An evidence-update on the prospective relationship between childhood sedentary behaviour and biomedical health indicators: a systematic review and meta-analysis

The cross-sectional association of parental psychosocial status with children's Body Mass Index z-score and the mediating role of children's energy balance behaviors - the ABCD Study

OBJECTIVE

Investigate the cross-sectional association between the psychosocial status of mothers and fathers and the BMI z-scores of their 10 to 12-year-old children. Explore whether this association is mediated by children's diet, physical activity, screen time and sleep. Analyze the moderating effect of the educational levels of both the mother and father on the association.

DESIGN

In a cross-sectional study design, children's height and weight were measured following a standardized protocol. Parents completed the validated Depression Anxiety and Stress questionnaire, while diet quality, sports participation, time spent in bed and screen time were assessed through child-report using previously validated questions.

PARTICIPANTS

The data for this study were obtained from the Amsterdam Born Children and their Development study, involving children aged 10 to 12 years and both of their parents (N = 1315).

RESULTS

The majority, 80%, of the parents were highly educated and born in the Netherlands, and 68% of the children had a healthy BMI. Maternal or paternal psychosocial status was not significantly associated with children's BMI z-score (maternal β -0.0037; 95% CI: -0.008 to 0.0007, paternal β 0.0028; 95% CI: -0.007 to 0.002). Screen time mediated the association between paternal psychosocial status and children's BMI z-score (β = 0.010, 95% CI: 0.002; 0.020). Children's diet, physical activity, and sleep did not mediate the association between paternal psychosocial status and children's BMI z-score. Parental educational level was not a moderator.

CONCLUSIONS

This research is unique in including four energy balance behaviors and including both mothers and fathers' psychosocial status. Children withfathers experiencing poorer psychosocial status engaged in more screen time which partly explained their higher BMI z-score.

Physical activity and amyloid beta in middle-aged and older adults: A systematic review and meta-analysis

BACKGROUND

One of the pathological hallmarks distinguishing Alzheimer's disease from other dementias is the accumulation of amyloid beta (Aβ). Higher physical activity is associated with decreased dementia risk, and one potential path could be through Aβ levels modulation. We aimed to explore the relationship between physical activity and Aβ in middle-aged and older adults.

METHODS

A systematic search of PubMed, Web of Science, PsycINFO, Cochrane Central Register of Controlled Trials, and SPORTDiscus was performed from inception to April 28, 2022. Studies were eligible if they included physical activity and Aβ data in adults aged 45 years or older. Multi-level meta-analyses of intervention and observational studies were performed to examine the role of physical activity in modulating Aβ levels.

RESULTS

In total, 37 articles were included (8 randomized controlled trials, 3 non-randomized controlled trials, 4 prospective longitudinal studies, and 22 cross-sectional studies). The overall effect size of physical activity interventions on changes in blood Aβ was medium (pooled standardized mean difference = -0.69, 95% confidence interval (95%CI): -1.41 to 0.03; I2 = 74.6%). However, these results were not statistically significant, and there were not enough studies to explore the effects of physical activity on cerebrospinal fluid (CSF) and brain Aβ. Data from observational studies were examined based on measurements of Aβ in the brain using positron emission tomography scans, CSF, and blood. Higher physical activity was positively associated with Aβ only in the CSF (Estimate r = 0.12; 95%CI: 0.05-0.18; I2 = 38.00%).

CONCLUSION

Physical activity might moderately reduce blood Aβ in middle-aged and older adults. However, results were only near statistical significance and might be interpreted with caution given the methodological limitations observed in some of the included studies. In observational studies, higher levels of physical activity were positively associated with Aβ only in CSF. Therefore, further research is needed to understand the modulating role of physical activity in the brain, CSF, and blood Aβ, as well as its implication for cognitive health.

Adherence to 24-hour integrated activity guidelines among infants, toddlers and preschool children in Singapore

This study examined children's adherence to the Singapore Integrated 24-Hour Activity Guidelines for Early Childhood in infants, toddlers and preschoolers aged 0-6 years. A total of 901 caregivers, comprising 219 infants, 379 toddlers, and 303 preschoolers, provided information regarding their children's physical activity (PA), screen viewing time (SVT), and sleep durations on both weekdays and weekends. Meeting the 24-hour integrated activity guidelines was defined as follows: for infants ≥ 30 minutes per day of tummy time or floor-based play; zero SVT; total sleep of 14-17 hours per day for ages 0-3 months, 12-16 hours per day for ages 4-11 months; for toddlers ≥ 180 minutes of total PA per day; zero SVT under 2 years; <1 hour for ages 2 to less than 3 years; and a total sleep of 11-14 hours per day; for preschoolers ≥ 180 minutes of total PA per day; SVT <1 hour per day; total sleep of 10-13 hours per day for those aged 3-5 years, and 10-11 hours per day for 6-year-olds. Chi-squared tests were used to examine the differences in guideline adherence between weekdays and weekends. Compared to weekdays, during weekends there was a higher proportion of toddlers and preschoolers adhering to the PA guidelines (68.9% vs 50.1%; 78.9% vs 55.4%, respectively, p<0.05), and a lower proportion of toddlers adhering to SVT (38.8% vs 21.8%; p = 0.001). There was a declining adherence to all three activity guidelines as age groups progressed from infants (44.7%) to toddlers (15.8%) and then to preschoolers (9.4%). Concurrently, there was a decrease in adherence to SVT recommendations across the age groups, with adherence rates being highest among infants (83.1%), followed by toddlers (15.8%), and preschoolers (9.4%). Decreasing compliance with all three guidelines, coupled with a corresponding decline in adherence to SVT guidelines as children transition from toddlerhood to preschool age, is a cause for concern. This underscores the need for proactive efforts to educate caregivers about reducing or eliminating SVT among infants and young children.

Change in screen time and overuse, and their association with psychological well-being among US-wide school-age children during the COVID-19 pandemic: analysis of the National Survey of Children's Health (NSCH) years 2018-21

BACKGROUND

Previous studies on screen use and children's mental health during the Coronavirus Disease 2019 (COVID-19) pandemic focused only on the timeframe during the pandemic, on children between narrow age ranges, only among a subset of children who have previously reported COVID-related severe family economic hardship or worries, or did not distinguish between instructive versus recreational device usage. Thus, in this study, we analyzed trends, specifically related to recreational screen use, and associations with psychological well-being (PWB) in the years before versus during the COVID-19 pandemic, among a wide range of school-aged children, widely across the nation.

METHODS

Using the National Survey of Children's Health (NSCH) years 2018-21, we analyzed a large random sample of school-aged children (6-17 years old) across the US (n = 88,823). We developed PWB issue scores (PWBIS) using self-reported measures relevant to this age group, and constructed regression models to assess the magnitude of the contribution of the pandemic on recreational screen use and PWB.

RESULTS

The prevalence of recreational screen overuse and PWBIS increased significantly during the pandemic, compared to prior years. We also detected a notable effect of the pandemic on increased PWBIS, as well as its interaction term finding that it strengthened the association between screen time and PWBIS (p < 0.01 across all regression models).

CONCLUSIONS

Accordingly, our results demonstrate the importance of the pandemic itself as an independent adverse factor and effect measure modifier for screen overuse and PWB more generally among all school-age children widely across the US. Our study used the most current data available, and future studies to evaluate whether these effects are persistent in the years after the pandemic are important.

An umbrella review of the benefits and risks associated with youths' interactions with electronic screens

The influence of electronic screens on the health of children and adolescents and their education is not well understood. In this prospectively registered umbrella review (PROSPERO identifier CRD42017076051 ), we harmonized effects from 102 meta-analyses (2,451 primary studies; 1,937,501 participants) of screen time and outcomes. In total, 43 effects from 32 meta-analyses met our criteria for statistical certainty. Meta-analyses of associations between screen use and outcomes showed small-to-moderate effects (range: r = -0.14 to 0.33). In education, results were mixed; for example, screen use was negatively associated with literacy (r = -0.14, 95% confidence interval (CI) = -0.20 to -0.09, P ≤ 0.001, k = 38, N = 18,318), but this effect was positive when parents watched with their children (r = 0.15, 95% CI = 0.02 to 0.28, P = 0.028, k = 12, N = 6,083). In health, we found evidence for several small negative associations; for example, social media was associated with depression (r = 0.12, 95% CI = 0.05 to 0.19, P ≤ 0.001, k = 12, N = 93,740). Limitations of our review include the limited number of studies for each outcome, medium-to-high risk of bias in 95 out of 102 included meta-analyses and high heterogeneity (17 out of 22 in education and 20 out of 21 in health with I2 > 50%). We recommend that caregivers and policymakers carefully weigh the evidence for potential harms and benefits of specific types of screen use.

Meeting the Canadian 24-Hour Movement Guidelines and physical-mental comorbidity among Chinese children and adolescents: Prevalence, associations, and the population impacts

OBJECTIVES

To examine the association between meeting the Canadian 24-Hour Movement Guidelines and physical-mental comorbidity among children and adolescents in a cross-sectional study.

METHODS

A total of 21,061 students aged 11-17 years from Zhejiang Province, China was recruited in the study. We examined the coexistence of five specific physical illnesses - hypertension, high myopia, dental caries, scoliosis, and obesity - with mental illness, specifically depressive symptoms. Generalized linear mixed models were performed to assess the association between overall and specific combinations of movement guidelines and physical-mental comorbidity, presented by odds ratio (OR) and 95% confidence interval (CI). Population attributable fraction (PAF) was calculated to estimate the preventable proportion of comorbid cases via meeting all three movement recommendations.

RESULTS

Of the included participants, 19.3% had physical-mental comorbidity. There were 3.8% and 17.0% meeting all three and none of the recommendations, respectively. Meeting at least one recommendation, except for moderate-to-vigorous physical activity recommendation only, was associated with a lower risk of physical-mental comorbidity, with ORs (95% CIs) ranging from 0.72 (0.66-0.79) to 0.40 (0.31-0.51). Meeting more recommendations was associated with decreased comorbid risks, and the association was stronger in 4th-6th graders. The association between specific combinations of recommendations and comorbid risks showed differences by gender and grade. Of the comorbid cases, 42.1% were attributed to not adhering to all three recommendations, and the PAFs varied from 27.4% to 55.7% across different genders and grades.

CONCLUSION

Adherence to the 24-h movement guidelines was associated with lower risks of physical-mental comorbidity among children and adolescents.

Sedentary Bout Patterns and Metabolic Health in the Hispanic Community Health Study/Study of Latino Youth (SOL Youth)

Background There is limited evidence on the potential negative metabolic health impacts of prolonged and uninterrupted sedentary bouts in structurally disadvantaged youth. This study investigated associations between sedentary bout variables and metabolic health markers in the Hispanic Community Health Study/SOL Youth (Study of Latino Youth). Methods and Results SOL Youth was a population-based cohort of 1466 youth (age range, 8-16 years; 48.5% female); 957 youth were included in the analytic sample based on complete data. Accelerometers measured moderate-to-vigorous physical activity (MVPA), total sedentary time, and sedentary bout patterns (daily time spent in sedentary bouts ≥30 minutes, median sedentary bout duration, and number of daily breaks from sedentary time). Clinical measures included body mass index, waist circumference, fasting glucose, glycated hemoglobin, fasting insulin, and the homeostasis model assessment of insulin resistance. After adjusting for sociodemographics, total sedentary time, and MVPA, longer median bout durations and fewer sedentary breaks were associated with a greater body mass index percentile (bbouts=0.09 and bbreaks=-0.18), waist circumference (bbouts=0.12 and bbreaks=-0.20), and fasting insulin (bbouts=0.09 and bbreaks=-0.21). Fewer breaks were also associated with a greater homeostasis model assessment of insulin resistance (b=-0.21). More time in bouts lasting ≥30 minutes was associated with a greater fasting glucose (b=0.18) and glycated hemoglobin (b=0.19). Conclusions Greater accumulation of sedentary time in prolonged and uninterrupted bouts had adverse associations with adiposity and glycemic control over and above total sedentary time and MVPA. Findings suggest interventions in Hispanic/Latino youth targeting both ends of the activity spectrum (more MVPA and less prolonged/uninterrupted sedentary patterns) may provide greater health benefits than those targeting only MVPA.

Associations of Home-Based Screen Time and Its' Changes With Follow-up Body Mass Index in Chinese Preschool-Aged Children

This study aimed to explore the associations of screen time (ST) and its' changes with follow-up body mass index (BMI) in preschool children. Parents of 805 preschoolers participated in our study at baseline and were followed up after 1 year in China. Linear regression models were used to analyze the dynamic relationship between ST and BMI in preschool children. A total of 662 preschoolers, including 342 boys (51.7%) and 320 girls (48.3%) were followed up. The changes in ST (from the initial ≤1 h/day to >1 h/day at follow-up vs keep ≤1 h/d, β(SE) = 0.21(0.09), P = .016) and follow-up ST of preschool children (>1 h/d vs ≤1 h/d, β(SE) = 0.17(0.07), P = .013) were significantly associated with an increase in the preschoolers' z-scored BMI at follow-up after adjusting for potential confounding factors. We concluded that the unfavorable change in ST was associated with increased BMI in preschool children.

Is the transition from primary to secondary school a risk factor for energy balance-related behaviours? A systematic review

OBJECTIVE

The substantial changes in the physical and social environment during the transition from primary to secondary school may significantly impact adolescents' energy balance-related behaviours (i.e. dietary behaviour, sedentary behaviour, sleep behaviour and physical activity (PA)). This is the first review systematically summarising evidence on changes in four energy balance-related behaviours of adolescents across the school transition from primary to secondary school.

DESIGN

For this systematic review, the electronic databases Embase, PsycINFO and SPORTDiscus were searched for relevant studies from inception to August 2021. PubMed was searched for relevant studies from inception to September 2022. Inclusion criteria were: (i) longitudinal studies reporting; (ii) one or more energy balance-related behaviours; and (iii) across the school transition, that is, with measurement(s) during both primary and secondary school.

SETTING

Transition from primary to secondary school.

PARTICIPANTS

Adolescents across the transition from primary to secondary school.

RESULTS

Thirty-four studies were eligible. We found strong evidence for an increase in sedentary time, moderate evidence for a decrease in fruit and vegetable consumption, and inconclusive evidence for a change in total, light, and moderate-to-vigorous PA, active transport, screen time, unhealthy snack consumption, and sugar-sweetened beverages consumption among adolescents across the school transition.

CONCLUSIONS

During the transition from primary to secondary school, sedentary time and fruit and vegetable consumption tend to change unfavourably. More high-quality, longitudinal research is needed specifically on changes in energy balance-related behaviour across the school transition, especially regarding sleep behaviour. (Prospero registration: CRD42018084799).

Microbial composition across body sites in polycystic ovary syndrome: a systematic review and meta-analysis

Polycystic ovary syndrome (PCOS) is an endocrine disorder affecting reproductive-aged women, but the cause remains unclear. Recent evidence has linked microbial composition with PCOS; however, the results are inconsistent. The aim of this systematic review was to gather current knowledge of the microbes across body sites (oral cavity, blood, vagina/cervix, gut) in women with PCOS, and meta-analyse the microbial diversity in PCOS. For this purpose, a systematic search using PubMed, Web of Science, Cochrane and Scopus was carried out. After selection, 34 studies met the inclusion criteria. Most of the studies associated changes in the microbiome with PCOS, whereas heterogeneity of the studies in terms of ethnicity, body mass index (BMI) and methodology, among other confounders, made it difficult to corroborate this relationship. In fact, 19 out of 34 of the studies were categorised as having high risk of bias when the quality assessment was conducted. Our meta-analysis on the gut microbiome of 14 studies demonstrated that women with PCOS possess significantly lower microbial alpha diversity compared with controls (SMD = -0.204; 95% CI -0.360 to -0.048; P = 0.010; I2 = 5.508, by Shannon Index), which may contribute to the development of PCOS. Nevertheless, future studies should specifically overcome the shortcomings of the current studies by through well planned and conducted studies with larger sample sizes, proper negative and positive controls and adequate case-control matching.

Sedentary behaviour profiles and longitudinal associations with academic performance in youth: The UP&DOWN study

The current study evaluated longitudinal associations between profile transitions of context-specific sedentary behaviour (SB) and changes in academic performance (AP) among school-aged youth. Participants were 466 children and 717 adolescents (50.8% males) aged 8-18 years (children = 7.92 ± 0.41 years; adolescents = 11.85 ± 1.53 years). Non-school SBs and AP were evaluated at baseline and two years later. General linear mixed models were implemented, controlling for age, region, parental education, body mass index, and cardiorespiratory fitness. Cross-sectionally, participants with an Educative-profile (i.e., highest scores in doing homework with/without computer and reading for fun) had higher AP when compared to other profiles. Longitudinally, males who changed from a Screen- to an Educative-profile had higher AP than males who changed from an Educative- to a Social- or Screen-SB profile (p < 0.01). No significant differences were found in females. These findings show the importance of analysing SB patterns from a qualitative perspective (i.e., context-specific for boosting school children AP) and highlighting time spent in educative as the most positive for AP, as well the need to implement interventions to reduce time on screen and social behaviours, especially targeting males.

Transform-Us! cluster RCT: 18-month and 30-month effects on children's physical activity, sedentary time and cardiometabolic risk markers

OBJECTIVE

To test the efficacy of the Transform-Us! school- and home-based intervention on children's physical activity (PA), sedentary behaviour (SB) and cardiometabolic risk factor profiles.

METHODS

A 30-month 2×2 factorial design cluster randomised controlled trial delivered in 20 primary schools (148 Year 3 classes) in Melbourne, Australia (2010-2012), that used pedagogical and environmental strategies to reduce and break up SB, promote PA or a combined approach, compared with usual practice. Primary outcomes (accelerometry data; n=348) were assessed at baseline, 18 and 30 months. Secondary outcomes included body mass index (BMI) and waist circumference (WC) (n=564), blood pressure (BP) (n=537) and biomarkers (minimum n=206). Generalised linear mixed models estimated the interactive effects of the PA and SB interventions on the outcomes. If there was no interaction, the main effects were assessed.

RESULTS

At 18 months, there were intervention effects on children's weekday SB (-27 min, 95% CI: -47.3 to -5.3) for the PA intervention, and on children's average day PA (5.5 min, 95% CI: 0.1 to 10.8) for the SB intervention. At 30 months, there was an intervention effect for children's average day SB (-33.3 min, 95% CI: -50.6 and -16.0) for the SB intervention. Children's BMI (PA and SB groups) and systolic BP (combined group) were lower, and diastolic BP (PA group) was higher. There were positive effects on WC at both time points (SB intervention) and mixed effects on blood parameters.

CONCLUSIONS

The Transform-Us! PA and SB interventions show promise as a pragmatic approach for reducing children's SB and adiposity indicators; but achieving substantial increases in PA remains challenging.

TRIAL REGISTRATION

ISRCTN83725066; ACTRN12609000715279.

Recreational screen time trajectories during early childhood and imaging-measured body composition at age 7 in the Odense child cohort

BACKGROUND

Children spend increasing amounts of time on recreational screen media, which may lead to an obesogenic environment.

OBJECTIVES

We investigated the association of trajectories of screen time across ages 3, 5 and 7 years with body composition at age 7 in the Odense Child Cohort.

METHODS

Data were collected in the Municipality of Odense, Denmark, between 2010 and 2019. Group-based trajectory modelling was applied to group participants into four trajectories of prospective parent-reported screen time. Body composition was assessed using dual-energy x-ray absorptiometry with calculated fat-mass index (FMI) as the primary outcome. Primary models were linear multivariable regression models adjusted for participants' sex, age, birthweight, maternal origin, maternal education, maternal body-mass-index, and maternal age. Further models were adjusted for additional possible confounders. Selection bias was addressed by inverse probability weighting.

RESULTS

In total, 803 children (48.2% female) were included in the primary analysis. Participants with screen time at all time points were assigned to four trajectory groups [constant low screen time (12.7%), low increase (36.3%), high increase between ages 3 and 5 (33.5%) and high increase in screen time (17.5%)]. Sample characteristics differed across missing data status and trajectories. Mean FMI (kg/m² ) and standard deviation (SD) were 3.7 (SD 1.3) and 3.9 (SD 1.6) for the constant low versus high screen time, respectively. No differences in FMI were found between screen time trajectory groups at age 7 (adjusted mean difference 0.1 kg/m² , 95% confidence interval -0.3, 0.5 for constant low versus high screen time). No consistent associations between screen time groups and secondary body composition outcomes were found.

CONCLUSIONS

Results from this study do not suggest that recreational screen time from age 3 to 7 years is associated with adiposity or other measures of body composition.

Sedentary Behavior Patterns of the Hungarian Adult Population

BACKGROUND AND AIM

Nowadays, a high level of sedentary behavior (SB) is an important health issue. Many studies have focused on evaluating the physical activity (PA) level, while evaluation of SB has received less attention. The main goal of the present study is to describe the sedentary lifestyle of the Hungarian adult population and identify the vulnerable groups with high amount of sitting time and the patterns of SB. Another aim of this study is to compare the two types of questionnaires (International Physical Activity Questionnaire-IPAQ and Sedentary Behavior Questionnaire-SBQ) related to sitting time.

METHODS

This study analyzed cross-sectional primary data using self-reported questionnaires collected by a Hungarian research market company among the adult population in Hungary. The final sample of this study consisted of 1295 participants with a mean age of 45.9 years (SD = 15.2). Analysis of variance (ANOVA) test with post-hoc (Tukey) analysis were used to analyze the link between sitting time and socio-demographic variables (sex, age, BMI, settlement type, education level, marital status, work category, working hours, employment status, sport activity) and body mass index (BMI).

RESULTS AND CONCLUSIONS

According to the SBQ, on average, Hungarians sit for 469.53 min per day (7.81 h) on weekdays and 421.25 min per day (7.01 h) on weekends, which suggested a significant difference compared to IPAQ data: 287.82 min per day (4.79 h) on weekdays and 224.30 min per day (3.73 h) on weekends. Young people (aged between 18 and 29) were reported to have the highest average sitting time, i.e., 545 min per day (more than 9 h), and are showing the highest prevalence (53%) of sitting at least 480 min (8 h) per day. Sitting workers also had a high average sitting time, i.e., 514.82 min per day, and a high prevalence (49.3%) of sitting at least 480 min (8 h) per day. People who live in the capital city had higher sitting time, especially on working days. Men sat longer than woman, i.e., 19 min on working days and 45 min on weekends. The most frequent sedentary activities are: working on computer (126 min) on working days and watching TV (130 min) on weekends. Our results clearly show that the self-report single-item measure (IPAQ) significantly underestimates sedentary time compared to the multi-item questionnaire (SBQ). We identified vulnerable groups with high sitting times: men, young adults, inhabitants of the capital city and sitting workers. Consequently, these groups should be continuously surveyed, and requires specific interventions and strategies that particularly counteract the increased sitting time.

Assessing policies to reduce adolescent overweight and obesity: Insights from a system dynamics model using data from the Health Behavior in School-Aged Children study

Adolescent overweight and obesity (AdOWOB) in Europe has proven to be a persistent and complex problem, and appropriate systems methods may help in evaluating potential policy options. This paper describes the development of a system dynamics model of AdOWOB as part of the EU-funded CO-CREATE project. The model was developed using literature and data from the Health Behavior in School-Aged Children (HBSC) study across 31 European countries. We identified 10 HBSC variables that were included as direct or indirect drivers of AdOWOB in the dynamic model, seven at the level of the individual, and three related to the social environment. The model was calibrated to 24 separate cases based on four gender and perceived wealth segments for each of the five CO-CREATE countries (The Netherlands, Norway, Poland, Portugal, and the UK) and for Europe overall. Out of 10 possible intervention points tested, exercise, fruit, life dissatisfaction, school pressure, and skipping breakfast were identified as the top five most influential ones across the 24 cases. These model-based priorities can be compared with the policy ideas suggested by the CO-CREATE adolescents.

Association of daily and time-segmented physical activity and sedentary behaviour with mental health of school children and adolescents from rural Northeastern Ontario, Canada

Physical activity (PA) and sedentary behaviour (SED) have been linked to the mental health of children and adolescents, yet the timing of behaviours may play a role in this relationship and clarifying this could inform interventions. We explored cross-sectional associations of PA and SED in varying time segments throughout the school day with the mental health of school-aged children and adolescents from rural Northeastern Ontario, Canada. A total of 161 students (56% female, M = 10.3 years old) wore accelerometers for 8 days (7 nights) and completed a self-report survey (parent reported for children younger than 11). Mental health was measured using the Strengths and Difficulties Questionnaire. Accelerometer-measured SED, light PA (LPA), and moderate and vigorous PA (MVPA) were estimated in the time-segments before school (06:00–08:44), school time (08:45–15:04), after school (15:05–16:59), and evenings (17:00–21:59). Associations were tested with multilevel linear regressions while adjusting for confounding factors. Students spent 72.6 min in MVPA, 209.0 min in LPA, and 621.0 min in SED per day. Daily SED was associated with less conduct problems (β = −0.27, p &lt; 0.05). Evening LPA was inversely associated with hyperactivity (β = −1.45, p &lt; 0.05), while SED was associated with hyperactivity and with peer problems before school (β = 1.70 and β = 1.01, respectively, p &lt; 0.05), and during school (β = −0.83 and β = −0.57, respectively, p &lt; 0.05). No associations were observed for MVPA, emotional symptoms, or prosocial behaviour. In conclusion, displacing SED with LPA in some specific periods of the day may benefit the mental health of students; taking this into account could strengthen interventions.

Increased Screen Time as a Cause of Declining Physical, Psychological Health, and Sleep Patterns: A Literary Review

Dependency on digital devices resulting in an ever-increasing daily screen time has subsequently also been the cause of several adverse effects on physical and mental or psychological health. Constant exposure to devices like smartphones, personal computers, and television can severely affect mental health- increase stress and anxiety, for example, and cause various sleep issues in both children as well as adults. Risk factors for obesity and cardiovascular disorders, including hypertension, poor regulation of stress, low HDL cholesterol, and insulin resistance are among the physical health repercussions we see. The psychological health effects comprise suicidal tendencies and symptoms of depression which are associated with digital device dependency, screen-time-induced poor sleep quality, and content-influenced negativity. Oftentimes it can cause the induction of a state of hyper-arousal, increase stress hormones, desynchronize the body clock or the circadian cycle, alter brain chemistry and create a drag on mental energy and development. With a focus on brain development in children and detrimental effects in both adults and children, this research article goes on to explore the various aspects of screen addiction and excessive screen exposure.

Is level of implementation linked with intervention outcomes? Process evaluation of the TransformUs intervention to increase children’s physical activity and reduce sedentary behaviour

Background

TransformUs was a four-arm school-based intervention to increase physical activity and reduce sedentary behaviour among primary school children. Pedagogical and environmental strategies targeted the classroom, school grounds and family setting. The aims of this study were to evaluate program fidelity, dose, appropriateness, satisfaction and sustainability, and associations between implementation level and outcomes among the three intervention arms.

Methods

At baseline, 18-months (mid-intervention) and 30-months (post-intervention), teachers, parents and children completed surveys, and children wore GT3X ActiGraph accelerometers for 8 days at each time point to determine physical activity and sedentary time. Implementation data were pooled across the three intervention groups and teachers were categorised by level of implementation: (i) ‘Low’ (< 33% delivered); (ii) ‘Moderate’ (33–67% delivered); and (iii) ‘High’ (> 67% delivered). Linear and logistic mixed models examined between group differences in implementation, and the association with children’s physical activity and sedentary time outcomes. Qualitative survey data were analysed thematically.

Results

Among intervention recipients, 52% (n = 85) of teachers, 29% (n = 331) of parents and 92% (n = 407) of children completed baseline evaluation surveys. At 18-months, teachers delivered on average 70% of the key messages, 65% set active/standing homework, 30% reported delivering > 1 standing lesson/day, and 56% delivered active breaks per day. The majority of teachers (96%) made activity/sports equipment available during recess and lunch, and also used this equipment in class (81%). Fidelity and dose of key messages and active homework reduced over time, whilst fidelity of standing lessons, active breaks and equipment use increased. TransformUs was deemed appropriate for the school setting and positively received. Implementation level and child behavioural outcomes were not associated. Integration of TransformUs into existing practices, children’s enjoyment, and teachers’ awareness of program benefits all facilitated delivery and sustainability.

Conclusions

This study demonstrated that intervention dose and fidelity increased over time, and that children’s enjoyment, senior school leadership and effective integration of interventions into school practices facilitated improved intervention delivery and sustainability. Teacher implementation level and child behavioural outcomes were unrelated, suggesting intervention efficacy was achieved irrespective of implementation variability. The potential translatability of TransformUs into practice contexts may therefore be increased. Findings have informed scale-up of TransformUs across Victoria, Australia.

Trial registration

International Standard Randomized Controlled Trial Number ISRCTN83725066; Australian New Zealand Clinical Trials Registry Number ACTRN12609000715279. Registered 19 August 2009. Available at: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=308387&isReview=true

Supplementary Information

The online version contains supplementary material available at 10.1186/s12966-022-01354-5.

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.

CHAP-child: an open source method for estimating sit-to-stand transitions and sedentary bout patterns from hip accelerometers among children

BACKGROUND

Hip-worn accelerometer cut-points have poor validity for assessing children's sedentary time, which may partly explain the equivocal health associations shown in prior research. Improved processing/classification methods for these monitors would enrich the evidence base and inform the development of more effective public health guidelines. The present study aimed to develop and evaluate a novel computational method (CHAP-child) for classifying sedentary time from hip-worn accelerometer data.

METHODS

Participants were 278, 8-11-year-olds recruited from nine primary schools in Melbourne, Australia with differing socioeconomic status. Participants concurrently wore a thigh-worn activPAL (ground truth) and hip-worn ActiGraph (test measure) during up to 4 seasonal assessment periods, each lasting up to 8 days. activPAL data were used to train and evaluate the CHAP-child deep learning model to classify each 10-s epoch of raw ActiGraph acceleration data as sitting or non-sitting, creating comparable information from the two monitors. CHAP-child was evaluated alongside the current practice 100 counts per minute (cpm) method for hip-worn ActiGraph monitors. Performance was tested for each 10-s epoch and for participant-season level sedentary time and bout variables (e.g., mean bout duration).

RESULTS

Across participant-seasons, CHAP-child correctly classified each epoch as sitting or non-sitting relative to activPAL, with mean balanced accuracy of 87.6% (SD = 5.3%). Sit-to-stand transitions were correctly classified with mean sensitivity of 76.3% (SD = 8.3). For most participant-season level variables, CHAP-child estimates were within ± 11% (mean absolute percent error [MAPE]) of activPAL, and correlations between CHAP-child and activPAL were generally very large (> 0.80). For the current practice 100 cpm method, most MAPEs were greater than ± 30% and most correlations were small or moderate (≤ 0.60) relative to activPAL.

CONCLUSIONS

There was strong support for the concurrent validity of the CHAP-child classification method, which allows researchers to derive activPAL-equivalent measures of sedentary time, sit-to-stand transitions, and sedentary bout patterns from hip-worn triaxial ActiGraph data. Applying CHAP-child to existing datasets may provide greater insights into the potential impacts and influences of sedentary time in children.

The associations between specific-type sedentary behaviors and cognitive flexibility in adolescents

Background: The prevalence of sedentary behavior in adolescents has aroused social attention. The association between sedentary behavior and cognitive flexibility remains unclear, and it may vary depending on the type of sedentary behavior. This study aimed to investigate the associations between specific-type sedentary behaviors and cognitive flexibility in adolescents.

Method: A total of 700 Chinese adolescents aged 10–15 years were recruited. The self-report questionnaire was used to assess total sedentary time, recreational screen-based sedentary time, and educational sedentary time. The More-odd shifting task was used to assess cognitive flexibility.

Results: The correlation analysis showed that recreational screen-based sedentary time was negatively correlated with cognitive flexibility, whereas educational sedentary time was positively correlated with cognitive flexibility. The regression analysis also further revealed that a significantly negative association between recreational screen-based sedentary time and cognitive flexibility, while a significantly positive association existed between educational sedentary time and cognitive flexibility.

Conclusion: The findings shown that the association between recreational screen-based sedentary behavior and cognitive flexibility differs from educational sedentary behavior in adolescents, providing new ideas for a more comprehensive understanding of the association between sedentary behavior and cognitive flexibility in adolescents.

Sedentary Behaviors and Health Outcomes among Young Adults: A Systematic Review of Longitudinal Studies

Objective: This study aimed to review and provide an informative synthesis of the findings from longitudinal studies that describe the relationship between sedentary behavior and various health outcomes among young adults. Methods: A literature search was conducted in Web of Science, PubMed, APA PsycInfo, MEDLINE, Embase, and the Cochrane Library for articles that examined the association between sedentary behavior and health outcomes among young adults aged 18–34 years. Two reviewers independently examined the articles and performed data extraction and quality assessment. The level of evidence was determined using the best-evidence synthesis. Results: A total of 34 studies were included in the analysis, 18 of which were high-quality studies. On the basis of inconsistency in the findings among studies, insufficient evidence was concluded for sedentary behavior and adiposity indicators, physical fitness, metabolic syndrome/cardiovascular disease risk factors, cognitive function, and mood disorders. Based on one high-quality study, moderate evidence for a negative relationship between sedentary behavior and physical fitness was observed. Conclusions: Given the trend toward increased time in sedentary behaviors and the inconsistent current findings, additional longitudinal studies of high methodologic quality are recommended to clarify the relationships between sedentary behavior and health outcomes among young adults.

Effect of Intensity and Duration of Exercise on Gut Microbiota in Humans: A Systematic Review

(1) Background: The gut microbiota might play a part in affecting athletic performance and is of considerable importance to athletes. The aim of this study was to search the recent knowledge of the protagonist played by high-intensity and high-duration aerobic exercise on gut microbiota composition in athletes and how these effects could provide disadvantages in sports performance. (2) Methods: This systematic review follows the PRISMA guidelines. An exhaustive bibliographic search in Web of Science, PubMed, and Scopus was conducted considering the articles published in the last 5 years. The selected articles were categorized according to the type of study. The risk of bias was assessed using the Joanna Briggs Institute's Critical Appraisal Tool for Systematic Reviews. (3) Results: Thirteen studies had negative effects of aerobic exercise on intestinal microbiota such as an upsurge in I-FABP, intestinal distress, and changes in the gut microbiota, such as an increase in Prevotella, intestinal permeability and zonulin. In contrast, seven studies observed positive effects of endurance exercise, including an increase in the level of bacteria such as increased microbial diversity and increased intestinal metabolites. (4) Conclusions: A large part of the studies found reported adverse effects on the intestinal microbiota when performing endurance exercises. In studies carried out on athletes, more negative effects on the microbiota were found than in those carried out on non-athletic subjects.

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.

Sedentary behavior and health-related quality of life in adolescents

Health-related quality of life (HRQoL) represents the perception of each person about different aspects of their lives in the health context (physical, psychological, social environment and interpersonal relationships). Among adolescents, HRQoL can change considering habits adopted in this phase of life. This study analyzed the association between time used on different sedentary behaviors (SB) and HRQoL in adolescents. This is a cross-sectional epidemiological study with adolescents between 10 - 15 years of age. The SB was measured using a questionnaire (n = 1,455 adolescents) and accelerometer (n = 844 adolescents), and HRQoL using KIDSCREEN - 27. Time on videogames/cell phones/tablets was inversely associated with overall HRQoL (β = -0.021; 95%CI: -0.026; -0.006), psychological well-being (β = -0.030; 95%CI: -0.050; -0.010), peer social support (β = -0.041; 95%CI: -0.066; -0.016) and school environment (β = -0.033; 95%CI: -0.056; -0.010) scores. Screen time was inversely associated with the school environment score (β = -0.011; 95%CI: -0.020; -0.003). Computer time was positively associated with the psychological well-being (β = 0.025; 95%CI: 0.006; 0.043) and peer social support scores (β = 0.029; 95%CI: 0.004; 0.053). It concluded that adolescents with more screen time had lower HRQoL. However, theses associations varied with the type and method of SB measurement and the HRQoL dimension.

Biomechanical variations in children who are overweight and obese during high-impact activities: A systematic review and meta-analysis

Youth who are obese or overweight demonstrate evidence of poor lower extremity joint health and alterations in gait characteristics compared with youth who are healthy weight. However, there is no consensus if altered movement patterns are still present during high-impact activities. The purpose of this review was to determine if spatiotemporal and kinematic and kinetic variables during high-impact activities were significantly different between youth who are overweight and obese compared with youth who are healthy weight. An electronic search of five databases was conducted, and a meta-analysis and qualitative evidence synthesis was performed to determine the level of evidence, analyzing three tasks: running, jumping, and hopping. The findings of this review include the following: (1) overweight/obese (OW/OB) had higher stance phase time during running, (2) OW/OB had decreased hip flexion angles during running and stationary running, (3) OW/OB had decreased knee flexion angles during landing phase of jumping and hopping, and (4) OW/OB had increased hip abduction moments during running and jumping. These altered kinematic and kinetic variables at the hip and knee may result in mechanical inefficiency with high-impact activities, as well as potentially increased risk of joint degradation and poor joint health into adulthood.

Start with reducing sedentary behavior: A stepwise approach to physical activity counseling in clinical practice

Recently, sedentary behavior recommendations have been included in the public health guidelines of multiple countries, pointing to new opportunities for prevention of chronic disease as well as a potential strategy for initiating long-term behavior change.

OBJECTIVE

To propose an evidence-informed approach to physical activity counseling that starts with a focus on reducing sedentary time.

METHODS

We put forward a case for addressing changes in sedentary behavior in clinical practice using a narrative review. We also propose a new approach for the assessment and counselling of patients with respect to movement behaviors.

RESULTS

There is evidence to support a stepwise approach to physical activity counseling that starts with targeting sedentary behavior, particularly in those who are highly sedentary, or those who have chronic disease, or physical impairments.

CONCLUSIONS

Our approach encourages clinicians to consider sedentary behavior counseling as a critical first step to physical activity counseling. For many patients, this initial step of reducing sedentary behavior could build a pathway to an active lifestyle.

PRACTICAL IMPLICATIONS

A shift from long periods of sedentary time to daily routines incorporating more light intensity physical activity could result in meaningful health improvements. Importantly, this approach may be more feasible for highly inactive patients.

The Impact of the COVID-19 Lockdown “Home Quarantine” on the Physical Activity and Lifestyle of Children in Qatar

Background

Several studies have investigated how the coronavirus disease 2019 (COVID-19) pandemic impacted children's lifestyle. To our knowledge, this is the first study that assesses the impact of quarantine on physical activity, screen time, sleep, and diet in children aged 5 to 12 in Qatar.

Methods

Cross-sectional data from an online survey distributed in Qatar was analyzed. The survey measured the parents' or caregivers' assessment on the change in the child's physical activity, sleep, screen time, and diet between the two periods (before quarantine and during quarantine). The data was analyzed using frequency distributions, paired t-test and McNemar's test.

Results

Data from 144 respondents were analyzed. Due to the quarantine, the total weekly average hours of physical activity significantly decreased with a greatest reduction for the school and after school durations. Only 4.5% of the children were engaging in at least 60 minutes of physical activity per day (in contrast to 25.6% prior to quarantine). The reported barriers for physical activity were screen time for school (52.8%) and leisure (51.4%). There was a significant increase in the total number of main meals per day, with a higher consumption of unhealthy food. The majority of the children had their bedtime and waketime shifted to later because of the quarantine. The parents' or caregivers' satisfaction with the child's lifestyle during quarantine showed that 49.1% were disappointed or very disappointed. Also, 53.8% described their child's mental health as “better before quarantine.”

Conclusions

Quarantine had a negative impact on the lifestyle of children in Qatar. When implementing restrictions, authorities should consider some interventions to counterpart such impact.

Screen time and health issues in Chinese school-aged children and adolescents: a systematic review and meta-analysis

Backgrounds

Many literature reviews summarized relationships between screen time and child health, but they only included a few studies conducted in Chinese children and adolescents. The potential influence of screen time may vary by social context. The current systematic review and meta-analysis aimed to evaluate relationships between screen time and health issues among Chinese school-aged children and adolescents.

Methods

Peer-reviewed articles written in Chinese and English were retrieved from CNKI, Wanfang, PubMed, Embase, and Web of Science from inception to June 2020. The Downs & Black checklist was applied to assess study quality. Meta analyses used random effect models and mixed effects model to calculate pooled adjusted odds ratios and 95% confidence intervals. Heterogeneity, sensitivity, and publication bias were assessed using Q and I² statistics, “one-study removed” analysis, the funnel plot, trim and fill analysis, and classical fail-safe N, respectively.

Results

In total, we identified 252 articles reporting 268 studies with unique samples. These studies investigated relationships between screen time and health issues of adiposity, myopia, psycho-behavioral problems, poor academic performance, cardiometabolic disease risks, sleep disorder, poor physical fitness, musculoskeletal injury, sub-health, and miscellaneous issues of height and pubertal growth, injury, sick leave, and respiratory symptoms. Proportions of studies reporting positive relationships with screen time were lowest in adiposity (50.6%) and higher in myopia (59.2%) and psycho-behavioral problems (81.8%). Other health issues were examined in 10 or less studies, all of which had more than half showing positive relationships. The pooled odds ratio from 19 studies comparing health risks with the screen time cutoff of 2 hours per day was 1.40 (95% CI: 1.31 to 1.50, I² = 85.9%). The pooled effect size was 1.29 (95% CI: 1.20 to 1.39) after trimming 7 studies for publication bias adjustments.

Conclusions

Findings exclusively generated from Chinese school-aged children and adolescents resonate those mainly from western countries. Evidence suggests that higher levels of screen time are related with greater risks of various health issues, although the relationships appear to be weak and intertwined with other confounding factors. Future studies need to investigate health-specific dose effects and mechanisms of screen time.

Supplementary information

The online version contains supplementary material available at 10.1186/s12889-022-13155-3.

Mechanisms linking physical activity with psychiatric symptoms across the lifespan: a protocol for a systematic review

INTRODUCTION

Persistent psychiatric symptomatology during childhood and adolescence predicts vulnerability to experience mental illness in adulthood. Physical activity is well-known to provide mental health benefits across the lifespan. However, the underlying mechanisms linking physical activity and psychiatric symptoms remain underexplored. In this context, we aim to systematically synthesise evidence focused on the mechanisms through which physical activity might reduce psychiatric symptoms across all ages.

METHODS AND ANALYSIS

With the aid of a biomedical information specialist, we will develop a systematic search strategy based on the predetermined research question in the following electronic databases: MEDLINE, Embase, Web of Science, Cochrane and PsycINFO. Two independent reviewers will screen and select studies, extract data and assess the risk of bias. In case of inability to reach a consensus, a third person will be consulted. We will not apply any language restriction, and we will perform a qualitative synthesis of our findings as we anticipate that studies are scarce and heterogeneous.

ETHICS AND DISSEMINATION

Only data that have already been published will be included. Then, ethical approval is not required. Findings will be published in a peer-reviewed journal and presented at conferences. Additionally, we will communicate our findings to healthcare providers and other sections of society (eg, through regular channels, including social media).

PROSPERO REGISTRATION NUMBER

CRD42021239440.

COVID-19 and screen-based sedentary behaviour: Systematic review of digital screen time and metabolic syndrome in adolescents

Aim

The COVID-19 pandemic has prompted governments around the globe to implement various restriction policies, including lockdown, social distancing, and school closures. Subsequently, there has been a surge in sedentary behaviour particularly screen time (ST) together with a significant decline in physical activity that was more marked amongst children and adolescents. Excessive screen exposure in adolescents has been correlated with cardio-metabolic risk factors including obesity, hypertension, high cholesterol, and glucose intolerance that may have adverse morbidity and mortality implications in adulthood. Thus, the current study aimed to synthesize the literature on the relationship between ST of various types and the risk of metabolic syndrome (MetS) in adolescents in the context of the COVID-19 pandemic.

Methods

In August 2021, a systematic search of the literature was undertaken using electronic databases: PubMed, PsycINFO, and the Cochran library. Studies were considered if they met the following key eligibility criteria: (i) Measure of ST as an exposure (TV, computer, videogames, internet, smartphone, tablet), using quantified duration/frequency either self-reported or observed; (ii) Measure of MetS as an outcome with standard definition and/or criteria required to establish MetS diagnosis. The Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies was used to assess the risk of bias.

Results

A total of ten studies met the inclusion criteria, and the majority were cross sectional studies. Most studies met fair bias scoring. Overall, the review revealed considerable evidence that suggests a significant negative association between ST and components of MetS among adolescents with dose-response association.

Conclusion

During the pandemic, screen usage may become more prevalent through periods of school closures, lockdowns, social isolation, and online learning classes. Public health policies and health promotion strategies targeting parents are needed to raise awareness of the adverse health effects associated with screen-based sedentary behaviour as a precursor of NCDs. Parent or home focused interventions might be effective in limiting adolescents’ screen exposure, alternatively substituted with an appropriate level of physical activity.

PROSPERO registration number

PROSPERO 2021 CRD42021272436.

Level of Physical Activity, Sedentary Behavior, and Sleep in the Child and Adolescent Population in the Autonomous Community of the Basque Country (6-17 Years Old): Protocol for the Mugikertu Study

Background

Physical inactivity and sedentary behavior are increasingly common problems in the general population, which can lead to overweight, obesity, diabetes, cardiovascular disease, and decreased motor and cognitive capacity among children and adolescents. Establishing healthy habits in childhood on the basis of the World Health Organization’s 2020 Physical Activity Guidelines is essential for proper physical, motor, and cognitive development.

Objective

The primary aim of this study is to describe the level of physical activity (PA), sedentary behavior, and sleep of the child and adolescent population from 6 to 17 years of age in the Basque Autonomous Community (BAC). Our secondary aim is to establish a starting point for future research and intervention protocols to improve the existing reality.

Methods

This cross-sectional study aims to recruit 1111 children and adolescents, aged 6 to 17 years from the BAC in a representative random sample. Participants will wear the ActiGraph WGT3X-BT triaxial accelerometer for 7 consecutive days in their nondominant wrist, and fill out a habit diary log of PA, mobility, and sleep routine. PA intensities, sedentary behavior, and sleep parameters (total bedtime, total sleep time, and sleep efficiency) will be calculated from raw accelerometer data using SPSS (IBM Corp). Participants will be randomly selected.

Results

The results of this study intend to demonstrate significant differences in PA levels in different age and gender groups since the volume of school PA in the BAC decreases as the age of the schoolchildren increases. The total study sample includes 1111 participants. In April 2021, up to 50% of the sample size was reached, which is expected to increase to 100% by April 2022. This sample will allow us to analyze, discuss, compare, and assess the reality of the school population, in a sensitive period of adherence to behavior patterns, using data from the geographical and administrative area of the BAC. This study will provide a realistic insight into PA levels among children and adolescents in the BAC. It will also offer scientific contributions on the positive relationship between PA levels and sleep quality in this population.

Conclusions

This study might highlight the need for the promotion of cross-sectional policies so that children and adolescents may increase their levels of PA, thus improving both the school environment and positive healthy behavior.

Trial Registration

ISRCTN Registry ISRCTN65573865; https://www.isrctn.com/ISRCTN65573865

International Registered Report Identifier (IRRID)

DERR1-10.2196/31325

The Influence of Family Sports Attitude on Children's Sports Participation, Screen Time, and Body Mass Index

Background: Children’s physical health is an important resource for a country’s future construction. However, researchers found that the physical fitness of young children around the world has declined during the two decades, from 1992 to 2012. The decline in the physique of young children has caused widespread concern around the world. Children’s main living places are families and kindergartens, so this research explores the impact of family factors on children’s body mass index (BMI) from the perspective of family attitudes, children’s sports participation, and screen time.

Methods: A cross-sectional study was used to conduct a questionnaire survey of children in China. A total of 600 children were investigated, and 589 valid questionnaires were obtained. SPSS21.0 statistical analysis software was used for descriptive analysis, mean comparison, and correlation analysis of the data. AMOS 21.0 was used to construct a structural equation model and carry out path analysis.

Results: (1) There are significant differences in children’s family sports attitude, sports participation, screen time, and BMI with different family structures, and parents’ education levels. (2) Family sports attitude is significantly positively correlated with parents’ education levels and children’s sports participation, and negatively correlated with children’s screen time and BMI. (3) Children’s sports participation and screen time play a chain-mediating role between family sports attitude and children’s BMI, and the role is a complete mediating role. Therefore, family sports attitudes can affect children’s physical health by affecting children’s sports participation and screen time. To promote children’s physical health, we should pay attention to the intervention of family sports attitude. (4) The mediating effects of exercise participation and screen time are similar in different family structures, so the structure of this study can be applied to different family structures.

Conclusions: Children’s family sports attitude, sports participation, and screen time can affect children’s BMI. Children’s screen time and sports participation play a chain-mediating role in the influence of family sports attitudes on the path of children’s BMI. The results of this study will provide a useful reference for teachers and parents to control children’s physical health.

Assessment and management of obesity and metabolic syndrome in children with CKD stages 2-5 on dialysis and after kidney transplantation-clinical practice recommendations from the Pediatric Renal Nutrition Taskforce

Obesity and metabolic syndrome (O&MS) due to the worldwide obesity epidemic affects children at all stages of chronic kidney disease (CKD) including dialysis and after kidney transplantation. The presence of O&MS in the pediatric CKD population may augment the already increased cardiovascular risk and contribute to the loss of kidney function. The Pediatric Renal Nutrition Taskforce (PRNT) is an international team of pediatric renal dietitians and pediatric nephrologists who develop clinical practice recommendations (CPRs) for the nutritional management of children with kidney diseases. We present CPRs for the assessment and management of O&MS in children with CKD stages 2-5, on dialysis and after kidney transplantation. We address the risk factors and diagnostic criteria for O&MS and discuss their management focusing on non-pharmacological treatment management, including diet, physical activity, and behavior modification in the context of age and CKD stage. The statements have been graded using the American Academy of Pediatrics grading matrix. Statements with a low grade or those that are opinion-based must be carefully considered and adapted to individual patient needs based on the clinical judgment of the treating physician and dietitian. Research recommendations are provided. The CPRs will be periodically audited and updated by the PRNT.

Indicators to Assess Physical Health of Children and Adolescents in Activity Research-A Scoping Review

Sufficient physical activity can help promote and maintain health, while its lack can jeopardize it. Since health and physical activity lay their foundation for later life in childhood and adolescence, it is important to examine this relationship from the beginning. Therefore, this scoping review aims to provide an overview of physical health indicators in children and adolescents in research on the effects of physical activity and sedentary behavior. We identified the indicators used to quantify or assess physical health and summarized the methods used to measure these indicators. We systematically searched Scopus, Pubmed, and Web of Science databases for systematic reviews. The search yielded 4595 records from which 32 records were included in the review. The measurements for physical health reported in the reviews contained measures of body composition, cardiometabolic biomarkers, physical fitness, harm/injury, or bone health. Body composition was the most used indicator to assess and evaluate physical health in children, whereas information on harm and injury was barely available. In future research longitudinal studies are mandatory to focus on the prospective relationships between physical activity or sedentary behavior, and physical health.

Associations of physical activity and sedentary behaviors with child mental well-being during the COVID-19 pandemic

BACKGROUND

The COVID-19 pandemic resulted in public health and policy measures to reduce in-person contact and the transmission of the virus. These measures impacted daily life and mental well-being (MWB). The aims of this study were to explore the MWB impacts of COVID-19 on children and assess the associations among perceived changes in physical activity (PA) and sedentary behaviors (SB), with perceived MWB changes, using a mixed-methods approach.

METHODS

A convergent parallel mixed-methods design consisting of an online survey with a convenience sample and interviews was conducted from May through July 2020 with parents/caregivers of kindergarten through 5th graders in the St. Louis region. Survey domains assessed included child MWB, PA, and SB. Interviews were recorded, transcribed, and qualitatively analyzed using a code book developed to elicit themes. Survey data was analyzed with chi-squared tests and logistic regressions. The dependent variable was perceived change in child MWB due to the impact of COVID-19. Independent variables included perceived changes in PA, SB, and child concerns about COVID-19.

RESULTS

Sample size consisted of 144 surveys and 16 interviews. Most parents reported a perceived decrease in child MWB (74%), a decrease in child PA (61%), and an increase in child SB (91%). Discontentment with stay-at-home orders and concern about COVID-19 were associated with a perceived decrease in MWB. Children whose PA decreased were 53% less likely to have the same or better MWB (OR 0.47) and children whose outside PA decreased were 72% less likely to have the same or better MWB (OR 0.28). Common qualitative themes included difficulty in adjusting to COVID-19 restrictions due to school closures and lack of socializing, child concerns about family getting sick, and PA benefits for improving MWB.

CONCLUSIONS

Based on parent perceptions, MWB decreased with COVID-19. Maintained or increased child PA improved the chances MWB would remain the same or improve. Parent interviews provide context to these findings by showing how COVID-19 impacted MWB and the associations between PA and MWB. Understanding protective factors for child MWB during COVID-19 is important to offset negative long-term health outcomes from this ongoing pandemic.

Bidirectional associations between sedentary time and sleep duration among 12- to 14-year-old adolescents

Background

The aim of this study was to investigate bidirectional associations between (prolonged) sitting time and sleep duration in 12- to 14-year-old adolescents using a between-subjects and within-subjects analyses approach.

Methods

Observational data were used from 108 adolescents (53% girls; mean age 12.9 (SD 0.7) years) from six schools in Flanders, Belgium. The Axivity AX3 triaxial accelerometer, worn on the thigh, was used to assess daily total sitting time and daily time spent in sedentary bouts of ≥30 min (as a proxy for prolonged sitting time). The Fitbit Charge 3 was used to assess nightly sleep duration. Both monitors were worn on schooldays only (ranging from 4 to 5 days). Linear mixed models were conducted to analyse the associations, resulting in four models. In each model, the independent variable (sleep duration, sitting time or prolonged sitting time) was included as within- as well as between-subjects factor.

Results

Within-subjects analyses showed that when the adolescents sat more and when the adolescents spent more time sitting in bouts of ≥30 min than they usually did on a given day, they slept less during the following night (p = 0.01 and p = 0.05 (borderline significant), respectively). These associations were not significant in the other direction. Between-subjects analyses showed that adolescents who slept more on average, spent less time sitting (p = 0.006) and less time sitting in bouts of ≥30 min (p = 0.004) compared with adolescents who slept less on average. Conversely, adolescents who spent more time sitting on average and adolescents who spent more time sitting in bouts of ≥30 min on average, slept less (p = 0.02 and p = 0.003, respectively).

Conclusions

Based on the between-subjects analyses, interventions focusing on reducing or regularly breaking up sitting time could improve adolescents’ sleep duration on a population level, and vice versa. However, the within-subjects association was only found in one direction and suggests that to sleep sufficiently during the night, adolescents might limit and regularly break up their sitting time the preceding day.

Trial registration

Data have been used from our trial registered at ClinicalTrials.gov (NCT04327414; registered on March 11, 2020).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-11694-9.

Physical Activity Among Preadolescents Modifies the Long-Term Association Between Sedentary Time Spent Using Digital Media and the Increased Risk of Being Overweight

BACKGROUND

This study aimed to examine whether sedentary digital media use in preadolescence increases the risk of being overweight 3 years later, and whether this association differs based on preadolescents' leisure-time physical activity (LTPA) levels.

METHODS

The authors conducted a 3-year follow-up study among 4661 participants with a mean (SD) age of 11 (1) years at baseline and 14 (1) years at follow-up. A web-based questionnaire assessed sedentary digital media use and LTPA. The authors categorized baseline LTPA duration into 3 levels: 0 to 5 (low), 6 to 8 (moderate), and ≥9 (high) hours per week. In addition, the authors categorized adolescents as normal weight or overweight/obese at follow-up.

RESULTS

Greater amounts of sedentary digital media use at baseline associated with an increased risk of being overweight 3 years later even after adjusting for confounders. This only held for preadolescents with low baseline LTPA (OR = 1.14; 95% confidence interval, 1.05-1.24), but not among those with moderate (OR = 1.02; 0.91-1.15) or high (OR = 0.96; 0.85-1.08) LTPA.

CONCLUSIONS

Preadolescent LTPA modified the long-term association between sedentary digital media use and being overweight; specifically, 6 hours per week or more of LTPA mitigated the increased risk of being overweight associated with higher amounts of digital media use.

The longitudinal association between early-life screen viewing and abdominal adiposity-findings from a multiethnic birth cohort study

IMPORTANCE

Screen viewing in adults has been associated with greater abdominal adiposity, with the magnitude of associations varying by sex and ethnicity, but the evidence is lacking at younger ages. We aimed to investigate sex- and ethnic-specific associations of screen-viewing time at ages 2 and 3 years with abdominal adiposity measured by magnetic resonance imaging at age 4.5 years.

METHODS

The Growing Up in Singapore Towards healthy Outcomes is an ongoing prospective mother-offspring cohort study. Parents/caregivers reported the time their child spent viewing television, handheld devices, and computer screens at ages 2 and 3 years. Superficial and deep subcutaneous and visceral abdominal adipose tissue volumes were quantified from magnetic resonance images acquired at age 4.5 years. Associations between screen-viewing time and abdominal adipose tissue volumes were examined by multivariable linear regression adjusting for confounding factors.

RESULTS

In the overall sample (n = 307), greater total screen-viewing time and handheld device times were associated with higher superficial and deep subcutaneous adipose tissue volumes, but not with visceral adipose tissue volumes. Interactions with child sex were found, with significant associations with superficial and deep subcutaneous and visceral adipose tissue volumes in boys, but not in girls. Among boys, the increases in mean (95% CI) superficial and deep subcutaneous and visceral adipose tissue volumes were 24.3 (9.9, 38.7), 17.6 (7.4, 27.8), and 7.8 (2.1, 13.6) mL per hour increase in daily total screen-viewing time, respectively. Ethnicity-specific analyses showed associations of total screen-viewing time with abdominal adiposity only in Malay children. Television viewing time was not associated with abdominal adiposity.

CONCLUSION

Greater total screen-viewing time (and in particular, handheld device viewing time) was associated with higher abdominal adiposity in boys and Malay children. Additional studies are necessary to confirm these associations and to examine screen-viewing interventions for preventing excessive abdominal adiposity and its adverse cardiometabolic consequences.

Moderate-to-Vigorous Physical Activity Is Associated With Cardiorespiratory Fitness Among Primary Schoolchildren Living in Côte d'Ivoire, South Africa, and Tanzania

Background: Physical inactivity and low cardiorespiratory fitness (CRF) are independent cardiovascular risk factors among children, but have rarely been investigated concurrently in sub-Saharan Africa. The purpose of this study was to compare physical activity (PA) and CRF of primary schoolchildren living in Côte d'Ivoire (CI), South Africa (ZA), and Tanzania (TZ), to test sex- and age-related differences, and to examine whether PA and CRF are associated with each other. Methods: Baseline data from an ongoing cluster-randomized controlled trial were used, including 499 children from CI (Taabo, 49% girls, M = 8.0 ± 1.6 years), 1,074 children from ZA (Gqeberha, 49% girls, M = 8.3 ± 1.4 years), and 593 children from TZ (Ifakara, 51% girls, M = 9.4 ± 1.7 years). PA was assessed by accelerometry and CRF by a 20 m shuttle-run test. The data were analyzed using multi-/univariate analyses of variance and mixed linear models. Results: Most children met recommendations put forward by the World Health Organization for moderate-to-vigorous PA (MVPA) and achieved high CRF scores. In CI, 89.6% of the children met MVPA recommendations (boys: 91.7%, girls: 87.4%), whereas this rate was 76.9% in ZA (boys: 91.0%, girls: 62.4%), and 93.8% in TZ (boys: 95.5%, girls: 92.0%). Children from TZ had the highest CRF and MVPA levels, followed by children from CI and ZA. Boys had higher MVPA levels than girls, whereas girls engaged in more sedentary behavior. Sex differences were strongest in ZA. Sedentary behavior and MVPA were higher among older schoolchildren compared to their younger peers. Higher MVPA, but not sedentary behavior, was associated with better CRF. Conclusions: In all three settings, higher levels of MVPA were associated with higher CRF scores. Nevertheless, children living in the most urbanized setting (such as observed in ZA) were physically less active and had lower CRF than peers living in more rural areas (such as observed in CI and TZ). Particularly for girls, urbanization might increase the risk for insufficient MVPA, which may have negative effects on their CRF, thus negatively influencing health and well-being at later age.

Understanding obesity-related behaviors in youth from a systems dynamics perspective: The use of causal loop diagrams

This paper reports how we applied systems dynamics methods to gain insight into the complexity of obesity-related behaviors in youth, including diet, physical activity, sedentary behavior, and sleep, by integrating a literature review into causal loop diagrams (CLDs). Results showed that the CLDs consisted of multiple subsystems and three types of dynamics appeared, including (1) feedback loops, (2) connections between feedback loops and subsystems, and (3) mechanisms. We observed clear similarities in the dynamics for the four behaviors in that they relate to "traditional" subsystems, such as home and school environments, as well as to newly added subsystems, including macroeconomics, social welfare, and urban systems. The CLDs provided insights that can support the development of intervention strategies, including (1) the confirmation that a range of mechanisms cover and connect multiple levels and settings, meaning that there is no silver bullet to address obesity; (2) understanding of how interventions in one particular setting, such as school, might be influenced by the interactions with other settings, such as urban systems; and (3) a comprehensive view of (un)intended consequences. This way of framing the problem will assist moving towards public health interventions that respond to and operate in the complexity of the real world.

Meeting 24-h movement guidelines: Prevalence, correlates, and the relationships with overweight and obesity among Chinese children and adolescents

BACKGROUND

Meeting 24-h movement guidelines by children and adolescents has been associated with improved indicators of health, although it has been under-studied in China. Hence, this study aimed to investigate the prevalence of meeting the 24-h movement guidelines, its correlates, and its relationships with body mass index in children and adolescents in China.

METHODS

Cross-sectional data from the 2017 Youth Study in China of 114,072 children and adolescents (mean age = 13.75 years, 49.18% boys) were used. Meeting 24-h movement guidelines (≥60 min of daily moderate-to-vigorous physical activity, ≤2 h of daily leisure screen time, 9-11 h and 8-10 h nightly sleep duration for 6-13-year-olds and 14-17-year-olds, respectively) and height and weight of all participants were assessed. The prevalence of meeting the 24-h movement guidelines and World Health Organization weight status categories were determined. Generalized linear models were used to determine the correlates of meeting the 24-h movement guidelines and the relationships of meeting the 24-h movement guidelines with overweight (OW) and obesity (OB).

RESULTS

Only 5.12% of Chinese children and adolescents met the 24-h movement guidelines, and 22.44% were classified as OW/OB. Older children and adolescents were less likely to meet the 24-h movement guidelines. Parental education level and family income were positively related to meeting the 24-h movement guidelines. Children and adolescents meeting the 24-h movement guidelines showed lower odds ratios for OW/OB. Compared with participants meeting the 24-h movement guidelines, boys in 4th-6th grades met none of the recommendations (OR = 1.22, 95%CI: 1.06-1.40), met the screen time recommendation only (OR = 1.13, 95%CI: 1.01-1.28), met the nightly sleep duration recommendation only (OR = 1.14, 95%CI: 1.03-1.28), and had significantly higher odds ratios for OW/OB. Similar trends were observed for girls in 4th-6th grades: meeting none of the guidelines (OR = 1.35, 95%CI: 1.14-1.59), meeting sleep duration guidelines only (OR = 1.23, 95%CI: 1.08-1.39), and meeting moderate-to-vigorous physical activity + nightly sleep duration guidelines (OR = 1.24, 95%CI: 1.01-1.54). For girls in 7th-9th grades, the following trend was observed: meeting none of the guidelines (OR = 1.30, 95%CI: 1.01-1.67).

CONCLUSION

Very few Chinese children and adolescents met the 24-h movement guidelines. Age (negatively correlated), parental education level, and family income (both positively correlated) were correlates of meeting the 24-h movement guidelines. Children and adolescents meeting the 24-h movement guidelines were more likely to have lower risks for OW/OB, especially in the youngest age group (Grades 4-6); and girls in the middle age group (Grades 7-9) were also more likely to have lower risks for OW/OB. Further research studies should explore additional correlates and determinants for meeting the 24-h movement guidelines. Also, future studies should use longitudinal or interventional designs to determine the relationships between meeting the 24-h movement guidelines and OW/OB and other health indicators, while taking sex and age differences into account.

Cardiorespiratory Fitness as Mediator of the Relationship of Recreational Screen Time on Mediterranean Diet Score in Schoolchildren

BACKGROUND

Studies have reported the association between cardiorespiratory fitness and higher adherence to the Mediterranean diet as well as lower recreational screen time. Similarly, higher screen time has been negatively linked to a lower adherence to the Mediterranean diet. However, the mediator effect of cardiorespiratory fitness on the influence of screen time on adherence to the Mediterranean diet is still unknown. The aim of this study was two-fold: first, to assess the combined association of recreational screen time and cardiorespiratory fitness with adherence to Mediterranean diet among Spanish schoolchildren, and second, to elucidate whether the association between recreational screen time and adherence to the Mediterranean diet is mediated by cardiorespiratory fitness.

METHODS

A descriptive and cross-sectional study was conducted. A total of 370 schoolchildren aged 6-13 years from six schools in the Region of Murcia (Spain) were included.

RESULTS

The mediation analysis showed that once screen time and cardiorespiratory fitness were included together in the model, cardiorespiratory fitness was positively linked to adherence to the Mediterranean diet (p = 0.020) and although screen time remained negatively related to adherence to the Mediterranean diet, this association was slightly attenuated (indirect effect = -0.027; 95% CI = (-0.080, -0.002)).

CONCLUSIONS

This research supports that cardiorespiratory fitness may reduce the negative association between screen time and Mediterranean dietary patterns.

Familial Correlates of Leisure Time Activities among Polish Early School-Age Children: A Cross-Sectional Study

The after-school period may play a critical role in the accumulation of children’s physical activity and sedentary time. The study aimed to characterize familial correlates of early school-age children’s leisure time activities. A cross-sectional study was conducted among a group of 223 children (mean age 8.7 ± 0.5) and their parents. The percentage of children with daily leisure time physical activity (LTPA) >1 h was 23.32%, and with daily screen time <2 h was 32.74%. The average children’s leisure time physical activity was significantly higher on weekend days than on weekdays (114.85 vs. 89.43 min, p = 0.005). Similarly, the average screen time was higher on weekend days than on weekdays (95.50 vs. 66.10 min, p < 0.001). The multivariate regression analysis revealed that independent predictors of children’s leisure time physical activity were the father’s education level and the father’s occupational status, whereas at least one parent with higher education correlated negatively with children’s longer screen time. The study showed that children’s leisure time activities are associated with parental education and differ significantly between weekdays and weekend days. These findings underline the need for screening for unfavorable health behaviors among early school-age children, and indicate that health promotion programs should be oriented on both parents and children aiming to improve parental health consciousness, reduce screen time and increase physical activity, especially during the weekend.

TV viewing during childhood and adult type 2 diabetes mellitus

We examined whether regular television (TV) viewing at ages 3-5 and 5-10 years is related to the incidence of type 2 diabetes mellitus (T2D) in adult women. We used data from 34,512 mother-nurse daughter dyads in the Nurses' Health Study (NHS) II and the Nurses' Mothers' Cohort Study. Mothers of NHS II participants completed a questionnaire on their pregnancy with the nurse and her early life experience. During 391,442 person-years of follow-up from 2001 to 2013, 1515 nurses developed T2D. Increasing levels of TV viewing at 3-5 years of age retrospectively reported by the mothers were related to a greater risk of T2D in adulthood: multivariable-adjusted hazard ratios (HRs) for ≤ 1, 2, and ≥ 3 h/day vs. no TV viewing were 1.11 [95% confidence interval (CI) 0.96-1.28], 1.20 (95% CI 1.02-1.41), and 1.35 (95% CI 1.11-1.65), p trend = 0.002, respectively, after adjustment for early life variables, including childhood physical activity and adiposity. Retrospectively reported TV viewing for ≥ 3 h/day at 5-10 years of age was associated with a 34% greater risk of adult T2D (HR 1.34, 95% CI 1.05-1.70, p trend < 0.001). Additional adjustments for adult variables, including adult TV viewing and current BMI attenuated the effect estimates (≥ 3 h/day TV viewing at 3-5 years: HR 1.22, 95% CI 0.99-1.49, p trend = 0.07; TV viewing at 5-10 years: 1.16, 95% CI 0.91-1.49, p trend = 0.09). The present study suggests that TV viewing during early childhood increases risk of T2D in adult women; adult BMI explains part of this association. Further research is required to confirm this observation and understand the mediating pathways.

Physical activity and prospective associations with indicators of health and development in children aged <5 years: a systematic review

BACKGROUND

Early childhood is a critical period for growth and development, yet the association with physical activity during this important period is unknown. The aim of this review is to critically summarize the evidence on the prospective associations between physical activity and health and development in children aged < 5 years.

METHODS

A systematic search in three electronic databases (Pubmed, PsycINFO, and Sportdiscus) was conducted to identify prospective studies examining the associations between physical activity (all types; specified by quantity) and health indicators (body composition, cardiometabolic health, bone health and risks/harm) or development (motor, cognitive and social-emotional development) in young children (mean age < 5 years at baseline). Two independent researchers assessed the methodological quality using the 'Quality Assessment Tool for Quantitative Studies' (EPHPP). This tool covers eight quality criteria: selection bias, study design, confounders, blinding, data collection methods, withdrawals and drop-outs, intervention integrity and data-analysis.

RESULTS

Thirty-nine studies, predominantly conducted in preschoolers (ages 3-5 years), were included of which nine were rated as high methodological quality. There was moderate evidence for a positive association between physical activity and motor (n = 11 studies) and cognitive development (n = 10 studies) based on consistent findings from studies having low-to-moderate methodological quality. There was insufficient evidence for an association between physical activity and body composition (n = 15 studies), cardiometabolic health indicators (n = 7 studies), social-emotional development (n = 2 studies) and bone health (n = 2 studies) based on inconsistent findings from studies having weak-to-high methodological quality.

CONCLUSIONS

There is a need for more high-quality research in order to determine the dose-response relationship between physical activity and health and development in early childhood. Special attention should be paid to studies in children below the age of 3 years.

Patterns of Sedentary Time in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) Youth

BACKGROUND

Total sedentary time and prolonged sedentary patterns can negatively impact health. This study investigated rates of various sedentary pattern variables in Hispanic/Latino youth.

METHODS

Participants were 956 youths (50.9% female) in the Hispanic Community Health Study/Study of Latinos Youth, a population-based cohort study of Hispanic/Latino 8- to 16-year-olds from 4 geographic regions in the United States (2012-2014). Total sedentary time and 10 sedentary pattern variables were measured through 1 week of accelerometer wear. Differences were examined by sociodemographic characteristics, geographic location, weekdays versus weekends, and season.

RESULTS

On average, youth were sedentary during 67.3% of their accelerometer wear time, spent 24.2% engaged in 10- to 29-minute sedentary bouts, and 7.2% in ≥60-minute bouts. 8- to 12-year-olds had more favorable sedentary patterns (less time in extended bouts and more breaks) than 13- to 16-year-olds across all sedentary variables. Sedentary patterns also differed by Hispanic/Latino background, with few differences across sex, household income, season, and place of birth, and none between weekdays versus weekends.

CONCLUSIONS

Variables representing prolonged sedentary time were high among Hispanic/Latino youth. Adolescents in this group appear to be at especially high risk for unhealthy sedentary patterns. Population-based efforts are needed to prevent youth from engaging in increasingly prolonged sedentary patterns.

Screen time and its effect on dietary habits and lifestyle among schoolchildren

OBJECTIVE

The aim of the study was to determine the associations between recreational screen time and dietary habits and lifestyle factors in a representative sample of schoolchildren.

METHODS

Observational, cross-sectional study data were derived from 177,091 children aged 8 to 17 years participating in a health survey. Recreational screen time, physical activity (PA), and sleeping hours were assessed through self-completed questionnaires. Dietary habits were evaluated via the Mediterranean Diet Quality Index for children and adolescents (KIDMED) test. Anthropometric and physical fitness (PF) estimations were obtained by trained investigators.

RESULTS

Binary logistic regression comparisons between screen time levels (e.g. < 2 vs. ≥ 2 - < 3 h/d, < 2 vs. ≥ 3 - < 4 h/d and < 2 vs. ≥ 4 h/d) and dietary habits showed that the longer the screen time the increased the odds of unhealthy dietary habits such as skipping breakfast, consuming fast food frequently, and eating sweets frequently, and the decreased the odds of healthy dietary habits such as consuming a second fruit every day, consuming fresh or cooked vegetables or/and fish regularly, in both genders, after adjusting for several covariates. Furthermore, the longer the screen time the increased the odds of total and central obesity, insufficient sleep (< 8-9 h/d), and inadequate PA, and the decreased the odds of healthy PF.

CONCLUSIONS

The longer the screen time the unhealthier dietary habits and lifestyle profile among schoolchildren, after adjusting for several covariates.

Mediating role of disordered eating in the relationship between screen time and BMI in adolescents: longitudinal findings from the Research on Eating and Adolescent Lifestyles (REAL) study

OBJECTIVE

This study investigated whether the duration and type of screen time (ST) (TV viewing, recreational computer use, video gaming) is longitudinally associated with z-BMI and if these relationships are mediated by disordered eating (emotional, restrained).

DESIGN

At baseline, participants were n 1197 (T1; 60 % female) adolescents (mean age = 13·51 years) who completed surveys over 2 years. ST was assessed by a self-reported measure created by the investigative team, while emotional and restrained eating was measured by the Dutch Eating Behaviour Questionnaire (DEB-Q). Height and weight were objectively measured to quantify z-BMI.

SETTING

Thirty-one public and two private schools from the region of Ottawa, Canada.

PARTICIPANTS

Students in grades 7-12.

RESULTS

Parallel multiple mediation analyses revealed that more time spent watching TV at baseline is associated with higher z-BMI at T3 (total effect; B = 0·19, se = 0·07, P = 0·01, 95 % CI 0·05, 0·34), but no relationships were observed for total ST exposure or other types of ST and z-BMI. Disordered eating did not mediate the positive association between baseline TV viewing and z-BMI at T3.

CONCLUSIONS

TV viewing was longitudinally associated with higher z-BMI in a community-based sample of adolescents, but disordered eating behaviours did not mediate this relationship. However, other non-pathological eating behaviours may mediate the association between ST and obesity and warrant further investigation. Finding suggests that targeting reduction in youth's TV viewing may be an effective component in the prevention of childhood obesity.