Association of objectively measured physical activity and bone health in children and adolescents: a systematic review and narrative synthesis

Mid-Childhood Plasma Concentrations of Per- and Polyfluoroalkyl Substances, Modifiable Lifestyle Factors, and Bone Mineral Density Through Late Adolescence

There is limited research on associations of per- and polyfluoroalkyl substances (PFAS) with areal bone mineral density (aBMD) through adolescence and whether bone-strengthening factors ameliorate effects. In the Project Viva cohort (N = 484; 50% female), we used sex-stratified linear regression and quantile g-computation mixture models to examine associations of mid-childhood (median: 7.8 years; 2007-2010) plasma PFAS concentrations with a dual-energy X-ray absorptiometry total-body aBMD Z-score in early and late adolescence (median: 12.9 and 17.6 years, respectively). We explored stratum-specific estimates by parent/self-reported physical activity and dairy intake. Using linear mixed models, we evaluated associations with aBMD accrual from mid-childhood through late adolescence. Females with higher perfluorooctanoate (PFOA) and perfluorodecanoate (PFDA) had lower early adolescent aBMD Z-score [e.g., β(95%CI)] per doubling PFOA: -0.19(-0.41, 0.03)]. Youth with higher PFOA and PFDA had lower late adolescent aBMD Z-score, but CIs were wide [e.g., PFOA: females, -0.12(-0.40, 0.16); males, -0.10(-0.42, 0.21)]. Mixture models generally corroborated single PFAS results, and in linear mixed models, females with higher PFAS concentrations, and males with higher PFOA, had slower aBMD accrual. Less active males with higher PFOA, PFDA, and the PFAS mixture had lower late adolescent aBMD Z-score. Some PFAS appeared more negatively associated with the aBMD Z-score among those who consumed less dairy, but there was not consistent evidence of effect modification. Exposure to select PFAS may affect bone accrual through adolescence, with possible resilience conferred by greater physical activity and dairy intake.

"I Use Technologies Strategically With My Family Now": Practices That Parents Value to Promote Physical Activity in Young Children

BACKGROUND

Although widely accessible digital technology (DT) provided multiple opportunities for young children's play, learning, and development, it also raised parents and professionals' concerns regarding its impact on children's physical activity. This study aimed to identify practices involving DT that were valued by parents in helping their young child to be physically active.

METHODS

Participants were parents of ambulatory young children (less than 5 y of age) engaged with a playgroup. The study involved representatives from 3 service organizations, who compiled a list of digital resources related to using DT to promote children's physical activity that were suitable to be shared and trialed by parents and young children. During a pretrial workshop, researchers, participants, and organization representatives collaboratively developed the intervention, which involved the delivery of selected resources by weekly email, over a 12-week period. Participants provided weekly feedback about their experiences and participated in a postintervention semistructured qualitative interview.

RESULTS

Thirteen families, with children aged between 15 and 36 months, completed the trial. Participants reported several valued practices to promote their children's physical activity, including those where the child was active while engaging with DT, where child engagement with DT acted as a prompt for later physical activity, where DT assisted parents in planning physical activity, where DT assisted parents in integrating movement with learning and play, and where DT was used to reinforce the child's enthusiasm for physical activity.

CONCLUSIONS

Parents reported several valued practices where children were physically active, rather than sedentary, while using digital technology.

Evaluation of the ActiMotus Software to Accurately Classify Postures and Movements in Children Aged 3-14

BACKGROUND

ActiMotus, a thigh-accelerometer-based software used for the classification of postures and movements (PaMs), has shown high accuracy among adults and school-aged children; however, its accuracy among younger children and potential differences between sexes are unknown. This study aimed to evaluate the accuracy of ActiMotus to measure PaMs among children between 3 and 14 years and to assess if this was influenced by the sex or age of children.

METHOD

Forty-eight children attended a structured ~1-hour data collection session at a laboratory. Thigh acceleration was measured using a SENS accelerometer, which was classified into nine PaMs using the ActiMotus software. Human-coded video recordings of the session provided the ground truth.

RESULTS

Based on both F1 scores and balanced accuracy, the highest levels of accuracy were found for lying, sitting, and standing (63.2-88.2%). For walking and running, accuracy measures ranged from 48.0 to 85.8%. The lowest accuracy was observed for classifying stair climbing. We found a higher accuracy for stair climbing among girls compared to boys and for older compared to younger age groups for walking, running, and stair climbing.

CONCLUSIONS

ActiMotus could accurately detect lying, sitting, and standing among children. The software could be improved for classifying walking, running, and stair climbing, particularly among younger children.

Per- and polyfluoroalkyl substances and bone mineral content in early adolescence: Modification by diet and physical activity

BACKGROUND

Per- and polyfluoroalkyl substance (PFAS) exposures may negatively impact bone mineral accrual, but little is known about potential mitigators of this relation. We assessed whether associations of PFAS and their mixture with bone mineral content (BMC) in adolescence were modified by diet and physical activity.

METHODS

We included 197 adolescents enrolled in a prospective pregnancy and birth cohort in Cincinnati, Ohio (2003-2006). At age 12 years, we collected serum for PFAS measurements and used dual-energy x-ray absorptiometry to measure BMC. We calculated dietary calcium intake and Health Eating Index (HEI) scores from repeated 24-h dietary recalls, physical activity scores using the Physical Activity Questionnaire for Older Children (PAQ-C), and average moderate to vigorous physical activity (MVPA) based on accelerometry. We estimated covariate-adjusted differences in BMC z-scores per interquartile range (IQR) increase of individual PFAS concentrations using linear regression and per simultaneous IQR increase in all four PFAS using g-computation. We evaluated effect measure modification (EMM) using interaction terms between each modifier and PFAS.

RESULTS

Higher serum perfluorooctanoic acid, perfluorooctanesulfonic acid, and perfluorononanoic acid concentrations and the PFAS mixture were associated with lower BMC z-scores. An IQR increase in all PFAS was associated with a 0.27 (-0.54, 0.01) lower distal radius BMC z-score. Associations with lower BMC were generally stronger among adolescents classified as < median for calcium intake, HEI scores, or MVPA compared to those ≥ median. The difference in distal radius BMC z-score per IQR increase in all PFAS was -0.38 (-0.72, -0.04) for those with

CONCLUSION

Healthy, calcium-rich diets and higher intensity physical activity may mitigate the adverse impact of PFAS on adolescent bone health.

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Key Words

• Adolescent health
• Bone mineral content
• Calcium
• Diet
• Perfluoroalkyl substances
• Physical activity

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MESH Headings

• Humans
• Female
• Fluorocarbons/blood
• Male
• Bone Density/drug effects
• Child
• Adolescent
• Diet
• Environmental Pollutants/blood
• Prospective Studies
• Ohio
• Alkanesulfonic Acids/blood
• Exercise
• Motor Activity/drug effects

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Grants

• R01 ES030078 NIEHS NIH HHS
• R01 ES033252 NIEHS NIH HHS
• R01 ES027224 NIEHS NIH HHS
• L40 ES032257 NIEHS NIH HHS
• P01 ES011261 NIEHS NIH HHS
• R01 ES032836 NIEHS NIH HHS
• R01 ES028277 NIEHS NIH HHS
• T32 ES007141 NIEHS NIH HHS
• R01 ES025214 NIEHS NIH HHS
• R01 ES020349 NIEHS NIH HHS

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Affiliation(s)

Jessie P Buckley Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
Junyi Zhou Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, USA
Katherine M Marquess Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, USA
Bruce P Lanphear Faculty of Health Sciences, Simon Fraser University, Vancouver, Canada
Kim M Cecil Department of Radiology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, USA; Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, USA
Aimin Chen Department of Biostatistics, Epidemiology and Informatics, University of Pennsylvania Perelman School of Medicine, Philadelphia, USA
Clara G Sears Christina Lee Brown Envirome Institute, Department of Medicine, Division of Environmental Medicine, University of Louisville, KY, USA
Yingying Xu Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, USA
Kimberly Yolton Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, USA
Heidi J Kalkwarf Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, USA
Joseph M Braun Department of Epidemiology, Brown University, Providence, USA
Jordan R Kuiper Department of Environmental and Occupational Health, The George Washington University Milken Institute School of Public Health, Washington, D.C., USA

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First report card on physical activity for children and adolescents in Slovakia: a comprehensive analysis, international comparison, and identification of surveillance gaps

BACKGROUND

National surveillance of physical activity (PA) is essential to establish public health policy actions for PA promotion and evaluation, thereby promoting accountability. The main goal of this study is to comprehensively analyse surveillance data on PA behaviours, outcomes, and influencing factors among Slovakian children and adolescents by using the methodology of the Active Healthy Kids Global Alliance Global Matrix (AHKGA-GM) project. Secondary goals are to provide comparisons with international data and the identification of surveillance gaps.

METHODS

A comprehensive multilevel search strategy for data about 10 core indicators and 1 additional indicator published between 2015 and 2020 (solely pre-COVID-19-pandemic data) was used. The data were then synthesised, and a set of standardised benchmarks was used to assign grades according to The Global Matrix 4.0 Grading Rubric.

RESULTS

A total of 552 potentially relevant data resources were retrieved, of which 34 were identified as eligible for data extraction. Grade B was assigned to four core indicators, grade C to five core indicators, and grade D to one core indicator. The additional Sleep indicator was graded a C-. Compared with the average grades from countries with high Human Development Index scores, Slovakia received higher grades in five core indicators (Overall Physical Activity, Active Transportation, Sedentary Behaviours, School, Government), and in the aggregate Behavioural average and Overall average. Compared with global averages, Slovakia had higher grades in the aforementioned core and aggregate indicators, and in the Community and Environment core indicator and aggregate Sources of Influence average indicator. Numerous surveillance gaps were identified.

CONCLUSIONS

The overall grading of the available surveillance data suggests the need for improvement in all 10 surveilled core indicators, and in additional Sleep indicator. Despite the fact that numerous identified surveillance gaps limit the overall informative value of the current grade, they provide the important information needed to enhance surveillance of PA-related indicators in Slovakia. For instance, the focus should be put on younger children and parents, on obtaining the device-measured data on various movement behaviours, on the topic of outdoor physical activities, and policy evaluation.

Autonomous motivation, social support, and physical activity in school children: moderating effects of school-based rope skipping sports participation

Purpose

Recent studies have shown that physical activity (PA) levels are low among children and adolescents globally. In order to reverse this trend, PA interventions are increasingly favoured. The school setting is the ideal place to address the issues that many children face. The purpose of this study was to (a) The primary focus of this study is to delve into the mediating role played by school-based rope skipping sports participation (SRSP) in the connection between social support and moderate to high-intensity physical activity (MVPA) among school children. (b) Additionally, this research aims to examine the moderating effect of within this pathway.

Methods

We conducted a survey involving 721 adolescents residing in Changsha City. The participants' ages ranged from 8 to 12 years, with an average age of 9.84 ± 1.535 years. Out of these participants, 406 were boys, and 315 were girls. To assess variables such as social support and autonomous motivation, we employed standardized measurement scales. Subsequently, we analyzed the collected data using various statistical methods, including independent s-amples t-tests, bivariate correlation analysis, descriptive statistical analysis, structural equation modeling (SEM), and the Johnson-Neyman method.

Results

An independent samples t-test revealed a statistically significant difference in MVPA between genders (p = 0.003 < 0.05), with boys exhibiting a higher level of engagement in MVPA compared to girls, Correlation analysis revealed significant positive associations among several key variables. Specifically, social support demonstrated a noteworthy positive correlation with autonomous motivation (r = 0.331, p < 0.01) as well as school children's engagement in MVPA (r = 0.308, p < 0.01). Moreover, autonomous motivation displayed a significant positive correlation with school children's involvement in MVPA (r = 0.459, p < 0.01). The moderating analysis revealed a significant influence of the interaction between increased participation in and social support on school children's engagement in MVPA.

Conclusion

Social support and autonomy support have been proven effective in enhancing school children's engagement in MVPA. They exert their influence indirectly by fostering autonomous motivation. Notably, robust social support can significantly benefit MVPA school children with high activity requirements, particularly those regularly engaged in MVPA during the school day.

Cross-sectional and longitudinal associations between the 24-hour movement behaviours, including muscle and bone strengthening activity, with bone and lean mass from childhood to adolescence

BACKGROUND

This study aimed to assess whether moderate-to-vigorous physical activity (MVPA), sport and exercise as a proxy measure of muscle and bone strengthening activity, sedentary behaviour, and sleep were associated with total-body-less-head (TBLH) bone mineral content (BMC) and TBLH lean mass cross-sectionally and longitudinally from age 6 to 9 years and age 9 to 11 years to age 15 to 17 years.

METHODS

We used longitudinal data from a population sample of Finnish children from the Physical Activity and Nutrition in Children study (age 6 to 9 years: n = 478, 229 females; age 9 to 11 years: n = 384, 197 females; age 15 to 17 years: n = 222, 103 females). Linear regression analysed the cross-sectional and longitudinal associations between accelerometer-assessed MVPA, sedentary time and sleep, and questionnaire-assessed sport and exercise participation and screen time with dual-energy X-ray absorptiometry-assessed TBLH BMC and lean mass.

RESULTS

In females, MVPA at age 6 to 9 years was positively associated with TBLH BMC at age 15 to 17 years (β = 0.008, p = 0.010). Sport and exercise at age 9 to 11 years was positively associated with TBLH BMC (β = 0.020, p = 0.002) and lean mass (β = 0.343, p = 0.040) at age 15 to 17 years. MVPA at age 9 to 11 years was positively associated with TBLH lean mass (β = 0.272, p = 0.004) at age 15 to 17 years. In males, sleep at age 6 to 9 years was positively associated with TBLH lean mass (β = 0.382, p = 0.003) at age 15 to 17 years. Sport and exercise at age 9 to 11 years was positively associated with TBLH BMC (β = 0.027, p = 0.012) and lean mass (β = 0.721, p < 0.001) at age 15 to 17 years.

CONCLUSIONS

Promoting engagement in the 24-hour movement behaviours in childhood, particularly sport and exercise to strengthen muscle and bone, is important in supporting bone and lean mass development in adolescence.

TRIAL REGISTRATION

NCT01803776; first trial registration date: 04/03/2013.

Childhood and adolescence physical activity and multimorbidity later in life: A systematic review

Background

No systematic summary exists on childhood physical activity and later-life multimorbidity risks. We primarily investigated the association of physical activity in childhood and adolescence and the development of multimorbidity in adulthood. Secondarily, we examined whether physical activity level differ in children and adolescents with and without multimorbidity and whether there is a cross-sectional association between physical activity and multimorbidity.

Methods

Following Cochrane Handbook guidelines and adhering to PRISMA recommendations, we included cross-sectional, case-control and longitudinal studies that investigated the association between physical activity in children and adolescents and development of multimorbidity. Results were summarized narratively and we assessed the certainty of the evidence using the GRADE approach. The protocol was registered in PROSPERO, CRD42023407063.

Results

Of 9064 studies identified, 11 were included in 13 papers. Longitudinals studies suggested that being physically active in childhood and adolescence was associated with a lower risk of multimorbidity in adulthood. Three out of five studies reported lower physical activity level in children and adolescents with multimorbidity compared to those without, and two did not find a between-group difference. Cross-sectional evidence on the association between multimorbidity and lower physical activity was uncertain. Overall, the evidence certainty for all outcomes was considered low due to the indirectness and inconsistency in findings.

Conclusions

Childhood and adolescence physical activity appeared to be linked with a reduced risk of later-life multimorbidity but the certainty of the evidence is low. These results support the promotion of physical activity during childhood and adolescence.

Gender differences in the distribution of children's physical activity: evidence from nine countries

BACKGROUND

Physical activity in childhood is thought to influences health and development. Previous studies have found that boys are typically more active than girls, yet the focus has largely been on differences in average levels or proportions above a threshold rather than the full distribution of activity across all intensities. We thus examined differences in the distribution of physical activity between girls and boys in a multi-national sample of children.

METHODS

We used the harmonised International Children Accelerometry Database (ICAD), including waist-worn accelerometry data from 15,461 individuals (Boys: 48.3%) from 9 countries. Employing Generalised Additive Models of Location, Shape, and Scale (GAMLSS) we investigated gender differences in the distribution of individuals, including comparisons of variability (SD) and average physical activity levels (mean and median) and skewness. We conducted this analysis for each activity intensity (Sedentary, Light, and Moderate-to-Vigorous (MVPA)) and a summary measure (counts per minute (CPM)).

RESULTS

Sizable gender differences in the distribution of activity were found for moderate to vigorous activity and counts per minute, with boys having higher average levels (38% higher mean volumes of MVPA, 20% higher CPM), yet substantially more between-person variability (30% higher standard deviation (SD) for MVPA, 17% higher SD for CPM); boys' distributions were less positively skewed than girls. Conversely, there was little to no difference between girls and boys in the distribution of sedentary or light-intensity activity.

CONCLUSIONS

Inequality in activity between girls and boys was driven by MVPA. The higher mean volumes of MVPA in boys occurred alongside greater variability. This suggests a need to consider the underlying distribution of activity in future research; for example, interventions which target gender inequality in MVPA may inadvertently lead to increased inequality within girls.

Reduced Peak Bone Mass in Young Adults With Low Motor Competence

Although suboptimal bone health has been reported in children and adolescents with low motor competence (LMC), it is not known whether such deficits are present at the time of peak bone mass. We examined the impact of LMC on bone mineral density (BMD) in 1043 participants (484 females) from the Raine Cohort Study. Participants had motor competence assessed using the McCarron Assessment of Neuromuscular Development at 10, 14, and 17 years, and a whole-body dual-energy X-ray absorptiometry (DXA) scan at 20 years. Bone loading from physical activity was estimated from the International Physical Activity Questionnaire at the age of 17 years. The association between LMC and BMD was determined using general linear models that controlled for sex, age, body mass index, vitamin D status, and prior bone loading. Results indicated LMC status (present in 29.6% males and 21.9% females) was associated with a 1.8% to 2.6% decrease in BMD at all load-bearing bone sites. Assessment by sex showed that the association was mainly in males. Osteogenic potential of physical activity was associated with increased BMD dependent on sex and LMC status, with males with LMC showing a reduced effect from increasing bone loading. As such, although engagement in osteogenic physical activity is associated with BMD, other factors involved in physical activity, eg, diversity, movement quality, may also contribute to BMD differences based upon LMC status. The finding of lower peak bone mass for individuals with LMC may reflect a higher risk of osteoporosis, especially for males; however, further research is required. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Relationship between body composition and bone mass in normal-weight and overweight adolescents

Adolescence is a period characterized by large accumulation of bone mass. Body composition is an important determinant of bone mass. This study aimed to assess the relationship of bone mass with lean mass (LM) and fat mass (FM) in normal-weight and overweight adolescents with consideration of sex, sexual maturation and physical activity covariates. A total of 118 adolescents (60 girls and 58 boys) aged between 10 and 14 years participated in the study. Individuals were classified as normal weight or overweight according to body mass index. Bone mineral density (BMD), bone mineral content (BMC), LM, and FM were measured by dual-energy X-ray absorptiometry. In normal-weight adolescents, LM (β = 0.725, p < 0.001) and FM (β = 0.185, p = 0.019) were associated with lumbar spine BMC, whereas in overweight adolescents only LM (β = 0.736, p < 0.001) was associated with lumbar spine BMC. Furthermore, in the normal-weight group, FM and LM were associated with total body less head BMD (LM, β = 0.792, p < 0.001; FM, β = 0.257, p = 0.007) and lumbar spine BMD (LM, β = 0.553, p < 0.001; FM, β = 0.199, p < 0.035). In the overweight group, only LM was associated with total body less head BMD (β = 0.682, p < 0.001) and lumbar spine BMD (β = 0.528, p < 0.001). LM was the main predictor of bone mass in normal-weight and overweight adolescents. FM was associated with bone mass in normal-weight adolescents only. LM may be considered an important and useful marker in adolescents, when investigating bone health in this population. Activities that promote LM gain to reduce the risk of bone fractures and diseases in adulthood are recommended.

Association of developmental coordination disorder and low motor competence with impaired bone health: A systematic review

AIMS

Individuals with developmental coordination disorder (DCD) and low motor competence (LMC) may be at increased risk of low bone health due to their lifetime physical activity patterns. Impaired bone health increases an individual's risk of osteoporosis and fracture; therefore, it is necessary to determine whether a bone health detriment is present in this group. Accordingly, this systematic review explores the association between DCD/LMC and bone health.

METHODS AND PROCEDURES

Studies were included with assessment of bone health in a DCD/LMC population. Study bias was assessed using the JBI critical appraisal checklist. Due to heterogeneity, meta-analysis was not possible and narrative synthesis was performed with effect size and direction assessed via harvest plots.

OUTCOMES AND RESULTS

A total of 16 (15 paediatric/adolescent) studies were included. Deficits in bone measures were reported for the DCD/LMC group and were more frequent in weight-bearing sites. Critical appraisal indicated very low confidence in the results, with issues relating to indirectness and imprecision relating to comorbidities.

CONCLUSIONS AND IMPLICATIONS

Individuals with DCD or LMC are at increased risk of bone health deficits. Bone impairment locations indicate insufficient loading via physical activity as a potential cause of bone deficits. Results indicate a potential for earlier osteoporosis onset.

Higher Running Speed and Cardiovascular Endurance Are Associated with Greater Level of Academic Achievement in Urban Catalan Primary School Children

The purpose of the present study was to determine the relationship between physical fitness and academic achievement in a sample of primary-school children. Data of 116 sixth-grade primary-school students (68 girls, 48 boys) from Barcelona (Catalonia, Spain) with a mean (SD) age of 11.4 years (0.4) was analyzed. To determine academic achievement, proficiency scores in the subjects Catalan language, Spanish language, English language, and Maths were derived from the Test de Compètencies Bàsiques. Physical fitness was assessed using the Cooper test (aerobic capacity), 20-m sprint test (linear velocity), and 4 × 10-m test (agility). The results showed that participants with a higher performance in the Cooper and 20-m sprint tests had significantly better academic achievement in the assessed subjects (p < 0.05; d range = 0.93 to −2.98). The findings of this investigation are interesting from a curricular perspective since a positive association between academic achievement and physical fitness indicates a strong reason to raise the physical education status in educational systems, a subject that has traditionally been considered less important by the educational community.

A comparison of the associations between bone health and three different intensities of accelerometer-derived habitual physical activity in children and adolescents: a systematic review

Positive associations have been identified between bone outcomes and accelerometer-derived moderate (MPA) and vigorous (VPA) physical activity (PA) in youth; however, it remains unclear which intensity is most beneficial. This systematic review aimed to summarise accelerometer-derived methods used to estimate habitual PA in children and adolescents and determine whether the magnitude of association was consistently stronger for a particular intensity (MPA/MVPA/VPA). Observational studies assessing associations between accelerometer-derived MPA and/or MVPA and VPA with bone outcomes in children and adolescents (≤ 18 years) were identified in MEDLINE, EMBASE, Web of Science, SPORTDiscus and the Cochrane Central Register of Controlled Trials. Thirty articles were included (total n = 20,613 (10,077 males), 4-18 years). Chi-square tests determined whether the proportion of significant associations and strongest within-study associations differed significantly between intensities. Results demonstrated that accelerometer methods were highly variable between studies. Of the 570 associations analysed, 186 were significant (p < 0.05). The proportion of within-study strongest associations differed by PA intensity (3 × 2 χ2 = 86.6, p < 0.001) and was significantly higher for VPA (39%) compared to MVPA (5%; 2 × 2 χ2 = 55.3, p < 0.001) and MPA (9%, 2 × 2 χ2 = 49.1, p < 0.001). Results indicated a greater benefit of VPA over MPA/MVPA; however, variability in accelerometer-derived methods used prevents the precise bone-benefitting amount of VPA from being identified. Long epochs and numerous intensity cut-point definitions mean that bone-relevant PA has likely been missed or misclassified in this population. Future research should explore the use of shorter epochs (1 s) and identify bone-specific activity intensities, rather than using pre-defined activity classifications more relevant to cardiovascular health.

Prevalence and Trends of Physical Activity in Thai Children and Young People: Pooled Panel Data Analysis from Thailand's Surveillance on Physical Activity 2012-2020

This study aims to describe the level and trends of physical activity (PA) in Thai children and young people and examine PA changes during transitional periods. Employing nine rounds of Thailand's Surveillance on Physical Activity (SPA) 2012-2020, this study pooled three sets of data and included children and young people aged 6-17 years in the analysis: 1595 in SPA2012-2016, 1287 in SPA2017-2019, and 853 persons in SPA2020. Face-to-face interviews were conducted in five regions, 13 provinces, and 36 villages in SPA2012-2019, whereas an online survey was administered in all provinces in SPA2020. The prevalence of sufficient moderate-to-vigorous PA (MVPA) among Thais aged 6-17 years ranged from 19.0 percent to 27.6 percent, with a significant drop during the period of COVID-19 spread in 2020. The average daily MVPA ranged from 46 to 57 min and dropped to 36 min during the pandemic. Boys were consistently more active than girls in all nine rounds of the SPA, and girls had more difficulty in maintaining or improving their PA level. A significant increase in the proportion of Thai children and young people with sufficient MVPA was observed during their transition from late primary to early secondary school grades.

The Impact of Diet and Physical Activity on Bone Health in Children and Adolescents

There is growing recognition of the role of diet and physical activity in modulating bone mineral density, bone mineral content, and remodeling, which in turn can impact bone health later in life. Adequate nutrient composition could influence bone health and help to maximize peak bone mass. Therefore, children's nutrition may have lifelong consequences. Also, physical activity, adequate in volume or intensity, may have positive consequences on bone mineral content and density and may preserve bone loss in adulthood. Most of the literature that exists for children, about diet and physical activity on bone health, has been translated from studies conducted in adults. Thus, there are still many unanswered questions about what type of diet and physical activity may positively influence skeletal development. This review focuses on bone requirements in terms of nutrients and physical activity in childhood and adolescence to promote bone health. It explores the contemporary scientific literature that analyzes the impact of diet together with the typology and timing of physical activity that could be more appropriate depending on whether they are children and adolescents to assure an optimal skeleton formation. A description of the role of parathyroid hormone (PTH) and gut hormones (gastric inhibitory peptide (GIP), glucagon-like peptide (GLP)-1, and GLP-2) as potential candidates in this interaction to promote bone health is also presented.

Children with Autism Spectrum Disorder Spent 30 Min Less Daily Time in Moderate-to-Vigorous Physical Activity than Typically Developing Peers: a Meta-Analysis of Cross-sectional Data

It remains unclear if participation in moderate-to-vigorous physical activity (MVPA) differs between children with ASD and typically developing children (TDC). We compared daily MVPA, time spent in MVPA during physical education (PE) and recess, and odds of not meeting MVPA recommendation (60 min/day) between children with ASD and TDC. Nine studies reporting accelerometer-measured MVPA were included in the meta-analyses. MVPA was 30 min lower/day, 12% and 8% lower during PE and recess, respectively, in children with ASD, and they had 4 times higher odds of not meeting MVPA recommendation when compared to TDC. Children with ASD engage in daily MVPA less than TDC and below the guidelines. Tailored interventions to increase MVPA in children with ASD are warranted.

The "Fat but Fit" Paradigm and Bone Health in Young Adults: A Cluster Analysis

The fat but fit paradox has suggested that obese individuals with good fitness levels have lower cardiometabolic risk compared to individuals with normal weight but lower fitness levels. This paradigm has not been explored in the context of bone health. The aim of this study was to test whether categories of fat but fit paradigm assessed by body fat percentage and handgrip strength holds up in young adults and to analyze the relationship between fat but fit categories and bone outcomes. Cluster cross-sectional analyses of data from 499 young adults aged 18 to 30 from Toledo and Cuenca, Spain were conducted. Body fat percentage, handgrip strength, bone mineral content (BMC), bone mineral density (BMD), and dietary nutrients such as, proteins, magnesium, calcium, phosphorus, potassium, and vitamin D were assessed. Cluster analysis of body fat percentage and handgrip z scores resulted in a classification of four clusters that could be interpreted according to Fat Unfit (FU), Unfat Unfit (UU), Fat Fit (FF) and Unfat Fit (UF) categories. ANCOVA models showed that young adults in clusters with higher handgrip strength levels (FF, UF) and with higher key bone nutrients levels (UF) had significantly higher total BMC values than their peers in the UU and FU cluster categories, after controlling for sex, age and height. This study provides two novel conclusions in relation to the fat but fit paradigm: first, it confirms the construct of the four clusters of body fat percentage and handgrip strength, and second, it reinforces the predictive validity of the fat but fit paradigm categories, indicating the positive effect, although it may not just be a causal relationship, of muscular strength and key bone nutrients on counteracting the negative effect of obesity on bone health.

Narrative review of the influence of high-intensity interval training on adolescents' bone health: commentary and perspectives

Although several benefits have been associated to high-intensity interval training (HIIT), there is a lack of clarity on the HIIT effects in adolescents, especially on bone health outcomes. To address this gap, our research aimed to perform a systematic review, which focus on the influence of HIIT on adolescents' bone health. Our search strategy was conducted on three databases (PubMed, SCOPUS, and Embase). For our review, we included articles with the following characteristics: (I) sample consisting of adolescents (10-19 years old), (II) HIIT interventions; and (III) assessment of bone health outcomes. Longitudinal and clinical trials studies with no language and year of publications restrictions were eligible to be included. A total of 63 eligible studies were identified. After removing the duplicates and screening the titles and abstracts, six articles remained to be read in full text. However, none of the articles met our criteria. Studies in which no article meets the eligibility criteria are also essential and need to be shared with the academic community because it may stimulate appropriate future investigations in this field. This lack in the review results highlights the need for further epidemiological research focusing on this topic, including high quality, large scale, and longitudinal studies, as well as randomized controlled trials to confirm or refute efficacy.

Temporal trend of cardiorespiratory endurance in urban Catalan high school students over a 20 year period

Background

Physical fitness is considered an important indicator of health in adolescents. However, in recent years several studies in the scientific literature have shown a considerable lower trend and an alarming worsening of the current adolescents’ physical condition when comparing with previous decades, especially in urban populations. The aim of the current study was to analyse the temporal trend in cardiorespiratory endurance (CRE) in urban Catalan adolescents over a 20-year period (1999–2019).

Methods

A cross-sectional analysis study considering the 20-m Shuttle Run test (SRT) results obtained in the last 20 years was carried out. 1,701 adolescents between 15 and 16 years old (914 boys and 787 girls) were divided into four groups, corresponding to consecutive periods of five years (Group 1: 1999–2004; Group 2: 2005–2009; Group 3: 2010–2014 and Group 4: 2015–2019). ANOVA was used to test the period effect on CRE and post hoc Bonferroni analysis was performed to test pairwise differences between groups (p < 0.05).

Results

Results showed a significantly lower performance in CRE in both sexes. The percentual negative difference was 0.67%, 9.6% and 7% for boys and 5.06%, 14.97% and 9.41% for girls, when comparing the performance in 20-m Shuttle Run test for the first period, respectively.

Conclusions

Results suggest that the physical fitness of Catalan urban adolescents is lower in both sexes when comparing the different analysed periods of time. Therefore, CRE adolescents should be improved in order to help to protect against cardiovascular disease and other health risks in adulthood.