Background: The Global Matrix 4.0 on physical activity (PA) for children and adolescents was developed to achieve a comprehensive understanding of the global variation in children’s and adolescents’ (5–17 y) PA, related measures, and key sources of influence. The objectives of this article were (1) to summarize the findings from the Global Matrix 4.0 Report Cards, (2) to compare indicators across countries, and (3) to explore trends related to the Human Development Index and geo-cultural regions. Methods: A total of 57 Report Card teams followed a harmonized process to grade the 10 common PA indicators. An online survey was conducted to collect Report Card Leaders’ top 3 priorities for each PA indicator and their opinions on how the COVID-19 pandemic impacted child and adolescent PA indicators in their country. Results: Overall Physical Activity was the indicator with the lowest global average grade (D), while School and Community and Environment were the indicators with the highest global average grade (C+). An overview of the global situation in terms of surveillance and prevalence is provided for all 10 common PA indicators, followed by priorities and examples to support the development of strategies and policies internationally. Conclusions: The Global Matrix 4.0 represents the largest compilation of children’s and adolescents’ PA indicators to date. While variation in data sources informing the grades across countries was observed, this initiative highlighted low PA levels in children and adolescents globally. Measures to contain the COVID-19 pandemic, local/international conflicts, climate change, and economic change threaten to worsen this situation.

The results indicate that vigorous PA in particular predicts overweight and obesity in boys. They should aim to do at least 60 minutes per day of MVPA. These results contribute to the recommendations suggesting that a minimum of 15 minutes per day of vigorous PA is desired to reduce the risk of developing overweight/obesity in later puberty.

Background/Aims: Many inflammation parameters are associated with obesity, but few comparable data are found in youth. This study aims to characterize the differences in serum levels of 13 biochemical inflammatory markers between boys with increased BMI and boys with normal BMI, and examine the relationships between inflammation markers, skinfold thicknesses, and body composition. Participants/Methods: The participants were 38 boys (BMI above 85th percentile) and 38 boys (normal BMI) at the age of 10–11 years. Measurements included BMI, 9 skinfold thicknesses, waist and hip circumferences, and total body and trunk fat mass and percentage as indices of obesity, fasting insulin, glucose, and serum concentrations of IL-2, IL-4, IL-6, IL-8, IL-10, VEGF, IFN-γ, TNF-α, IL-1α, IL-1β, monocyte chemoattractant protein-1 (MCP-1), epidermal growth factor, and CRP. Results: Overweight boys (OWB) were taller and more frequently in puberty than normal-weight boys (NWB). Skinfold thicknesses and body composition parameters were higher in OWB. They had significantly higher serum IL-6, IL-8, IFN-γ, MCP-1, and CRP values compared to NWB. Conclusions: Six of 13 measured biochemical markers were significantly increased in OWB, indicating that many low-grade inflammatory processes are already involved in the development of obesity in childhood.

One of the key determinants of adult skeletal health is the maximization of bone mass during the growth period. Physical activity (PA) in combination with lean mass and fat mass contribute to a great extent to bone mineral accrual; however, PA changes significantly during puberty. The aim of the present study was to examine PA exposure relative to bone mass acquisition during a longer observation period. Daily PA was measured with 7-day accelerometry and bone mineral parameters by DXA in 11- to 13-year-old peripubertal boys (n = 169). Similar testing was done after 1 calendar year. Changes in sedentary time were negatively related to changes in whole-body bone mineral density (BMD), lumbar spine bone mineral content (BMC), lumbar spine bone area (BA), femoral neck (FN) BMD, and FN BMC (r > -0.157; p < 0.05). Sedentary time emerged as the main PA level in predicting changes in FN BMC (p = 0.027) and in combination with vigorous PA predicting changes in FN BMD (p < 0.024). In addition to the effect of body composition on the skeleton, increase in sedentary time emerged as one main physical activity predictor (in addition to vigorous PA) of bone mineral acquisition during a 12-month period in peripubertal boys.

The aim of our longitudinal study was to investigate the relationships between physical activity and bone mass in boys with different body mass status during the years surrounding pubertal growth spurt. Two hundred and six boys entering puberty took part in this study. The subjects were divided into underweight (), normal weight (), overweight () and obese () groups at baseline according to age related categories. Whole-body DXA scans were performed at baseline, after 12 and 24 months to assess body composition (lean body mass, fat mass), and total body (TB), lumbar spine (LS) and femoral neck (FN) bone mineral density (BMD) parameters. Physical activity was measured by 7- day accelerometry. For longitudinal analysis, multilevel fixed effects regression models were constructed. Biological age, height and lean body mass had an effect for explanation of TB BMD, FN BMD and LS BMD. Moderate to vigorous physical activity (MVPA), vigorous physical activity (VPA) and sedentary time (SED) had the significant effect only on FN BMD. Being an underweight boy at the baseline indicated greater chance (p<0.01) to have lower TB BMD in the future (2 years at follow up) development, compared to normal weight (estimates = −0.038), overweight (estimates = −0.061) and obese boys (estimates = −0.106).

The results of the study indicate that CVF has a stronger longitudinal prediction value compared to moderate to vigorous physical activity in terms of metabolic risk factors in adolescent boys. Fitness remained a significant predictor if the influence of body fatness was removed from the analysis. Am. J. Hum. Biol. 28:782-788, 2016. © 2016Wiley Periodicals, Inc.

Subjective energy intake (sEI) is often misreported, providing unreliable estimates of energy consumed. Therefore, relating sEI data to health outcomes is difficult. Recently, Börnhorst et al. compared various methods to correct sEI-based energy intake estimates. They criticised approaches that categorise participants as under-reporters, plausible reporters and over-reporters based on the sEI:total energy expenditure (TEE) ratio, and thereafter use these categories as statistical covariates or exclusion criteria. Instead, they recommended using external predictors of sEI misreporting as statistical covariates. We sought to confirm and extend these findings. Using a sample of 190 adolescent boys (mean age=14), we demonstrated that dual-energy X-ray absorptiometry-measured fat-free mass is strongly associated with objective energy intake data (onsite weighted breakfast), but the association with sEI (previous 3-d dietary interview) is weak. Comparing sEI with TEE revealed that sEI was mostly under-reported (74 %). Interestingly, statistically controlling for dietary reporting groups or restricting samples to plausible reporters created a stronger-than-expected association between fat-free mass and sEI. However, the association was an artifact caused by selection bias - that is, data re-sampling and simulations showed that these methods overestimated the effect size because fat-free mass was related to sEI both directly and indirectly via TEE. A more realistic association between sEI and fat-free mass was obtained when the model included common predictors of misreporting (e.g. BMI, restraint). To conclude, restricting sEI data only to plausible reporters can cause selection bias and inflated associations in later analyses. Therefore, we further support statistically correcting sEI data in nutritional analyses. The script for running simulations is provided.

BackgroundWe investigated longitudinal relationships between the biochemical markers of bone and adipose tissue with bone mineral content (BMC), bone mineral density (BMD), moderate-to-vigorous physical activity (MVPA) and sedentary time (SED) in pubertal boys.MethodsNinety-six boys (11.9 ± 0.6 years old) were measured at baseline, after 12 and 24 months. Body composition (fat mass [FM], lean body mass [LBM]), and whole body (WB), lumbar spine (LS) and femoral neck (FN) BMD and BMC were assessed. Additionally, serum leptin, adiponectin, osteocalcin (OC) and C-terminal telopeptide of type I collagen (CTX) were measured.ResultsOC had a strong longitudinal inverse effect on changes in WB_BMD (p < 0.001) and LS_BMD (p = 0.021), while CTX had an inverse effect only on changes in FN_BMD (p = 0.011). Leptin had an inverse effect on changes in WB_BMC/WB_BMD (p = 0.001), FN_BMD (p = 0.002) and LS_BMD (p = 0.001). MVPA showed a longitudinal inverse effect on changes in leptin (p = 0.030), however no longitudinal effect of SED to biochemical markers of bone and adipose tissue was found.ConclusionsBone metabolism markers have negative effect on bone mineral accrual during puberty. Increases in MVPA affect leptin, suggesting a positive link of MVPA through leptin metabolism on increases in bone mineralization during puberty.