Time spent in sedentary behavior and changes in childhood BMI: a longitudinal study from ages 9 to 15 years

Gender diversity among adolescents with obesity in a weight management programme

Gender dysphoria (GD) and obesity share commonalities, including associations with mental health comorbidities, disordered eating, body dissatisfaction and may intensify with physical and developmental changes during adolescence. While associations of obesity and gender diversity have been identified, rates of gender diversity among adolescents with obesity remain unclear. The aim was to examine gender diversity among adolescents with obesity in a weight management programme. A single-centre cross-sectional questionnaire study was conducted. Eligible adolescents received the Gender Identity/GD Questionnaire for Adolescents and Adults (GIDYQ-AA), a validated instrument measuring gender diversity and GD. Gender identities, sexual orientations, questionnaire scores, and frequency of GD (GIDYQ-AA score <3) were determined. The relationship of GIDYQ-AA scores and BMI Z-score (BMIz) was assessed. Of 72 consenting youth, 29 assigned females (AF) and 17 assigned males (AM) completed GIDYQ-AA and demographic questions. Seventeen (59%) AF reported non-heterosexual orientations, and 6 (21%) reported non-cisgender identities. One (6%) AM reported non-cisgender identity. Two (4%) AF individuals had GD based on GIDYQ-AA scores. GIDYQ-AA scores did not correlate with BMIz. In conclusion, adolescents with obesity, particularly AF with non-heterosexual orientation, reported high rates of non-cisgender identity and GD. Routine screening for gender-related concerns in weight management settings may be warranted.

The association between device-measured sitting time and cardiometabolic health risk factors in children

BACKGROUND

There is limited evidence of the associations between postural-derived sitting time, waist-worn derived sedentary time and children's health and the moderation effect of physical activity (PA). This study examined associations of children's device-measured sitting time with cardiometabolic health risk factors, including moderation by physical activity.

METHODS

Cross-sectional baseline data from children (mean-age 8.2 ± 0.5 years) in Melbourne, Australia (2010) participating in the TransformUs program were used. Children simultaneously wore an activPAL to assess sitting time and an ActiGraph GT3X to assess sedentary time and physical activity intensity. Cardiometabolic health risk factors included: adiposity (body mass index [BMI], waist circumference [WC]), systolic and diastolic blood pressure (SBP, DBP), high-density lipoprotein (HDL), low-density lipoprotein (LDL), cholesterol, triglycerides, fasting plasma glucose (FPG), serum insulin, and 25-hydroxyvitaminD (25[OH]D). Linear regression models (n = 71-113) assessed associations between sitting time with each health risk factor, adjusted for different PA intensities (i.e. light [LIPA], moderate-vigorous intensities [MVPA], separately on each model), age, sex, adiposity, and clustering by school. Interaction terms examined moderation. The analyses were repeated using device-measured sedentary time (i.e. ActiGraph GT3X) for comparison.

RESULTS

Sitting time was positively associated with SBP (b = 0.015; 95%CI: 0.004, 0.026), DBP (b = 0.012; 95%CI:0.004, 0.020), and FPG (b = 0.001; 95%CI: 0.000, 0.000), after adjusting for higher PA intensities. The association between sitting time and insulin (b = 0.003; 95%CI: 0.000, 0.006) was attenuated after adjusting for higher PA intensities. When the models were adjusted for LIPA and MVPA, there was a negative association with LDL (b=-0.001; 95%CI: -0.002, -0.000 and b=-0.001; 95%CI: -0.003, -0.000, respectively). There was a negative association of sedentary time with WCz (b=-0.003; 95%CI: -0.005, 0.000) and BMIz (b=-0.003; 95%CI: -0.006, -0.000) when the models were adjusted by MVPA. Sedentary time was positively associated with triglycerides (b = 0.001; 95%CI: 0.000, 0.001) but attenuated after adjusting for MVPA. No evidence of moderation effects was found.

CONCLUSIONS

Higher volumes of sitting and sedentary time were associated with some adverse associations on some cardiometabolic health risk factors in children. These associations were more evident when sitting time was the predictor. This suggests that reducing time spent sitting may benefit some cardiometabolic health outcomes, but future experimental research is needed to confirm causal relationships and identify the biological mechanisms that might be involved.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry: ACTRN12609000715279.

A school-based physical activity intervention in primary school: effects on physical activity, sleep, aerobic fitness, and motor competence

Objective

The "Super Quinas" project evaluated the effectiveness of an intervention program to improve physical activity, aerobic fitness, sleep, and motor competence on children in primary school.

Methods

The experimental group (n = 19) enrolled in a 12-week intervention program (one more extra-curricular activity class of 60 min per week) compared to the CG (n = 19), all aged 9-10 years. Physical activity (PA) and sleep were measured by accelerometry, and aerobic fitness was measured by Children's Yo-Yo test (YYIR1C) during the 1st week (PRE), the 6th week (DUR), and the 12th week (POST) of the intervention program. Motor Competence in PRE and POST intervention was also assessed by the Motor Competence Assessment (MCA) instrument. Heart rate (HR, assessed using HR monitors), and enjoyment level were recorded during all intervention program classes. A linear mixed model analysis (i.e., within-subject analyses) was performed.

Results

Comparing the EG and CG in DUR and POST, the EG spent ~18 min and ~ 34 min more time in moderate to vigorous physical activity (MVPA) per day (p < 0.001); had ~44 min and ~ 203 min less sedentary time per day (p < 0.001); performed more 44 and 128 m in the Children's Yo-Yo test compared to CG (p < 0.001) and slept more 17 and 114 min per night (p < 0.001). In POST motor competence was significantly better (27%) in the EG compared to CG (p < 0.001). The %HRmax during the extra-curricular classes ranged between 65 and 81% (i.e., light to moderate intensities), and the enjoyment between fun and great fun.

Conclusion

Our findings suggest that adding one more extra-curricular activity class of 60 min per week for 12 weeks effectively increased the levels of physical activity, aerobic fitness, sleep duration, and motor competence in children aged 9-10 years.

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

BACKGROUND/OBJECTIVES

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

SUBJECTS/METHODS

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

RESULTS

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

CONCLUSIONS

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

A natural experiment to assess recess frequency on children's physical activity in Arizona (U.S.) elementary schools

BACKGROUND

In the United States, the number of state policies mandating recess in schools has rapidly increased over the past decade; however, few policies specify recess frequency. Informed by an ecological model of physical activity (PA) policy, this study examined and compared total amounts and intensity of PA expended during recess among children attending schools in compliance with Arizona recess policy ARS§ 15-118 mandating 2 + daily recess periods versus not.

METHODS

PA during recess was measured among grade three children (ages 8-10) in four randomly selected elementary schools (two complying averaging 30 daily recess minutes; two non-complying averaging 15 daily recess minutes) in Maricopa County, Arizona. Group-level PA was assessed by direct observation using the System for Observing Play and Leisure (137 observations). A subset of students (N = 134) from all schools wore ActiGraph GT3X + devices during recess to measure individual PA. General linear mixed effects models were used to analyze the impact of recess frequency on group and individual PA during recess.

RESULTS

Students attending complying schools spent significantly greater proportions of time in moderate-to-vigorous PA (MVPA) based on direct observation (5%) and accelerometry (15%) and less time being sedentary based on accelerometry (14%) during recess. Across the school day, this would equate to 5.1 more MVPA minutes based on systematic direct observation and 9.5 more MVPA minutes based on accelerometry, and 4.1 less minutes being sedentary based on accelerometry if students received two daily 15-minute recess periods compared to one.

CONCLUSIONS

Students attending elementary schools implementing 2 + recesses, in accordance with state policy, demonstrated greater MVPA and less sedentary time, providing preliminary evidence that recess frequency is associated with greater PA intensity among children during recess. Schools that adhere to state-level PA policies may provide a more supportive environment for PA, resulting in increased movement among students. Specifying recess frequency should be considered in statewide recess policy.

Adolescent sedentary behavior and body composition in early adulthood: results from a cohort study

BACKGROUND

This study investigates the cross-sectional and prospective associations between accelerometer-measured sedentary behavior and body composition from adolescence to early adulthood.

METHODS

Data from the Santiago Longitudinal Study were analyzed (n = 212). Sedentary time was measured at age 16 years, and body composition (body mass index [BMI], waist circumference, waist-to-height ratio [WHtR], fat mass percentage, and lean mass percentage) was examined at both age 16 and 23 years. Adjusted linear regression models estimated associations between sedentary time, sedentary bout duration, and body composition, overall and by sex.

RESULTS

In all analyses, mean sedentary bout duration was not associated with body composition. In cross-sectional analyses, more sedentary time during adolescence was significantly associated with lower BMI, waist circumference, WHtR, fat mass percentage, and higher lean mass percentage (p < 0.05). One standard deviation increase in daily sedentary time was prospectively associated with lower body mass index (β = -1.22 kg/m2, 95% CI: -2.02, -0.42), waist circumference (β = -2.39 cm, 95% CI: -4.03, -0.75), and WHtR (β = -0.014, 95% CI: -0.024, -0.004). Sedentary time at 16 years was not associated with changes in body composition from 16 to 23 years.

CONCLUSIONS

Sedentary behavior in adolescence is not adversely associated with body composition profiles in early adulthood.

IMPACT

Little is known about the effect of device-measured sedentary behavior on body composition during the transition from adolescence to early adulthood. Among participants in the Santiago Longitudinal Study, more accelerometer-measured sedentary time during adolescence was associated with lower BMI, waist circumference, and waist-to-height ratio in early adulthood though point estimates were generally small in magnitude. Sedentary behavior in adolescence was not detrimentally associated with healthy body composition profiles in early adulthood. Public health interventions aimed at reducing obesity rates could consider other behaviors, such as physical activity and healthy diet, instead of sitting time.

Do Weightbearing Restrictions Cause Excess Weight Gain in Children With LEGG-Calvé-Perthes Disease?

BACKGROUND

Restricted weight bearing is commonly prescribed in Legg-Calvé-Perthes Disease (LCPD), raising concerns of causing overweight or obesity. This study utilizes prospectively collected data to address the following questions: (1) does body mass index (BMI) Z-score increase over the course of LCPD follow-up; (2) is having a BMI category of normal, overweight, or obese at baseline associated with BMI Z-score changes over the course of follow-up; and (3) is the duration of weight bearing restrictions (no restrictions, <3, 3 to <6, 6 to 9, or >9 mo) associated with BMI Z-score changes.

METHODS

Data of 130 children aged 5 to 12 years with unilateral early-stage LCPD were extracted from an international database. Nation-specific BMI Z-scores and percentile-based weight categories were determined, and the duration of follow-up and weight bearing restrictions were calculated. Longitudinal changes in BMI Z-scores were evaluated for the 3 study questions using mixed effects linear regression models with surgery as a covariate. Sensitivity analyses were used to determine the influence of socio-cultural background (USA vs. India) for each study question.

RESULTS

During the 35.5±15.9 months of follow-up, no statistically significant increase in BMI Z-scores was observed across the entire cohort, or following stratification by baseline weight categories or the duration of the weight bearing restriction. Sensitivity analyses indicated that patients in the USA had no change in their BMI Z-score. When stratified by weight categories, the normal weight of US children had a small increase in their BMI Z-score (0.005 per mo, 95% confidence interval: 0.0002, 0.009), but this was not seen in other BMI categories. The cohort of Indian children had a small but significant decrease in their BMI Z-score (-0.005/mo, 95% CI: -0.009, -0.0002). After stratification by weight categories, a small decrease of the BMI Z-score was observed only in the Indian overweight children (-0.016 per mo, 95% CI: -0.027, -0.005) and no other BMI category.

CONCLUSIONS

Weightbearing restrictions over the course of follow-up for our cohort of children with early-stage LCPD were not associated with clinically meaningful increases of BMI Z-scores. Weight gain is multi-factorial and probably not caused by weight bearing restrictions alone.

LEVEL OF EVIDENCE

III Diagnostic Study.

Sedentary behavior and neck pain in children and adolescents; a systematic review and meta-analysis

Background: Sedentary behavior (SB) is considered a risk factor for musculoskeletal pain. We aimed to explore the association of sedentary behavior indicators with neck pain among children and adolescents. Methods: A comprehensive review was performed in different databases until the end of January 2022. Odds ratios (ORs) with 95% confidence intervals were used as desired effect sizes to evaluate the association between prolonged screen time or mobile phone (MP) usage and neck pain risk. Results: Among 1651 records, 15 cross-sectional studies were included in the systematic review, and 7 reports were included in the meta-analysis. Our results suggested a significant relationship between prolonged MP use and neck pain (OR=1.36, 95% CI=1.001-1.85, I²=40.8%, P value for heterogeneity test=0.119). Furthermore, a marginally insignificant association was found between prolonged screen time and neck pain (OR=1.13, 95% CI=0.98-1.30, I²=60.3%, P value=0.01); however, after sensitivity analysis and removing one study, this association became significant (OR=1.30, 95% CI=1.03-1.64). Moreover, a significant association between prolonged sitting time and neck pain was reported in two studies. Conclusion: Available good-quality evidence reveals a significant mild association between sedentary behavior and the risk of neck pain among children and adolescents. However, longitudinal studies with objective measurement tools are warranted. In particular, potential preventive educational programs are suggested for pediatrics to reduce sedentary behavior and neck pain.

Does light-intensity physical activity moderate the relationship between sitting time and adiposity markers in adolescents?

BACKGROUND

While the relationship between sedentary time and adiposity markers may be independent of moderate-to-vigorous intensity physical activity (MVPA) among adolescents, little is known about the role of light-intensity physical activity (LIPA) in this relationship. The aim of this cross-sectional study was to examine whether device-measured LIPA and MVPA moderate the associations between objectively measured sitting time and adiposity markers (body mass index (BMI)) and waist circumference (WC)) among adolescents.

METHODS

This study included accelerometer and inclinometer data obtained from 219 adolescents (age = 14.9 ± 1.6 years, mean ± SD), collected during 2014 and 2015 in Melbourne, Australia. ActiGraph GT3X accelerometers were used to determine time spent in total-LIPA (101 counts/min to 3.99 metabolic equivalents (METs)) was dichotomized into low-LIPA (101-799 counts/min) and high LIPA (800 counts/min to 3.99 METs), and MVPA (≥ 4 METs). The average time spent sitting was obtained from activPAL inclinometers. Anthropometric measures were assessed by trained staff. Interactions between sitting and total-LIPA, low-LIPA, high-LIPA, and MVPA on BMI z-score (zBMI) and WC z-score (zWC), respectively, were examined using linear regression, adjusting for age and sex; and moderation by total-LIPA, low-LIPA, high-LIPA, and MVPA were examined by adding interaction terms. Significant interaction effects were probed by comparing associations at the mean and at 1 SD below and above the mean.

RESULTS

Total-LIPA significantly moderated the association between sitting time and zBMI, and low-LIPA significantly moderated the association between sitting time and zBMI and zWC. No other associations were found for total-LIPA, high-LIPA, or MVPA. Specifically, at high levels of total-LIPA (+1 SD), there is a negative association between sitting time and zBMI. In addition, at high levels of low-LIPA (+1 SD), there is a negative association between sitting time and zBMI and zWC.

CONCLUSION

Associations between sitting and adiposity depended on time spent in total-LIPA and low-LIPA, but not high-LIPA or MVPA. Results suggest that increasing time spent in LIPA may provide protection from the deleterious effects of sitting on adiposity markers among adolescents. Experimental evidence is needed to support these conclusions.

Changes in physical activity patterns of students from primary to secondary school: a 5-year longitudinal study

This study aimed to annually examine anthropometric characteristics and physical activity (PA) among children transitioning from fourth grade (9–10 years of age) to eighth grade (13–14 years of age) in Japan. The participants’ (n = 63) age, grade, sex, weight, height, and weight status were recorded at baseline. Accelerometry assessments were performed annually following established protocols. Time spent on activities requiring ≥ 3 metabolic equivalents (METs), 1.6–2.9 METs, and ≤ 1.5 METs were defined as moderate-to-vigorous intensity PA (MVPA), light PA (LPA), and sedentary behavior (SB), respectively. Two linear mixed models were used to examine whether MVPA, LPA, and SB min/day changed over time. Fifty-five participants provided complete data. A significant, nonlinear, longitudinal decline in MVPA, an increase in SB, and a linear decline in LPA were observed. Changes in MVPA and SB were accelerated in seventh grade (12–13 years of age). Male sex and maintenance of normal weight status were associated with higher MVPA levels. Changes in LPA and SB were not associated with sex or weight status. During the transition period from primary to secondary school, MVPA and SB showed nonlinear accelerations. Sex and normal weight were associated with more time spent performing MVPA.

Relations between physical activity, sedentary time, and body fat from childhood to adolescence: Do they differ by sex?

BACKGROUND

Efforts to reveal the direction of influence between physical activity (PA), sedentary time (ST) and body fat in youth have produced inconsistent results, possibly due to a lack of adjustment for confounders and other factors. Sex-specific associations have rarely been studied.

METHODS

A sample from two Norwegian birth cohorts (n = 809) were followed biennially over five waves from the age of 6-14 years. Physical activity and ST were recorded by accelerometers, and body fat was assessed by bioelectrical impedance measurements.

RESULTS

By applying a dynamic panel model (DPM) that adjusts for all time-invariant confounding factors, it was found that among boys, increased fat mass index (FMI) at ages 8, 10 and 12 years predicted decreased PA two years later (8-10 years: B = -0.67, (95% CI: -1.1, -0.24); 10-12 years: B = -0.33, (95% CI: -0.61, -0.05); 12-14 years: B = -0.29, (95% CI: -0.52, -0.06)). Regarding the opposite direction of influence, more PA at age 12 forecasted reduced FMI at age 14 (B = -0.16, (95% CI: -0.24, -0.07)), whereas increased FMI predicted increased ST across all time points in boys only (6-8 years: B = 0.23, (95% CI:0.02.43); 8-10 years: B = 0.23, (95% CI:.08.39); 10-12 years: B = 0.13, (95% CI:.03.23); 12-14 years: B = 0.17, (95% CI:.07, 26)). The revealed relationships were significantly stronger in boys compared to the (absent) relations in girls. Sensitivity analyses examining moderate to vigorous PA (MVPA) rather than total PA were in accordance with the main findings.

CONCLUSIONS

In boys, increased FMI predicted reduced PA and increased ST two years later from childhood to adolescence. The opposite direction of influence was evident from only ages 12-14. There were no prospective relationships between FMI and PA or ST among girls.

There is a clinical need to consider the physical activity - sedentary pattern in children with obesity. Position paper of the European Childhood Obesity Group

INTRODUCTION

While international prevention guidelines recently advocated, in addition to moderate and vigorous physical activity (MVPA) guidelines, for a minimization of sedentary time (SED), recommendations remain to be developed for youths with obesity.

METHODS

A literature search was conducted in PubMed, the Cochrane Library plus the reference lists of selected articles for relevant publications in English, including original papers, systematic reviews, and meta-analyses, with search terms "sedentary behaviors" or "sedentary time" or "screen time" AND "children" or "adolescents" AND "obesity" or "adiposity" or "cardiometabolic risk" or "cardiometabolic disease". The results were summarized as a narrative review and presented to the scientific board of the European Childhood Obesity Group (ECOG) who then discussed their implication in clinical practice and proposed the position outlined in this paper.

RESULTS

SED and screen times are associated with adiposity and cardiometabolic risks independently of youths' physical activity level. Besides considering MVPA and SED times as separate variables, comprehensive studies have questioned the impact of different patterns of MVPA and SED levels. Although lower body adiposity and better cardiometabolic health are achieved among those with desirable movement behaviors patterns (i.e., more MVPA/less SED or active/not sedentary), youths with intermediate patterns (i.e., high MVPA/high SED and low MVPA/low SED, or active /sedentary and inactive/not sedentary) have been found to be associated with intermediate risks.

CONCLUSION

There is a need to decrease SED behaviors irrespective of MVPA and to consider PA-SED patterns in youths with obesity. The European Childhood Obesity Group (ECOG) encourages anti-obesity strategies targeting both physical activity (PA) and SED behaviors to support the shift from long periods of SED time, especially screen time, to daily routines incorporating bouts of PA. Stepwise or sequential approaches to movement behavior counseling might start with targeting SED at first to decrease cardiometabolic risks when implementing MVPA is not yet possible.

Parental Working Hours and Children's Sedentary Time: A Cross-sectional Analysis of the J-SHINE

BACKGROUND

Sedentary behaviors are prevalent among children and can have a detrimental effect on their health. Little is known about the influence of parental time on children's sedentary behavior. This study examined the association between parental working hours and children's sedentary time.

METHODS

Cross-sectional data were drawn from the Japanese Study on Stratification, Health, Income, and Neighborhood (J-SHINE) in 2010 and 2011. Participants were 886 children aged 7-18 years and their parents. The primary outcome was self-reported sedentary time after school that comprised screen time and non-screen time. The main explanatory variable was parental working hours. We used multiple regression analysis adjusting for sociodemographic factors.

RESULTS

Children's mean sedentary time was 222 (standard deviation [SD], 123) min/day; 144 (SD, 108) min/day screen time and 78 (SD, 65) min/day non-screen time. Children whose mothers worked ≥20 hours/week had 28 (95% CI, 9 to 48) min/day longer sedentary time than children of homemakers (240 min/day vs 214 min/day). The longer maternal working hours, the longer sedentary time (P for trend <0.01). In contrast, children whose fathers worked ≥48 hours/week had 82 (95% CI, -156 to -7) min/day shorter sedentary time than children of non-working fathers (179 min/day vs 264 min/day). When limited to children whose fathers worked, there was no statistically significant association between children's sedentary time and paternal working hours.

CONCLUSIONS

Children with mothers who work long hours or fathers not working tend to sit more. Supplementing the shortages in resources for childcare may be necessary among those families.

Trajectories of objectively measured physical activity and childhood overweight: longitudinal analysis of the IDEFICS/I.Family cohort

BACKGROUND

Since only few longitudinal studies with appropriate study designs investigated the relationship between objectively measured physical activity (PA) and overweight, the degree PA can prevent excess weight gain in children, remains unclear. Moreover, evidence is limited on how childhood overweight determines PA during childhood. Therefore, we analyzed longitudinal trajectories of objectively measured PA and their bi-directional association with weight trajectories of children at 2- and 6-year follow-ups.

METHODS

Longitudinal data of three subsequent measurements from the IDEFICS/I.Family cohort study were used to analyze the bi-directional association between moderate-to-vigorous PA (MVPA) and weight status by means of multilevel regression models. Analyses comprised 3393 (2-year follow-up) and 1899 (6-year follow-up) children aged 2-15.9 years from eight European countries with valid accelerometer data and body mass index (BMI) measurements. For categorized analyses, children's weight status was categorized as normal weight or overweight (cutoff: 90th percentile of BMI) and children's PA as (in-) sufficiently active (cutoffs: 30, 45 and 60 min of MVPA per day).

RESULTS

Children engaging in at least 60 min MVPA daily at baseline and follow-ups had a lower odds of becoming overweight (odds ratio [OR] at 2-year follow-up: 0.546, 95% CI: 0.378, 0.789 and 6-year follow-up: 0.393, 95% CI: 0.242, 0.638), compared to less active children. Similar associations were found for 45 min MVPA daily. On the other side, children who became overweight had the lowest odds to achieve 45 or 60 min MVPA daily (ORs: 0.459 to 0.634), compared to normal weight children.

CONCLUSIONS

Bi-directional associations between MVPA and weight status were observed. In summary, at least 60 min MVPA are still recommended for the prevention of childhood overweight. To prevent excess weight gain, 45 min MVPA per day also showed preventive effects.

Relationship of Physical Activity and Sedentary Time with Metabolic Health in Children and Adolescents Measured by Accelerometer: A Narrative Review

The purpose of this study was to summarize the associations of physical activity (PA) and sedentary time (SED) with metabolic health and examine the effects of time reallocation on metabolic health in adolescents using accelerometer data. A literature search was conducted using PubMed, ScienceDirect, Web of Science, Cochran Library, and Google Scholar, and 27 articles were reviewed. Recent research generally confirms the associations of PA and SED with metabolic health. High PA levels and low SED levels had a positive relationship with metabolic health. Moreover, reallocating 10 min of daily SED to PA was associated with better metabolic health indicators. These results were stronger for moderate-to-vigorous physical activity than for light intensity PA. Thus, efforts to convert SED into PA of at least moderate intensity appear to be an effective strategy to prevent metabolic disease development in children and adolescents. However, some of the associations between PA and metabolic health indicators were inconsistent, depending on age, obesity degree, and PA intensity. Additionally, various accelerometer data collection and processing criteria impact the interpretation of the results. Therefore, consistent accelerometer data collection and analysis methods are needed in future studies. Further, intervention studies are required to verify the causality and effectiveness of the isotemporal substitution model.

Identification of the minimum data set to design a mobile-based application on overweight and obesity management for children and adolescents

PURPOSE

Designing mobile-based applications is one of the tools to raise the awareness of patients and the care team. Aim of this study is to identify the data elements of a mobile-based application to overweight and obesity management for children and adolescents from the experts' point of view.

METHODS

In this descriptive-analytical article, data collection was conducted through library and Internet research. The research population comprised 30 nutritionists selected via simple sampling method. The research instrument was a questionnaire developed by the researcher in four sections: demographic data, assessment data, therapeutic recommendations and application capabilities. Validity and reliability were confirmed by Content Validity Ratio (CVR) and Delphi method respectively.

RESULTS

The Minimum Data Set (MDS) required for overweight and obesity management in children and adolescents was designed based on the data from the guidelines of the United States, Canada, Australia, Britain, Iran, and experts' opinions. The importance of this MDS suggested was calculated based on the percentage points given by experts for the demographic data of 100%, the assessment data of 88.33%, the therapeutic recommendations of 97.67%, and the application capabilities of 88.94%.

CONCLUSION

Identifying prevention and control minimum data set of overweight and obesity in children and adolescents from the point of view of experts will be effective in improving the applications in this field. This MDS has two parts of data elements: the first for recognition of the framework of evaluating and applying therapeutic methods that can empower parents to manage the child's body mass and the second as a patient's personal record for storage a set of data that can be used by nutritionists in visits to healthcare centers.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s40200-021-00807-1.

Associations of Mothers' and Children's Stress With Children's Device-Measured Physical Activity and Sedentary Behavior Trajectories Across 3 Years

BACKGROUND

Psychological stress has adverse effects on health-related behaviors, yet longitudinal research is lacking. Research examined how children's and mothers' perceived stress are associated with children's physical activity and sedentary behavior trajectories across 3 years.

METHODS

Mothers and their children (N = 186 dyads; 8-12 y at baseline, 57% Hispanic) completed 6 assessments across 3 years. Children and mothers self-reported perceived stress using the Stress in Children Scale and Perceived Stress Scale, respectively. Children's moderate to vigorous physical activity (MVPA) and sedentary behavior were assessed using accelerometers. Mixed models examined interactions of mothers' and children's perceived stress by time elapsed in the study on children's MVPA and sedentary behavior.

RESULTS

The perceived stress × time elapsed interactions were significant for children's MVPA and sedentary behavior (Ps < .05). Higher average perceived stress in mothers was associated with greater decreases in children's MVPA and increases in children's sedentary behavior. The child stress × time elapsed interactions was significant for children's MVPA (P < .05) but not sedentary behavior. Higher average perceived stress in children was associated with smaller decreases in children's MVPA.

CONCLUSION

Interventions to promote physical activity and reduce screen time in children should mitigate the effects of psychological stress, especially among mothers, on these behaviors.

Leading by Example: Association Between Mother and Child Objectively Measured Physical Activity and Sedentary Behavior

PURPOSE

The authors examined the relationship between mother and child activity.

METHODS

The authors compared moderate-vigorous physical activity (MVPA) and sedentary time of low-income mothers with obesity and their 6- to 12-year-old children on week (WD) and weekend (WE) days. A total of 196 mother-child pairs wore accelerometers simultaneously for a week. Mothers completed questionnaires. Spearman correlation and multivariate regression were used.

RESULTS

WE MVPA (accelerometry) was significantly correlated between mothers with children aged 6-7 (rs = .35) and daughters (rs = .27). Self-reported maternal PA time spent with one of their children was significantly correlated with the WE MVPA of all children (rs = .21) and children aged 8-10 (rs = .22) and with the WD MVPA of all children (rs = .15), children aged 8-10 (rs = .23), aged 11-12 (rs = .52), and daughters (rs = .37), and inversely correlated to the WD sedentary time of all children (rs = -.21), children aged 8-10 (rs = -.30), aged 11-12 (rs = -.34), daughters (rs = -.26), and sons (rs = -.22). In multivariate regression, significant associations were identified between reported child-mother PA time together and child MVPA and sedentary time (accelerometry).

CONCLUSIONS

Mothers may influence the PA levels of their children with the strongest associations found in children aged 6-7 and daughters. Mother-child coparticipation in PA may lead to increased child MVPA and decreased sedentary behavior.

Bi-directional prospective associations between sedentary time, physical activity and adiposity in 10-year old Norwegian children

There is an adverse cross-sectional association between sedentary time, physical activity (PA) and adiposity, but weak and inconsistent estimates raise question to the direction of associations. The present study aims to examine whether the prospective association between sedentary time, different PA intensities and indicators of adiposity is bi-directional. The Active Smarter Kids Study obtained data from 869 ten-year-old children with valid measurements for sedentary time, PA, and adiposity at baseline and follow-up. Time spent sedentary and PA was measured by accelerometry, adiposity was assessed by three different measures: body mass index (BMI), waist circumference (WC) and sum of four skinfolds (S4SF). Neither overall PA nor time spent sedentary predicted lower BMI or WC at follow-up, but the time spent in moderate-and-vigorous PA (MVPA) and vigorous PA (VPA) predicted lower S4SF at follow-up among boys (MVPA β - 0.066 [95% CI -0.105, -0.027] p = 0.001). Baseline BMI and WC predicted less overall PA, MVPA and VPA in boys. All adiposity measures predicted more time spent sedentary at follow-up in boys. The results suggest that overall PA and sedentary time do not predict future adiposity. Baseline adiposity may rather predict more sedentary time and less higher intensity activity.

Disentangling individual, school, and neighborhood effects on screen time among adolescents and young adults in the United States

OBJECTIVES

To examine the association between individual, neighborhood, and school-level influences on individual screen time among adolescents and young adults (AYAs) in the National Longitudinal Study of Adolescent to Adult Health.

METHODS

We classified screen time continuously as self-reported total hours per week of television, videos, and video/computer games at baseline and categorical as extended screen time (≥14 h per week). We fit cross-classified multilevel models (CCMM) to examine to examine the individual-, school- and neighborhood-level demographic and socioeconomic factors associated with screen time. Models were fit using MLwiN with Bayesian estimation procedures.

RESULTS

AYAs reported an average of 22.8 (SD = 19.4) and 21.9 (SD = 20.3) hours of screen time, respectively. At the individual level, younger age, male sex, Black/multiracial race, receipt of public assistance, and lower parental education were associated with higher screen time. At the school level, being out of session (i.e., school and national holidays including summer), having a higher proportion of non-White students, and having a lower proportion of parents with a college education were associated with higher individual screen time.

CONCLUSIONS

We found that individual-level factors most influence youth screen time, with smaller contributions from school factors.

Adiposity and High Blood Pressure during Childhood: A Prospective Analysis of the Role of Physical Activity Intensity and Sedentary Time in the GECKO Drenthe Cohort

Whereas in adults, physical inactivity is strongly related to obesity and hypertension, in young children the evidence is inconsistent and scarce. We examined the association between physical activity (PA) behaviours at 5-6 years of age and adiposity and blood pressure (BP) at 10-11 years in 947 children (51% boys) from the Groningen Expert Center for Kids with Obesity (GECKO) Drenthe cohort. Sedentary time (ST) and light, moderate, and vigorous PA were assessed using accelerometry (ActiGraph GT3X, wear time > 600 min/day, ≥3 days). Body mass index (BMI), waist circumference (WC), and systolic and diastolic BP were measured at 5-6 and 10-11 years of age and standardized as age- and sex-adjusted (and height-adjusted, for BP) z-scores. Adjusted linear and logistic regression models showed that most PA behaviours were not related to standardized BMI or WC, overweightness/obesity, abdominal overweightness/obesity, standardized systolic or diastolic BP, pulse pressure, or prehypertension at 10-11 years of age. Only if children spent more time in vigorous PA was WC slightly lower (B (95% CI) = -0.08 (-0.16, -0.01) SD, stdβ = -0.068) and the increase in WC over the years was less (B (95% CI) = -0.10 (-0.18, -0.01) SD; stdβ = -0.083). To conclude, at this very young age, PA behaviours are not a strong predictor for overweightness/obesity or hypertension later in childhood.

Associations between daily ambient temperature and sedentary time among children 4-6 years old in Mexico City

BACKGROUND

Sedentary behavior is a worldwide public health concern. There is consistent and growing evidence linking sedentary behavior to mortality and morbidity. Early monitoring and assessment of environmental factors associated with sedentary behaviors at a young age are important initial steps for understanding children's sedentary time and identifying pertinent interventions.

OBJECTIVE

This study examines the association between daily temperature (maximum, mean, minimum, and diurnal variation) and all-day sedentary time among 4-6 year old children in Mexico City (n = 559) from the year 2013 to 2015.

METHODS

We developed a spatiotemporally resolved hybrid satellite-based land use regression temperature model and calculated percent daily sedentary time from aggregating 10-second epoch vertical counts captured by accelerometers that participants wore for one week. We modeled generalized additive models (GAMs), one for each temperature type as a covariate (maximum, mean, minimum, and diurnal variation). All GAMs included percent all-day sedentary time as the outcome and participant-level random intercepts to account for repeated measures of sedentary time. Our models were adjusted for demographic factors and environmental exposures.

RESULTS

Daily maximum temperature, mean temperature, and diurnal variation have significant negative linear relationships with all-day sedentary time (p<0.01). There is no significant association between daily minimum temperature and all-day sedentary time. Children have on average 0.26% less daily sedentary time (approximately 2.2 minutes) for each 1°C increase in ambient maximum temperature (range 7.1-30.2°C), 0.27% less daily sedentary time (approximately 2.3 minutes) for each 1°C increase in ambient mean temperature (range 4.3-22.2°C), and 0.23% less daily sedentary time (approximately 2.0 minutes) for each 1°C increase in diurnal variation (range 3.0-21.6°C).

CONCLUSIONS

These results are contrary to our hypothesis in which we expected a curvilinear relationship between temperature (maximum, mean, minimum, and diurnal variation) and sedentary time. Our findings suggest that temperature is an important environmental factor that influences children's sedentary behavior.

Tracking Children's Physical Activity Patterns across the School Year: A Mixed-Methods Longitudinal Case Study

Despite the breadth of health benefits associated with regular physical activity (PA), many children in the UK are not sufficiently active enough to meet health guidelines, and tend to become less active as they mature into and throughout adolescence. Research has indicated that children's school, home and neighbourhood environments can all significantly influence their opportunities to engage in moderate-to-vigorous physical activity (MVPA). However, less is known about how children's MVPA patterns within these key environments may change across the school year. The current mixed-methods case study aims to explore this issue by tracking key stage 2 (KS2) and key stage 3 (KS3) children's MVPA patterns across the school year. Fifty-eight children (29 boys, 29 girls, KS2 = 34, KS3 = 24) wore an integrated global positioning systems (GPS) and heart rate (HR) monitor over four consecutive days in the first term of school (autumn), before these measurements were repeated in the two remaining school terms (winter-summer). A subsample of children (n = 6-8 per group) were invited to take part in one of six focus groups each term to further explore their PA behaviours and identify the barriers and facilitators to PA. The children's MVPA was significantly lower (p = 0.046) in term 2 (winter/spring term) than during the warmer terms (autumn and summer). All the locations showed reductions in MVPA in term 2, except indoor MVPA, which increased, and MVPA on foot in the neighbourhood, which remained consistent. Focus groups revealed location, friends, and the variety of options to be associated with MVPA, and poor weather, parental permission, and time limitations to be barriers to MVPA. This mixed-methodological, repeated-measures design study highlights differences in the activity patterns and perceptions of children over the school year. Future studies should implement longitudinal, multi-method approaches to gain deeper insight into how children's PA behaviours differ over time. Consequently, this can inform future health policies promoting children's PA throughout the year.

The association between obesity and sedentary behavior or daily physical activity among children with Down's syndrome aged 7-12 years in Japan: A cross-sectional study

Background

An assessment of the adverse health effects of obesity in children with Down's syndrome (DS) is required to develop programs that facilitate the acquisition of healthy behaviors. Individuals with DS are often obese. These individuals must develop health related behaviors in childhood. For this reason, it is necessary to clarify the factors associated with obesity in children with DS.

Aims

This study had two purposes. The first was to assess the obesity and to evaluate the sedentary behavior (SB) and physical activity of Japanese elementary school children with Down's syndrome. The second was to investigate the association between obesity and SB or moderate to vigorous physical activity (MVPA).

Methods and procedures

Ninety-three children (male/female: 51/42) with DS in elementary school grades 1 to 6 (aged 7–12 years) participated in this study in Japan. Physical characteristics were obtained from the questionnaire completed by their parents. The questionnaire provided information on regular school checkups. SB and MVPA were evaluated using a triaxial accelerometer.

Results

Approximately 20% of the children with DS were obese. Nearly half of the children with DS achieved 60 min of MVPA. SB time was significantly longer in the upper grades (aged 11–12 years) than in the lower grades (aged 7–8 years). Comparing weekdays and weekend days, the middle (aged 9–10 years) and upper grades had significantly shorter MVPA times on weekend days. The frequency of obesity was significantly associated with shorter MVPA times in the lower grades and longer SB time in the middle grades.

Conclusions and implications

Children with DS may increase their SB time as their age group (grade category) increases. Increasing opportunities for MVPA during weekends may increase physical activity. The observed relationship between obesity and SB time or MVPA time may apply only to younger and middle grade children with DS. Further investigation is necessary to confirm these relationships.

Feasibility and applicability of Evenson sedentary behavior cut points applied to children with and without intellectual and developmental disabilities

AIM

Sedentary behavior (SB) is widely studied as it is associated with cardiometabolic health and obesity issues. However, children with Intellectual and Developmental Disabilities (IDD) have been understudied. Accelerometers are commonly used to measure SB in typically developing populations but may be inappropriate for IDD populations due to differences in body movement and physiologic responses to the activity. The use of Evenson sedentary cut-points, created based on typically developing children, has yet to be applied and/or examined in children with IDD.

PURPOSE

A descriptive cross-sectional study was conducted to (1) Assess the feasibility of applying Evenson sedentary cut-points in children with IDD (2) Describe SB over a two-week period between diagnosis groups.

METHODS

The SB of 22 participants (8 children with Down syndrome, 6 children with spina bifida, 8 children with no chronic illness) was assessed on two separate occasions: (1) during a 7-minute sedentary protocol, and (2) over a two-week period.

RESULTS

The study supports the preliminary efficacy of using Evenson cut-points for this population, with 100% of participants being within the Evenson counts per minute (0-100 cpm) during the 7-minute sedentary protocol. The total volume of SB over a two-week period was not significantly different between diagnosis groups (8.8 h, 8.6 h, and 7.1 h of SB for children with Down syndrome, spina bifida, or those with no chronic illness, respectively; p = 0.36).

CONCLUSIONS

Evenson sedentary cut-points can be used for children with IDD. Preliminary data suggest that children with IDD do not engage in significantly different SB than children without a chronic illness. Further study is warranted.Implications for rehabilitationObjective measures of physical activity and sedentary behavior for children with Down syndrome or spina bifida are rarely used due to potential differences in body movement (e.g., gait) during ambulation compared to typically developing peers that may influence the accuracy of cut-points.This study supports that Evenson sedentary cut-points can be used in children with Down syndrome or spina bifida to assess sedentary activity.Preliminary findings from this study demonstrate similarities in patterns of sedentary behaviors exhibited by our sample of children with Down syndrome, spina bifida, or no chronic illness.

Evaluation of a program targeting sports coaches as deliverers of health-promoting messages to at-risk youth: Assessing feasibility using a realist-informed approach

Unequal access to health promotion resources and early prevention services is a major determinant of health inequity among youth. Initiatives that improve the access to and adoption of health promotion messages are important undertakings, e.g., sport. Sport-for-development (SFD) programs are seen as valuable delivery tools, in which coaches are used as change agents to increase health awareness and behavior among at-risk youth. The delivery of such messages requires specific knowledge and skills that can be attained through training; however, the effectiveness of such training requires assessment. In this study, we evaluated the feasibility of such a training program for SFD coaches using process evaluation from a realist perspective, and views from multiple stakeholders, among other sources. We also clarified the inner workings of the training and investigated how context shaped the training outcomes. Increased health awareness and a sense of responsibility from acting as a role model for at-risk youth were among the perceived training outcomes. Building a safe environment for learning, engagement, and bonds of trust increased the confidence to learn, and resulted in a sense of critical self-reflection and self-development of SFD coaches towards health and prevention messages. Importantly, the unique situations (or context) of SFD coaches and SFD in general presented challenging variables, e.g., a precarious life history or living conditions, mental health issues, or low educational skills, that hampered the impact of the mechanisms put in place by the training. Here, we present a process in which the development of the ‘right mind-set,’ engagement and bonds of trust, in combination with the right settings are key elements for SFD coaches to learn how to convey health-promoting messages and take responsibility as role models for at-risk youth.

Physical Activity Habits and Well-Being among 6-Year-Old Children: The "Improving Umbrian Kids' Healthy Lifestyle", an Uncontrolled Pilot Study Project

There is evidence that promoting physical activity programs and decreasing sedentary behavior is a potential strategy for improving health-outcomes, peer relationships and social/emotional well-being in at-risk youth. The World Health Organization recommends enhancing physical education and school-based programs with multi-component and evidence-based assessment methodology. In Umbria (Italy) an uncontrolled pilot study project referred to as "Improving Umbrian kids' healthy lifestyle" was implemented as a systemic school-based intervention directed at 6-year-old primary school children. The intervention applied a consolidated assessment methodology developed by the C.U.R.I.A.Mo. and Eurobis projects that inserted two hours per week of physical education activity into the school curriculum, structured and supervised by specialists with Exercise and Sport Science degrees, for eight months (from October to June) of the school year. We measured anthropometric values (BMI, waist circumference, waist-to-height ratio index) with objective tools. Moreover, we evaluated physical performance variables (speed, strength, and flexibility) using standard tests. Additionally, self-report measures (measured physical activity during the week, sedentary habits, and psychological well-being) were assessed using validated questionnaires. We observed a significant decrease in waist to height ratio, and improvements in physical performance values and self-report questionnaire measures. Our study suggests that the promotion of physical activity in the school setting is likely to result in physically, mentally, and psycho-socially healthier primary-school-age children.

Association of Reallocating Time in Different Intensities of Physical Activity with Weight Status Changes among Normal-Weight Chinese Children: A National Prospective Study

Background: Time spent in different intensity-specific physical activities is codependent, but the substitution effect of different activities on weight status changes in children remains unclear. This study aims to investigate the prospective association between reallocating time in different intensities of physical activity and weight status changes among Chinese children. Methods: A national sample of 15,100 normal-weight children aged 7–18 years (46.7% boys) were recruited in September 2013 and followed up for nine months. Vigorous-intensity physical activity (VPA), moderate-intensity physical activity (MPA), walking, and sedentary time were obtained by International Physical Activity Questionnaire Short Form (IPAQ-SF). Height and weight were objectively measured, by which body mass index (BMI) and BMI z-score were calculated. Weight status was classified by the Chinese criteria for 7- to 18-year-old children. Isotemporal substitution analyses (including single-factor model, partition model, and isotemporal substitution model) were applied to examine the association of time allocation with weight status changes. Results: Each 30 min/day of increase in VPA was favorably associated with a 13.2% reduced risk of incident overweight/obesity in a single-factor model and a 15.6% reduced risk in a partition model. Negative associations were found between VPA, MPA, walking and the risk of being underweight in the single-factor model, but not in the partition model. In substitution models, replacing 30 min/day sedentary time with an equal amount of VPA was favorably associated with a 16.1% reduction of the risk of being overweight/obese. Conclusion: These findings highlight the need for promoting vigorous-intensity physical activity in children.

Accelerometer-measured physical activity and sedentary behavior in Chinese children and adolescents: a systematic review and meta-analysis

OBJECTIVE

To synthesize evidence on accelerometer-measured moderate-to-vigorous physical activity (MVPA) and sedentary behavior (SB) levels of Chinese children and adolescents.

STUDY DESIGN

This is both a systematic review and meta-analysis study.

METHODS

Online databases were searched for studies published from January 2009 up to February 2019. These studies reported accelerometer-measured daily minutes of MVPA and/or SB among Chinese children and adolescents. Random-effects meta-analysis was used to separately pool the time spent in MVPA and SB.

RESULTS

Of 4754 records, 20 studies were included in the meta-analysis. Sample sizes ranged from 96 to 2163. The meta-analysis showed that Chinese children and adolescents spent 41.11 min/day in MVPA and 529.83 min/day in SB averagely. Boys spent more time in MVPA compared with girls (P = 0.01). Children accumulated more MVPA time than adolescents (P = 0.05), and children spent less time in SB than adolescents (P = 0.05). Unlike weekdays, SB was lower on weekends (P = 0.02). There were significant differences in children and adolescents' MVPA time in regions (P < 0.001).

CONCLUSIONS

MVPA level in Chinese children and adolescents is well below international recommendations, and their SB level is very high.

Videogame-related experiences among regular adolescent gamers

The objective of this study was to identify the videogame-related experiences expressed by regular adolescent gamers and to explore the socio-family factors related to these experiences. A cross-sectional observational and descriptive study was carried out with a convenience sample of regular Spanish videogamers between 16 and 18 years old. To measure the use of videogames for evasion and its negative consequences, the Questionnaire of Videogame-Related Experiences (Cuestionario de Experiencias Relacionadas con Videojuegos, CERV) was used and socio-family variables collected, evaluating their relationship with the results of the CERV. A total of 206 adolescents participated, 89.3% men [84.3-93.2] and 17.9% [12.9-23.9] allocating more than 35 hours a week to videogames. The CERV subscale related to the evasive use of videogames (max. = 24 points) obtained a mean value of 11.71 (SD = 3.52) and the mean value for the subscale related to the negative consequences (max. = 27 points) was 7.14 (SD = 3.33). A higher frequency of high values of evasive use (p = .038) and higher scores of this subscale (p = .02) were found in gamers without brothers or sisters. Higher scores and larger numbers of negative consequences were found in gamers who play more than 21 hours a week (p = .032). In conclusion, frequent use of videogames does not seem to be carried out with an evasive purpose, except in the case of absence of siblings. Frequent videogame use has only proven to carry a higher level of negative consequences when playing more than 21 hours a week. No other socio-family variables related to these subscales of the CERV have been identified.

Changes in physical activity and sedentary time during adolescence: Gender differences during weekdays and weekend days

OBJECTIVES

The objective of this study was to determine the gender-specific and time-segmented changes in accelerometer measured physical activity (PA) and sedentary time (ST) during adolescence.

METHODS

The study population (N = 970) consisted of children from nine schools throughout Finland. At the baseline, the children were in grades 4-7 (ages 10-13). Five times during the two-year follow-up period, hip-worn accelerometers (ActiGraph GT3X+) were deployed for seven consecutive days in order to monitor the pupils' PA. The daily time spent in vigorous (VPA), moderate to vigorous (MVPA), and light physical activity(LPA), as well as sedentary time(ST), were assessed.

RESULTS

Significant gender differences were observed in terms of the changes in MVPA and ST during the follow-up period. The total MVPA declined significantly in boys (by 2.2min/day/year from 60 min/d at baseline) but not in girls (49 min/d at baseline). The total ST increased both in boys (by 20.7%-points/y) and in girls (by 16.1%-points/y, P < .001). However, when we compared the results during the weekdays and weekend days separately, we observed that the declines in MVPA and increases in ST were greater in boys than in girls during the weekend days.

CONCLUSION

A greater decrease in PA and a greater increase in ST during adolescence were observed among boys than among girls, especially during weekend days. In order to diminish these unfavorable behavioral changes during adolescence, we encourage the separate tailoring of interventions for boys and girls and for weekdays and weekends.

Development and Validation of the Reasons to Exergame (RTEX) Scale in Young Adults: Exploratory Factors Analysis

Background

Exergaming is associated with positive health benefits; however, little is known about what motivates young people to exergame.

Objective

This study aimed to develop a new Reasons to Exergame (RTEX) scale and describe its psychometric properties (Study 1) including test-retest reliability (Study 2). We also examined the test-retest reliability of self-report exergaming behavior measures (Study 2).

Methods

We identified scale items in consultation with experts. In Study 1, we conducted an Exploratory Factor Analysis of RTEX and examined how the factors identified relate to exergaming frequency and intensity in a population-based sample of 272 young adults. In Study 2, we examined the test-retest reliability of RTEX factors and self-report measures of past-week exergaming frequency and intensity among 147 college students.

Results

We identified four factors in RTEX: exergaming for fitness, exergaming for enjoyment, preferring exergaming over other gaming options, and choosing exergaming over competing interests (eg, sports). Test-retest reliability of RTEX factors (ICC 0.7-0.8) and self-report exergaming frequency (ICC 0.4-0.9) was adequate. Exergaming for fitness and enjoyment were positively associated with the frequency of exergaming with friends and family, and with exergaming intensity. Preferring exergaming over other gaming options and choosing exergaming over competing interests (eg, sports) were not related to exergaming behavior.

Conclusions

RTEX is a psychometrically sound scale with four factors that measure reasons to exergame. Replication of these findings is needed in larger, more diverse samples.

Sedentary Behavior and the Use of Wearable Technology: An Editorial

Globally, we continue to face a mounting issue of obesity combined with inactivity; sedentary behaviour is independently associated with poor health outcomes including disease and mortality. As such, exploring ways to try to reduce sedentary behaviour and decrease the risk of diseases is an important area of consideration. The role of wearable technology, such as fitness trackers, to encourage and subsequently increase physical activity is relatively well documented. These devices have been successful at encouraging populations to increase daily activity levels. While time being sedentary is often correlated with physical activity participation, this is not always the case. Therefore, it may be just as important to consider the activity an individual is not doing when evaluating health and well-being. This Editorial will summarize the importance of distinguishing between physical activity and sedentary behaviour. It will also discuss how wearable technology, in the form of fitness trackers, may be used to encourage someone to break up sedentary bouts more often. Finally, we will consider important future research directions.

Latin American interventions in children and adolescents' sedentary behavior: a systematic review

OBJECTIVE To identify and evaluate the effects of community-based interventions on the sedentary behavior (SB) of Latin American children and adolescents. METHODS A systematic review on community-based trials to reduce and/or control SB in Latin American countries (Prospero: CRD42017072157). Five databases (PubMed, Web of Science, Scopus, SciELO and Lilacs) and a reference lists were searched. RESULTS Ten intervention studies met the eligibility criteria and composed the descriptive synthesis. These studies were conducted in Brazil (n=5), Mexico (n=3), Ecuador (n=1) and Colombia (n=1). Most interventions were implemented in schools (n=8) by educational components, such as meetings, lessons, and seminars, on health-related subjects (n=6). Only two studies adopted specific strategies to reduce/control SB; others focused on increasing physical activity and/or improving diet. Only one study used an accelerometer to measure SB. Seven studies investigated recreational screen time. Eight studies showed statistically significant effects on SB reduction (80%). CONCLUSIONS Latin America community-based interventions reduced children and adolescents' SB. Further studies should: define SB as a primary outcome and implement strategies to reduce such behaviour; focus in different SBs and settings, other than recreational screen time or at-home sitting time; and use objective tools together with questionnaires to measure sedentary behaviour in.

Heavy Screen Use on Weekends in Childhood Predicts Increased Body Mass Index in Adolescence: A Three-Year Follow-Up Study

PURPOSE

We aimed to examine whether sedentary screen time changes when transitioning from childhood to adolescence and whether children's screen time, separately for school days and weekends, affects body mass index (BMI) in adolescents.

METHODS

This prospective 3-year follow-up study included 5,084 children with a mean (standard deviation) age of 11 (1) years at baseline and 14 (1) years at follow-up. Children reported screen time, more specifically, time spent viewing TV programs and using a computer outside school while sitting. We categorized children into light, medium, and heavy TV viewers and computer users separately for school days and weekends. We also calculated the age- and gender-specific BMI z-score (BMIz).

RESULTS

Time spent viewing TV changed from baseline to follow-up on school days and on weekends (p < .001 for both); the proportion of heavy TV viewers on school days (≥3 h/d) increased from 16% to 23% and on weekends (≥4 h/d) from 19% to 30%. Heavy TV viewers and computer users on both school days and on weekends had a higher BMIz 3 years later (p < .001 for all). After adjusting for age, gender, language, baseline BMIz, sleep duration, eating habits, exercise, and the other screen-time variables, heavy TV viewing on weekends remained significantly associated with an increased BMIz at follow-up (B = .078; p = .013).

CONCLUSIONS

The proportion of heavy screen users increases when transitioning from childhood to adolescence. Moreover, heavy screen use, especially on weekends in 11-year-old children, is associated with an increased BMI 3 years later.

Latent class analysis of sexual health markers among men and women participating in a British probability sample survey

BACKGROUND

Despite known associations between different aspects of sexual health, it is not clear how patterning of adverse sexual health varies across the general population. A better understanding should contribute towards more effective problem identification, prevention and treatment. We sought to identify different clusters of sexual health markers in a general population, along with their socio-demographic, health and lifestyle correlates.

METHODS

Data came from men (N = 5113) and women (N = 7019) aged 16-74 who reported partnered sexual activity in the past year in Britain's third National Survey of Sexual Attitudes and Lifestyles, undertaken in 2010-2012. Latent class analysis used 18 self-reported variables relating to adverse sexual health outcomes (STI and unplanned pregnancy, non-volitional sex, and sexual function problems). Correlates included socio-demographics, early debut, alcohol/drug use, depression, and satisfaction/distress with sex life.

RESULTS

Four classes were found for men (labelled Good Sexual Health 83%, Wary Risk-takers 4%, Unwary Risk-takers 4%, Sexual Function Problems 9%); six for women (Good Sexual Health 52%, Wary Risk-takers 2%, Unwary Risk-takers 7%, Low Interest 29%, Sexual Function Problems 7%, Highly Vulnerable 2%). Regardless of gender, Unwary Risk-takers reported lower STI/HIV risk perception and more condomless sex than Wary Risk-takers, but both were more likely to report STI diagnosis than Good Sexual Health classes. Highly Vulnerable women reported abortion, STIs and functional problems, and more sexual coercion than other women. Distinct socio-demographic profiles differentiated higher-risk classes from Good Sexual Health classes, with depression, alcohol/drug use, and early sexual debut widely-shared correlates of higher-risk classes. Females in higher-risk classes, and men with functional problems, evaluated their sex lives more negatively than those with Good Sexual Health.

CONCLUSIONS

A greater prevalence and diversity of poor sexual health appears to exist among women than men in Britain, with more consistent effects on women's subjective sexual well-being. Shared health and lifestyle characteristics of higher-risk groups suggest widespread benefits of upstream interventions. Several groups could benefit from tailored interventions: men and women who underestimate their STI/HIV risk exposure, women distressed by low interest in sex, and women experiencing multiple adverse outcomes. Distinctive socio-demographic profiles should assist with identification and targeting.

Longitudinal changes in moderate-to-vigorous-intensity physical activity in children and adolescents: A systematic review and meta-analysis

Moderate-to-vigorous-intensity physical activity (MVPA) is important for childhood obesity prevention and treatment, yet declines with age. Timing and magnitude of the decline in MVPA in children and adolescents are unclear but important for informing effective obesity intervention development. This systematic review aimed to determine and compare the year-to-year changes in MVPA among children and adolescents. Longitudinal studies were identified by searching 10 relevant databases up to December 2018. Studies were eligible for inclusion if they reported accelerometer-assessed MVPA (min day^-1 ) separately for boys and girls and had follow-up duration of at least 1 year. After screening 9,232 studies, 52 were included representing 22,091 aged 3 to 18 year olds (boys=8,857; girls=13,234). Pooled-analysis of the relative change in MVPA per year showed a decline of -3.4% (95% CI, -5.9 to -0.9) in boys and -5.3% (95% CI, -7.6 to -3.1) in girls, across all age groups. There were notable declines in MVPA at age 9 for both boys (-7.8%, 95% CI, -11.2 to -4.4) and girls (-10.2%, 95% CI, -14.2 to -6.3). The relative decline in MVPA affects both sexes from an early age; however, it is greater among girls. Interventions to promote MVPA should start before adolescence.

Exploring Children's Physical Activity Behaviours According to Location: A Mixed-Methods Case Study

The school environment is ideally placed to facilitate physical activity (PA) with numerous windows of opportunity from break and lunch times, to lesson times and extracurricular clubs. However, little is known about how children interact with the school environment to engage in PA and the other locations they visit daily, including time spent outside of the school environment i.e., evening and weekend locations. Moreover, there has been little research incorporating a mixed-methods approach that captures children’s voices alongside objectively tracking children’s PA patterns. The aim of this study was to explore children’s PA behaviours according to different locations. Sixty children (29 boys, 31 girls)—35 key stage 2 (aged 9–11) and 25 key stage 3 (aged 11–13)—wore an integrated global positioning systems (GPS) and heart rate (HR) monitor over four consecutive days. A subsample of children (n = 32) were invited to take part in one of six focus groups to further explore PA behaviours and identify barriers and facilitators to PA. Children also completed a PA diary. The KS2 children spent significantly more time outdoors than KS3 children (p = 0.009). Boys engaged in more light PA (LPA) when on foot and in school, compared with girls (p = 0.003). KS3 children engaged in significantly more moderate PA (MPA) at school than KS2 children (p = 0.006). Focus groups revealed fun, enjoyment, friends, and family to be associated with PA, and technology, costs, and weather to be barriers to PA. This mixed methodological study highlights differences in the PA patterns and perceptions of children according to age and gender. Future studies should utilize a multi-method approach to gain a greater insight into children’s PA patterns and inform future health policies that differentiate among a range of demographic groups of children.

The Acute Effects of a "Reduced Sitting Preschool Day" on Executive Function and Musculoskeletal Health in Preschoolers: A Randomized Cross-Over Study

PURPOSE

To examine the acute effects of a reduced sitting day on executive function (EF) and musculoskeletal health in preschoolers.

METHODS

A sample of 29 children (54% boys; 4-5 y) participated in a randomized cross-over trial. Each child completed 2 protocols, which simulate a day at childcare in random order for 2.5 hours; a typical preschool day (50% sitting) and a reduced preschool day (25% sitting) where most sitting activities were replaced with standing activities. Sitting, standing, and stepping time were objectively assessed using an activPAL accelerometer. EF was evaluated using tablet-based EF assessments (inhibition, working memory, and task shifting). Musculoskeletal health was assessed using a handheld dynamometer and goniometer.

RESULTS

Compared with the typical preschool day, the reduced sitting day showed no significant differences for EF scores. Effect sizes for inhibition (d = 0.04), working memory (d = 0.02), and shifting (d = 0.11) were all small. For musculoskeletal health, no significant differences were reported after the reduced preschool day. The effect sizes for the hip extension force, hamstring flexibility, gastrocnemius length, and balancing on 1 leg were all small (d = 0.21, d = 0.25, d = 0.28, and d = 0.28).

CONCLUSIONS

This study suggests that reducing sitting time is unlikely to result in acute changes in EF and musculoskeletal health among preschoolers.

Associations of accelerometer-measured sedentary time, sedentary bouts, and physical activity with adiposity and fitness in children

Sedentary time (ST) has been inconsistently associated with adiposity and cardiorespiratory fitness in children in previous studies. We studied cross-sectional associations of ST, light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA) with fat mass index (FMI) and cardiorespiratory fitness (estimated VO₂max). Associations were evaluated with and without considering pattern of ST by bout length. We measured ST and activity by a wrist-worn accelerometer, FMI by bioelectrical impedance, and VO₂max by Pacer test in 443 children (51.2% girls, 10.2 ± 0.6 years). Isotemporal substitution regression models estimated the effects of substituting ST, LPA, and MVPA on FMI and VO₂max. Further models repeated analyses separating ST into short (<10 min) and long (≥10 min) bouts. Only replacing ST or LPA with MVPA was consistently associated with lower FMI and greater VO₂max. When separated by bout length, only one unique association was found where replacing long ST bouts with short ST bouts was associated with lower FMI in girls only. In conclusion, activity pattern is associated with adiposity in girls and fitness in boys and girls. Separating ST into long and short ST bouts may be of minimal importance when assessing associations with adiposity and fitness using wrist-worn accelerometry in children.

Health Promotion in Socially Vulnerable Youth: Sports as a Powerful Vehicle?

Community sport has emerged in the past decades and uses sports as a lever to improve health and well-being among socially disadvantaged youth. Despite this premise, we do not know whether and to what extent health promotion aims are achieved within community sports practice. Measurable actions are needed, but it can be hard for researchers or practitioners to know how to approach this. This study aimed at developing a health-promoting intervention targeting youth attending community sports. To this aim, we used a planned approach for intervention design within a community-based participatory research design. The result is a group-based program promoting health-supportive behavior among community sport coaches, as we found coaches to be quintessential in fostering motivation toward health behavior change in vulnerable youth attending community sports. The design of such a complex intervention is difficult, yet tractable, when using a planned approach. Of importance, community engagement was the core of our work and we provide the reader with detailed examples on the combined use of participatory research and planned intervention design. This article provides an exemplar of how to approach the development of a health-promoting intervention in hard-to-reach populations.

Overweight and obesity in sexual and gender minority adolescents: A systematic review

Population data indicate that sexual and gender minority adolescents may be at increased risk for excess weight gain compared with cisgender, heterosexual youth. However, no studies, to our knowledge, have systematically reviewed the literature on weight disparities in this population nor explored risk for overweight and obesity by sexual and gender minority subgroup across studies. The current systematic review, therefore, identified 21 studies that assessed the relationship between sexual and gender minority status and weight among adolescents. Results indicated an overall greater prevalence of overweight and obesity among sexual and gender minority adolescents compared with cisgender, heterosexual youth. However, cisgender sexual minority males demonstrated lower or no added risk for overweight and obesity, whereas cisgender sexual minority females demonstrated greater risk for overweight and obesity. Findings were mixed among gender minority adolescents. This study highlights weight disparities in sexual and gender minority youth, although important subgroup differences exist. Additional research is needed to elucidate the mechanisms that may contribute to differential weight trajectories in this population and to develop tailored approaches for prevention and treatment.

Executive function and probabilities of engaging in long-term sedentary and high calorie/low nutrition eating behaviors in early adolescence

PURPOSE

Consumption of high calorie/low nutrition (HCLN) foods, as well as high levels of sedentary behavior (SB), may play a substantial role in the development of childhood overweight and obesity. However, the choice to engage or not engage in this behavior may be impacted by limits in executive functioning (EF) - a set of higher order functions related to decision making, planning, and inhibitory processes.

METHODS

The present study, as part of a large multiple health risk behavior trial designed to prevent substance use and obesity, evaluated the relationship between specific subdomains of EF and long-term patterns of HCLN food consumption and SB among a population of elementary school students (n = 709).

RESULTS

Utilizing a form of mixture modeling based on a latent transition analysis framework, subdomains of EF were found to influence the probability that students would report high levels of HCLN food consumption and SB over a thirty-month period. Gender and socioeconomic status further influenced the likelihood that students with poor EF would repeatedly engage in these unhealthy behaviors.

CONCLUSIONS

HCLN food consumption and SB in childhood can lead to an increased risk of becoming overweight or obese. Findings suggest that long term EF training, as well as the creation of environments that support appropriate decision-making, could be an important focus of future health promotion and education.

Maternal BMI Change Linked to Child Activity Change in Family-Based Behavioral Interventions for Pediatric Weight Management

Background: This study investigated whether change in maternal BMI was associated with change in child's moderate-to-vigorous physical activity (MVPA) and prolonged sedentary time during the course of family-based behavioral interventions (FBBIs) for pediatric weight management. Methods: Children (n = 120) ages 5-12 [mean age = 9.04 ± 1.7) years with a baseline BMI ≥85th percentile (mean BMIz = 1.8 ± 0.5) and families were enrolled in one of three similar FBBIs for pediatric weight management and followed over 6-12 months. Activity data were collected through accelerometers. Mixed effects regression models assessed the relationship of maternal change in BMI to child change in (1) minutes/d of MVPA and (2) proportion of time spent in sedentary bouts lasting ≥10 minutes (termed prolonged sedentary time), and whether the effect of maternal BMI change was moderated by child age, sex, and race/ethnicity. Results: A decrease in maternal BMI was associated with both an increase in child MVPA, B = -2.77, t = -2.03, p = 0.048, and a decrease in proportion/d of prolonged sedentary time, B = 0.02, t = 2.40, p = 0.020, from baseline to follow-up. Child age moderated the association between maternal BMI change and change in child prolonged sedentary time (p = 0.095), whereby the association was limited to 5- to 10-year-olds and became stronger as age decreased. Conclusions: Improvement in maternal BMI showed important positive associations with child MVPA and prolonged sedentary time over the course of FBBIs for pediatric weight management. Targeting parent weight loss could improve child outcomes in FBBIs, particularly in younger children.

Drivers of adolescent adiposity: Evidence from the Australian LOOK study

OBJECTIVES

To contribute to our understanding of the drivers of body composition during adolescence we sought to employ valid and reliable measures to investigate cross-sectional and longitudinal relationships between percentage body fat (%BF) and physical activity (PA), moderate and vigorous PA (MVPA), sedentary time (ST), total energy, sugar and fat intake.

DESIGN

Longitudinal cohort study.

METHODS

We measured 556 (289 male) participants at age 12.4 (SD 0.4) years, and 269 (123 males) at 16.3 (SD 0.4) years, for %BF (dual energy X-ray absorptiometry); habitual PA, MVPA, ST (accelerometry); and dietary intake ('multi-pass' weekday and weekend 24-h recall). Accounting for likely under-reporting of energy intake (Goldberg cut-off), general linear mixed modelling was used to generate relationships with %BF.

RESULTS

Cross-sectional analyses indicated that 10min more MVPA per day was associated with 0.6 lower %BF (95%CI 0.4-0.9, p<0.001), and 10min less ST/day with 0.07 lower %BF (95%CI 0.00-0.15, p<0.001), independently of PA. In contrast, %BF was unrelated to total energy (p=0.4), sugar intake (p=0.2) or fat intake (p=0.9). Longitudinal analysis showed that if PA was increased by 3% (10,000 counts/day) over the 4 years, then %BF was reduced by 0.08 (95%CI 0.05-0.12, p=0.06).

CONCLUSIONS

The independent relationships of %BF with PA and ST, but absence of relationships with energy, sugar or fat intake, suggest that general community campaigns in a developed country directed at reducing adolescent obesity through modifications to energy intake and output would benefit from a more concerted focus on the latter.

Association between television viewing and early childhood overweight and obesity: a pair-matched case-control study in China

BACKGROUND

Television (TV) viewing may affect children's obesity status. In the present study the association between TV viewing and early childhood overweight/obese status was investigated as well as the association based on age difference.

METHODS

The present study included 933 children 1-5 years of age that were individually matched on a 1:2 (cases: controls) ratio based on age and community. Cochran-Mantel-Haenszel test was used to evaluate the association between TV viewing time and the related unhealthy behaviors. Conditional logistic regression models were used to quantify the association between TV viewing and children overweight/obese status in two age groups. The effects of TV viewing-related behaviors on the associations were further investigated.

RESULTS

TV viewing time > 1 h was positively associated with the prevalence of TV viewing-related unhealthy behaviors (P < 0.05). After controlling for these behaviors, the association between TV viewing and childhood overweight/obese status was significant among 4- to 5-year-old children (odds ratio, OR = 1.72, 95% confidence interval, CI: 1.16--2.54), but not significant among 1- to 3-year-old children.

CONCLUSIONS

Childhood overweight/obese status was positively associated with longer TV viewing time only among 4- to 5-year-old children. The results from the present study may help in identifying the population susceptible for overweight and obesity caused by TV viewing.

Skipping breakfast is associated with adiposity markers especially when sleep time is adequate in adolescents

Adolescence is a critical stage of development and has an important influence on energy balance-related behaviours (EBRBs). When adolescents are associated with obesity it can lead to increased cardiometabolic risk. Here we assess if EBRBs adopted by adolescents included in a subsample are associated with markers of total and abdominal adiposity in a multicentre European study, Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA-CSS) and a Brazilian study, Brazilian Cardiovascular Adolescent Health (BRACAH study), and whether sleep duration influence the association between skipping breakfast, physical activity and sedentary behaviours, with total and abdominal obesity (AO). Multilevel linear regression models using fixed and random intercepts were used to analyse the association between markers of obesity and EBRBs. Skipping breakfast was the prevalent behaviour in association with obesity among European and Brazilian boys besides European girls, even after stratification by sleep time. Moreover, European boys who slept properly and skipped breakfast had an increased waist circumference (WC), while body mass index (BMI) increased in Brazilian boys. Among Brazilian boys less sleep was protective for total obesity (β = −0.93 kg/m²; 95% CI: −1.80; −0.07). European girls when they were more sedentary, showed an increase in WC, especially for those who reported they slept adequately. Skipping breakfast was associated with total and AO in adolescents independent of sleep duration.