Associations of social jetlag with physical activity and sedentary behaviour in children and adolescents: A systematic review and meta-analysis.

Sleep and daytime movement behaviours occur co-dependently with each other within a finite 24 h day. Sleep parameters other than sleep duration, such as social jetlag and chronotype, have been linked to health problems and unhealthy behaviours among children and adolescents. Given the increasing number of studies examining sleep timing/chronotype and weight-related behaviours, including physical activity and sedentary behaviour, in the past decade, this systematic review and meta-analysis collated and evaluated the evidence on the relationships of social jetlag and chronotype with physical activity and sedentary behaviour among children and adolescents aged 3-17 years. Seven databases were searched on 16 March 2022, and 52 studies were identified as eligible for inclusion, 47 of which were suitable for the meta-analysis. A positive association was found between social jetlag and screen media use (r = 0.14, 95% CI: 0.04-0.24; I2 = 96%; p = 0.008). The morning chronotype was associated with a higher level of physical activity and a lower level of sedentary behaviour than the evening chronotype. No relationship was found between social jetlag and physical activity. The magnitude of heterogeneity among the included studies was high. Further experimental studies are urgently required to understand how circadian preference or misalignment affects activity behaviours. Interventions to promote an active lifestyle in young populations should consider their circadian preference, especially among individuals with the evening chronotype.

The effects of physical activity on pediatric eyes: A systematic review and meta-analysis.

INTRODUCTION: Examining the retina represents a non-invasive method to evaluate abnormalities pertaining to the nervous and cardiovascular systems. Evidence indicates that physical activity is a non-pharmacological intervention to enhance the nervous and cardiovascular systems. However, little is unknown about its effects on ocular characteristics in children and adolescents. The purpose of this study was to examine the effects of physical activity interventions on ocular characteristics in children and adolescents. METHOD: The electronic bases Web of Science, Embase, Cochrane Library, PubMed, SPORTDiscus, CINAHL, and ERIC were searched from inception to May 2023. Incorporated were randomized controlled trials or quasi-experimental designs that had implemented acute or chronic physical activity interventions among children and adolescents to evaluate various eye-related attributes via clinical examinations or surveys. Two authors independently performed the data extraction and risk of bias assessment, utilizing the Physiotherapy Evidence Database checklist. RESULTS: A total of 474 articles were identified, of which eight articles underwent a systematic review, and six were chosen for meta-analysis. Chronic physical activity interventions positively impacted central retinal artery equivalent (CRAE) with a small to moderate effect (SMD = 0.21; 95% CI 0.04 to 0.39, p = 0.034, I2 = 0%) and central retinal venular equivalent (CRVE) with a small effect (SMD = 0.098; 95% CI 0.08 to 0.11; p = 0.008, I2 = 0%). Intraocular pressure, kinetic visual acuity, and eye strain also improved significantly after physical activity interventions. DISCUSSION: Participating in chronic physical activity programs appear to impact children and adolescents' eye-related attributes positively.

Effects of volume-matched once-weekly and thrice-weekly high-intensity interval training (HIIT) on body adiposity in adults with central obesity: Study protocol for a randomized controlled trial.

Objective: This study aims to examine the comparative effects of 75 min of volume-matched once-weekly and thrice-weekly high-intensity interval training (HIIT) on body adiposity in adults with central obesity. Methods: This assessor-blinded, three-arm, randomized controlled trial will recruit 315 physically inactive adults with central obesity (aged ≥18 years, body mass index ≥23, waist circumference ≥90 cm for men and ≥80 cm for women). Participants will be randomly allocated to the once-weekly HIIT, thrice-weekly HIIT or usual care control group. Participants in the HIIT groups will receive weekly exercise training sessions for 16 weeks, prescribed either once or three times weekly. Each HIIT session will consist of a supervised program of four 4-min high-intensity intervals at 85%-95% peak heart rate (HRpeak) interspersed with 3-min active recovery intervals at 50%-70% HRpeak. Participants in the once-weekly HIIT group will perform the 25-min HIIT bout three times with a break between each 25-min HIIT bout. The usual care control group will receive bi-weekly health education classes. The outcome assessments will be conducted at baseline, 16 weeks (post-intervention) and 32 weeks (follow-up). The primary outcome will be total body adiposity assessed by dual-energy X-ray absorptiometry (DXA). The secondary outcome measures will include markers of cardiovascular and metabolic health (body composition, cardiorespiratory fitness, blood pressure, and blood lipids), mental health, cognitive performance, health-related quality of life, sleep quality, habitual physical activity, diet, medication, adverse events and adherence to the intervention. Impact of the project: The findings from this study are expected to consolidate the therapeutic efficacy of HIIT for the management of central obesity and inform the comparative compliance, feasibility and suitability of once-weekly and thrice-weekly HIIT as exercise strategies to manage obesity. In particular, the present study is expected to provide a novel perspective on the utility of low-frequency HIIT (i.e., once-weekly) as an effective and sustainable exercise strategy to tackle the obesity pandemic. The anticipated findings will hold substantial translational value by informing public health policies and enhancing exercise compliance in the physically inactive obese population. Trial registration: ClinicalTrials.gov (NCT04887454).

Dose-response effects of exercise and caloric restriction on visceral adiposity in overweight and obese adults: a systematic review and meta-analysis of randomised controlled trials.

OBJECTIVE: To determine and compare the dose-response effects of exercise and caloric restriction on visceral adipose tissue in overweight and obese adults, while controlling for the weekly energy deficit induced by the interventions. METHODS: PubMed, Embase, CINAHL and Web of Science were searched for randomised controlled trials comparing exercise or caloric restriction against eucaloric controls in overweight or obese adults. The primary outcome was the change in visceral fat measured by CT or MRI. Meta-analyses and meta-regressions were performed to determine the overall effect size (ES) and the dose-dependent relationship of exercise and caloric restriction on visceral fat. Heterogeneity, risk of bias and the certainty of evidence were also assessed. RESULTS: Forty randomised controlled trials involving 2190 participants were included. Overall, exercise (ES -0.28 (-0.37 to -0.19); p<0.001; I2=25%) and caloric restriction (ES -0.53 (-0.71 to -0.35); p<0.001; I2=33%) reduced visceral fat compared with the controls. Exercise demonstrated a dose-response effect of -0.15 ((-0.23 to -0.07); p<0.001) per 1000 calories deficit per week, whereas the effect of caloric restriction was not dose-dependent (ES 0.03 (-0.12 to 0.18); p=0.64). Most of the studies showed a moderate risk of bias. CONCLUSIONS: These findings support the dose-dependent effects of exercise to reduce visceral fat in overweight and obese adults. Caloric restriction did not demonstrate a dose-response relationship, although this may be attributed to the smaller number of studies available for analysis, compared with exercise studies. PROSPERO REGISTRATION NUMBER: CRD42020210096.

Results and SWOT Analysis of the 2022 Hong Kong Report Card on Physical Activity for Children and Adolescents With Special Educational Needs.

BACKGROUND: Following the 2019 Hong Kong Para Report Card, the 2022 Hong Kong Para Report Card aimed to provide an updated and evidence-based assessment for nine indicators related to physical activity in children and adolescents with special educational needs and to assess the results using a SWOT (strengths, weaknesses, opportunities, and threats) analysis. METHODS: Using a systematic process, the best available data on nine indicators were searched from the past 10 years and were assessed by a research work group. Letter grades were assigned and considered by stakeholders and auditors. RESULTS: Four indicators were assigned a letter grade (overall physical activity: F [mixed device-measured and self-reported data]; sedentary behaviors: D [device-measured data]; active transportation: D-; government strategies & investment: C+). SWOT analysis highlighted opportunities for facilitating children and adolescents with special educational needs to achieve health recommendations. CONCLUSION: There were deteriorating trends in physical activity and sedentary behaviors. Effective, multilevel, and cross-sector interventions are recommended to promote active behavior in children and adolescents with special educational needs.

Results from the Hong Kong's 2022 report card on physical activity for children and adolescents.

Background/objective: This paper aimed to summarize the findings of the third (2022) Active Healthy Kids Hong Kong Report Card on Physical Activity for Children and Adolescents and evaluate the secular trends of physical activity related indicators. Methods: Five behavioral indicators (Overall Physical Activity, Organized Sport and Physical Activity, Active Play, Active Transportation, and Sedentary Behavior), three outcome indicators (Physical Fitness, Sleep, and Obesity) and four sources of influence indicators (Family and Peers, School, Community and Environment, and Government) were assigned a letter grade (ranging from A+ to F or incomplete) based on the best available evidence following a harmonized approach developed by the Active Healthy Kids Global Alliance. Data sources included published journal articles, government reports, manual searches, and personal contacts; and consisted of both pre-COVID-19 and after-COVID-19 evidence. Results: Grades for Overall Physical Activity (D-∗∗) and Sedentary Behavior (D) deteriorated compared to the 2018 Report Card. The other three behavioral indicators, Organized Sport and Physical Activity, Active Play, and Active Transportation, were assigned B-, D, and B+, respectively. Physical Fitness (D), Sleep (C-), and Obesity (D-) obtained the same grades as in the 2018 Report Card. School (B) and Government (C+) grades slightly improved, while Community and Environment grade (B) was stable. Family and Peers was not graded due to insufficient evidence. Conclusions: Despite slight improvements in influence indicators, physical activity and sedentary behavior have changed unfavorably for children and adolescents in Hong Kong. Strategic investments are needed to improve adoption and implementation of effective interventions.

Wearing Compression Garment Enhances Central Hemodynamics? A Systematic Review and Meta-Analysis.

ABSTRACT: Lee, DCW, Ali, A, Sheridan, S, Chan, DKC, and Wong, SHS. Wearing compression garment enhances central hemodynamics? a systematic review and meta-analysis. J Strength Cond Res 36(8): 2349-2359, 2022-Compression garments (CG) are believed to enhance exercise performance and recovery by improving central hemodynamic responses. However, evidence is inconclusive. We performed a systematic review and meta-analysis to determine the effect of wearing CG at rest or after a physiological challenge on central hemodynamic responses, including cardiac output, stroke volume (SV), heart rate (HR), systolic blood pressure, diastolic blood pressure (DBP), and systemic vascular resistance in healthy individuals. The English language searches of the electronic databases SPORTDiscus, MEDLINE, and Web of Science were conducted from November 2018-February 2019. The studies involved were limited to the following: (a) original articles; (b) randomized controlled trials; (c) monitoring of central hemodynamic responses (either at rest or after a physiological challenge: maximal exercise or orthostatic challenge); and (d) healthy individuals. Of the 786 studies identified, 12 were included in the systematic review and meta-analysis. Meta-analysis was performed by the restricted maximum likelihood method. The results indicated that the effect size (ES) of wearing CG on improving central hemodynamic responses was large overall (Hedges' g = 0.55) and was large in SV (Hedges' g = 1.09) and HR (Hedges' g = 0.65). Subgroup analysis showed that the ESs in "post-physiological challenge" was large in overall (Hedges' g = 0.98), SV (Hedges' g = 1.78), HR (Hedges' g = 1.10), and DBP (Hedges' g = 0.75). Their ESs in "at rest" were not significant in all central hemodynamic responses, apart from a significant medium ES observed in SV (Hedges' g = 0.44). Healthy individuals who wear CG have marked improvement in central hemodynamic responses, particularly after a physiological challenge. More pronounced effects of CG are observed in increasing SV and reducing HR.

Walking Initiated 20 Minutes before the Time of Individual Postprandial Glucose Peak Reduces the Glucose Response in Young Men with Overweight or Obesity: A Randomized Crossover Study.

BACKGROUND: Although a single bout of postmeal exercise can lower postprandial glucose (PPG), its optimal timing remains unclear. OBJECTIVE: This study aimed to investigate the effect of exercise timing using an individualized approach on PPG in overweight or obese young men. METHODS: Twenty men [age: 23.0 ± 4.3 y; BMI (kg/m2): 27.4 ± 2.8] each completed three 240-min trials in a randomized order separated by 6-14 d: 1) sitting (SIT), 2) walking initiated at each participant's PPG-peak time (PPGP) (iP), and 3) walking initiated 20 min before the PPGP (20iP). For each participant, PPGP was predetermined using continuous glucose monitoring. Walking was performed at 50% maximal oxygen consumption for 30 min. Venous blood was collected at 15- and 30-min intervals for 0-120 min and 120-240 min, respectively. The primary outcome was plasma PPG. Generalized estimating equations were used for comparison between trials. RESULTS: Compared with SIT, the 4-h incremental AUCs (iAUCs) for plasma PPG (-0.6 mmol · L-1 · h; P = 0.047) and insulin (-28.7%, P < 0.001) were reduced in 20iP only, and C-peptide concentrations were lower after iP (-14.9%, P = 0.001) and 20iP (-28.7%, P < 0.001). Plasma insulin (-11.1%, P = 0.006) and C-peptide (-8.3%, P = 0.012) were lower due to the 20iP compared with iP treatment. Finally, PPG reductions due to iP and 20iP occurred only in men with a BMI > 27.5 kg/m2 (iP, -11.2%; 20iP, -14.7%; P = 0.047) and higher glucose iAUC values during SIT (iP, -25.5%; 20iP, -25.7%; P < 0.001). CONCLUSIONS: Walking initiated 20 min before PPGP lowered PPG and plasma insulin and C-peptide concentrations in young men with overweight or obesity, in particular in those with high BMI or glucose iAUC values during SIT; it also lowered plasma insulin and C-peptide concentrations more effectively than did exercise initiated at PPGP. This trial was registered at the Chinese Clinical Trial Registry (http://www.chictr.org.cn/index.aspx) as ChiCTR1900023175.

The impact of exercise interventions concerning executive functions of children and adolescents with attention-deficit/hyperactive disorder: a systematic review and meta-analysis.

BACKGROUND: Previous studies found that exercise interventions have positive effects on executive functions of the general population. However, studies seldom target executive functions of children and adolescents with attention-deficit hyperactivity disorder (ADHD). This study aimed to synthesise empirical studies regarding the effects of exercise interventions on executive functions of children and adolescents with ADHD. METHODS: A systematic search of the relevant literature was conducted in March 2020 through six electronic databases: CINAHL Complete, Eric, MEDLINE, PsychINFO, SPORTDiscus with Full Text, and Web of Science. Randomised controlled trials/quasi-experimental designs that applied exercise interventions and assessed executive functions through neurocognitive tasks among children and adolescents with ADHD were included. Altogether, 314 studies were identified, from which 31 full texts were independently assessed by two authors for eligibility. Finally, 21 studies underwent systematic reviews and 15 were selected for meta-analysis. Data extraction procedures and risk of bias analysis were conducted by two independent authors using the Physiotherapy Evidence Database (PEDro) scale. RESULTS: The findings indicated that exercise interventions improved overall executive functions of children and adolescents with ADHD (SMD = 0.611, 95% CI [0.386 to 0.836], p < 0.01). Exercise interventions had a moderate-to-large positive effect on inhibitory control (g = 0.761, 95% CI [0.376 to 1.146], p < 0.01) and cognitive flexibility (g = 0.780, 95% CI [0.331 to 1.228], p < 0.001). Likewise, during the subgroup analysis, intervention intensity and sessions of exercise (acute vs chronic) significantly moderated exercise intervention rather than intervention type. CONCLUSIONS: Chronic sessions of exercise interventions with moderate intensity should be incorporated as treatment for children with ADHD to promote executive functions.

Adaptation and evaluation of the neighborhood environment walkability scale for youth for Chinese children (NEWS-CC).

BACKGROUND: The physical activity-environment relationship has been infrequently investigated in Chinese children. Reliable and valid environmental measures specific to the age group and the local context are crucial for better understanding this relationship. The purposes of this study were to adapt the Neighborhood Environment Walkability Scale for youth (NEWS-Y) for Chinese children (termed NEWS-CC), and to examine the reliability and factorial validity of the NEWS-CC. METHODS: The development of the NEWS-CC involved the translation of the NEWS-Y to Chinese and the addition of nine new items capturing Hong Kong specific environmental attributes which were generated in our previous study. A total of 953 Hong Kong children aged 9-14 years volunteered to complete the NEWS-CC twice with 7-14 days apart. Confirmatory factor analysis (CFA) was performed to examine the factorial validity of the NEWS-CC. Test-retest reliability of subscales and individual items in the NEWS-CC was examined by intraclass correlation coefficients (ICCs). RESULTS: The CFA identified a 7-factor measurement model for the NEWS-CC which fitted the data well, with an additional "pollution" factor not included in the original NEWS-Y. The final NEWS-CC consisted of 67 items in 10 subscales. The test-retest reliability of subscales (range of ICC = 0.47-0.86) and individual items (range of ICC = 0.41-0.79) in the final NEWS-CC was moderate to good. CONCLUSION: The results of this study support the psychometric properties of the NEWS-CC. The NEWS-CC can be used to assess physical activity-related neighborhood environment among children in Hong Kong, as well as cities that share similar urban forms with Hong Kong.

Wearing compression tights post-exercise enhances recovery hemodynamics and subsequent cycling performance.

PURPOSE: To investigate sports compression garment (CG)-induced recovery hemodynamics and their potential impact on subsequent cycling performance. METHODS: In a randomized crossover design, 13 physically active men (20.9 ± 1.4 years; 65.9 ± 7.8 kg; 173.3 ± 4.8 cm; peak power output 254.2 ± 27.2 W) underwent 2 experimental trials. During each experimental trial, the subjects performed 20-min fatiguing preload cycling followed by 60-min passive recovery wearing either a sports CG (28.6 ± 9.4 mmHg) or gymnastic pants (CON). A 5-min all-out cycling performance test was subsequently conducted and power output and cadence were recorded. Cardiac output (CO) and stroke volume (SV) were measured using Doppler ultrasound (USCOM®). Heart rate (HR), blood lactate [BLa-], ratings of perceived exertion (RPE), leg muscle soreness (LMS), mean arterial pressure (MAP) and systemic vascular resistance (SVR) were monitored at 5, 15, 30, 45, 60 min during passive recovery. RESULTS: During the subsequent 5-min all-out cycling performance test, power output (215.2 ± 24.0 vs. 210.8 ± 21.5 W, CG vs. CON) and cadence (72.5 ± 3.8 vs. 71.2 ± 4.8 rpm, CG vs. CON) were higher in CG than CON (P < 0.05). SV was higher at 15, 30 and 45 min (P < 0.05), CO was higher at 5 and 45 min (P < 0.05), HR was lower at 15 and 30 min (P < 0.05) and [BLa-] was lower at 5 and 15 min (P < 0.05) during passive recovery, while LMS was lower at all time-points (P < 0.05) compared with CON. CONCLUSION: Sports CG improves subsequent cycling performance by enhancing hemodynamic responses and attenuating perceived muscle soreness during passive recovery in physically active men.

Maximal oxygen consumption and oxygen uptake efficiency in adolescent males.

BACKGROUND/OBJECTIVE: Measures of oxygen uptake efficiency (OUE) have been used to evaluate cardiorespiratory fitness (CRF) in adolescents unable to perform maximal exercise. The oxygen uptake efficiency slope (OUES) and oxygen uptake efficiency plateau (OUEP) have been proposed as surrogates for maximal oxygen consumption (V̇O2max). We assessed the validity of the OUES and OUEP as predictors of V̇O2max in healthy male adolescents. METHODS: Sixty-three healthy male adolescents aged 15.40 ± 0.34 years underwent an incremental treadmill test to determine V̇O2max, OUES and OUEP. OUE throughout the test was assessed by dividing each V̇O2 value by the corresponding minute ventilation (V̇E) value. OUEP was determined as the 90 s average highest consecutive values for OUE. OUES was determined using data up to the ventilatory threshold (VT) by calculating the slope of the linear relation between V̇O2 and the logarithm of V̇E. RESULTS: Limits of agreement for V̇O2max predicted by OUES (±13.3 mL kg-1.min-1) and OUEP (±16.7 mL kg-1.min-1) relative to V̇O2max were wide and a magnitude bias was found for OUES and OUEP as predictors of V̇O2max (p < 0.001). CONCLUSION: The OUES and OUEP do not accurately predict V̇O2max in male adolescents and should not replace V̇O2max when assessing CRF in this population.

Compression Garment-induced Leg Changes Increase Hemodynamic Responses in Healthy Individuals.

This study evaluated the morphological changes of the lower limb and associated hemodynamic responses to different lower-body compression pressures (COMPs) in physically active, healthy individuals at rest. Each of the 32 participants underwent three trials with three different degrees of lower-body compression applied: "Low" (2.2±1.4 mmHg), "Medium" (12.9±3.9 mmHg), and "High" (28.8±8.3 mmHg). In each COMP, a cross-sectional area of leg muscles (CSAmuscle), subcutaneous fat (CSAfat), superficial vessels (SupV), deep arteries (DA), and deep veins (DV) at the calf, knee, and thigh levels were measured using magnetic resonance imaging (MRI). Additionally, blood pressure (BP), heart rate (HR), cardiac output (CO), stroke volume (SV), and systemic vascular resistance (SVR) were measured using Doppler ultrasound (USCOM®). With High COMP, calf CSAmuscle and SupV were smaller (p<0.01), whereas DA and DV were larger (p<0.05). Calf CSAfat, however, was similar among all COMPs. There were no major changes in CSAmuscle and CSAfat at knee and thigh levels. CO (3.2±0.9 L/min) and SV (51.9±16.4 mL) were higher (p<0.05) only with High COMP, but other hemodynamic variables showed no significant changes across different COMPs. The High COMP at the lower limb induces leg morphological changes and increases associated hemodynamic responses of physically active healthy individuals at rest.

Results from the Hong Kong's 2018 report card on physical activity for children and youth.

BACKGROUND/OBJECTIVE: The Active Healthy Kids 2018 Hong Kong Report Card provides evidence-based assessment across 12 indicators of physical activity behaviors, sleep, and related community and government initiatives for children and youth. METHODS: The systematic development process provided by the Active Healthy Kids Global Alliance was used. The best available data from the past 10 years were reviewed by a panel of experts. According to predefined benchmarks, letter grades were assigned to 12 indicators (Overall Physical Activity, Organized Sport Participation, Active Play, Active Transportation, Sedentary Behaviors, Physical Fitness, Sleep, Family, School, Community and Environment, Government, and Obesity). RESULTS: Three of the five activity behaviors received C- or C grades: Overall Physical Activity (C-), Sedentary Behaviors (C-), and Organized Sport Participation (C). Active Transportation was graded B + . Same to the 2016 Hong Kong Report Card, Active Play could not be graded. School and Government were graded C. Family and Community and Environment was graded D- and B, respectively. Three new indicators were added after the 2016 Report Card and they were graded from C- (Sleep) to D (Physical Fitness) or D- (Obesity). CONCLUSIONS: Children and youth in Hong Kong have low physical activity and physical fitness levels and high sedentary behaviors despite a generally favorable community environment. A high prevalence of obesity and low levels of family support warrant more public health action. Researchers should address the surveillance gap in active play and peer support.

Effects of body-mapping-designed clothing on heat stress and running performance in a hot environment.

To investigate clothing-induced differences in human thermal response and running performance, eight male athletes participated in a repeated-measure study by wearing three sets of clothing (CloA, CloB, and CloC). CloA and CloB were body-mapping-designed with 11% and 7% increased capacity of heat dissipation respectively than CloC, the commonly used running clothing. The experiments were conducted by using steady-state running followed by an all-out performance running in a controlled hot environment. Participants' thermal responses such as core temperature (Tc), mean skin temperature ([Formula: see text]), heat storage (S), and the performance running time were measured. CloA resulted in shorter performance time than CloC (323.1 ± 10.4 s vs. 353.6 ± 13.2 s, p = 0.01), and induced the lowest [Formula: see text], smallest ΔTc, and smallest S in the resting and running phases. This study indicated that clothing made with different heat dissipation capacities affects athlete thermal responses and running performance in a hot environment. Practitioner Summary: A protocol that simulated the real situation in running competitions was used to investigate the effects of body-mapping-designed clothing on athletes' thermal responses and running performance. The findings confirmed the effects of optimised clothing with body-mapping design and advanced fabrics, and ensured the practical advantage of developed clothing on exercise performance.

Correlates of physical activity in children and adolescents with physical disabilities: A systematic review.

BACKGROUND: The benefits of physical activity (PA) for children with disabilities are well documented, and children with physical disabilities (PD) are often less active than peers with other disability types. Various correlates associated with PA in children with PD have been identified in separate studies, and a thorough analysis of these correlates could aid in understanding and designing interventions that promote children with PD to be more physically active. The purpose of this systematic review was to provide a comprehensive summary of the correlates of PA in children with PD. METHOD: A systematic search using PubMed, CINAHL, Cochrane Library, PsychINFO, Eric, and EMbase was initiated in October 2014 to identify studies examining the correlates of PA in children with PD aged 6-18years. Two researchers independently screened studies, assessed their methodological quality, and extracted relevant data. The correlates were synthesized and further assessed semi-quantitatively. RESULTS: A total of 45 articles were included in the detailed review. Several modifiable physical, psychological, and environmental correlates were consistently and positively associated with PA in children with PD. Some non-modifiable correlates (e.g., intellectual ability, parents' ethnicity) were found to be consistently and negatively associated with PA. CONCLUSIONS: The correlates of PA in children with PD are multifaceted and along many dimensions. This review can have implications for future studies and these may confirm the consistency of variables related to PA. Insights derived from the outcomes may also foster the measurement of the magnitude of associations that could assist the development of future interventions.

Relationship of BMI to the incidence of hypertension: a 4 years' cohort study among children in Guangzhou, 2007-2011.

BACKGROUND: In China, there has been a dramatic increase in overweight and obesity among children and adolescents in recent decades. However, little longitudinal studies reported BMI in relation to the risk for hypertension among children in China. We examined the longitudinal relations between BMI and hypertension in Chinese schoolchildren via a retrospective cohort study. METHODS: The cohort study was carried out in 7203 children (3821 boys and 3382 girls) in Guangzhou aged 6-8 years, with a continuous 4 years of follow-up. The participants, evaluated by body mass index (BMI), were categorized as thinness, normal weight, overweight, and obesity groups. The age and gender-specific BMI cutoffs newly developed by the Working Group on Obesity in China (WGOC) were used to define overweight and obesity. The thinness was defined by the international age- and gender-specific cut-off points for BMI for thinness grade 1. Hypertension was defined by using percentiles of systolic and diastolic values on the basis of height percentile, age, and gender. The Cox proportional hazards model was used to estimate the single or joint effect of BMI on the risk of hypertension. This study was approved by The Ethical Committee of School of Public Health, Sun Yat-sen University. RESULTS: During a follow-up of 4 years, a shocking high cumulative incidence of hypertension was found in Chinese overweight (50.1 %) and obesity (70 %) schoolchildren. The incidence of children hypertension were markedly higher among overweight and obesity group than normal weight and thinness group (24.3 %, 18.5 % vs 11.1 %, 7.4 %). Compared with the children in the normal weight group, the adjusted HRs and 95 % CIs of developing hypertension in thinness, overweight, and obesity group were 0.972 (0.851, 1.110), 1.313 (1.179, 1.461), and 1.816 (1.634, 2.081), respectively. Additionally, the protective effect of thinness on hypertension was observed in boys 0.808 (0.666, 0.981), but not in girls 1.158 (0.966, 1.389). CONCLUSIONS: The 4-year longitudinal study indicated that the overweight and obesity can predict the higher risk of hypertension in Chinese children, whereas, the thinness predict the lower risk of hypertension only in boys.

Effect of wearable activity trackers on physical activity in children and adolescents: a systematic review and meta-analysis.

BACKGROUND: Physical inactivity in children and adolescents has become a pressing public health concern. Wearable activity trackers can allow self-monitoring of physical activity behaviour and promote autonomous motivation for exercise. However, the effects of wearable trackers on physical activity in young populations remain uncertain. METHODS: In this systematic review and meta-analysis, we searched PubMed, Embase, SPORTDiscus, and Web of Science for publications from database inception up to Aug 30, 2023, without restrictions on language. Studies were eligible if they were randomised controlled trials or clustered randomised controlled trials that examined the use of wearable activity trackers to promote physical activity, reduce sedentary behaviours, or promote overall health in participants with a mean age of 19 years or younger, with no restrictions on health condition or study settings. Studies were excluded if children or adolescents were not the primary intervention cohort, or wearable activity trackers were not worn on users' bodies to objectively track users' physical activity levels. Two independent reviewers (WWA and FR) assessed eligibility of studies and contacted authors of studies if more information was needed to assess eligibility. We also searched reference lists from relevant systematic reviews and meta-analyses. Systematic review software Covidence was used for study screening and data extraction. Study characteristics including study setting, participant characteristics, intervention characteristics, comparator, and outcome measurements were extracted from eligible studies. The two primary outcomes were objectively measured daily steps and moderate-to-vigorous physical activity. We used a random-effects model with Hartung-Knapp adjustments to calculate standardised mean differences. Between-study heterogeneity was examined using Higgins I2 and Cochran Q statistic. Publication bias was assessed using Egger's regression test. This systematic review was registered with PROSPERO, CRD42023397248. FINDINGS: We identified 9619 studies from our database research and 174 studies from searching relevant systematic reviews and meta-analyses, of which 105 were subjected to full text screening. We included 21 eligible studies, involving 3676 children and adolescents (1618 [44%] were female and 2058 [56%] were male, mean age was 13·7 years [SD 2·7]) in our systematic review and meta-analysis. Ten studies were included in the estimation of the effect of wearable activity trackers on objectively measured daily steps and 11 were included for objectively measured moderate-to-vigorous physical activity. Compared with controls, we found a significant increase in objectively measured daily steps (standardised mean difference 0·37 [95% CI 0·09 to 0·65; p=0·013]; Q 47·60 [p<0·0001]; I2 72·7% [95% CI 53·4 to 84·0]), but not for moderate-to-vigorous physical activity (-0·08 [-0·18 to 0·02; p=0·11]; Q 10·26 [p=0·74]; I2 0·0% [0·0 to 53·6]). INTERPRETATION: Wearable activity trackers might increase daily steps in young cohorts of various health statuses, but not moderate-to-vigorous physical activity, highlighting the potential of wearable trackers for motivating physical activity in children and adolescents. More rigorously designed trials that minimise missing data are warranted to validate our positive findings on steps and to explore possible long-term effects. FUNDING: The Hong Kong University Grants Committee and Seed Fund for Basic Research of the University of Hong Kong.

A systematic review and meta-analysis on the ocular characteristics in children and adolescents with neurodevelopmental disorders.

To conduct a systematic review and meta-analysis of the association between children and adolescents with attention deficit hyperactivity disorder (ADHD) or autism spectrum disorder (ASD) and ocular characteristics. Systematic review with meta-analysis. Six databases (PubMed, Scopus, APA PsycInfo, Embase, EBSCOhost, and Cochrane library) were selected for a systematic literature search from database inception to July 2022. The observational studies assessing and reporting at least one outcome regarding ocular characteristics in children and adolescents with ADHD or ASD aged 6-17 were included. Studies in languages other than English, studies of adult or elderly human populations, and animal studies were excluded. The results were analyzed following the PRISMA guideline 2020. The findings of 15 studies, including 433 participants with ADHD, 253 participants with ASD, and 514 participants with typical development (TD), revealed that there were no significant differences in retinal nerve fiber layer, ganglion cell complex, and macular thickness between the ADHD group and the TD group. In subgroup analysis, significant differences in inferior ganglion cell (MD = - 3.19; 95% CI = [- 6.06, - 0.31], p = 0.03) and nasal macular thickness (MD = 5.88; 95% CI = [- 0.01, 11.76], p = 0.05) were detected between the ADHD group and the TD group. A significant difference in pupillary light reflex (PLR) was also observed between the ASD group and the TD group (MD = 29.7; 95% CI = [18.79, 40.63], p < 0.001). Existing evidence suggests a possible association between children and adolescents with ADHD or ASD and ocular characteristics. Given the limited number of studies, further research on a larger cohort is necessary to claim a possible diagnosis of ADHD or ASD through ocular characteristics.