was positively associated with BMI z-score (β=0.01, p = 0.05).

CONCLUSION

This study is the first to show sex and age differences in the patterns of physical activity, and to report on objectively measured and maternal reported physical activity and sedentary behaviour in the first two years of life in South Africa infants. Infants and toddlers should be provided with as many opportunities to be active through play as possible, and TV time should be limited.

Nighttime Sleep Duration and Sleep Behaviors among Toddlers from Low-Income Families: Associations with Obesogenic Behaviors and Obesity and the Role of Parenting

BACKGROUND

Shortened sleep duration is associated with poor health and obesity among young children. Little is known about relationships among nighttime sleep duration, sleep behaviors, and obesogenic behaviors/obesity among toddlers. This study characterizes sleep behaviors/duration and examines relationships with obesogenic behaviors/obesity among toddlers from low-income families.

METHODS

Mothers of toddlers (age 12-32 months) were recruited from urban/suburban sites serving low-income families. Mothers provided demographic information and completed the Brief Infant Sleep Questionnaire (BISQ); a 6-item Toddler Sleep Behavior Scale was derived (TSBS-BISQ, higher score reflects more recommended behaviors). Toddler weight/length were measured; obesity defined as ≥95th percentile weight-for-length. Measures of obesogenic behaviors: physical activity [accelerometry, minutes/day in Moderate-to-Vigorous Physical Activity (MVPA)] and diet quality [24-hour recall, Healthy Eating Index 2005 (HEI-2005)]. Bivariate and adjusted multivariable models examined associations between nighttime sleep behaviors/duration and obesogenic behaviors/obesity.

RESULTS

Sample included 240 toddlers (mean age = 20.2 months), 55% male, 69% black, 59% urban. Toddlers spent 55.4 minutes/day in MVPA, mean HEI-2005 score was 55.4, 13% were obese. Mean sleep duration was 9.1 hours, with 35% endorsing 5-6 recommended sleep behaviors (TSBS-BISQ). In multivariable models, MVPA was positively related to sleep duration; obese toddlers had a shorter nighttime sleep duration than healthy weight toddlers [odds ratio = 0.69, p = 0.014]. Nighttime sleep duration was associated with high TSBS-BISQ scores, F = 6.1, p = 0.003.

CONCLUSIONS

Toddlers with a shorter nighttime sleep duration are at higher risk for obesity and inactivity. Interventions to promote healthy sleep behaviors among toddlers from low-income families may improve nighttime sleep duration and reduce obesogenic behaviors/obesity.