Physical activity intensity, sedentary time, and body composition in preschoolers

Sedentary Time Patterns Among Preschoolers: Do Sex Disparities Exist?

Background: Examining sedentary time (ST) by disaggregating the day into periods such as before, during, and after preschool allows interventionists to understand when sedentary behaviors are most severe. This study aimed to determine if there are sex differences in ST before, during, and after preschool hours in US preschoolers. Methods: A secondary analysis of a two-cohort study with a sample size of 292 preschoolers (67% African Americans/Blacks; 100% from low-income families) was used. Measures were collected in Fall 2017 and Fall 2018. Preschoolers wore an accelerometer on the non-dominant wrist for 8 consecutive days to obtain ST minutes before, during, and after preschool periods. Three separate linear regressions were conducted to test sex differences in ST before, during, and after preschool hours. ST for each period of the day was considered the outcome variable predicted by sex and covarying for BMI percentile. Results: Girls were more sedentary than boys during preschool (F (1, 226) = 5.15, p = 0.006; b = -0.09 [-0.15, -0.03]), but not before preschool (F(1, 225) = 0.98, p = 0.32; b = 2.50 [-2.46, 7.45]) nor after preschool (F(1, 227) = 3.62, p = 0.06; b = 6.60 [-0.21, 13.42]). Conclusions: This difference in ST could have an unfavorable health impact among preschool girls. Given that childhood obesity prevalence dramatically increases from preschool age to childhood, there is a need to design family-based interventions that provide parents/caregivers strategies to develop habits around healthy eating and physical activity that they can carry into later life stages.

Longitudinal Relationships of Physical Activity, Sedentary Time, Cardiorespiratory Fitness, and Muscular Fitness with Body Fatness in Preschoolers

There is still insufficient knowledge about the potential benefits of physical activity and fitness or the adverse impact of sedentary behaviours on body composition at preschool age. Therefore, we aimed to study the relationships of moderate-to-vigorous physical activity (MVPA), sedentary time (ST), cardiorespiratory fitness (CRF), and muscular fitness (MF) with body fat percentage (BF%) in boys and girls. Participants were investigated twice: in the final year of kindergarten, when the boys' median age was 7 years and the girls' median age was 6 years (p = 0.240), and again in the first grade of school. MVPA and ST were measured with an accelerometer, BF% was derived from skinfold thicknesses, CRF was measured with a 20 m shuttle run test, and MF was represented by the mean z-scores from standing long jump and relative upper-limb strength. In girls, higher ST (β = 0.587, p = 0.021) and lower MF (β = -0.231, p = 0.009) at preschool age were related to higher BF% in the first grade of school after adjustment for confounders. MVPA and CRF in preschool children were unrelated to BF% in school among boys and girls. In conclusion, sitting less and having greater muscular fitness at preschool age appear to be beneficial for lower body fatness in the first grade among girls, but not in boys. MVPA and CRF at preschool age are unrelated to body fatness at school age in boys and girls. Our results indicate that girls may especially benefit from decreasing sedentary behaviours and increasing upper- and lower-limb muscular strength at preschool age for a healthy weight profile in the first grade of school.

A cohort study of factors influencing the physical fitness of preschool children: a decision tree analysis

Objective

Based on the decision tree model, to explore the key influencing factors of children's physical fitness, rank the key influencing factors, and explain the complex interaction between the influencing factors.

Methods

A cohort study design was adopted. 1,276 children (ages 3-6) from 23 kindergartens in Nanchang, China, were chosen for the study to measure the children's physical fitness at baseline and a year later and to compare the physical fitness scores at the two stages. The study was conducted following the Chinese National Physical Fitness Testing Standard (Children Part); To identify the primary influencing factors of changes in physical fitness, a decision tree model was developed, and a questionnaire survey on birth information, feeding patterns, SB, PA, dietary nutrition, sleep, parental factors, and other relevant information was conducted.

Results

The levels of physical fitness indicators among preschool children showed a significant increase after 1 year. The accuracy of the CHAID model is 84.17%. It showed that 7 variables were strongly correlated with the physical changes of children's fitness, the order of importance of each variable was weekend PA, weekend MVPA, mother's BMI, mother's sports frequency, father's education, mother's education, and school day PA. Three factors are related to PA. Four factors are related to parental circumstances. In addition to the seven important variables mentioned, variables such as breakfast frequency on school day, puffed food, frequency of outing, school day MVPA, parental feeling of sports, father's occupation, and weekend breakfast frequency are all statistically significant leaf node variables.

Conclusion

PA, especially weekend PA, is the most critical factor in children's physical fitness improvement and the weekend MVPA should be increased to more than 30 min/d based on the improvement of weekend PA. In addition, parental factors and school day PA are also important in making decisions about changes in fitness for children. The mother's efforts to maintain a healthy BMI and engage in regular physical activity are crucial for enhancing the physical fitness of children. Additionally, other parental factors, such as the parents' educational levels and the father's occupation, can indirectly impact the level of physical fitness in children.

Compositional functional regression and isotemporal substitution analysis: Methods and application in time-use epidemiology

The distribution of time that people spend in physical activity of various intensities has important health implications. Physical activity (commonly categorised by the intensity into light, moderate and vigorous physical activity), sedentary behaviour and sleep, should not be analysed separately, because they are parts of a time-use composition with a natural constraint of 24 h/day. To find out how are relative reallocations of time between physical activity of various intensities associated with health, herewith we describe compositional scalar-on-function regression and a newly developed compositional functional isotemporal substitution analysis. Physical activity intensity data can be considered as probability density functions, which better reflects the continuous character of their measurement using accelerometers. These probability density functions are characterised by specific properties, such as scale invariance and relative scale, and they are geometrically represented using Bayes spaces with the Hilbert space structure. This makes possible to process them using standard methods of functional data analysis in the L 2 space, via centred logratio (clr) transformation. The scalar-on-function regression with clr transformation of the explanatory probability density functions and compositional functional isotemporal substitution analysis were applied to a dataset from a cross-sectional study on adiposity conducted among school-aged children in the Czech Republic. Theoretical reallocations of time to physical activity of higher intensities were found to be associated with larger and more progressive expected decreases in adiposity. We obtained a detailed insight into the dose-response relationship between physical activity intensity and adiposity, which was enabled by using the compositional functional approach.

Associations between abdominal adiposity, body size and objectively measured physical activity in infants from Soweto, South Africa

OBJECTIVES

Considering the importance of the early life period, in conjunction with the increasing prevalence of adiposity and insufficient physical activity already evident in early childhood, this study aimed to determine associations between abdominal adiposity, body size, and objectively measured physical activity in infancy.

METHODS

Infants (n = 138, aged 3-24 months) from Soweto, South Africa were recruited to this cross-sectional study. Visceral (VAT) and subcutaneous abdominal fat (SAT) were measured using ultrasound. Physical activity was assessed using accelerometry and analysed at the hourly level. Multilevel linear regression analyses were run with body composition exposures adjusted for age, sex, and length; models with VAT and SAT were also adjusted for total abdominal fat.

RESULTS

Mean (SD) age was 11.8 (7.6) months; 86% were normal weight, 7% were underweight and 7% overweight. In linear models, no body composition variable was significantly associated with physical activity. Physical activity was higher with each increasing length tertile (ANOVA p < 0.01); with a mean(95%CI) 29(60-60)mg in the lowest tertile, 39(71-71)mg in the middle tertile, and 50(81-82)mg in the highest tertile. Infants with normal weight had higher mean(95%CI) physical activity (40(70-80)mg) than underweight (34(73-85)mg, p = 0.01) or overweight infants (31(63-78)mg, ANOVA p < 0.01). When also adjusting for total abdominal fat, infants in the lowest SAT tertile had higher physical activity than those in the middle or highest SAT tertiles (p < 0.01).

CONCLUSIONS

These findings lend support for higher physical activity as a marker of healthy growth in the first two years of life.

Revisiting the cross-sectional and prospective association of physical activity with body composition and physical fitness in preschoolers: A compositional data approach

BACKGROUND

Information is limited for the benefits of physical activity (PA) in preschoolers. Previous research using accelerometer-assessed PA may be affected for multicollinearity issues.

OBJECTIVES

This study investigated the cross-sectional and prospective associations of sedentary behaviour (SB) and PA with body composition and physical fitness using compositional data analysis.

METHODS

Baseline PA and SB were collected in 4-year-old (n = 315) using wrist-worn GT3X+ during seven 24 h-periods. Body composition (air-displacement plethysmography) and physical fitness (PREFIT test battery) were assessed at baseline and at the 12-month follow-up.

RESULTS

Increasing vigorous PA at expenses of lower-intensity behaviours for 4-year-old was associated with body composition and physical fitness at cross-sectional and longitudinal levels. For example, reallocating 15 min/day from lower intensities to vigorous PA at baseline was associated with higher fat-free mass index (+0.45 kg/m2 , 95% confidence intervals [CI]: 0.18-0.72 kg/m2 ), higher upper-body strength (+0.6 kg, 95% CI: 0.1-1.19 kg), higher lower-body strength (+8 cm, 95% CI: 3-13 cm), and shorter time in completing the motor fitness test (-0.4 s, 95% CI: -0.82 to [-0.01] s) at the 12-month follow-up. Pairwise reallocations of time indicated that the behaviour replaced was not relevant, as long as vigorous PA was increased.

CONCLUSIONS

More time in vigorous PA may imply short- and long-term benefits on body composition and physical fitness in preschoolers. These findings using compositional data analysis corroborate our previously published results using isotemporal substitution models.

Increasing Children's physical Activity by Policy (CAP) in preschools within the Stockholm region: study protocol for a pragmatic cluster-randomized controlled trial

Background

Systematic reviews suggest that preschool environmental/organizational changes may be effective in increasing physical activity (PA) levels of preschool children, but evidence is scarce regarding feasible, effective, and equitable interventions that can be scaled up. Specifically, it is essential to understand whether introducing a multicomponent organizational change in terms of policy in the preschool context may be beneficial for children’s PA levels and concomitant health outcomes. To bridge this knowledge gap, our main aim is to examine the feasibility and effectiveness of a policy package in increasing PA levels in preschool children, using a large-scale pragmatic cluster-randomized controlled trial.

Methods

This proposed study is a pragmatic cluster-randomized controlled trial with two conditions (intervention and control with a 1:1 ratio) with preschools as clusters and the unit of randomization. We aim to recruit approximately 4000 3–5-year-old children from 90 preschools and retain more than 2800 children from 85 preschools to provide adequate statistical power for the analyses. The intervention to implement is a co-created, multicomponent policy package running for 6 months in preschools randomized to intervention. Change in accelerometer measured PA levels in children between intervention and control from pre- and post-intervention will be the primary outcome of the study, while secondary outcomes include health outcomes such as musculoskeletal fitness, psychosocial functioning, and absence due to illness in children among others. Implementation will be studied carefully using both quantitative (dose, fidelity) and qualitative (interview) methodologies. The change in primary and secondary outcomes, from pre- to post-intervention, will be analyzed with linear mixed-effect models (to allow both fixed and random effects) nested on a preschool level.

Discussion

This is a large-scale co-creation project involving the City of Stockholm, childcare stakeholders, preschool staff, and the research group with the potential to influence more than 30,000 preschool children within the Stockholm area. The study will add reliable evidence for the implementation of PA policies at the organizational level of preschools and clarify its potential effect on objectively measured PA and health markers in children.

Trial registration

ClinicalTrials.govNCT04569578. Prospectively registered on September 20, 2020.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06513-4.

Determinants of High Fat Mass Index in Preschoolers Living in Brazilian Urban Areas

OBJECTIVE

Determine the social, environmental, and personal factors associated with high fat mass index in preschoolers.

DESIGN

A quantitative, exploratory, and cross-sectional study.

SETTING AND PARTICIPANTS

Fifty-one Brazilian preschoolers from public schools living in urban areas.

MAIN OUTCOME MEASURE(S)

The preschoolers' fat mass index was determined using dual-energy radiological absorptiometry. The quality of home and school environments were accessed using the Early Childhood Home Observation for Measurement of the Environment and Early Childhood Environment Rating Scales. The physical activity levels were recorded by accelerometers. The daily energy intake was recorded and sociodemographic data using the Brazilian Economic Classification criterion. Data on exposure time to screens and parental obesity were collected according to the parents' reports.

ANALYSIS

Data analyses were performed using simple and multiple regressions models.

RESULTS

Parental obesity (β, 0.516; 95% confidence interval [CI], 2.078-5.133), high quality of environmental stimulation of home (β, 0.429; 95% CI, 1.294-4.023), and high exposure time to screens (β, 0.256; 95% CI, 0.215-2.554) explained 43% of preschoolers' high fat mass index.

CONCLUSIONS AND IMPLICATIONS

Identification of parental obesity, high quality of environmental stimulation of home, and high exposure time to screens as the most important determinants of the high fat mass index in preschoolers from Brazilian urban areas.

Effect of a Fundamental Motor Skills Intervention on Fundamental Motor Skill and Physical Activity in a Preschool Setting: A Cluster Randomized Controlled Trial

PURPOSE

To determine the effect of a 12-week fundamental motor skill (FMS) program on FMS and physical activity (PA) on preschool-aged children.

METHOD

A cluster randomized controlled trial. The intervention (PhysicaL ActivitY and Fundamental Motor Skills in Pre-schoolers [PLAYFun] Program) was a 12-week games-based program, delivered directly to the children in childcare centers by exercise physiologists. Children in the control arm received the usual preschool curriculum. Outcomes included FMS competence (Test of Gross Motor Development-2) and PA (accelerometer) assessed at baseline, 12 weeks, and 24 weeks (12-wk postintervention).

RESULTS

Fifty children (mean age = 4.0 [0.6] y; 54% male) were recruited from 4 childcare centers. Two centers were randomized to PLAYFun and 2 centers were randomized to the waitlist control group. Children attended on average 2.0 (1.0) 40-minute sessions per week. The PLAYFun participants demonstrated significant increases in object control (P < .001) and total FMS (P = .010) competence at week 12, compared with controls in a group × time interaction. Girls, but not boys, in PLAYFun significantly increased moderate to vigorous PA after the intervention (P = .004). These increases were not maintained 12-week postcompletion of PLAYFun.

CONCLUSIONS

The PLAYFun Program is effective at improving FMS competence in boys and girls and increasing PA in girls. However, improvements are not maintained when opportunities to practice are not sustained.

Associations between Movement Behaviours and Obesity Markers among Preschoolers Compliant and Non-Compliant with Sleep Duration: A Latent Profile Analysis

This study identifies physical activity (PA) and sedentary behaviour (SB) clusters in preschoolers compliant (C) or non-compliant (NC) with sleep recommendations; and associates these clusters with obesity markers. PA and SB were objectively assessed (Actigraph WGT3-X) in 272 preschoolers (4.4 ± 0.7 years old). Sleep duration was parent-reported, and preschoolers were classified as C (3-4 years old: 600-780 min/day; 5 years old: 540-660 min/day) or NC with sleep recommendations. Body mass index (BMI) and waist circumference (WC) were assessed according to international protocols. Moderate to vigorous physical activity (MVPA) and light physical activity (LPA) were categorized as low/high (<60 min/>60 min/day or <180 min/180 min/day, respectively). SB was defined according to mean values between clusters. Latent profile analysis was performed. Associations between the observed clusters and obesity markers were determined using linear regression (RStudio; 1.3.1073). Four cluster solutions for C and NC preschoolers were identified. A negative association between C/Low MVPA cluster and BMI, and a positive association between NC/Low MVPA and BMI (β = -0.8, 95%CI = -1.6;-0.1, and β = 0.9, 95%CI = 0.1;1.7, respectively) were observed. No association was seen for SB clusters. Adequate sleep duration may have a protective role for preschoolers' BMI, even if the children do not comply with MVPA recommendations.

Association of sedentary patterns with body fat distribution among US children and adolescents: a population-based study

BACKGROUND/OBJECTIVES

Children and adolescents spend a substantial amount of time being sedentary. The impact of prolonged sedentary patterns on fat distribution has not been elucidated especially in the context of physical activity level. Our objective is to examine the independent and joint associations of prolonged sedentary patterns and physical activity level with fat distribution among children and adolescents.

SUBJECTS/METHODS

This included US children (8-11 years) and adolescents (12-19 years) from the National Health and Nutrition Examination Survey 2003-2006. Sedentary patterns comprise accelerometer-measured average sedentary bout duration and self-reported time of sitting watching TV/videos. Fat distribution (trunk and total fat percentage) was determined via dual X-ray absorptiometry.

RESULTS

Among 810 children and 2062 adolescents, average sedentary bout duration was associated with greater total and trunk fat percentages only among male children, after adjusting for moderate-to-vigorous physical activity (MVPA) level by accelerometer. Prolonged sitting watching TV/videos was associated with higher total and trunk fat percentages in male children and all adolescents, independent of levels of MVPA (all P for trend <0.05). Compared with ≤1 h/day, male children who spent ≥4 h/day sitting watching TV/videos had 4.43% higher trunk fat (95% CI, 1.69-7.17%), with similar associations for female (3.53%; 95% CI, 1.03-6.03%) and male adolescents (4.78%; 95% CI, 2.97-6.60%). About 13-17% children and adolescents spent <1 h on MVPA and ≥4 h sitting watching TV/videos per day. Compared with the most active group (MVPA ≥ 1 h/day and sitting watching TV/videos ≤1 h/day), trunk fat in this least active group was 6.21% higher in female children, 9.90% higher in male children, 6.84% higher in female adolescents, and 5.36% higher in male adolescents.

CONCLUSIONS

Prolonged time spent on sitting watching TV/videos was associated with fat accumulation among children and adolescents, independent of physical activity level.

No association between maternal exercise during pregnancy and the child's weight status at age 7 years: The MoBa study

INTRODUCTION

Maternal lifestyle during pregnancy may affect the development of overweight and obesity in the child. We examined whether maternal exercise during pregnancy is associated with offspring overweight and obesity in childhood. A secondary aim was to examine whether the association is affected by the child's physical activity level.

MATERIALS AND METHODS

This study is based on data from the Norwegian Mother, Father and Child Cohort Study (MoBa), including 44 352 pregnancies and children (n = 32 304 in week 17 and n = 32 419 in week 30 in the final adjusted model). Maternal exercise during pregnancy was self-reported in gestational weeks 17 and 30. We conducted linear and logistic regression separately for girls and boys, and outcomes were the child's body mass index (BMI) and weight status (overweight/obese) at age 7 years. We further examined the additive joint association between maternal exercise during pregnancy and the child's leisure time physical activity on weight status at age 7 years.

RESULTS

In total, 12.4% of the children were classified as overweight or obese, and 1.7% as obese. The results suggest no association between maternal exercise in both gestational weeks 17 and 30 and the weight status of the child at age 7 years. The association between maternal exercise and the child's weight status at age 7 years appears not to be affected by the child's physical activity level.

CONCLUSION

Maternal exercise level during pregnancy does not appear to be associated with the child's BMI or odds of being overweight or obese in childhood.

Associations of diarised sleep onset time, period and duration with total and central adiposity in a biethnic sample of young children: the Born in Bradford observational cohort study

OBJECTIVES

To investigate associations of parent-reported sleep characteristics with adiposity levels in a biethnic sample of young children.

DESIGN

A cross-sectional observational study.

SETTING

The Born in Bradford 1000 study, UK.

PARTICIPANTS

Children aged approximately 18 months (n=209; 40.2% South Asian; 59.8% white) and 36 months (n=162; 40.7% South Asian; 59.3% white).

PRIMARY AND SECONDARY OUTCOME MEASURES

Children's body mass index (BMI) z-score, sum of two-skinfolds (triceps and subscapular) and waist circumference. Adjusted regression was used to quantify associations of sleep parameters with adiposity stratified by ethnicity and age group. The results are beta coefficients (95% CIs) and unless otherwise stated represent the difference in outcomes for every 1-hour difference in sleep parameters.

RESULTS

The average sleep onset time was markedly later in South Asian (21:26±68 min) than white children (19:41±48 min). Later sleep onset was associated with lower BMI z-score (-0.3 (-0.5 to -0.0)) and sum of two-skinfolds (-1.5 mm (-2.8 mm to -0.2 mm)) in white children aged 18 months and higher BMI z-score in South Asian children aged 36 months (0.3 (0.0-0.5)). Longer sleep duration on weekends than weekdays was associated with higher BMI z-score (0.4 (0.1-0.8)) and waist circumference (1.2 cm (0.3-2.2 cm)) in South Asian children aged 18 months, and later sleep onset on weekends than weekdays was associated with larger sum of two-skinfolds (1.7 mm (0.3-3.1 mm)) and waist circumference (1.8 cm (0.6-2.9 cm)). Going to sleep ≥20 min later on weekends than weekdays was associated with lower waist circumference in white children aged 18 months (-1.7 cm (-3.2 cm to -0.1 cm)).

CONCLUSIONS

Sleep timing is associated with total and central adiposity in young children but associations differ by age group and ethnicity. Sleep onset times and regular sleep schedules may be important for obesity prevention.

Hyperactivity is associated with higher fat-free mass and physical activity in Swedish preschoolers: A cross-sectional study

Aim

We investigated psychological strengths and difficulties in a Swedish population of preschool children and analysed how these behavioural variables were related to body composition, cardiorespiratory fitness, physical activity levels, sedentary behaviour and diet.

Methods

Three hundred and fifteen boys and girls were recruited during 2014‐2015. Body composition was measured using air‐displacement plethysmography, and anthropometric measures were taken. Parents responded to questions about age, sex and educational attainment, diet, physical activity levels and smoking habits, as well as the Strengths and Difficulties Questionnaire (SDQ). Regression models were created to analyse associations between psychological variables, body composition and health behaviours.

Results

Hyperactivity scores were positively related to fat‐free mass (β = 0.20, P = .001) and moderate‐to‐vigorous physical activity (β = 0.16, P = .003) and negatively associated with sedentary behaviours (β = 0.18, P = .001), but showed no statistically significant associations with fat mass.

Conclusion

Our findings suggest that the adverse health consequences of hyperactivity on obesity and obesity‐related health behaviours may be established after the preschool period. Questions about the time frame of contributing and modulating factors in obesity development are discussed.

Association between objectively measured body composition, sleep parameters and physical activity in preschool children: a cross-sectional study

OBJECTIVE

Associations between self-reported sleep duration and obesity indices in children are well recognised; however, there are no studies on associations between objectively measured other sleep parameters and physical activity with body composition in preschoolers. Therefore, the aim of this study was to determine the associations between sleep parameters and moderate-to-vigorous physical activity (MVPA) with body composition indices in preschoolers using objective measures.

DESIGN

A cross-sectional study.

PARTICIPANTS

The study group consisted of 676 children aged 5-6 years, who were enrolled in kindergartens in the 2017/2018 school year.

OUTCOME MEASURES

Sleep parameters and MVPA were measured using accelerometers for 7 days. Bioelectrical impedance analysis was used to estimate body composition.

RESULTS

Sleep duration and sleep efficiency were inversely associated with body fat percentage (BFP) (β=-0.013 and β from -0.311 to -0.359, respectively) and body mass index (BMI) (β from -0.005 to -0.006 and from -0.105 to -0.121, respectively), and directly associated with fat-free mass (FFM) (β from 0.010 to 0.011 and from 0.245 to 0.271, respectively) and muscle mass (β from 0.012 to 0.012 and from 0.277 to 0.307, respectively) in unadjusted and adjusted models. BFP was inversely associated with MVPA and positively associated with number of awakenings and sleep periods. Number of sleep periods was inversely associated with FFM, and positively with BMI and muscle mass. Correlation matrix indicated significant correlation between BFP, FFM and muscle mass with sleep duration, sleep efficiency, number of sleep periods and MVPA.

CONCLUSIONS

Periodic assessment of sleep parameters and MVPA in relation to body composition in preschool children may be considered, especially in those who are at risk for obesity.

The Association of Different Sedentary Patterns and Health-Related Physical Fitness in Pre-schoolers

Background: The results of sedentary time (ST) and health-related physical fitness (HPF) are not completely consistent and the studies concentrated on pre-schoolers are very limited. Methods: We measured ST and ST patterns (ST Bouts time, ST Breaks times) by accelerometer. The health-related physical fitness T-score (HPFT) was calculated by five indexes: height-weight standard score, 20 m shuttle-run test, grip strength, standing long jump and 2 × 10 m shuttle-run test. Results: We included 375 pre-schoolers (211 boys, 164 girls) in the final analysis. The total ST and ST Bouts times negatively correlated with HPFT in pre-schoolers. HPFT reduced by 1.69 and 0.70 points per 10 min increased in total ST and ST Bouts times, respectively. HPFT of the highest quartile group reduced by 9.85 points in total ST, and 10.54 points in ST Bouts time compared with the lowest quartile group. However, the HPFT increased by 0.09 points per 10 times increased in ST Breaks times; the HPFT increased by 16.21 and 15.59 points when moderate to vigorous physical activity (MVPA) replaced total ST and ST Bouts time. Conclusions: HPF negatively correlated with the Total ST and ST Bouts times, but positively correlated with ST Breaks times; and HPF significantly improved when MVPA replaced ST in pre-schoolers.

Relationship between children physical activity, inflammatory mediators and lymphocyte activation: possible impact of social isolation (COVID-19)

Objective

Lifestyle and body composition may be simultaneously responsible for immune response modulation. This study aimed to compare plasmatic adipokines concentration and lymphocyte cytokine production in children with different daily steps (DS) range, as well as to discuss the potential negative impact of the social isolation during COVID-19 pandemic in this context. DS can be a useful and low-cost way of monitoring children's health status.

Study design

Fifty children were classified into clusters based in DS measured by pedometer: Sedentary Group (DS = 9338 ± 902 steps) and Active Group (DS = 13,614 ± 1003 steps). Plasma and lymphocytes were isolated and cultured to evaluate cytokine production.

Results

Sedentary group presented lower adiponectin (7573 ± 232 pg/mL), higher leptin (16,250 ± 1825 pg/mL) plasma concentration, and higher lymphocyte production of IL-17, IFN-gamma, TNF-, IL-2 in relation to active group, suggesting predominance of Th1 response. Otherwise, the active group presented higher lymphocyte supernatant concentration of IL-10 and higher regulatory T cell (Treg) percentage.

Conclusion

These results indicate that lymphocytes of children performing higher DS have an anti-inflammatory profile, especially of Treg. Besides, the prolonged social isolation in children during the COVID-19 pandemic, limiting physical mobility and exercise, reduces DS and increases adiposity, which could impair the immune system function and raise the susceptibility to inflammatory diseases.

Adiposity, cardiovascular, and health-related quality of life indicators and the reallocation of waking movement behaviors in preschool children with overweight and obesity: An isotemporal data analysis

BACKGROUND

Isotemporal substitution evaluates hypothetical time replacement scenarios of physical movement on health, with few studies conducted among ethnically diverse preschool-aged populations. This study examines the reallocation of waking movement behaviors on adiposity, cardiovascular, and quality of life indicators among low-income, majority Hispanic preschool-aged youth (2-5 years) with overweight.

METHODS

Participants wore an ActiGraph monitor (waist) and completed adiposity, cardiovascular, and health-related quality of life health assessments. Covariates included age, sex, ethnicity, and socioeconomic status. The isotemporal substitution approach was employed to address study aims.

RESULTS

Complete data were available for 131 preschoolers. For boys, reallocating 5 minutes of stationary time with light intensity, moderate to vigorous intensity, or total physical activity showed a relation with beneficial reductions in adiposity indicators; for girls, these relations were statistically null. For boys and girls, reallocating 5 minutes of stationary time [-2.2 (95% CI: -3.7, -0.7) mmHg], light intensity [-2.1 (95% CI: -3.7, -0.7) mmHg], or moderate intensity activity [-2.7 (95% CI: -5.0, -0.4) mmHg] to vigorous intensity activity was related to favorable systolic blood pressure. Reallocating 5 minutes of stationary time to moderate to vigorous intensity activity [0.6 (95% CI: -1.0, -0.1) mmHg] or total physical activity [-0.2 (95% CI: -0.3, -0.01) mmHg] was related to lowered systolic blood pressure. Reallocating 5 minutes of stationary time to moderate to vigorous intensity activity [0.6 (95% CI: -1.1, -0.02) bpm] was related to lowered resting heart rate. No significant results for quality of life were found.

CONCLUSION

Reallocation of time from stationary time to other movement behaviors is associated with several favorable adiposity and cardiovascular health outcomes among preschool children with overweight and obesity.

Relationship Between the Practice of Physical Activity and Physical Fitness in Physical Education Students: The Integrated Regulation As a Mediating Variable

The practice of physical activity (PA) contributes to the prevention of chronic diseases such as obesity, metabolic syndrome or cardiovascular diseases, being also directly related to the individual’s physical fitness. Therefore, it is necessary to measure and monitoring the levels of PA in childhood and adolescence, since it may be useful to describe their current health status and the association with physical fitness, as well as to reveal putative consequences in the future. Within the educational field, it has been shown that physical education (PE) classes are a favorable context for the creation of healthy physical-sports habits and self-determined motivation could be a key for explaining the level of PA practice. For this reason, the purpose of this research was to study the mediating role of integrated regulation (IR) on the relationship between PA and physical fitness in children and adolescents. A total of 325 students between 11 and 14 years old participated in the study. The level of PA was estimated through the specific Physical Activity Questionnaire for Children (PAQ-C), while motivation and IR were measured by using the Perceived Locus of Causality scale (PLOC-2). In addition, physical fitness was measured through the Eurofit fitness battery of tests, composed of three body composition measures and seven tests of different physical capacities. The physical fitness score showed no differences when genders were compared. After regression analysis, the resulting models revealed a good adjustment and correlation between PA practice and physical fitness (β = 0.173; p < 0.001), being established through the macro Process that this relationship is partially conditioned by the IR (β = 0.122; p = 0.03). ROC curve analysis estimated the score of 5.88 as a cut-off point to discriminate between levels of IR for students, classified as physically active or not (AUC = 0.67; p < 0.001). The conclusions from these main and other complementary analyses reporting complete mediations, suggest that the IR could be decisive in predicting and explaining the relationship between the practice of PA and physical fitness at these ages, highlighting its importance for a greater adherence to the practice.

Associations between physical activity, body composition, and physical fitness in the transition from preschool to school

The purpose of the study was to assess the longitudinal associations of physical activity (PA) with body composition and physical fitness (PF) at the 12-month follow-up during the transition from kindergarten to school in Estonian children aged 6 to 8 years (n = 147). PA and sedentary behavior (SB) were assessed using the accelerometer. Body composition was measured from triceps and subscapular skinfold thicknesses and PF using PREFIT test battery. SB at the mean age of 6.6 year had negative relation with upper and lower body strength and motor fitness at the mean age of 7.6 year in adjusted models. Light PA (LPA) and moderate PA(MPA) at 6.6 year were positively and SB was negatively associated with fat-free mass index (FFMI) at 7.6 year after adjustments for confounders [vigorous PA (VPA), total awake wear time, child's sex, age at measurement]. Substituting 5 min/d of SB at 6.6 year with 5 min of VPA was related to higher FFMI at 7.6 year. In adjusted models, VPA at 6.6 year was positively associated with cardiorespiratory fitness at 7.6 year, greater baseline VPA or moderate-to-vigorous PA (MVPA) predicted greater upper body strength a year later and LPA, MPA, VPA, MVPA at 6.6 year were positively related to lower body strength at follow-up. In adjusted analysis greater VPA at 6.6 year was related to better motor fitness at follow-up. Promoting higher-intensity PA and reducing SB at preschool may have long-term effects on body composition and PF in children at the first grade.

Different amounts of moderate to vigorous physical activity and change in glycemic variability in adolescents with type 1 diabetes: is there dose-response relationship?

OBJECTIVE

To identify the level of physical activity and glycemic variability of adolescents with type 1 diabetes mellitus and to compare glycemic variability on days with different amounts of moderate to vigorous physical activity (MVPA).

SUBJECTS AND METHODS

A sample of 34 subjects aged 10 to 15 years, 18 (52.94%) female; age: 13.04 ± 1.94; HbA1c: 9.76 ± 1.51. Physical activity was measured by wGT3X accelerometer. The glucose data were obtained using continuous glucose monitoring, and the following glycemic variability measures were calculated: standard deviation (SD), low blood glucose index (LBGI), high blood glucose index (HBGI), mean amplitude of glycemic excursions (MAGE), glycemic risk assessment in diabetes equation (GRADE) and coefficient of variation (CV). The most and least active days (the days with greater and lesser time dedicated to physical activities of moderate to vigorous intensity, respectively) were identified. In addition, based on the whole period of accelerometer use, daily means of time spent in MVPA were identified among participants, who were then divided into three groups: up to 100 minutes; from 101 to 200 minutes and above 201 minutes. Then, the measures of glycemic variability were compared among the most and least active days and among the groups too.

RESULTS

The amount of MVPA was significantly different between the days evaluated (237.49 ± 93.29 vs. 125.21 ± 58.10 minutes), but glycemic variability measures did not present a significant difference.

CONCLUSION

Despite the significant differences in the amount of MVPA between the two days evaluated, the glycemic variability did not change significantly. Arch Endocrinol Metab. 2020;64(3):312-8.

Lean mass accretion in children born very low birth weight is significantly associated with estimated changes from sedentary time to light physical activity

BACKGROUND

Few studies have investigated how lifestyle is associated with body composition in children born very low birth weight (VLBW, <1500 g), a population at increased risk of obesity and metabolic syndrome in later life.

OBJECTIVES

Determine how time spent in physical activity, sedentary time, and sleep are associated with body composition in children born VLBW.

METHODS

In this prospective cohort study of 5.5-year-old children born VLBW, height, weight, body composition (skinfolds, air displacement plethysmography), and 7 days of movement data (logbooks and accelerometers) were collected.

RESULTS

Of 158 participants, 53% were male, and mean (SD) birth weight was 1013 (264) g. Only 52% achieved 60 minutes/day of moderate-to-vigorous physical activity, but 96% achieved sleep recommendations. Reallocating 30 minutes of sedentary time to light physical activity (LPA) was associated with 0.20 kg/m² (95% CI, 0.02 to 0.37) greater fat-free mass index. An equivalent inverse association was found when reallocating LPA to sedentary time. No associations were found for other movement behaviours.

CONCLUSIONS

Promoting LPA and reducing sedentary time may be an important strategy in reducing the elevated risk of obesity and metabolic syndrome amongst those born VLBW by supporting lean mass accretion. Funded by CIHR (FHG 129919) and SickKids Restracomp.

Obesity and Body Composition in Preschool Children with Different Levels of Actigraphy-Derived Physical Activity-A Cross-Sectional Study

Detailed associations between physical activity (PA) and body composition in preschoolers remain unclear. The aim of this study was to assess body composition among preschool children differentiated according to their levels of PA and to assess whether meeting the current PA recommendations is associated with a lower risk of obesity, determined by body mass index (BMI) and body fat percentage (BFP). Free-living PA was measured using accelerometers for 7 days in children aged 5 to 6 years. Bioelectrical impedance analysis was used to estimate body composition. Significant differences in content of BFP, fat-free mass (FFM), and total body water (TBW) were found between boys meeting and not meeting moderate-to-vigorous PA (MVPA) recommendations. Meeting the MVPA recommendation was associated with a twofold lower risk of obesity determined by BFP in boys but not in girls. In contrast, the total number of recommended steps per day was not related to adiposity in boys or girls. No statistically significant differences were observed in body composition indices and quintiles of MVPA. Boys in the 3rd–5th quintiles of steps per day presented significantly lower BFP and higher muscle mass and TBW than their peers in quintile 1. However, different associations were observed between body composition indices and quintiles of PA.

Heritability of objectively assessed and self-reported sedentary behavior

Understanding the sources of the large individual differences in sedentary behavior is of great importance as this behavior is associated with pre-mature mortality and non-communicable diseases. Here, we report on the contribution of genetic and environmental factors to the variation in objectively assessed (accelerometer) sedentary behavior and self-reported sitting and their shared genetic basis. In addition, the overlap of the genetic risk factors influencing sedentary time and moderate-to-vigorous physical activity (MVPA) was estimated. A sample of 800 individuals (twins and their siblings) was equipped with an Actigraph accelerometer for 7 days and reported on their sitting time and time spent on MVPA on those days using the IPAQ-SF. Genetic factors explained 56% (CI: 44%, 65%) of the individual differences in objective sedentary behavior (Actigraph) and 26% (CI: 0%, 51%) of the individual differences in self-reported sedentary behavior (IPAQ-SF). A modest correlation (0.33) was found between these measures, which was for 45% accounted for by genetic influences. The genetic correlation was 0.49 reflecting a partly overlapping set of genes that influenced both measurements. A modest correlation (-0.27) between Actigraph-derived sedentary time and MVPA was found, which was 13% accounted for by genetic effects. The genetic correlation was -0.31, indicating that there are overlapping genetic variants that increase sedentary time and decrease MVPA or vice versa. To conclude, more than half of the individual differences in objective sedentary time could be attributed to genetic differences, while for self-reported sitting this was much lower. In addition, using objective measurements, this study confirms that sedentary time is not simply the inverse of MVPA. Future studies are needed to understand the pathways translating genomic variation into variation in these behaviors and how this knowledge might feed into the development of health promotion interventions.

Correlates of sedentary time in young children: A systematic review

Background: Young children appear to spend large portions of their waking time being sedentary. Understanding the correlates of sedentary time would assist in developing effective interventions among young children. The purpose of this systematic review was to summarize the current literature on the correlates of objectively measured sedentary time in young children aged 1-5.99y. Methods: This review was registered with PROSPERO (registration no. CRD42017081374) and aligned with the PRISMA Statement for systematic reviews. Five electronic databases (MEDline, CINAHL Complete, PsycINFO, SportDiscus, Scopus) were searched up to October 26, 2017 for studies investigating correlates of sedentary time measured using objective devices. A semiquantitative approach was used to synthesize data. Results: Forty-five studies were retrieved comprising 13,430 participants, and 84 correlates of sedentary time in young children were evaluated. The associations between sex, sleep habits, daily patterns (childcare vs. non-childcare hours), childcare type and sedentary time were indeterminate. Thirty-nine correlates were consistently unrelated. Forty-one potential correlates were examined in too few studies (<4) to make confident conclusions. Parental sedentary behaviour was reported 3 times and maternal sedentary behaviour was reported once. Out of these four studies, three were positively associated with child sedentary time. Conclusions: Despite reviewing 45 studies that evaluated associations for 84 correlates, this review was unable to identify any consistent correlates of sedentary time in young children. Additional research is needed in this area to provide robust evidence of the correlates of sedentary time in young children, particularly for those examined in only a small number of studies.

Evening exercise is associated with lower odds of visual field progression in Chinese patients with primary open angle glaucoma

Background

Exercise is widely known to lower intraocular pressure and increase ocular blood flow, which may be beneficial for glaucoma management. However, there are few studies that have reported on the relationship between exercise and glaucoma progression. The aim of our study was to investigate the exercise habits of those with primary open angle glaucoma (POAG) and its association with the progression of visual field (VF) loss.

Methods

Daily physical activity (PA) was monitored by an accelerometer (ActiGraph wGT3x-BT) which patients wore for more than 10 h of being awake on their right wrists for 1 week.

Results

Seventy-one non-progressive and 27 progressive patients were enrolled in the study. 24-h moderate to vigorous physical activity (MVPA) exercise showed that POAG patients had similar variation trends consisting of 3 wave peaks and 2 wave hollows. Minutes spent in MVPA was 19.89 ± 15.81 and 21.62 ± 15.10 during 07:00–09:00 h (p = 0.204), 15.40 ± 14.49 and 15.67 ± 12.43 during 15:00–17:00 h (p = 0.822) and 17.26 ± 21.11 and 11.42 ± 11.58 during 18:00–20:00 h (p = 0.001) in the non-progressive and progressive group, respectively. Univariate analysis indicated that 10 min of MVPA (18:00–20:00 h) [odds ratio, OR (95% CI) = 0.82 (0.73, 0.92)], average mean arterial pressure [OR (95% CI) = 0.96 (0.94, 0.98)], age [OR (95% CI) = 1.06 (1.03, 1.08)], male [OR (95% CI) = 0.67 (0.48, 0.96)], spherical equivalent [OR (95% CI) = 1.14 (1.07, 1.22)] and IOP-lowering medications [OR (95% CI) = 1.54 (1.16, 2.05)] were significantly correlated with having progressive VF damage. Multivariable analysis showed that 10 min of MVPA (18:00–20:00 h) [OR (95% CI) = 0.85 (0.75, 0.97)] was associated with progressive VF loss even after adjusting for other risk factors.

Conclusions

Evening exercise may lower the odds of VF progression, suggesting that exercise habits possibly play an important role in glaucoma progression.

Unravelling the association between accelerometer-derived physical activity and adiposity among preschool children: A systematic review and meta-analyses

Evidence on the association between physical activity (PA) and adiposity in young children is inconclusive. A systematic review and meta-analyses were conducted to examine associations between accelerometer-derived PA and varying adiposity outcomes in preschool children. Searches were conducted in Embase, MEDLINE and Web of Science to identify studies on the association between total PA, sedentary behaviour or different PA intensities and adiposity in children aged 2 to 7 years. Separate random effects meta-analyses were performed for varying PA intensities and adiposity outcomes. Fifty-six articles were included in the review and 48 in the meta-analyses. There was substantial evidence of an inverse association between moderate-to-vigorous- or vigorous PA and body fat percentage (stdβ [SE] = -0.162[0.041]; 5 studies), weight status (r = -0.120, P<.001; 11 studies), fat mass (stdβ [SE] = -0.103[0.051]; 5 studies), fat mass index (stdβ [SE] = -0.121[0.036]; 2 studies) and skinfold thickness (stdβ [SE] = -0.145[0.036]; 4 studies). However, total PA, sedentary behaviour, and different PA intensities were not associated with body mass index (BMI) or waist circumference. Adiposity levels were lower among preschool children engaged in more (moderate-to-) vigorous PA compared with their peers, but no associations between PA and BMI or waist circumference were found.

Maternal and child factors associated with child body fatness in a Ghanaian cohort

OBJECTIVE

We aimed to identify factors (child diet, physical activity; maternal BMI) associated with body composition of Ghanaian pre-school children.

DESIGN

Longitudinal analysis of the International Lipid-Based Nutrient Supplements (iLiNS)-DYAD-Ghana randomized trial, which enrolled 1320 pregnant women at ≤20 weeks' gestation and followed them and their infants until 6 and 18 months postpartum, respectively. At follow-up, child age 4-6 years, we collected data on body composition (by 2H dilution), physical activity and diet, extracted dietary patterns using factor analysis, and examined the association of children's percentage body fat with maternal and child factors by regression analysis.

SETTING

Eastern Region, Ghana.

PARTICIPANTS

Children 4-6 years of age.

RESULTS

The analysis included 889 children with percentage body fat and dietary data at follow-up. We identified two major dietary patterns, a snacking and a cooked foods pattern. Percentage body fat was positively associated (standardized β (se)) with maternal BMI at follow-up (0·10 (0·03); P = 0·003) and negatively associated with physical activity (-0·15 (0·05); P = 0·003, unadjusted for child gender), but not associated with the snacking (0·06 (0·03); P = 0·103) or cooked foods (-0·05 (0·07); P = 0·474) pattern. Boys were more active than girls (1470 v. 1314 mean vector magnitude counts/min; P < 0·0001) and had lower percentage body fat (13·8 v. 16·9 %; P < 0·0001).

CONCLUSIONS

In this population, maternal overweight and child physical activity, especially among girls, may be key factors for addressing child overweight/obesity. We did not demonstrate a relationship between the dietary patterns and body fatness, which may be related to limitations of the dietary data available.

Associations between adolescents' preference for fitness activities and achieving the recommended weekly level of physical activity

This study aimed to explore differences in rates of achieving the weekly physical activity (PA) recommendation between adolescents who preferred fitness PA and those who did not. Furthermore, we investigated the types of PA practiced by adolescents. In total, 9513 participants from the Czech Republic and Poland, aged 15-18 years took part in the study between 2009 and 2016. Out of this source sample, 4977 self-reported their weekly PA using the IPAQ-Long Form, and 1348 objectively monitored their weekly PA using pedometers and recorded the type of PA. Boys ranked fitness PA third, after team and individual sports. For girls, the preference for fitness PA grew at the expense of dance and outdoor PA. Among Czech and Polish boys as well as Czech girls, those who preferred fitness PA were more likely to achieve the recommended weekly PA level than those who did not prefer fitness PA. We did not find a significant difference in other types of PA and rates of achieving the recommendation of 11,000 steps/day. Preference for fitness PA was associated with an increased likelihood (OR = 1.30; 95% CI = 1.12-1.52; p < 0.001) of achieving the recommendation for PA. When promoting adolescents' PA, it is necessary to consider preferred PA types. The PA recommendation was met by almost 33% of adolescents who indicated a preference for fitness PA, but only by 22% of those not preferring fitness activities. Organized PA is also important for meeting PA recommendations.

Association of physical activity with adiposity in preschoolers using different clinical adiposity measures: a cross-sectional study

BACKGROUND

More research is needed about the association between physical activity (PA), sedentary behaviour (SB), and adiposity in preschoolers, particularly using more direct clinical measures of adiposity. Therefore, the main objective of this study was to investigate the association between objectively measured PA and different clinical adiposity measures in a large sample of preschoolers.

METHODS

Four hundred sixty-three predominantly normal-weight (77%) 2-6-year-old preschool children participated in the Swiss Preschoolers' Health Study (SPLASHY). Physical activity was measured using accelerometers and was analyzed using 15-s (uni-axial) epoch length using validated cut-offs. Adiposity measures included body mass index (BMI), the sum of four skinfolds, and waist circumference (WC). Multilevel linear regression modeling, adjusted for age, sex and wear time, was used to assess the association between PA and SB with BMI, WC, and skinfold thickness.

RESULTS

Total PA and different PA intensities were positively and SB was inversely associated with BMI in the total sample and in the normal-weight children (p < 0.05). Total PA was inversely associated with skinfold thickness in overweight and obese children (p < 0.05), while there was only a weak association for vigorous PA (p > 0.05). Moderate and moderate-to-vigorous PA were positively, and SB was negatively associated with WC in the total sample and in the normal-weight children (p < 0.05). Additional adjustment for potential sociocultural and biological confounding variables attenuated some of the results.

CONCLUSIONS

In this very young and predominantly normal-weight population, PA is positively related to BMI and WC, but this relationship is not observed in overweight and obese children. In this latter population, PA is inversely, and SB is positively related to skinfold thickness. Skinfold thickness could represent a useful and simple clinical measure of body fat in preschoolers. The role of vigorous PA in the prevention of early childhood obesity should be further investigated in future studies.

TRIAL REGISTRATION

ISRCTN ISRCTN41045021 . Retrospectively registered 06 May 2014.

Are Preschoolers Meeting the Mark? Comparing the Dietary, Activity, and Sleep Behaviors of Preschoolers With Obesity to National Recommendations

Objective

National health organizations and expert committees have issued recommendations for health behaviors related to obesity risk. Behavioral and family-based weight management interventions for preschoolers often target improving adherence to these recommendations, but it is unknown how the health behaviors of preschoolers with obesity enrolled in weight control treatments (WCTs) compare with these guidelines. In this study, the dietary intake, activity, and sleep behaviors of preschoolers with obesity enrolled in a family-based behavioral WCT are described and compared with national health behavior recommendations.

Methods

Health behaviors of 151 preschoolers with obesity (M age = 4.60, SD = 0.93) enrolled in a clinical trial of a weight management program were measured at baseline through caregiver-report questionnaires, three 24-hr dietary recalls, and accelerometers.

Results

In total, 70% of the sample exceeded daily caloric recommendations, only 10 and 5% met recommendations for fruit and vegetable intake, respectively, and only 30% met the recommendation of consuming no sugar-sweetened beverages. The majority of the sample met the daily recommendations for 60 min of moderate-to-vigorous activity (80%), < 2 hr of screen time (68%), and sleep duration (70%).

Conclusions

Behavioral weight management interventions for preschoolers with obesity should target the health behaviors where children are not meeting recommendations.

Early life risk factors for childhood obesity-Does physical activity modify the associations? The MoBa cohort study

OBJECTIVES

High maternal pre-pregnancy body mass index (BMI), high birth weight, and rapid infant weight gain are associated with increased risk of childhood obesity. We examined whether moderate-to-vigorous physical activity (MVPA) or vigorous physical activity (VPA) in 9- to 12-year-olds modified the associations between these early life risk factors and subsequent body composition and BMI.

METHODS

We used data from a sub-cohort of the Norwegian Mother and Child Cohort Study (MoBa), including 445 children with available data on accelerometer assessed physical activity (PA). All participants had data on BMI, 186 of them provided data on body composition (dual energy X-ray absorptiometry (DXA)). We used multiple regression analyses to examine the modifying effect of PA by including interaction terms.

RESULTS

Maternal pre-pregnancy BMI and infant weight gain were more strongly related to childhood body composition in boys than in girls. Higher VPA attenuated the association between maternal pre-pregnancy BMI and BMI in boys (low VPA: B = 0.32, 95% CI = 0.22, 0.41; high VPA B = 0.22, 95% CI = 0.12, 0.31). Birth weight was unrelated to childhood body composition, and there was no effect modification by PA. PA attenuated the associations between infant weight gain and childhood fat mass (low MVPA: B = 2.32, 95% CI = 0.48, 4.17; high MVPA: B = 1.00, 95% CI = 0.10, 1.90) and percent fat (low MVPA: B = 3.35, 95% CI = 0.56, 6.14; high MVPA: B = 1.41, 95% CI = -0.06, 2.87) in boys, but not girls.

CONCLUSION

Findings from this study suggest that MVPA and VPA may attenuate the increased risk of an unfavorable body composition and BMI due to high maternal pre-pregnancy BMI and rapid infant weight gain in boys, but not in girls.

Physical fitness and physical activity of 6-7-year-old children according to weight status and sports participation

BACKGROUND

The aim of this study was to investigate physical fitness and physical activity (PA) of 6-7-year-old children just before entering school according to their sports club (SC) participation and weight status, and to examine possible associations of their body mass index, fat mass and fat-free mass with physical fitness and PA.

METHODS

A total of 256 preschoolers aged 6 to 7 years participated in the study. Physical fitness was assessed using PREFIT test battery and objective PA by 7 day accelerometry. Body composition was estimated using two skinfold thickness parameters. SC participation and parental data were assessed by questionnaires.

RESULTS

Children participating in SC had higher moderate-to-vigorous PA, vigorous PA and cardiorespiratory fitness than children not participating in SC. Overweight children had lower results in cardiorespiratory fitness and all weight-bearing fitness tests, and better results in handgrip strength test in comparison with normal weight children. Significant associations were found between body composition indices and physical fitness tests. PA level was associated with fat-free mass and physical fitness but not with fatness indices.

CONCLUSIONS

Weight-status and body composition together with PA level were associated with physical fitness level. The differences in physical fitness based more upon weight status than SC participation among 6-7-years old children.

Prevalence of objectively measured sedentary behavior in early years: Systematic review and meta-analysis

BACKGROUND

The early years have been identified as a critical period during which sedentary habits may be established, as this behavior appears to track throughout life.

OBJECTIVE

The purpose of this systematic review and meta-analysis is to summarize the current literature on the prevalence of sedentary behavior in children aged 1-5.99 years, reporting differences between boys and girls, weekdays and weekend days, childcare hours and nonchildcare hours, and between time spent indoors and outdoors while children attended childcare.

METHODS

Five databases were searched until 26.10.2017 and meta-analyses were conducted to estimate prevalence and calculate mean differences in prevalence between groups.

RESULTS

Fifty studies representing 14 598 children (2-5.99 years) were included. Children spent 51.4% of their waking time in sedentary behaviors. Boys spent less time being sedentary than girls (estimate difference = -1.4%; 95%CI = -2.0: -0.7; P < .001). No significant differences were found between weekdays/weekend days (estimate difference = -0.4; 95%CI = -2.0: 1.2; P = .61) nor between childcare hours/nonchildcare hours (estimate difference = %; 95%CI = -0.9: 6.6; P = .136). While attending childcare centers, children were more sedentary indoors than outdoors (estimate difference = 14.4%; 95%CI = 11.8: 16.9; P < .001).

CONCLUSIONS

Our results suggest that young children spend a significant portion of their waking hours in sedentary behaviors. While at childcare, young children accumulated more sedentary behavior indoors than outdoors. Girls were more likely to be more sedentary than boys. No significant differences were found between weekdays and weekends, or between childcare and nonchildcare hours. There is a need for higher-quality studies with strong designs, using age and device appropriate cut-off points, to improve evidence-base and to better establish prevalence of sedentary behavior in young children.

Association of diet in nurseries and physical activity with zBMI in 2-4-year olds in England: a cross-sectional study

BACKGROUND

Childhood obesity tracks into adulthood with detrimental effects on health. We aimed to examine the relationships of diet in childcare settings and daily physical activity (PA) of preschoolers with body mass index z-score (z-BMI).

METHODS

We conducted a cross-sectional study of 150 children aged 2-4-years participating in the Nutrition and Physical Activity Self-Assessment for Child Care (NAP SACC) UK study to examine the associations of their diet in childcare settings and daily PA with z-BMI. Dietary intake was observed and recorded by fieldworkers using a validated tick-list food questionnaire and diet quality was assessed based on adherence to Children's Food Trust (CFT) guidelines. PA was measured using accelerometers. We derived z-BMI scores using the UK 1990 and International Obesity Taskforce growth reference charts. Multilevel regression models were used to estimate associations between diet and PA with z-BMI separately, adjusted for age, gender, ethnicity, parental education level and clustering.

RESULTS

Among children who consumed one main meal or snack at childcare, 34.4% and 74.3% met the standards on fruits and vegetables and high sugar or fat snacks, respectively. Adherence to CFT guidelines was not associated with zBMI. Only 11.4% of children met recommended UK guidelines of three hours per day of physical activity. Minutes spent in light PA (β = 0.08, 95% CI = 0.01, 0.15) and active time (β = 0.07, 95% CI = 0.01, 0.12) were positively associated with UK 1990 zBMI scores.

CONCLUSIONS

The low proportion of children meeting the standards on fruits and vegetables and high sugar or fat snacks and recommended physical activity levels highlight the need for more work to support nurseries and parents to improve preschool children's diet and activity. In our exploratory analyses, we found children with higher zBMI were more physically active which could be attributed to fat-free mass or chance finding and so requires replication in a larger study.

TRIAL REGISTRATION

ISRCTN16287377 . Registered 12 June 2014.

Childcare Correlates of Physical Activity, Sedentary Behavior, and Adiposity in Preschool Children: A Cross-Sectional Analysis of the SPLASHY Study

Background

The childcare (CC) environment can influence young children's physical activity (PA), sedentary behavior (SB), and adiposity. The aim of the study was to identify a broad range of CC correlates of PA, SB, and adiposity in a large sample of preschoolers.

Methods

476 preschool children (mean age 3.9 yrs; 47% girls) participated in the Swiss Preschoolers' Health Study (SPLASHY). PA and SB were measured by accelerometry. Outcome measures included total PA (TPA), moderate-to-vigorous PA (MVPA), SB, body mass index (BMI), and skinfold thickness (SF). PA measures consisted of both daily PA during CC attendance days and overall daily PA (CC and non-CC days).

Results

We identified the following CC correlates for higher TPA and/or higher MVPA or lower SB during CC attendance days: older age, sex (boys), more frequent child-initiated interactions during CC, mixing different ages within a group, and the presence of a written PA policy in the CC (all p ≤ 0.02). The CC correlates for overall TPA and/or MVPA or lower overall SB including both CC and non-CC days were the following: older age, sex (boys), more frequent child-initiated interactions during CC, mixing different ages within a group, less parental PA involvement in the CC, and having a larger surface area in CC (all p ≤ 0.046). Correlates for lower SF were sex (boys) and parental PA involvement in the CC (all p ≤ 0.02), and, for lower BMI, only increased age (p=0.001) was a correlate.

Conclusions

More frequent child-initiated interactions and mixing different ages in CC, the presence of a written PA policy, and a larger CC surface are correlates of PA and SB during CC attendance days and/or of overall PA. Parental involvement in CC PA projects was a correlate for reduced body fat. These novel factors are mostly modifiable and can be tackled/addressed in future interventions.

Associations of TV Viewing Duration, Meals and Snacks Eaten When Watching TV, and a TV in the Bedroom with Child Adiposity

OBJECTIVE

This study aimed to examine the associations of TV parameters with adiposity in early life.

METHODS

Data were collected as part of the Born in Bradford (BiB) longitudinal birth cohort study. Child TV viewing duration was parent reported, and BMI, the sum of triceps and subscapular skinfolds, and waist circumference were measured at ~12, 18, 24, and 36 months of age in 1,338 children. Mixed effects models were used to quantify adjusted associations of TV viewing duration with adiposity markers, incorporating data from all time points. Linear regression was used to investigate differences in adiposity levels across frequencies of eating meals and snacks while watching TV at age ~24 months and between children who did and did not have a TV in their bedroom at age ~36 months.

RESULTS

Every 1 h/d of TV viewing was associated with a 0.075-cm larger (95% CI: 0.0034-0.15) waist circumference, independent of covariates including sleep duration, dietary factors, and physical activity level. There was no evidence for any other associations.

CONCLUSIONS

TV viewing duration is independently associated with abdominal adiposity in young children. Limiting TV viewing from an early age may be important for primary prevention of obesity.

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.

Prevention of overweight and obesity in early life

Childhood obesity is a serious challenge for public health. The problem begins early with most excess childhood weight gained before starting school. In 2016, the WHO estimated that 41 million children under 5 were overweight or obese. Once established, obesity is difficult to reverse, likely to persist into adult life and is associated with increased risk of CVD, type 2 diabetes and certain cancers. Preventing obesity is therefore of high importance. However, its development is multi-factorial and prevention is a complex challenge. Modifiable lifestyle behaviours such as diet and physical activity are the most well-known determinants of obesity. More recently, early-life factors have emerged as key influencers of obesity in childhood. Understanding risk factors and how they interact is important to inform interventions that aim to prevent obesity in early childhood. Available evidence supports multi-component interventions as effective in obesity prevention. However, relatively few interventions are available in the UK and only one, TrimTots, has been evaluated in randomised controlled trials and shown to be effective at reducing obesity risk in preschool children (age 1-5 years). BMI was lower in children immediately after completing TrimTots compared with waiting list controls and this effect was sustained at long-term follow-up, 2 years after completion. Developing and evaluating complex interventions for obesity prevention is a challenge for clinicians and researchers. In addition, parents encounter barriers engaging with interventions. This review considers early-life risk factors for obesity, highlights evidence for preventative interventions and discusses barriers and facilitators to their success.

Longitudinal Physical Activity, Body Composition, and Physical Fitness in Preschoolers

PURPOSE

This study aimed to investigate longitudinal associations of objectively measured physical activity (PA) and sedentary behavior (SB) with body composition and physical fitness at a 12-month follow-up in healthy Swedish 4-yr-old children.

METHODS

The data from the population-based MINISTOP trial were collected between 2014 and 2016, and this study included the 138 children who were in the control group. PA and SB were assessed using the wrist-worn ActiGraph (wGT3x-BT) accelerometer during seven 24-h periods and, subsequently, defined as SB, light-intensity PA, moderate-intensity PA, vigorous-intensity PA (VPA), and moderate-to-vigorous PA (MVPA). Body composition was measured using air-displacement plethysmography and physical fitness (cardiorespiratory fitness, lower and upper muscular strength as well as motor fitness) by the PREFIT fitness battery. Linear regression and isotemporal substitution models were applied.

RESULTS

Greater VPA and MVPA at the age of 4.5 yr were associated with higher fat-free mass index (FFMI) at 5.5 yr (P < 0.001 and P = 0.044, respectively). Furthermore, greater VPA and MVPA at the age of 4.5 yr were associated with higher scores for cardiorespiratory fitness, lower body muscular strength, and motor fitness at 12-month follow-up (P = 0.001 to P = 0.031). Substituting 5 min·d of SB, light-intensity PA, or moderate-intensity PA for VPA at the age of 4.5 yr were associated with higher FFMI, and with greater upper and lower muscular strength at 12-month follow-up (P < 0.001 to P = 0.046).

CONCLUSION

Higher VPA and MVPA at the age of 4.5 yr were significantly associated with higher FFMI and better physical fitness at 12-month follow-up. Our results indicate that promoting high-intensity PA at young ages may have long-term beneficial effects on childhood body composition and physical fitness, in particular muscular strength.

Daily Patterns of Preschoolers' Objectively Measured Step Counts in Six European Countries: Cross-Sectional Results from the ToyBox-Study

This study is part of the ToyBox-study, which is conducted in six European countries (Belgium, Bulgaria, Germany, Greece, Poland and Spain), aiming to develop a cost-effective kindergarten-based, family-involved intervention to prevent overweight and obesity in four- to six-year-old preschool children. In the current study, we aimed to examine and compare preschoolers' step count patterns, across the six European countries. A sample of 3578 preschoolers (mean age: 4.8 ± 0.4) was included. Multilevel analyses were performed to take clustering of measurements into account. Based on the average hourly steps, step count patterns for the six European countries were created for weekdays and weekend days. The step count patterns during weekdays were related to the daily kindergarten schedules. Step count patterns during weekdays showed several significant peaks and troughs (p < 0.01) and clearly reflected the kindergartens' daily schedules, except for Germany. For example, low numbers of steps were observed during afternoon naptimes and high numbers of steps during recess. In Germany, step count patterns did not show clear peaks and troughs, which can be explained by a less structured kindergarten schedule. On weekend days, differences in step count patterns were observed in the absolute number of steps in the afternoon trough and the period in which the evening peak occurred. Differences in step count patterns across the countries can be explained by differences in (school) policy, lifestyle habits, and culture. Therefore, it might be important to respond to these step count patterns and more specifically to tackle the inactive periods during interventions to promote physical activity in preschoolers.

A cross-sectional and prospective analyse of reallocating sedentary time to physical activity on children's cardiorespiratory fitness

Cardiorespiratory fitness (CRF) is associated with health benefits in children, improving cardiac morphology, cardiovascular disease risk factors, and biological outcomes. This study aimed to examine the substitution effects of displaying a fixed duration of sedentary time with a fixed duration of physical activity (PA) at different intensities on children's CRF. A total of 315 children (136 boys) were assessed (age: 10.6 ± 0.6 years old). Outcomes at baseline and follow-up (16-months) were CRF determined using a maximal cycle test and sedentary time and PA measured with accelerometers. Data were analysed by isotemporal substitution analyses estimating the effect of reallocating 30 min/day of sedentary time by light (LPA), moderate (MPA) and vigorous physical activity (VPA) on CRF. VPA was positively and significantly associated with CRF cross-sectional (β = 0.026, p < 0.001) and prospectively (β = 0.010, p < 0.001). Reallocating 30 min/day of sedentary time into VPA was positively cross-sectionally (β = 0.780, p < 0.001) and prospectively (β = 0.303, p < 0.05) associated with CRF. Conversely, relocating 30-minutes of sedentary time into 30 minutes of LPA and MPA was not associated with CRF. These results suggest that reallocating an equal amount of time from sedentary into VPA is cross-sectional and prospectively associated with a favourable CRF.

Systematic review of the relationships between sedentary behaviour and health indicators in the early years (0-4 years)

Background

The purpose of this systematic review was to examine the relationships between sedentary behaviour (SB) and health indicators in children aged 0 to 4 years, and to determine what doses of SB (i.e., duration, patterns [frequency, interruptions], and type) were associated with health indicators.

Methods

Online databases were searched for peer-reviewed studies that met the a priori inclusion criteria: population (apparently healthy, 1 month to 4.99 years), intervention/exposure and comparator (durations, patterns, and types of SB), and outcome/health indicator (critical: adiposity, motor development, psychosocial health, cognitive development; important: bone and skeletal health, cardiometabolic health, fitness, risks/harm). The quality of the evidence was assessed by study design and outcome using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework.

Results

Due to heterogeneity, meta-analyses were not possible; instead, narrative syntheses were conducted, structured around the health indicator and type of SB. A total of 96 studies were included (195,430 participants from 33 countries). Study designs were: randomized controlled trial (n = 1), case-control (n = 3), longitudinal (n = 25), longitudinal with additional cross-sectional analyses (n = 5), and cross-sectional (n = 62). Evidence quality ranged from “very low” to “moderate”. Associations between objectively measured total sedentary time and indicators of adiposity and motor development were predominantly null. Associations between screen time and indicators of adiposity, motor or cognitive development, and psychosocial health were primarily unfavourable or null. Associations between reading/storytelling and indicators of cognitive development were favourable or null. Associations between time spent seated (e.g., in car seats or strollers) or in the supine position, and indicators of adiposity and motor development, were primarily unfavourable or null. Data were scarce for other outcomes.

Conclusions

These findings continue to support the importance of minimizing screen time for disease prevention and health promotion in the early years, but also highlight the potential cognitive benefits of interactive non-screen-based sedentary behaviours such as reading and storytelling. Additional high-quality research using valid and reliable measures is needed to more definitively establish the relationships between durations, patterns, and types of SB and health indicators, and to provide insight into the appropriate dose of SB for optimal health in the early years.

Electronic supplementary material

The online version of this article (10.1186/s12889-017-4849-8) contains supplementary material, which is available to authorized users.

Systematic review of the relationships between physical activity and health indicators in the early years (0-4 years)

Background

Given the rapid development during the early years (0-4 years), an understanding of the health implications of physical activity is needed. The purpose of this systematic review was to examine the relationships between objectively and subjectively measured physical activity and health indicators in the early years.

Methods

Electronic databases were originally searched in April, 2016. Included studies needed to be peer-reviewed, written in English or French, and meet a priori study criteria. The population was apparently healthy children aged 1 month to 59.99 months/4.99 years. The intervention/exposure was objectively and subjectively measured physical activity. The comparator was various volumes, durations, frequencies, patterns, types, and intensities of physical activity. The outcomes were health indicators ranked as critical (adiposity, motor development, psychosocial health, cognitive development, fitness) and important (bone and skeletal health, cardiometabolic health, and risks/harm). The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) framework was used to assess the quality of evidence for each health indicator by each study design.

Results

Ninety-six studies representing 71,291 unique participants from 36 countries were included. Physical activity interventions were consistently (>60% of studies) associated with improved motor and cognitive development, and psychosocial and cardiometabolic health. Across observational studies, physical activity was consistently associated with favourable motor development, fitness, and bone and skeletal health. For intensity, light- and moderate-intensity physical activity were not consistently associated with any health indicators, whereas moderate- to vigorous-intensity, vigorous-intensity, and total physical activity were consistently favourably associated with multiple health indicators. Across study designs, consistent favourable associations with health indicators were observed for a variety of types of physical activity, including active play, aerobic, dance, prone position (infants; ≤1 year), and structured/organized. Apart from ≥30 min/day of the prone position for infants, the most favourable frequency and duration of physical activity was unclear. However, more physical activity appeared better for health. Evidence ranged from “very low” to “high” quality.

Conclusions

Specific types of physical activity, total physical activity, and physical activity of at least moderate- to vigorous-intensity were consistently favourably associated with multiple health indicators. The majority of evidence was in preschool-aged children (3-4 years). Findings will inform evidence-based guidelines.

Electronic supplementary material

The online version of this article (10.1186/s12889-017-4860-0) contains supplementary material, which is available to authorized users.

Transforming Growth Factor β/Activin signaling in neurons increases susceptibility to starvation

Animals rely on complex signaling network to mobilize its energy stores during starvation. We have previously shown that the sugar-responsive TGFβ/Activin pathway, activated through the TGFβ ligand Dawdle, plays a central role in shaping the post-prandial digestive competence in the Drosophila midgut. Nevertheless, little is known about the TGFβ/Activin signaling in sugar metabolism beyond the midgut. Here, we address the importance of Dawdle (Daw) after carbohydrate ingestion. We found that Daw expression is coupled to dietary glucose through the evolutionarily conserved Mio-Mlx transcriptional complex. In addition, Daw activates the TGFβ/Activin signaling in neuronal populations to regulate triglyceride and glycogen catabolism and energy homeostasis. Loss of those neurons depleted metabolic reserves and rendered flies susceptible to starvation.

Physical Activity, Sedentary Time, and Fatness in a Biethnic Sample of Young Children

PURPOSE

This study aimed to investigate associations of objectively measured physical activity (PA) and sedentary time with adiposity in a predominantly biethnic (South Asian and White British) sample of young children.

METHODS

The sample included 333 children age 11 months to 5 yr who provided 526 cross-sectional observations for PA and body composition. Total PA volume (vector magnitude counts per minute), daily time at multiple intensity levels (the cumulative time in activity >500, >1000, >1500, …, >6000 counts per minute), and time spent sedentary (<820 counts per minute), in light PA (820-3907 counts per minute) and in moderate-to-vigorous PA (≥3908 counts per minute) were estimated with triaxial accelerometry. Indicators of adiposity included body mass index, waist circumference, and the sum of subscapular and triceps skinfold thicknesses. Statistical analyses were performed using multilevel regression and isotemporal substitution models adjusted for confounders. Effect modification by ethnicity was examined.

RESULTS

There was no evidence for effect modification by ethnicity (P interaction ≥ 0.13). In the whole sample, the accumulated time spent above 3500 counts per minute (i.e., high light-intensity PA) was inversely associated with the sum of skinfolds (β = -0.60 mm, 95% confidence interval [CI] = -1.19 to -0.021, per 20 min·d), and the magnitude of association increased dose dependently with PA intensity (peaking for time spent >6000 counts per minute = -1.57 mm, 95% CI = -3.01 to -0.12, per 20 min·d). The substitution of 20 min·d of sedentary time with moderate-to-vigorous PA was associated with a lower sum of skinfolds (-0.77 mm, 95% CI = -1.46 to -0.084).

CONCLUSIONS

High light-intensity PA appears to be beneficial for body composition in young South Asian and White British children, but higher-intensity PA is more advantageous.

Objectively measured physical activity patterns, sedentary time and parent-reported screen-time across the day in four-year-old Swedish children

Background

Physical activity (PA) improves health outcomes accumulating evidence suggests that sedentary time (ST), especially parent-reported screen-time, is associated with negative health outcomes in children. The aim of the present study is to describe levels and patterns of PA and ST across the day and week and activity pattern differences between the sexes, across all weekdays and time spent in and outside the preschool in four-year old children.

Methods

In total 899 four-year old Swedish children who had both complete questionnaire data on screen-time behaviors and objective activity variables and at least 4 days, including one weekend day, with more than 10 h of GT3X+ Actigraph accelerometer wear time data were included in the study. Patterns of PA and ST across the day and week and differences between sexes, weekdays vs. weekend days and time in preschool vs. time spent outside preschool were assessed.

Results

Children engaged in 150 min (SD 73) and 102 min (SD 60) of screen-time on weekend days and weekdays, with 97% and 86% of children exceeding the 1 h guideline for screen-time on weekend days and weekdays, respectively. Accelerometer data showed that boys are more active and less sedentary compared with girls and both sexes were more active and less sedentary on weekdays compared with weekend days, while parent-reported data showed that boys engage in more screen-time compared with girls. Children accumulated 24.8 min (SD. 19) MVPA during preschool time and 26.6 min (SD. 16) outside preschool hours on weekdays, compared with 22.4 min (SD. 18) MVPA during preschool time and 25.3 min (SD. 22) outside preschool hours on weekend days.

Conclusions

Four-year old Swedish children display different activity patterns across the day on weekdays compared to weekend days, with preschool hours during weekdays being the most active segments and preschool hours during weekend days being the least active segments of the day.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-017-4600-5) contains supplementary material, which is available to authorized users.

Evaluation of the wrist-worn ActiGraph wGT3x-BT for estimating activity energy expenditure in preschool children

BACKGROUND/OBJECTIVES

Easy-to-use and accurate methods to assess free-living activity energy expenditure (AEE) in preschool children are required. The aims of this study in healthy preschool children were to (a) evaluate the ability of the wrist-worn ActiGraph wGT3x-BT to predict free-living AEE and (b) assess wear compliance using a 7-day, 24-h protocol.

SUBJECTS/METHODS

Participants were 40 Swedish children (5.5±0.2 years) in the Mobile-based intervention intended to stop obesity in preschoolers (MINISTOP) obesity prevention trial. Total energy expenditure (TEE) was assessed using the doubly labeled water method during 14 days. AEE was calculated as (TEEx0.9) minus predicted basal metabolic rate. The ActiGraph accelerometer was worn on the wrist for 7 days and outputs used were mean of the daily and awake filtered vector magnitude (mean VM total and mean VM waking).

RESULTS

The ActiGraph was worn for 7 (n=34, 85%), 6 (n=4, 10%), 5 (n=1, 2.5%) and 4 (n=1, 2.5%) days (a valid day was ⩾600 awake minutes). Alone, mean VM total and mean VM waking were able to explain 14% (P=0.009) and 24% (P=0.001) of the variation in AEE, respectively. By incorporating fat and fat-free mass in the models 58% (mean VM total) and 62% (mean VM waking) in the variation of AEE was explained (P<0.001).

CONCLUSIONS

The wrist-worn ActiGraph wGT3x-BT in combination with body composition variables explained up to the 62% of the variation in AEE. Given the high wear compliance, the wrist-worn ActiGraph has the potential to provide useful information in studies where physical activity in preschool children is measured.

Associations of Parental Self-Efficacy With Diet, Physical Activity, Body Composition, and Cardiorespiratory Fitness in Swedish Preschoolers: Results From the MINISTOP Trial

BACKGROUND

High parental self-efficacy (PSE) has been associated with healthy diets and higher levels of physical activity (PA) in children; however, data on PSE in relation to body weight and body composition are scarce. The objective of this study was to investigate associations of PSE with measures of diet, PA, body composition, and physical fitness in early childhood.

METHOD

We used baseline data from the MINISTOP trial in healthy Swedish children ( n = 301; 4.5 ± 0.15 years). PSE was assessed using a questionnaire, dietary data were collected using a mobile technology-assisted methodology, and PA was obtained (sedentary behavior and moderate-to-vigorous) by accelerometry. Body composition was measured using the pediatric option for BodPod and cardiorespiratory fitness by the 20 m shuttle run. Linear regression was conducted to evaluate cross-sectional associations of the outcomes in relation to total PSE and scores computed for the individual PSE factors: (1) diet, (2) limit setting of unhealthful behaviors, and (3) PA.

RESULTS

Higher scores of total PSE and the diet factor were associated with higher fruit intake (β = 0.82 g/point and 1.99 g/point; p = .014 and .009, respectively) and lower consumption of unhealthy snacks (β = -0.42 g/point and -0.89 g/point; p = .012 and .020, respectively) after adjustment for parental body mass index and education, respondent, and child's sex and age. No associations were observed between PSE and PA, body composition, or cardiorespiratory fitness.

CONCLUSIONS

Our study noted that PSE should be considered in conjunction with other strategies for a sustainable impact on childhood obesity.