Longitudinal associations of physical activity and sedentary time with cardiometabolic risk factors in children

Association between arterial health and cognition in adolescents: The PANIC study

We investigated the associations of the measures of arterial health with cognition in adolescents and whether physical activity (PA) or sedentary time (ST) confounds these associations. One hundred sixteen adolescents (71 boys) aged 15.9 ± 0.4 participated in the study. PA and ST were assessed using a combined accelerometer/heart rate monitor. Overall cognition was computed from the results of psychomotor function, attention, working memory, and paired-associate learning tests. Pulse wave velocity was measured by impedance cardiography, carotid intima-media thickness, and carotid artery distensibility by carotid ultrasonography. Systolic and diastolic blood pressure (SBP and DBP) were measured using an aneroid sphygmomanometer. SBP was inversely associated with overall cognition (standardized regression coefficient [β] = -0.216, 95% confidence interval (CI) -0.406 to -0.027, p = 0.025). Pulse wave velocity (β = -0.199, 95% CI -0.382 to -0.017, p = 0.033) was inversely associated with working memory task accuracy. SBP was directly associated with reaction time in the attention (β = 0.256, 95% CI 0.069 to 0.443, p = 0.008) and errors in the paired-associate learning tasks (β = 0.308, 95% CI 0.126 to 0.489, p = 0.001). Blood pressure was inversely associated with overall cognition. PA or ST did not confound the associations. Results suggest that preventing high blood pressure is important for promoting cognition in adolescents.

Effects of 2-year dietary and physical activity intervention on cognition in children-a nonrandomized controlled trial

BACKGROUND AND OBJECTIVE

We investigated the effects of a combined dietary and PA intervention on cognition in children and whether changes in diet quality, PA, sedentary behavior (SB), and sedentary time (ST) are associated with changes in cognition.

METHODS

We conducted a 2-year nonrandomized controlled trial in 504 children aged 6-9 years at baseline. The children were allocated to a combined dietary and PA intervention group (n = 237) or a control group (n = 160) without blinding.

INTERVENTIONS

The children and their parents allocated to the intervention group had six dietary counseling sessions of 30-45 min and six PA counseling sessions of 30-45 min during the 2-year intervention period. The children were also encouraged to participate in after-school exercise clubs. Cognition was assessed by the Raven's Colored Progressive Matrices. We assessed dietary factors by 4 days food records and computed the Baltic Sea Diet Score (BSDS) as a measure of diet quality. PA and ST were assessed by a combined heart rate and body movement monitor, types of PA and SB by a questionnaire.

RESULTS

The intervention had no effect on cognition. Increased BSDS and consumption of low-fat milk and decreased consumption of red meat and sausages were associated with improved cognition over 2 years. Increased organized sports, ST, and reading were positively, while unsupervised PA, computer use, and writing were negatively associated with cognition.

CONCLUSION

Combined dietary and PA intervention had no effect on cognition. Improved diet quality and increased organized sports and reading were associated with improved cognition.

Physical Activity and Cardiovascular Risk Factors in Children from 4 to 9 Years of Age

BACKGROUND

Physical activity guidelines for children encourage moderate-to-vigorous intensity activities (MVPA); however, some studies have found that only vigorous intensity activities (VPA) might promote health benefits in young children. Thus, the aim of this study is to investigate cross-sectional and 5-year longitudinal associations of VPA and MVPA with cardiovascular disease (CVD) risk factors in childhood using compositional data analysis.

RESULTS

This study utilized data from the SPINACH study (n = 411). Physical activity was measured with accelerometers at 4- and 9-years of age. CVD risk factors were measured at 9-years of age, and included blood pressure (BP), lipid metabolism, and glucose metabolism biomarkers, as well as a continuous metabolic syndrome risk score (MetS). Cross-sectional and longitudinal linear regression models were built using compositional data analysis standards. Cross-sectionally, reallocating time to VPA from lower-intensity behaviours at 9-years was associated with lower waist circumference (B = - 3.219, P = 0.002), diastolic BP (B = - 1.836, P = 0.036), triglycerides (B = - 0.214, P < 0.001), glucose (B = - 0.189, P = 0.033), insulin (B = - 2.997, P < 0.001), and HOMA-IR (B = - 0.778, P < 0.001). Similarly, reallocating time to VPA at 4-years was associated with lower MetS (B = - 0.831, P = 0.049), waist circumference (B = - 4.211, P = 0.015), systolic BP (B = - 5.572, P = 0.015), diastolic BP (B = - 2.931, P = 0.044), triglycerides (B = - 0.229, P = 0.034), glucose (B = - 0.325, P = 0.032), insulin (B = - 5.114, P = 0.001), and HOMA-IR (B = - 0.673, P = 0.001) at 9-years. Reallocations of time to MVPA at 4- or 9-years were not associated with CVD risk factors at 9-years.

CONCLUSIONS

VPA was associated with CVD risk factors in children both cross-sectionally (9-years) and longitudinally (at 4- and 9-years). MVPA seemed not to be a stimulus of enough intensity to trigger these potential cardiometabolic benefits in healthy children. Thus, these findings suggest the importance of higher intensity activities, i.e., VPA already in early childhood for cardiometabolic health.

Obesogenic sleep patterns among Chinese preschool children: A latent profile and transition analysis of the association sleep patterns and obesity risk

OBJECTIVE

This paper utilized a person-centered approach to examine whether sleep patterns on school and free days are associated with obesity risk in preschool children aged 3-6 years.

METHODS

The cross-sectional analysis included 204 children from the Wuhan Healthy Start Project with valid sleep data in at least four consecutive days gathered via Actigraph GT3X+. Based on three domains of sleep duration, sleep onset, and sleep offset, we used latent profile analysis to identify distinct sleep patterns on school and free days separately. Additionally, we conducted latent transition analysis to explore the probabilities of sleep patterns transitions between school and free days. The multivariate logistic regression model investigated the associations of sleep patterns with overweight/obesity (OWO) (BMI ≥ age- and sex-specific 85th percentile) and abdominal obesity (AO) (WC ≥ age- and sex-specific 75th percentile).

RESULTS

Two sleep patterns were identified for school days: "EL-sc" (early-to-sleep/longer-duration) (n = 119; 58.3%) and "LS-sc" (late-to-sleep/shorter-duration) (n = 85; 41.7%). Similarly, "LES-fr" (late-to-sleep/early-to-wake/shorter-duration) (n = 118; 57.8%) and "ELL-fr" (early-to-sleep/late-to-wake/longer-duration) (n = 86; 42.2%) patterns were identified for free days. LTA categorized the participants into four distinct transition groups, i.e., "EL-sc→ELL-fr" (32.9%), "EL-sc→LES-fr" (24.0%), "LS-sc→LES-fr" (33.8%), and "LS-sc→ELL-fr" (9.3%). Compared with the "ELsc→ELL-fr", the "LS-sc→LES-fr" had a higher risk of OWO (AOR 4.76; 95% CI: 1.39-20.33) and AO (AOR, 2.78; 95% CI, 1.21-6.62), respectively. Neither "EL-sc→LES-fr" (AOR, 1.11; 95% CI, 0.14-6.67) nor "LS-sc→ELL-fr" (AOR, 0.74; 95% CI, 0.03-6.14) was significantly associated with OWO. Likewise, no significant association was observed for "EL-sc→LES-fr" (AOR, 0.96; 95% CI, 0.35-2.62) and "LS-sc→ELL-fr" (AOR, 0.56; 95% CI, 0.11-2.18) with AO.

CONCLUSIONS

"LS-sc→LES-fr" pattern is significantly associated with an increased risk of general and abdominal obesity, indicating its obesogenic nature. Furthermore, although not statistically associated with obesity outcomes, "LS-sc→ELL-fr" and "EL-sc→LES-fr" patterns exhibit a semi-obesogenic characteristic. In addition, we identified a concerning trend that preschool children are at risk of transitioning to and persisting in sleep patterns characterized by delayed and shorter sleep. These findings underscore the importance of implementing interventions and strategies to address sleep patterns as a crucial step to minimize the risk of obesity.

Longitudinal physical activity patterns and the development of cardiometabolic risk factors during adolescence

PURPOSE

To examine the associations between longitudinal physical activity (PA) patterns and the development of cardiometabolic risk factors from adolescence to young adulthood.

METHODS

This cohort study encompassed 250 participants recruited from sports clubs and schools, and examined at mean age 15 and 19. Device-measured moderate-to-vigorous PA was grouped into five patterns (via a data-driven method, using inactivity maintainers as a reference). The outcomes were: glucose, insulin, homeostasis model assessment for insulin resistance (HOMA-IR), total cholesterol, HDL and LDL cholesterol, triglycerides, blood pressure, and body mass index (BMI). Linear growth curve models were applied with adjustment for sex, age, fruit/vegetable consumption, cigarette/snuff use, and change in the device wear-time.

RESULTS

Insulin and BMI increased among decreasers from moderate to low PA (β for insulin 0.23, 95% CI 0.03-0.46; β for BMI 0.90; CI 0.02-1.78). The concentration of HDL cholesterol decreased (β -0.18, CI -0.31 to -0.05) and that of glucose increased (β 0.18, CI 0.02-0.35) among decreasers from high to moderate PA. By contrast, among increasers, blood pressure declined (systolic β -6.43, CI -12.16 to -0.70; diastolic β -6.72, CI -11.03 to -2.41).

CONCLUSIONS

Already during the transition to young adulthood, changes in PA are associated with changes in cardiometabolic risk factors. Favorable blood pressure changes were found among PA increasers. Unfavorable changes in BMI, insulin, glucose, and HDL cholesterol were found in groups with decreasing PA. The changes were dependent on the baseline PA and the magnitude of the PA decline.

Association of physical activity with metabolic profile from adolescence to adulthood

OBJECTIVE

Physical activity benefits cardiometabolic health, but little is known about its detailed links with serum lipoproteins, amino acids, and glucose metabolism at young age. We therefore studied the association of physical activity with a comprehensive metabolic profile measured repeatedly in adolescence.

METHODS

The cohort is derived from the longitudinal Special Turku Coronary Risk Factor Intervention Project. At ages 13, 15, 17, and 19 years, data on physical activity were collected by a questionnaire, and circulating metabolic measures were quantified by nuclear magnetic resonance metabolomics from repeatedly assessed serum samples (age 13: n = 503, 15: n = 472, 17: n = 466, and 19: n = 361).

RESULTS

Leisure-time physical activity (LTPA;MET h/wk) was directly associated with concentrations of polyunsaturated fatty acids, and inversely with the ratio of monounsaturated fatty acids to total fatty acids (-0.006SD; [-0.008, -0.003]; p < 0.0001). LTPA was inversely associated with very-low-density lipoprotein (VLDL) particle concentration (-0.003SD; [-0.005, -0.001]; p = 0.002) and VLDL particle size (-0.005SD; [-0.007, -0.003]; p < 0.0001). LTPA showed direct association with the particle concentration and size of high-density lipoprotein (HDL), and HDL cholesterol concentration (0.004SD; [0.002, 0.006]; p < 0.0001). Inverse associations of LTPA with triglyceride and total lipid concentrations in large to small sized VLDL subclasses were found. Weaker associations were seen for other metabolic measures including inverse associations with concentrations of lactate, isoleucine, glycoprotein acetylation, and a direct association with creatinine concentration. The results remained after adjusting for body mass index and proportions of energy intakes from macronutrients.

CONCLUSIONS

Physical activity during adolescence is beneficially associated with the metabolic profile including novel markers. The results support recommendations on physical activity during adolescence to promote health and possibly reduce future disease risks.

Dose-response relationship between physical activity and cardiometabolic risk in obese children and adolescents: A pre-post quasi-experimental study

Objective: This study aims to explore the dose-response relationship between the daily duration of moderate to vigorous physical activity and the improvement of cardiometabolic risk indicators in obese children and adolescents. Methods: Seventy-seven obese children and adolescents aged 10-17 years were randomly recruited for a 4-week exercise intervention in a closed camp during 2019-2021, physical activity was monitored by ActiGraph GT3X + to obtain daily MVPA duration, and the improvement of CMR indicators were reflected by the changes (Δ) of waist circumference, systolic blood pressure, diastolic blood pressure, total cholesterol, triglyceride , high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, fasting insulin, fasting plasma glucose, and homeostasis model assessment of insulin resistance before and after the intervention, calculated as ''Δ+indicator" = values after intervention-values before intervention. The groups were divided into different doses of Q1∼Q3 according to the daily MVPA duration from low to high. The differences in the improvement of different dose groups were compared by one-way analysis of covariance, and the dose-response relationship between MVPA duration and CMR indicators improvement was analyzed by linear regression and piecewise regression. The nonlinear relationship was analyzed by restricted cubic spline. Results: 1) Compared with indicators before the intervention, WC, SBP, DBP, TC, TG, HDL-C, LDL-C, FINS, and HOMA-IR were significantly lower after the intervention (p-value < 0.05). 2) The dose-response relationship between MVPA and LDL-C improvement was non-linear (P-Nonlinear < 0.05). When MVPA >77.1min/day, ΔLDL-C further decreased with the increase of MVPA duration [β = -0.009, 95% confidence interval (CI): -0.013, -0.005], and when MVPA ≤77.1min/day, increasing the MVPA duration did not increase the improvement of ΔLDL-C. Conclusion: There was a nonlinear dose-response relationship between the daily MVPA duration and LDL-C improvement in obese children and adolescents. In order to obtain more significant improvement in LDL-C through increased MVPA duration, MVPA duration should be higher than 77.1 min/day.

The effect of different intensity physical activity on cardiovascular metabolic health in obese children and adolescents: An isotemporal substitution model

Objective: This study's purpose was to investigate the effects of different intensities of physical activity on cardiovascular metabolism in obese children and adolescents based on an isochronous replacement model. Methods: A total of 196 obese children and adolescents (mean age, 13.44 ± 1.71 years) who met the inclusion criteria and attended a summer camp from July 2019 to August 2021 were recruited for this study, and all subjects wore a GT3X + triaxial motion accelerometer uniformly around the waist to record physical activity levels. We collected the subjects' height, weight, and cardiovascular risk factors such as waist circumference, hip circumference, fasting lipids, blood pressure, fasting insulin, and fasting glucose before and after 4 weeks of camp and constructed cardiometabolic risk score (CMR-z). We analyzed the effects of different intensities of physical activity on cardiovascular metabolism in obese children using isotemporal substitution model (ISM). Results: After 4 weeks, cardiovascular risk factors such as body weight, waist circumference, triglyceride, and total cholesterol were reduced in adolescents with obesity (p <0.01), and CMR-z was also reduced (p <0.01). ISM analysis revealed that all sedentary behavior (SB) replacement with 10 min of light physical activity (LPA) reduced CMR-z [β = -0.10, 95% CI (-0.20, -0.01)]; 10-min of moderate physical activity (MPA) replacement of SB reduced CMR-z [β = -0.32, 95% CI (-0.63, -0.01)]; 10-min of vigorous physical activity (VPA) replacement of SB reduced CMR-z [β = -0.39, 95% CI (-0.66, -0.12)]. Conclusion: Replacement of SB with 10 min of LPA, MPA, and VPA were all effective in improving cardiovascular risk health, respectively, but MPA or VPA was more effective.

Sedentary patterns and cardiometabolic risk factors in Mexican children and adolescents: analysis of longitudinal data

BACKGROUND

Sedentary behavior is a modifiable risk factor for cardiometabolic health; however, the assessment of total sedentary time may not capture youth's highly active and interrupted activity patterns. This study examined the associations between sedentary activity patterns and cardiometabolic risk factors among Mexican youth, who have a disproportionate burden of metabolic diseases, using a repeated measure design out of a longitudinal data.

METHODS

570 subjects in the Early Life Exposure in Mexico to ENvironmental Toxicants (ELEMENT) birth cohort, who were followed up to three-time points during adolescence, were included. Bout duration, and frequency and percentages of waking time spent in specific intensities of activity, were quantified using ActiGraph wGT3X-BT wrist accelerometers. Self-reported questionnaires were used to query the usual duration of different sedentary behaviors. Outcomes were fasting lipid profile, markers for glucose homeostasis, anthropometry, and blood pressure. Associations were modeled using linear mixed-effects models, and isotemporal substitution approach was additionally used to assess the effect of replacing objectively assessed sedentary activity with other activity intensities, adjusting for potential confounders.

RESULTS

Each hour of self-reported screen-based time was positively associated with diastolic blood pressure (mm Hg) [β = 0.30, 95% confidence interval (95% CI) = 0.10, 0.51], and an hour of other sedentary time was associated with log serum glucose (mg/dL) [β = 0.01, 95% CI = 0.004, 0.017]. Substitution models showed that replacing 5% of sedentary time with moderate to vigorous physical activity (MVPA) was associated with lower waist circumference (cm) [β = - 1.35, 95% CI = - 1.91, - 0.79] and log serum triglycerides (mg/dL) [β = - 0.11, 95% CI = - 0.18, - 0.03]. Substituting one uninterrupted sedentary bout with light activity was associated with lower insulin (μIU/mL) [β = - 0.06, 95% CI = - 0.10, - 0.02].

CONCLUSIONS

Sedentary time was associated with cardiometabolic risk factors in Mexican youth in a context-specific manner. Replacing sedentary time with higher intensities was associated with improvements in some cardiometabolic markers.

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.

Associations of diet quality, food consumption, eating frequency and eating behaviour with dental caries experience in Finnish children: a 2-year longitudinal study

We examined cross-sectional and longitudinal associations of dietary factors with caries experience in a population sample of 487 children aged 6-9 years at baseline examinations of the Physical Activity and Nutrition in Children (PANIC) Study. Altogether, 406 of these children attended 2-year follow-up examinations. Food consumption and eating frequency were assessed using 4-day food records, diet quality using the Baltic Sea Diet Score (BSDS) and eating behaviour using the Children's Eating Behavior Questionnaire. Caries experience was examined clinically. The cross-sectional associations of dietary factors with caries experience at baseline were analysed using linear regression and the longitudinal associations of dietary factors with a change in caries experience over follow-up using generalised mixed-effects regression adjusted for other risk factors. A higher consumption of high-fibre grain products (standardised regression coefficient β = -0·16, P = 0·003) and milk (β = -0·11, P = 0·025) and higher BSDS (β = -0·15, P = 0·007) were associated with lower caries experience, whereas a higher consumption of potatoes (β = 0·11, P = 0·048) and emotional overeating (β = 0·12, P = 0·025) were associated with higher caries experience. Higher snacking frequency (fixed coefficient β = 0·07, P = 0·033), desire to drink (β = 0·10, P = 0·046), slowness in eating (β = 0·12, P = 0·027) and food fussiness (β = 0·12, P = 0·018) were associated with higher caries experience, whereas enjoyment of food (β = -0·12, P = 0·034) and higher BSDS (β = -0·02, P = 0·051) were associated with lower caries experience.

Associations of physical activity, sedentary time, and diet quality with biomarkers of inflammation in children

We investigated the associations of physical activity (PA), sedentary time (ST), and diet quality with biomarkers of inflammation in 390 children (192 girls, 198 boys) aged 6-8 years. PA energy expenditure (PAEE), light PA, moderate PA (MPA), vigorous PA (VPA), moderate-to-vigorous PA (MVPA), and ST were assessed by combined movement and heart rate sensor. Finnish Children Healthy Eating Index was calculated using data from 4 d food records. Body fat percentage (BF%) was measured by dual-energy X-ray absorptiometry. High-sensitivity C-reactive protein (Hs-CRP), leptin, interleukin-6 (IL-6), adiponectin, tumour necrosis factor-α, and glycoprotein acetyls were measured from fasting blood samples. PAEE, MPA, VPA, and MVPA were inversely associated with hs-CRP (β=-191 to -139, 95% CI=-0.294 to -0.024), leptin (β=-0.409 to -0.301, 95% CI=-0.499 to -0.107), IL-6 (β=-0.136 to -0.104, 95% CI=-0.240 to -0.001) and PAEE, MPA, and MVPA were inversely associated with glycoprotein acetyls (β=-0.117 to -0.103, 95% CI=-0.213 to -0.001). ST was directly associated with hs-CRP (β=0.170, 95% CI=0.070-0.269), leptin (β=0.355, 95% CI=0.265-0.445), and IL-6 (β=0.105, 95% CI=0.005-0.205). VPA was inversely associated with hs-CRP, leptin, and IL-6 in children with higher BF% (β=-0.344 to -0.181, 95% CI=-0.477 to -0.033) but not among children with lower BF% (β=-0.007-0.033, 95% CI=-0.183-0.184). In conclusion, PA was inversely and ST directly associated with circulating levels of biomarkers of inflammation among children. Furthermore, we observed that PA was inversely associated with these biomarkers for inflammation in children with a higher BF%. HighlightsSystemic inflammation, as indicated by increased circulating concentrations of biomarkers for inflammation, may be important in causal pathways leading to insulin resistance, sub-clinical atherosclerosis, and eventually clinical manifestations of cardiovascular diseases.Higher levels of physical activity and lower levels of sedentary time were associated with more favourable inflammatory profile.Body fat percentage modified these associations and especially vigorous intensity physical activity was inversely associated with biomarkers of inflammation on children with higher body fat percentage but not in children with lower body fat percentage.

Investigating the influence of physical activity composition on arterial stiffness in youth

Physical activity is beneficial for arterial health in children but less is known about how all daily movement behaviours influence arterial stiffening. Compositional analysis can account for the co-dependent nature of these behaviours and therefore was employed to explore how the movement composition influences arterial health. Augmentation index (AIx) and pulse wave velocity were measured cross-sectionally in healthy children (n = 129; 12.4 ± 1.6 years). Time spent in sedentary, light physical activity (LPA), moderate-to-vigorous physical activity (MVPA) and asleep were derived from seven-day hip-worn accelerometry. The relative effects of individual behaviours and the overall movement composition on arterial stiffness were explored utilising compositional analysis, with predictive modelling used to predict effects of the substituting time between behaviours. Girls (n = 45, 12.1 ± 1.5yrs, 20.5 ± 3.6kg·m^-2) had a higher AIx (+ 3.94; p < 0.05) and accrued physical activity predominantly in LPA, whereas boys (n = 56, 12.6 ± 1.7yrs, 20.6 ± 4.0kg·m^-2) accrued physical activity predominantly in MVPA. Individual behaviours and the movement composition were not significant predictors of any measure of arterial stiffness (P > 0.05), and the reallocation of 20-minutes between behaviours did not elicit significant change in arterial stiffness, irrespective of sex (P > 0.05). The reallocation of time to MVPA from any other behaviour did not predict an improvement in arterial stiffness. This highlights the high potential dose of MVPA required to improve arterial health and the complex nature of the determinants of arterial stiffness. HighlightsMovement behaviours in isolation nor combination predicted arterial stiffness in youth.The reallocation of behaviours from any other behaviour to MVPA did not affect arterial stiffness in youth.Arterial stiffness is a complex, multidimensional health parameter that does not appear to be primarily determined by physical activity levels or intensity.

Fat-free/lean body mass in children with insulin resistance or metabolic syndrome: a systematic review and meta-analysis

BACKGROUND

Lean / Fat Free Body Mass (LBM) is metabolically involved in active processes such as resting energy expenditure, glucose uptake, and myokine secretion. Nonetheless, its association with insulin sensitivity / resistance / glucose tolerance and metabolic syndrome remains unclear in childhood.

METHODS

The current investigation aimed to examine the differences in fat-free mass /lean body mass according to the presence of insulin sensitivity/insulin resistance/glucose tolerance/metabolic syndrome in children. A systematic search was carried out in Medline/PubMed, Embase, Scopus, Web of Science, and SciELO, covering the period from each database's respective start to 21 June 2021. Two researchers evaluated 7111 studies according to the inclusion criteria: original human studies, written in English or Spanish, evaluating fat-free mass/lean body mass in children and adolescents including both with and without insulin sensitivity/insulin resistance /glucose tolerance and metabolic syndrome and reported the differences between them in terms of fat free mass/lean body mass. The results of the studies were combined with insulin sensitivity, insulin, resistance, glucose tolerance and metabolic syndrome. The standardized mean difference (SMD) in each study was calculated and combined using the random-effects model. Heterogeneity between studies was tested using the index of heterogeneity (I2), leave-one-out sensitivity analyses were performed, and publication bias was assessed using the Egger and Begg tests.

RESULTS

Finally, 15 studies which compared groups defined according to different glucose homeostasis criteria or metabolic syndrome out of 103 eligible studies were included in this systematic review and 12 studies in the meta-analysis. Meta-analysis showed lower fat-free mass/lean body mass percentage in participants with insulin resistance/glucose tolerance/metabolic syndrome (SMD -0.47; 95% CI, - 0.62 to - 0.32) while in mass units (kg), higher values were found in the same group (SMD, 1.01; 95% CI, 0.43 to 1.60).

CONCLUSIONS

Our results identified lower values of fat-free mass/lean body mass (%) in children and adolescents with insulin resistance/glucose tolerance/metabolic syndrome and higher values of fat-free mass/lean body mass when these are expressed in kg. The evidence of the impact of lean mass on children's glucose homeostasis or metabolic syndrome is limited, so future studies research should focus on explaining the effect of fat-free mass/lean body mass on different metabolic outcomes. Moreover, it may be interesting to evaluate the quality (muscle density) or functional (muscle strength) outcomes in addition to both absolute (kg) and relative (%) values in future studies. The systematic review was prospectively registered at PROSPERO (registration number CRD42019124734; available at: http://www.crd.york.ac.uk/prospero [accessed: 05 April 2019]).

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Parent perceptions of their child's and their own physical activity after treatment for childhood cancer

PURPOSE

Parents are important facilitators of physical activity for children, yet little is known about the perceptions of parents of childhood cancer survivors. We investigated parent perceptions of their own and their child's physical activity levels after cancer treatment and examined associations with clinical, demographic, and psychosocial factors.

METHODS

We conducted a cross-sectional survey among 125 parents and 125 survivors. Parents reported on the perceived importance of their child being physically active and concerns regarding exercising after cancer treatment.

RESULTS

Parents and survivors self-reported median (range) of 127.5 (0-1260) and 220 (0-1470) min/week of moderate-to-vigorous physical activity. Most parents (n = 109, 98%) believed that physical activity was highly important for their child. Some parents (n = 19, 17%) reported concerns, most commonly regarding exercise safety (n = 7, 22%). Parents were more likely to perceive that their child should increase physical activity if their child was an adolescent and had high body fat percentage.

CONCLUSIONS

Physical activity levels varied widely among survivors, reflecting factors including parents' lifestyles, limited understanding of exercise benefits and perceptions of risk. Given survivors' insufficient physical activity levels and sedentary behaviour among families, embedding physical activity promotion into health systems and follow-up support could benefit the entire family unit.

Cross-sectional associations between cardiorespiratory fitness and NMR-derived metabolic biomarkers in children - the PANIC study

OBJECTIVE

Cardiorespiratory fitness has been inversely associated with cardiovascular risk across the lifespan. Some studies in adults suggest that higher cardiorespiratory fitness is associated with cardioprotective metabolite profile, but the evidence in children is lacking. Therefore, we investigated the cross-sectional association of cardiorespiratory fitness with serum nuclear magnetic resonance derived metabolic biomarkers in children.

METHODS

A population sample of 450 children aged 6-8 years was examined. Cardiorespiratory fitness was assessed by a maximal exercise test on a cycle ergometer and quantified as maximal power output normalised for lean body mass assessed by dual-energy X-ray absorbtiometry. Serum metabolites were assessed using a high throughput nuclear magnetic resonance platform. The data were analysed using linear regression analyses adjusted for age and sex and subsequently for body fat percentage (BF%) assessed by DXA.

RESULTS

Cardiorespiratory fitness was directly associated with high density lipoprotein (HDL) cholesterol (β=0.138, 95% CI=0.042 to 0.135, p=0.005), average HDL particle diameter (β=0.102, 95% CI=0.004 to 0.199, p=0.041), and the concentrations of extra-large HDL particles (β=0.103, 95% CI=0.006 to 0.201, p=0.038), large HDL particles (β=0.122, 95% CI=0.025 to 0.220, p=0.014), and medium HDL particles (β=0.143, 95% CI=0.047 to 0.239, p=0.004) after adjustment for age and sex. Higher cardiorespiratory fitness was also associated with higher concentrations of ApoA1 (β=0.145, 95% CI=0.047 to 0.242, p=0.003), glutamine (β=0.161, 95% CI=0.064 to 0.257, p=0.001), and phenylalanine (β=0.187, 95% CI=0.091 to 0.283, p<0.001). However, only the direct associations of cardiorespiratory fitness with the concentrations of HDL cholesterol (β=0.114, 95% CI=0.018 to 0.210, p=0.021), medium HDL particles (β=0.126, 95% CI=0.030 to 0.223, p=0.010), ApoA1 (β=0.126, 95% CI=0.030 to 0.223, p=0.011), glutamine (β=0.147, 95% CI=0.050 to 0.224, p=0.003), and phenylalanine (β=0.217, 95% CI=0.122 to 0.311, p<0.001) remained statistically significant after further adjustment for BF%.

CONCLUSIONS

Higher cardiorespiratory fitness was associated with a cardioprotective biomarker profile in children. Most associations were independent of BF% suggesting that the differences in serum metabolites between children are driven by cardiorespiratory fitness and not adiposity.

Impact of Physical Activity Intensity Levels on the Cardiometabolic Risk Status of Children: The Genobox Study

Childhood obesity has been related to metabolic syndrome and low-grade chronic inflammation. This study aimed to evaluate the impact of physical activity intensities and practice on inflammation, endothelial damage, and cardiometabolic risk factors in children. There were 513 participants, aged 6-14 years, recruited for the study. Physical activity was measured by accelerometry, and the children were classified into four groups according to quartiles of moderate to vigorous physical activity (MVPA) practice as very low active, low active, moderate active, and high active. Anthropometric measures, blood pressure, and plasma metabolic and proinflammatory parameters were analyzed. Very low active group presented a worse lipid profile and higher insulin, leptin, adiponectin, resistin, matrix metallopeptidase-9, and tissue plasminogen activator inhibitor-1, while lower levels of tumor necrosis factor-alpha, Type 1 macrophages, and interleukin 8 than high-active children. Regression analyses showed that a higher MVPA practice was associated with lower levels of triacylglycerols (β: -0.118; p = .008), resistin (β: -0.151; p = .005), tPAI (β: -0.105; p = .046), and P-selectin (β: -0.160; p = .006), independently of sex, age, and body mass index (BMI). In contrast, a higher BMI was associated with higher levels of insulin (β: 0.370; p < .001), Homeostasis Model Assessment (β: 0.352; p < .001), triacylglycerols (β: 0.209; p < .001), leptin (β: 0.654; p < .001), tumor necrosis factor-alpha (β: 0.182; p < .001), Type 1macrophages (β: 0.181; p < .001), and tissue plasminogen activator inhibitor (β: 0.240; p < .001), independently of sex, age, and MVPA. A better anthropometric, metabolic, and inflammatory profile was detected in the most active children; however, these differences were partly due to BMI. These results suggest that a higher MVPA practice and a lower BMI in children may lead to a better cardiometabolic status.

Impact of the COVID-19 Pandemic on Sedentary Time and Behaviour in Children and Adults: A Systematic Review and Meta-Analysis

The aim of this meta-analysis was to quantify the change in sedentary time during the COVID-19 pandemic and its effect on health outcomes in the general population. One thousand six hundred and one articles published after 2019 were retrieved from five databases, of which 64 and 40 were included in the systematic review and meta-analysis, respectively. Studies were grouped according to population: children (<18 years), adults (18–64 years) and older adults (>65 years). Average sedentary time was calculated, with sub-analyses performed by country, behaviour type and health outcomes. Children were most affected, increasing their sedentary time by 159.5 ± 142.6 min day⁻¹, followed by adults (+126.9 ± 42.2 min day⁻¹) and older adults (+46.9 ± 22.0 min day⁻¹). There were no sex differences in any age group. Screen time was the only consistently measured behaviour and accounted for 46.8% and 57.2% of total sedentary time in children and adults, respectively. Increases in sedentary time were negatively correlated with global mental health, depression, anxiety and quality of life, irrespective of age. Whilst lockdown negatively affected all age groups, children were more negatively affected than adults or older adults, highlighting this population as a key intervention target. As lockdowns ease worldwide, strategies should be employed to reduce time spent sedentary. Trial registration: PROSPERO (CRD42020208909).

Trends of Sedentary Time and Domain-Specific Sedentary Behavior in Spanish Schoolchildren

Purpose: To examine the temporal trends of accelerometer-based total daily sedentary time (ST) and self-reported domain-specific sedentary behavior (SB) on weekdays and weekends in Spanish children. Method: A total of 560 (50.53% girls) children (4th graders) in 2011/12 from 23 Spanish schools and 462 (48.70% girls) children (4th graders) in 2017/18 from 19 schools across Cadiz participated. Hip-worn accelerometers and questionnaires were used to assess total daily ST and self-reported time in SB modalities, respectively. Results: The objectively measured total daily ST tended to increase in boys on weekdays and weekends. Time spent watching television (TV) decreased during the week and weekend days, while time surfing on the internet increased on weekdays and weekends. Playing video-games increased in boys during the weekends. The trend to increase the time spent on educational activities with a computer during the weekdays and weekends was accompanied by a reduction of the same activities without using a computer. There was a trend to increase reading for fun, talking on the phone and total time in other SB, on weekdays and weekends in boys and girls. Conclusion(s): Spanish boys tended to increase objectively measured total daily ST. Moreover, SB modalities have changed in recent years in children, replacing TV viewing by computer use for both educational and non-educational purposes, as well as by the use of smartphones or other sedentary activities that does not imply the presence of a screen. These findings highlight the need to promote interventions to decrease total daily ST and reduce SB activities.

Effects of a Physical Education Program on Physical Activity and Emotional Well-Being among Primary School Children

(1) Background: It has been identified that schools that adopt at least two hours a week of physical education and plan specific contents and activities can achieve development goals related to physical level, such as promoting health, well-being, and healthy lifestyles, on a personal level, including bodily awareness and confidence in physical skills, as well as a general sense of well-being, greater security and self-esteem, sense of responsibility, patience, courage, and mental balance. The purpose of this study was to establish the effect of physical education programs on the physical activity and emotional well-being of primary school children. (2) Methods: The experimental group comprised 45 girls and 44 boys aged 6–7 years (First Grade) and 48 girls and 46 boys aged 8–9 years (Second Grade), while the control group comprised 43 girls and 46 boys aged 6–7 years (First Grade) and 47 girls and 45 boys aged 8–9 years (Second Grade). All children attended the same school. The Children’s Physical Activity Questionnaire was used, which is based on the Children’s Leisure Activities Study Survey questionnaire, which includes activities specific to young children (e.g., “playing in a playhouse”). Emotional well-being status was explored by estimating three main dimensions: somatic anxiety, personality anxiety, and social anxiety. The Revised Children’s Manifest Anxiety Scale (RCMAS) was used. (3) Results: When analysing the pre-test results of physical activity of the 6–7- and 8–9-year-old children, it turned out that both the First Grade (92.15 MET, min/week) and Second Grade (97.50 MET, min/week) participants in the experimental group were physically active during physical education lessons. When exploring the results of somatic anxiety in EG (4.95 ± 1.10 points), both before and after the experiment, we established that somatic anxiety in EG was 4.55 ± 1.00 points after the intervention program, demonstrating lower levels of depression, seclusion, somatic complaints, aggression, and delinquent behaviours (F = 4.785, p < 0.05, P = 0.540). (4) Conclusions: We established that the properly constructed and purposefully applied eight-month physical education program had positive effects on the physical activity and emotional well-being of primary school children (6–7 and 8–9 years) in three main dimensions: somatic anxiety, personality anxiety, and social anxiety. Our findings suggest that the eight-month physical education program intervention was effective at increasing levels of physical activity. Changes in these activities may require more intensive behavioural interventions with children or upstream interventions at the family and societal levels, as well as at the school environment level. These findings have relevance for researchers, policy makers, public health practitioners, and doctors who are involved in health promotion, policy making, and commissioning services.

Home and Neighborhood Physical Activity Location Availability among African American Adolescent Girls Living in Low-Income, Urban Communities: Associations with Objectively Measured Physical Activity

Based on the ecological model of active living, the neighborhood environment may relate to individual physical activity (PA) behaviors. The purposes of this study were to (1) generate a replicable neighborhood-level physical activity location availability score (PALAS) from data variables associated with physical activity among adolescents and adults, and apply this score to Baltimore City, Maryland, and (2) determine if relationships exist between PA and PA location availability. Geographic information systems (GISs) were used to create the PALAS. Using linear regression models, we examined relations between objectively measured PA among low-income, urban, predominantly African American adolescent girls (n = 555, 2009-2012 data collection), and the PALAS rating of their neighborhood environment (neighborhood PALAS) and their home neighborhood area (PALAS variables/subcomponents within 0.25 miles of the home). A PALAS map of the study area was created, illustrating neighborhoods varying in availability and variety of PA locations. After adjusting for confounders, a higher neighborhood PALAS (β = 0.10, p = 0.041) and the presence of a recreation center in the home neighborhood area (β = 0.46, p = 0.011) were associated with more minutes per day spent in moderate to vigorous PA. Policy makers and stakeholders should consider increasing access to PA locations as a strategy to promote PA among adolescent girls.

Is device-measured vigorous physical activity associated with health-related outcomes in children and adolescents? A systematic review and meta-analysis

OBJECTIVE

This study sought to analyze the prospective association between vigorous-intensity physical activity (VPA) and health-related outcomes in children and adolescents.

METHODS

Studies reporting associations between device-measured VPA and health-related factors in children and adolescents aged 3-18 years were identified through database searches (MEDLINE, EMBASE, and SPORTDiscus). Correlation coefficients were pooled if outcomes were reported by at least 3 studies, using DerSimonian-Laird random effects models.

RESULTS

Data from 23 studies including 13,674 participants were pooled using random effects models. Significant associations were found between VPA at baseline and overall adiposity (r = -0.09, 95% confidence interval (95%CI): -0.15 to -0.03; p = 0.002; I² = 89.8%), cardiometabolic risk score (r = -0.13, 95%CI: -0.24 to -0.02, p = 0.020; I² = 69.6%), cardiorespiratory fitness (r = 0.25, 95%CI: 0.15-0.35; p < 0.001; I² = 57.2%), and total body bone mineral density (r = 0.16, 95%CI: 0.06 to 0.25; p = 0.001; I² = 0%).

CONCLUSION

VPA seems to be negatively related to adiposity and cardiometabolic risk score and positively related to cardiorespiratory fitness and total body bone mineral density among children and adolescents at follow-up. Therefore, our findings support the need to strengthen physical activity recommendations regarding VPA due to its health benefits in children and adolescents.

A 2 year physical activity and dietary intervention attenuates the increase in insulin resistance in a general population of children: the PANIC study

AIMS/HYPOTHESIS

We studied for the first time the long-term effects of a combined physical activity and dietary intervention on insulin resistance and fasting plasma glucose in a general population of predominantly normal-weight children.

METHODS

We carried out a 2 year non-randomised controlled trial in a population sample of 504 children aged 6-9 years at baseline. The children were allocated to a combined physical activity and dietary intervention group (306 children at baseline, 261 children at 2-year follow-up) or a control group (198 children, 177 children) without blinding. We measured fasting insulin and fasting glucose, calculated HOMA-IR, assessed physical activity and sedentary time by combined heart rate and body movement monitoring, assessed dietary factors by a 4 day food record, used the Finnish Children Healthy Eating Index (FCHEI) as a measure of overall diet quality, and measured body fat percentage (BF%) and lean body mass by dual-energy x-ray absorptiometry. The intervention effects on insulin, glucose and HOMA-IR were analysed using the intention-to-treat principle and linear mixed-effects models after adjustment for sex, age at baseline, and pubertal status at baseline and 2 year follow-up. The measures of physical activity, sedentary time, diet and body composition at baseline and 2 year follow-up were entered one-by-one as covariates into the models to study whether changes in these variables might partly explain the observed intervention effects.

RESULTS

Compared with the control group, fasting insulin increased 4.65 pmol/l less (absolute change +8.96 vs +13.61 pmol/l) and HOMA-IR increased 0.18 units less (+0.31 vs +0.49 units) over 2 years in the combined physical activity and dietary intervention group. The intervention effects on fasting insulin (regression coefficient β for intervention effect -0.33 [95% CI -0.62, -0.04], p = 0.026) and HOMA-IR (β for intervention effect -0.084 [95% CI -0.156, -0.012], p = 0.023) were statistically significant after adjustment for sex, age at baseline, and pubertal status at baseline and 2 year follow-up. The intervention had no effect on fasting glucose, BF% or lean body mass. Changes in total physical activity energy expenditure, light physical activity, moderate-to-vigorous physical activity, total sedentary time, the reported consumption of high-fat (≥60%) vegetable oil-based spreads, and FCHEI, but not a change in BF% or lean body mass, partly explained the intervention effects on fasting insulin and HOMA-IR.

CONCLUSIONS/INTERPRETATION

The combined physical activity and dietary intervention attenuated the increase in insulin resistance over 2 years in a general population of predominantly normal-weight children. This beneficial effect was partly mediated by changes in physical activity, sedentary time and diet but not changes in body composition.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01803776 Graphical abstract.

Changes in Physical Activity and Sedentary Patterns on Cardiometabolic Outcomes in the Transition to Adolescence: International Children's Accelerometry Database 2.0

OBJECTIVE

To examine the associations of changes in physical activity and sedentary patterns with changes in cardiometabolic outcomes from childhood to adolescence.

STUDY DESIGN

Youth from the International Children's Accelerometry Database (n = 1088; 55% girls), aged 8-13 years and followed for ∼4 years, were used in this analysis. Hip-mounted accelerometers were used and all physical activity intensities were expressed as the % of total wear-time. Sedentary time was separated into time spent in bouts <10 minutes and ≥10 minutes. A composite z score for cardiometabolic risk (CMR score) was computed by summing the standardized values for systolic and diastolic blood pressure, triglycerides (TG), low-density lipoprotein cholesterol (LDL-c), and the inverse high-density lipoprotein cholesterol. Multivariate analyses were performed using adjusted linear regression models.

RESULTS

Increase in sedentary time was unfavorably associated with changes in CMR score (β = 0.021; CI 0.004-0.037), TG (β = 0.003; CI 0.001-0.005), and diastolic blood pressure (β = 0.068; CI 0.009-0.128). Decrease in moderate-to-vigorous physical activity was unfavorably associated with changes in LDL-c (β = -0.009; CI -0.017 to -0.001) and TG (β = -0.007; CI -0.013 to -0.001). Increase in ≥10 minutes sedentary time was unfavorably associated with changes in CMR score (β = 0.017; CI 0.004-0.030), LDL-c (β = 0.003; CI 0.000-0.005), and TG (β = 0.003; CI 0.000-0.004). Decrease in light-intensity physical activity was unfavorably associated with changes in CMR score (β = -0.020; CI = -0.040 to 0.000).

CONCLUSIONS

More physical activity and less prolonged sedentary time are beneficial for cardiometabolic health in youth transitioning to adolescence.

Association Between Physical Activity Intensity Levels and Arterial Stiffness in Healthy Children

BACKGROUND

Physical activity (PA) has a substantial impact on arterial stiffness in adults; however, evidence regarding children is scarce. The aim of this study was to examine the association between objectively measured PA with different intensities and surrogate measures of arterial stiffness in healthy children.

METHODS

Altogether, 80 children (41 girls and 39 boys, ranging from 8-11 y) participated in this prospective, cross-sectional study. Sedentary time and PA of light, moderate, and vigorous intensity levels were measured over a period of 7 days by accelerometry. Arterial stiffness parameters, including pulse wave velocity and central systolic blood pressure (cSBP), were noninvasively assessed by the oscillometric Mobil-O-Graph. Associations were tested using multiple linear regressions with adjustments for potential confounders (α ≤ .05).

RESULTS

PA of moderate intensity was negatively associated with cSBP (β = -0.266, P = .017). PA of vigorous intensity was inversely related to pulse wave velocity (β = -0.225, P = .045) and cSBP (β = -0.286, P = .010), respectively.

CONCLUSION

Higher time spent in PA of moderate and vigorous intensity is associated with reduced pulse wave velocity and lower cSBP values in children. It suggests that PA is a favorable determinant of arterial health.

Validity of traditional physical activity intensity calibration methods and the feasibility of self-paced walking and running on individualised calibration of physical activity intensity in children

There are no practical and valid methods for the assessment of individualised physical activity (PA) intensity in observational studies. Therefore, we investigated the validity of commonly used metabolic equivalent of tasks (METs) and pre-determined PA intensity classification methods against individualised PA intensity classification in 35 children 7–11-years-of-age. Then, we studied validity of mean amplitude deviation (MAD) measured by accelerometry during self-paced walking and running in assessment of individualised PA intensity. Individualised moderate PA (MPA) was defined as V̇O₂ ≥ 40% of V̇O_2reserve and V̇O₂ < ventilatory threshold (VT) and vigorous PA (VPA) as V̇O₂ ≥ VT. We classified > 3–6 (or alternatively > 4–7) METs as MPA and > 6 (> 7) METs as VPA. Task intensities were classified according to previous calibration studies. MET-categories correctly identified 25.9–83.3% of light PA, 85.9–90.3% of MPA, and 56.7–82.2% of VPA. Task-specific categories correctly classified 53.7% of light PA, 90.6% of MPA, and 57.8% of VPA. MAD during self-paced walking discriminated MVPA from light PA (sensitivity = 67.4, specificity = 88.0) and MAD during self-paced running discriminated VPA from MPA (sensitivity = 78.8, specificity = 79.3). In conclusion, commonly used methods may misclassify PA intensity in children. MAD during self-paced running may provide a novel and practical method for determining individualised VPA intensity in children.

Cardiorespiratory Fitness, Physical Activity, and Insulin Resistance in Children

PURPOSE

Few studies have investigated the independent and joint associations of cardiorespiratory fitness (CRF) and body fat percentage (BF%) with insulin resistance in children. We investigated the independent and combined associations of CRF and BF% with fasting glycemia and insulin resistance and their interactions with physical activity (PA) and sedentary time among 452 children age 6 to 8 yr.

METHODS

We assessed CRF with a maximal cycle ergometer exercise test and used allometrically scaled maximal power output (Wmax) for lean body mass (LM) and body mass (BM) as measures of CRF. The BF% and LM were measured by dual-energy X-ray absorptiometry, fasting glycemia by fasting plasma glucose, and insulin resistance by fasting serum insulin and Homeostatic Model Assessment for Insulin Resistance (HOMA-IR). The PA energy expenditure, moderate-to-vigorous PA (MVPA), and sedentary time were assessed by combined movement and heart rate sensor.

RESULTS

Wmax/LM was not associated with glucose (β = 0.065, 95% confidence interval [CI] = -0.031 to 0.161), insulin (β = -0.079, 95% CI = -0.172 to 0.015), or HOMA-IR (β = -0.065, 95% CI = -0.161 to 0.030). Wmax/BM was inversely associated with insulin (β = -0.289, 95% CI = -0.377 to -0.200) and HOMA-IR (β = -0.269, 95% CI = -0.359 to -0.180). The BF% was directly associated with insulin (β = 0.409, 95% CI = 0.325 to 0.494) and HOMA-IR (β = 0.390, 95% CI = 0.304 to 0.475). Higher Wmax/BM, but not Wmax/LM, was associated with lower insulin and HOMA-IR in children with higher BF%. Children with higher BF% and who had lower levels of MVPA or higher levels of sedentary time had the highest insulin and HOMA-IR.

CONCLUSIONS

Children with higher BF% together with less MVPA or higher levels of sedentary time had the highest insulin and HOMA-IR. Cardiorespiratory fitness appropriately controlled for body size and composition using LM was not related to insulin resistance among children.

Longitudinal associations of physical activity and pubertal development with academic achievement in adolescents

OBJECTIVE

We sought to investigate the longitudinal associations of moderate-to-vigorous physical activity (MVPA) and pubertal development with academic achievement in adolescents.

METHODS

A total of 635 adolescents (283 boys, 352 girls) aged 11-13 years participated in the study. MVPA was assessed by the Health Behaviour in School-aged Children study questionnaire, and pubertal development was assessed by the Pubertal Development Scale at beginning of the 6th grade (baseline) and end of the 7th grade (follow-up). Grade point average (GPA) at the end of Grades 5 and 7 was computed from data acquired from the school registers. The data were analyzed using linear regression and analyses of covariance.

RESULTS

In boys, MVPA was positively associated with GPA at baseline after adjustment for age (β = 0.144, 95% confidence interval (CI): 0.028-0.260, p = 0.028). In girls, the Pubertal Development Scale was positively associated with GPA at baseline (β = 0.104, 95%CI: -0.004 to 0.211, p = 0.058) and follow-up (β = 0.104, 95%CI: -0.002 to 0.211, p = 0.055) after adjustment for age, and these associations strengthened after further adjustment for MVPA (p < 0.05). Adolescents who were inactive at baseline or at baseline and follow-up had lower GPA during follow-up than their continuously highly active peers (mean difference = -0.301, 95%CI: -0.543 to -0.058, p = 0.009) and all other adolescents (mean difference = -0.247, 95%CI: -0.475 to -0.019, p = 0.029). These differences were greater in girls than in boys.

CONCLUSION

Lower levels of MVPA were associated with lower GPA in boys at baseline. Girls who were continuously inactive had lower GPA over the follow-up period than those who were continuously active. Finally, earlier pubertal development was associated with better academic achievement in girls.

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

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

The trajectory of patterns of light and sedentary physical activity among females, ages 14-23

PURPOSE

Light physical activity (LPA) and patterns of sedentary behavior influence cardio-metabolic health independently of moderate-to-vigorous physical activity. Understanding the trajectory and determinants of these activity levels over time may provide insights relevant to public health practice.

METHODS

We measured a cohort of young women recruited in middle school (age 14) using accelerometry for 1 week and remeasured them in high school (age 17) and again at age 23 (n = 385). We assessed changes in LPA and patterns of sedentary behavior by hours in a day. We examined the association of social and contextual factors, including employment status, screen time, and neighborhood context with LPA and sedentary behavior patterns.

RESULTS

The amount of LPA decreased over time, while the length of LPA bouts tended to increase. Sedentary bout durations increased over time and sedentary breaks decreased. Sedentary time and bout length were correlated with internet use, rather than with TV or videogaming. Employment was associated with less sedentary time; being a student was associated with longer sedentary time and bouts.

CONCLUSIONS

Because LPA and sedentary breaks can be protective for cardio-metabolic health, and the duration of sedentary bouts increase as women age from adolescence to young adulthood, worksites and college campuses should remind employees and students to take frequent activity breaks when they use computers and the internet for long stretches.

SEDENTARY BEHAVIOR AND CARDIOVASCULAR RISK IN CHILDREN: A SYSTEMATIC REVIEW

ABSTRACT In recognition of the increasing time spent in sedentary activities in modern life, an emerging area of study linking sedentary time to health has highlighted its role in the development of chronic diseases. Therefore, the objective of this systematic review was to investigate the indicators and characteristics of sedentary behavior associated with cardiovascular risk factors in children and adolescents. The databases SciVerse Scopus, MEDLINE®/PubMed and LILACS were selected as a source of reference, using the associated terms “sedentary lifestyle” or “sedentary behavior” or “sedentary” AND “cardiovascular diseases” AND “child or adolescent” to identify studies published from January 2006 to March 2019. The methodological quality of the studies was evaluated and a score was assigned. Fifty articles were included in this review at the end. Extensive sedentary time, especially greater screen and TV exposure time, were associated with cardiovascular risk factors. In addition, the accumulation of prolonged sedentary bouts with few breaks in sedentary time tended to compromise the cardiometabolic profile. These findings highlight the importance of differentiating and considering these various indicators and characteristics of sedentary behavior. Further studies are needed to elucidate the multiple and overlapping facets of sedentary behavior and their relationship with health, and to encourage the development of evidence-based recommendations for this population. Level of Evidence I; Systematic Review of Level I Studies.

Associations of physical activity, sedentary time, and cardiorespiratory fitness with heart rate variability in 6- to 9-year-old children: the PANIC study

Purpose

To study the associations of physical activity (PA), sedentary time (ST), and cardiorespiratory fitness (CRF) with heart rate variability (HRV) in children.

Methods

The participants were a population sample of 377 children aged 6–9 years (49% boys). ST, light PA (LPA), moderate PA (MPA), vigorous PA (VPA), and moderate-to-vigorous PA (MVPA), and PA energy expenditure (PAEE) were assessed using a combined heart rate and movement sensor, maximal power output per kilograms of lean body mass as a measure of CRF by maximal cycle ergometer exercise test, and HRV variables (SDNN, RMSSD, LF, and HF) using 5 min resting electrocardiography. Data were analysed by linear regression adjusted for years from peak height velocity.

Results

In boys, ST was inversely associated (β = − 0.185 to − 0.146, p ≤ 0.049) and MVPA, VPA, PAEE, and CRF were directly associated (β = 0.147 to 0.320, p ≤ 0.048) with HRV variables. CRF was directly associated with all HRV variables and PAEE was directly associated with RMSSD after mutual adjustment for ST, PAEE, and CRF (β = 0.169 to 0.270, p ≤ 0.046). In girls, ST was inversely associated (β = − 0.382 to − 0.294, p < 0.001) and LPA, MPA, VPA, MVPA, and PAEE were directly associated with HRV variables (β = 0.144 to 0.348, p ≤ 0.049). After mutual adjustment for ST, PAEE, and CRF, only the inverse associations of ST with HRV variables remained statistically significant.

Conclusions

Higher ST and lower PA and CRF were associated with poorer cardiac autonomic nervous system function in children. Lower CRF in boys and higher ST in girls were the strongest correlates of poorer cardiac autonomic function.

Electronic supplementary material

The online version of this article (10.1007/s00421-019-04231-5) contains supplementary material, which is available to authorized users.

Interventions promoting active transport to school in children: A systematic review and meta-analysis

The systematic review investigated the effectiveness of active travel (AT) interventions on physical activity and fitness in primary school children. The review assessed intervention effectiveness, design, complexity, and study quality. Searches were conducted in five databases on 30/08/2018. Studies with an AT intervention compared to an inactive control, in 4 to 11 year olds, measuring AT or fitness outcomes were included. Two-stage screening identified relevant studies. Relevant data were extracted using Cochrane Extraction Form, Quality Assessment Tool for Quantitative Studies, Active Living by Design model, and intervention Complexity Assessment Tool for Systematic Reviews. Meta-analysis and Cohen's D effect size assessed effectiveness. Seventeen eligible studies were included. Effectiveness assessment found a statistically significant standardised mean difference (SMD) in AT outcomes in favour of the intervention (continuous AT - SMD 0.78 (CI 0.11-1.46); frequency AT - SMD 1.87 (CI 0.88-2.86)). Cohen's D calculation concurred with this finding. Fifteen studies had SMD favouring the intervention - two studies had SMD favouring the control. Sixteen studies received a weak quality rating - one study rated moderate. Active travel shows promise in increasing physical activity in primary school children. The review found walking school buses and educational strategies most effective for increasing relevant outcomes, although overall study quality was weak. Effect size did not associate with the complexity of an intervention, therefore supporting efforts to promote active travel through interventions may be easier to scale. Further intervention studies of greater methodological quality are necessary to confirm these findings due to the limited evidence available.