Substituting prolonged sedentary time and cardiovascular risk in children and youth: a meta-analysis within the International Children's Accelerometry database (ICAD)

Associations of Sedentary Time and Physical Activity From Childhood With Lipids: A 13-Year Mediation and Temporal Study

CONTEXT

Among children, evidence on long-term longitudinal associations of accelerometer-measured sedentary time, light physical activity (LPA), and moderate to vigorous PA (MVPA) with lipid indices are few. The mediating role of body composition and other metabolic indices in these associations remains unclear and whether poor movement behavior precedes altered lipid levels is unknown.

OBJECTIVE

This study examined the associations of sedentary time, LPA, and MVPA from childhood through young adulthood with increased lipids, the mediating role of body composition, and whether temporal interrelations exist.

METHODS

Data from 792 children (58% female; mean [SD] age at baseline, 11.7 [0.2] years), drawn from the Avon Longitudinal Study of Parents and Children (ALSPAC) UK birth cohort, who had at least 2 time-point measures of accelerometer-based sedentary time, LPA, and MVPA during clinic visits at ages 11, 15, and 24 years and complete fasting plasma high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglyceride, and total cholesterol measured during follow-up visits at ages 15, 17, and 24 years were analyzed.

RESULTS

Total fat mass partly mediated the inverse associations of LPA with low-density lipoprotein cholesterol by 13%, triglyceride by 28%, and total cholesterol by 6%. Total fat mass mediated the inverse associations of MVPA with low-density lipoprotein cholesterol by 37% and total cholesterol by 48%, attenuating the effect on total cholesterol to nonsignificance (P = .077). In the temporal path analyses, higher MVPA at age 15 years was associated with lower low-density lipoprotein cholesterol at 24 years (β = -0.08, SE, 0.01, P = .022) but not vice versa.

CONCLUSION

Sedentary time worsens lipid indices, but increased LPA had a 5- to 8-fold total cholesterol-lowering effect and was more resistant to the attenuating effect of fat mass than MVPA.

Accelerometer-based sedentary time, light physical activity, and moderate-to-vigorous physical activity from childhood with arterial stiffness and carotid IMT progression: A 13-year longitudinal study of 1339 children

AIMS

We examined the longitudinal associations of sedentary time (ST), light physical activity (LPA), and moderate-to-vigorous PA (MVPA) from childhood with carotid-femoral pulse wave velocity (cfPWV), a measure of arterial stiffness and carotid intima-media thickness (cIMT).

METHODS

We studied 1339 children, aged 11 years from Avon Longitudinal Study of Parents and Children, UK, followed up for 13 years. Accelerometer-based ST, LPA, and MVPA were assessed at ages 11, 15, and 24 years clinic visits. cfPWV and cIMT were measured with Vicorder and ultrasound, respectively, at ages 17 and 24 years.

RESULTS

Among 1339 [56.4% female] participants, mean ST increased from ages 11 through 24 years, while mean LPA and MVPA decreased. Persistently high ST tertile from childhood was associated with increased cfPWV progression, effect estimate 0.047 m/s; [(95% CI 0.005 to 0.090); p = 0.030], but not cIMT progression. Persistently high LPA tertile category was associated with decreased cfPWV progression in males -0.022 m/s; [(-0.028 to -0.017); p < 0.001] and females -0.027 m/s; [(-0.044 to -0.010); p < 0.001]. Cumulative LPA exposure decreased the odds of progressively worsening cfPWV [Odds ratio 0.994 (0.994-0.995); p < 0.0001] and cIMT. Persistent exposure to ≥60 min/day of MVPA was paradoxically associated with increased cfPWV progression in males 0.053 m/s; [(0.030 to 0.077); p < 0.001] and females 0.012 m/s; [(0.002 to 0.022); p = 0.016]. Persistent exposure to ≥60 min/day of MVPA was inversely associated with cIMT progression in females -0.017 mm; [(-0.026 to -0.009); p < 0.001].

CONCLUSION

LPA >3 h/day from childhood may attenuate progressively worsening vascular damage associated with increased ST in youth.

Mediating effect of fat mass, lean mass, blood pressure and insulin resistance on the associations of accelerometer-based sedentary time and physical activity with arterial stiffness, carotid IMT and carotid elasticity in 1574 adolescents

This study examined the mediating effect of total body fat mass, lean mass, blood pressure (BP) and insulin resistance on the associations of sedentary time (ST), light physical activity (LPA) and moderate-to-vigorous PA (MVPA) with carotid-femoral pulse wave velocity (cfPWV), carotid intima-media thickness (cIMT) and carotid elasticity in 1574 adolescents from the Avon Longitudinal Study of Parents and Children birth cohort, UK. ST, LPA and MVPA were assessed with ActiGraph accelerometer. ST and LPA were sex-categorised in tertiles as low (reference), moderate and high, while MVPA was categorised as <40 min/day (reference), 40-<60 min/day and ≥60 min/day. cfPWV, cIMT and carotid elasticity were measured with Vicorder and ultrasound. Fat mass and lean mass were assessed with dual-energy X-ray absorptiometry and homeostatic model assessment of insulin resistance (HOMA-IR) was computed. Mediation analyses structural equation models and linear mixed-effect models adjusted for cardiometabolic and lifestyle factors were conducted. Among 1574 adolescents [56.2% female; mean (SD) age 15.4 (0.24) years], 41% males and 17% females accumulated ≥60 min/day of MVPA. Higher ST was associated with lower cIMT partly mediated by lean mass. Higher LPA (standardized β = -0.057; [95% CI -0.101 to -0.013; p = 0.014]) and the highest LPA tertile were associated with lower cfPWV. BP had no significant mediating effect movement behaviour relations with vascular indices. Lean mass partially mediated associations of higher MVPA with higher cIMT (0.012; [0.007-0.002; p = 0.001], 25.5% mediation) and higher carotid elasticity (0.025; [0.014-0.039; p = 0.001], 28.1% mediation). HOMA-IR mediated the associations of higher MVPA with higher carotid elasticity (7.7% mediation). Engaging in ≥60 min/day of MVPA was associated with higher carotid elasticity. In conclusion, higher LPA was associated with lower arterial stiffness, but higher MVPA was associated with thicker carotid wall explained by higher lean mass.

Replacing screen time, with physical activity and sleep time: influence on cardiovascular indicators and inflammatory markers in Brazilian children

OBJECTIVE

To examine if the substitution of different screen time intervals with light physical activity (LPA), moderate to vigorous physical activity (MVPA) and sleep is associated with cardiovascular indicators and inflammatory markers in children.

METHODS

This is a cross-sectional study developed with 186 children aged between six and 11 years old from public schools in southern Brazil. CRF was measured with the 6-minute running and walking test, following the Brazil Sports Project procedures. The percentage of fat was evaluated through DXA. LPA and MVPA were measured using accelerometers. Sleep and screen time were assessed by questionnaires answered by parents. Leptin and C-reactive protein were measured by fasting blood collection. Systolic and diastolic blood pressure were determined through a digital sphygmomanometer. Isotemporal substitution models were used for statistical analysis.

RESULTS

Replacing 1 h of screen time with MVPA was associated with lower BMI, systolic and diastolic blood pressure, fat percentage, leptin, and C-reactive protein. When screen time was substituted for sleep time, lower waist circumference was observed. Regarding the substitution of 1 h of screen time with LPA, significant values were found only for leptin.

CONCLUSION

The replacement of screen time with physical activities of different intensities and sleep time was associated with benefits in cardiovascular indicators and inflammatory markers in childhood.

Sociodemographic disparities in sedentary time among US youth vary by period of the day

INTRODUCTION

Studies have reported sex and race/ethnicity disparities in sedentary time (ST), but none have evaluated ST by well-defined periods of the weekday (before school, during school, afterschool, and evening) and weekend day (morning, afternoon, and evening). Comparing sex and race/ethnicity disparities in ST at different periods of a weekday and weekend day can deepen our understanding of disparities and inform intervention efforts. This study tests sex and race/ethnicity disparities in ST by period of day in a representative sample of US youth.

METHODS

Youth (N = 2,972) from the 2003-2006 NHANES waves reported demographic variables and wore an accelerometer for 7 consecutive days to assess ST. Linear regressions were conducted to test relationships between sex and race/ethnicity and ST (min/hour) during each period of a weekday and weekend day. ST differences by sex and race/ethnicity were calculated to identify the periods of the day presenting the largest opportunity to reduce disparities.

RESULTS

Females were more sedentary than males during school (p < 0∙0001), afterschool (p < 0∙0001), and weekday evenings (p < 0∙0001) after controlling for covariates. After controlling for covariates, race/ethnicity only was a significant predictor of ST during weekend mornings (p < 0∙0001). During school and afterschool emerged as the periods with the largest opportunities to reduce sex disparities in ST. Weekend mornings were identified as the largest opportunity to reduce race/ethnic disparities in ST.

CONCLUSIONS

Sex disparities in ST appear to be driven mostly by the during school period of the day, while race/ethnic disparities in ST seem to be driven by the weekend morning period. Future intervention work should consider these periods when aiming to reduce ST disparities in youth.

Effects of accelerometer-based sedentary time and physical activity on DEXA-measured fat mass in 6059 children

Globally, childhood obesity is on the rise and the effect of objectively measured movement behaviour on body composition remains unclear. Longitudinal and causal mediation relationships of accelerometer-based sedentary time (ST), light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA) with dual-energy X-ray absorptiometry-measured fat mass were examined in 6059 children aged 11 years followed-up until age 24 years from the Avon Longitudinal Study of Parents and Children (ALSPAC), UK birth cohort. Over 13-year follow-up, each minute/day of ST was associated with 1.3 g increase in fat mass. However, each minute/day of LPA was associated with 3.6 g decrease in fat mass and each minute/day of MVPA was associated with 1.3 g decrease in fat mass. Persistently accruing ≥60 min/day of MVPA was associated with 2.8 g decrease in fat mass per each minute/day of MVPA, partly mediated by decrease insulin and low-density lipoprotein cholesterol. LPA elicited similar and potentially stronger fat mass-lowering effect than MVPA and thus may be targeted in obesity and ST prevention in children and adolescents, who are unable or unwilling to exercise.

Longitudinal Mediating Effect of Fat Mass and Lipids on Sedentary Time, Light PA, and MVPA with Inflammation in Youth

CONTEXT

Inflammation has been associated with atherosclerosis and metabolic disorders in youth. Preventing inflammation through exposure to different accelerometer-based movement behaviors has not been longitudinally examined.

OBJECTIVE

This work aimed to examine the mediating role of fat mass, lipids, and insulin resistance on the associations of cumulative sedentary time (ST), light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA) with inflammation.

METHODS

From the Avon Longitudinal Study of Parents and Children, United Kingdom, 792 children with data on at least 2 time-point measures of accelerometer-based ST, LPA, and MVPA during age 11, 15, and 24 years follow-up clinic visits with complete high-sensitivity C-reactive protein (hsCRP) measures at age 15, 17, and 24 years were studied. Mediating associations were examined using structural equation models. When the magnitude of the association between the exposure and outcome is increased after including a third variable, suppression occurred but mediation if decreased.

RESULTS

Among 792 (58% female; mean [SD] age at baseline, 11.7 [0.2] years), ST increased, LPA decreased, and MVPA had a U-shaped increase while hsCRP increased during 13-year follow-up. Insulin resistance partly suppressed (23.5% suppression) the positive associations of ST with hsCRP among participants who were overweight/obese. Fat mass partly mediated (30% mediation) the negative associations of LPA with hsCRP. Fat mass had a 77% mediation effect on the negative associations of MVPA with hsCRP.

CONCLUSION

ST worsens inflammation, but increased LPA had a 2-fold inflammatory-lowering effect and was more resistant to the attenuating effect of fat mass compared with MVPA, and hence should be targeted in future interventions.

A lifestyle pattern characterised by high consumption of sweet and salty snacks, sugar sweetened beverages and sedentary time is associated with blood pressure in families at risk for type 2 diabetes mellitus in Europe. The Feel4Diabetes Study

BACKGROUND

Individuals from families at high-risk for type 2 diabetes mellitus (T2DM) are also at high risk for hypertension (HTN) and cardiovascular disease. Studies identifying lifestyle patterns (LPs) combining dietary, physical activity or sedentary variables and examining their possible role with respect to developing blood pressure (BP) are limited. The present study aimed to examine the association of different LPs with BP levels in families at high risk for T2DM in Europe.

METHODS

In total, 1844 adults (31.6% males) at high-risk for T2DM across six European countries were included in this cross-sectional study using data from the baseline assessment of the Feel4Diabetes Study. BP measurements and dietary and physical activity assessments were conducted, and screen times were surveyed. LPs were revealed with principal component analysis of various data regarding diet, physical activity, screen time and smoking.

RESULTS

Three LPs were identified. LP3 (high consumption of sweet and salty snacks, sugar sweetened soft drinks and juices, and high amount of screen time) was positively associated with diastolic BP (B, 0.52; 95% confidence interval = 0.05-0.99) and the existence of HTN (odds ratio = 1.12; 95% confidence interval = 1.00-1.25). Participants in the highest tertile of LP3 spent mean 3 h of screen time, consumed 1.5 portions of sweet and/or salty snacks and 1 L of soft drinks on a daily basis, were associated with 12% higher risk of HTN.

CONCLUSIONS

Focusing on the combination of eating and lifestyle behaviours may more accurately identify, and therefore guide preventive measures tailored to the specific needs of high-risk populations.

Association between Sleep, Sedentary Time, Physical Activity, and Adiposity in Adolescents: A Prospective Observational Study

PURPOSE

This study aimed to examine the effects of substituting sedentary time with sleep or physical activity on adiposity in a longitudinal sample of adolescents.

METHODS

Adolescents (10-16 yr) were recruited for a prospective observational cohort. Parents and adolescents reported demographic characteristics and pubertal development. Accelerometry was used to measure sleep, physical activity, and sedentary time. Adiposity was quantified with imaging techniques. Isotemporal substitution modeling was conducted to examine the effect of substituting 10 min of sedentary time with sleep or differing intensities of physical activity. Results were stratified by sex and race and adjusted for covariates.

RESULTS

A total of 217 adolescents provided complete measures at both baseline and 2 yr later (58.1% White, 51.8% girls; 12.9 ± 1.9 yr at baseline). Sleep was negatively related to adiposity 2 yr later when considering other movement behaviors, but substituting baseline sedentary time with sleep was not related to future adiposity ( P > 0.05). In boys and non-White adolescents, substituting sedentary time with vigorous-intensity physical activity was related to lower adiposity 2 yr later ( P < 0.05). Substituting sedentary time for moderate- to vigorous-intensity physical activity was not associated with future adiposity.

CONCLUSIONS

Substituting sedentary time with vigorous-intensity physical activity was related to lower adiposity in later adolescence in certain groups. Opportunities to promote an adequate balance of sleep, sedentary time, and physical activity in all adolescents are encouraged for optimal development.

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.

Active School-Based Interventions to Interrupt Prolonged Sitting Improve Daily Physical Activity: A Systematic Review and Meta-Analysis

BACKGROUND

Sedentary behavior (SB) is a negative routine for health, especially during advancing age. Promoting an active lifestyle and reducing SB is a global endeavor. The aim of this study was to analyze the effects of active school-based programs to interrupt prolonged sitting for daily physical activity (PA) and daily SB in children and adolescents.

METHODS

A systematic review was conducted. Clinical trials analyzing the effect of interrupting prolonged sitting with active breaks and classroom-based PA were included. Studies that implemented PA in class without interrupting prolonged sitting or those that implemented multimodal interventions were excluded. A systematic search was conducted in 6 databases: Medline, WOS, Cochrane Library, SPORTDiscus, CINAHL and EMBASE. Primary outcomes were daily PA and daily SB, while moderate-to vigorous physical activity (MVPA) was considered a secondary outcome.

RESULTS

Six studies were included, with a total of 976 participants between 6-14 years. The interventions were heterogeneous in duration of the sitting time interruption (5-30 min), frequency (1-3 times per-day up to three times per-week) and total duration (five days to three years). 50% of the studies scored "high risk" of bias. Three meta-analyses were performed for daily PA, MVPA and SB, showing a significant improvement in the daily PA and MVPA.

CONCLUSIONS

School-based programs aimed to interrupt prolonged sitting could be a good strategy to improve daily PA and MVPA levels. (Registration number: CRD42022358933).

Detrimental effects of physical inactivity on peripheral and brain vasculature in humans: Insights into mechanisms, long-term health consequences and protective strategies

The growing prevalence of physical inactivity in the population highlights the urgent need for a more comprehensive understanding of how sedentary behaviour affects health, the mechanisms involved and what strategies are effective in counteracting its negative effects. Physical inactivity is an independent risk factor for different pathologies including atherosclerosis, hypertension and cardiovascular disease. It is known to progressively lead to reduced life expectancy and quality of life, and it is the fourth leading risk factor for mortality worldwide. Recent evidence indicates that uninterrupted prolonged sitting and short-term inactivity periods impair endothelial function (measured by flow-mediated dilation) and induce arterial structural alterations, predominantly in the lower body vasculature. Similar effects may occur in the cerebral vasculature, with recent evidence showing impairments in cerebral blood flow following prolonged sitting. The precise molecular and physiological mechanisms underlying inactivity-induced vascular dysfunction in humans are yet to be fully established, although evidence to date indicates that it may involve modulation of shear stress, inflammatory and vascular biomarkers. Despite the steady increase in sedentarism in our societies, only a few intervention strategies have been investigated for their efficacy in counteracting the associated vascular impairments. The current review provides a comprehensive overview of the evidence linking acute and short-term physical inactivity to detrimental effects on peripheral, central and cerebral vascular health in humans. We further examine the underlying molecular and physiological mechanisms and attempt to link these to long-term consequences for cardiovascular health. Finally, we summarize and discuss the efficacy of lifestyle interventions in offsetting the negative consequences of physical inactivity.

Association between alanine aminotransferase as surrogate of fatty liver disease and physical activity and sedentary time in adolescents with obesity

To compare patterns of sedentary (SED) time (more sedentary, SED + vs less sedentary, SED-), moderate to vigorous physical activity (MVPA) time (more active, MVPA + vs less active, MVPA-), and combinations of behaviors (SED-/MVPA + , SED-/MVPA-, SED + /MVPA + , SED + /MVPA-) regarding nonalcoholic fatty liver diseases (NAFLD) markers. This cross-sectional study included 134 subjects (13.4 ± 2.2 years, body mass index (BMI) 98.9 ± 0.7 percentile, 48.5% females) who underwent 24-h/7-day accelerometry, anthropometric, and biochemical markers (alanine aminotransferase (ALT) as first criterion, and aspartate aminotransferase (AST), gamma-glutamyl transpeptidase (GGT), AST/ALT ratio as secondary criteria). A subgroup of 39 patients underwent magnetic resonance imaging-liver fat content (MRI-LFC). Hepatic health was better in SED- (lower ALT, GGT, and MRI-LFC (p < 0.05), higher AST/ALT (p < 0.01)) vs SED + and in MVPA + (lower ALT (p < 0.05), higher AST/ALT (p < 0.01)) vs MVPA- groups after adjustment for age, gender, and Tanner stages. SED-/MVPA + group had the best hepatic health. SED-/MVPA- group had lower ALT and GGT and higher AST/ALT (p < 0.05) in comparison with SED + /MVPA + group independently of BMI. SED time was positively associated with biochemical (high ALT, low AST/ALT ratio) and imaging (high MRI-LFC) markers independently of MVPA. MVPA time was associated with biochemical markers (low ALT, high AST/ALT) but these associations were no longer significant after adjustment for SED time.

CONCLUSION

Lower SED time is associated with better hepatic health independently of MVPA. Reducing SED time might be a first step in the management of pediatric obesity NAFLD when increasing MVPA is not possible.

WHAT IS KNOWN

• MVPA and SED times are associated with cardiometabolic risks in youths with obesity. • The relationships between NAFLD markers and concomitant MVPA and SED times have not been studied in this population.

WHAT IS NEW

• Low SED time is associated with healthier liver enzyme profiles and LFC independent of MVPA. • While low SED/high MVPA is the more desirable pattern, low SED/low MVPA pattern would have healthier liver enzyme profile compared with high MVPA/high SED, independent of BMI, suggesting that reducing SED time irrespective of MVPA is needed to optimize liver health.

Two-Year Effectiveness of a Controlled Trial With Physically Active Lessons on Behavioral Indicators of School Children

Purpose: In this study, we evaluated the effectiveness of two years of an intervention with physically active lessons on indicators of sedentary behavior and physical activity measured objectively in elementary school children. Methods: A controlled clinical trial with cluster sampling was carried out in 2018 and 2019, with four classes of children in the 2nd year of elementary school. The intervention group classes received dynamic activities linked to the pedagogical content (n = 34) for 2 years. The indicators of sedentary behavior and physical activities were evaluated using ActivPal and ActiGraph GT3X accelerometers during the school shift. Crude and adjusted models of Generalized Estimation Equations with Bonferroni's post hoc were used to identify the differences between the groups (three evaluations in 2018 and two evaluations in 2019). Results: There was a reduction in stationary behavior (p = .01) and an increase in light physical activity (p = .044) during the two years. In the first year there were reductions in standing time (p = .044) and number of transitions (p ≤ .001), and an increase in walking time (p = .017). However, in the second year, the mean differences in percentage points were smaller than in the first year. No differences were found for sitting time as well as for moderate and vigorous physical activity. We observed a large effect size for all variables. Conclusions: The introduction of physically active lessons in the classroom reduced time in stationary behavior and increased time in light physical activity. However, the effects on behavior observed in the first year were not maintained in the second year of intervention.

Device-measured sedentary time in Norwegian children and adolescents in the era of ubiquitous internet access: secular changes between 2005, 2011 and 2018

Background

Access to screen-based media has been revolutionized during the past two decades. How this has affected sedentary time (ST) accumulation in children is poorly understood.

Methods

This study, based on the Physical Activity among Norwegian Children Study (PANCS), uses accelerometer data from population-based samples of 9- and 15‐year-olds, collected in 2005 (n = 1722), 2011 (n = 1587) and 2018 (n = 1859). Secular changes between surveys were analysed using random-effects linear regression models adjusted for survey-specific factors. Data on ST were collected using hip-worn ActiGraphs and ST was defined using a threshold equivalent to <100 counts/min. Sedentary bouts were grouped by duration: <1, 1–5, 5–15, 15–30 and ≥30 min.

Results

Between 2005 and 2018, ST increased by 29 min/day in 9-year-old boys (95% CI: 19, 39; P <0.001), by 21 min/day in 15-year-old boys (95% CI: 8, 34; P = 0.002) and by 22 min/day in 15-year-old girls (95% CI: 10, 35; P <0.001), but not in 9-year-old girls at 6 min/day (95% CI: -3, 16; P = 0.191). All age-sex groups accumulated less ST in bouts lasting <5 min and more ST in longer bouts, particularly in 5–15-min bouts. Adolescent girls also increased ST accumulation in 15–30-min and ≥30-min bouts. Changes were largely mirrored before, during and after school on weekdays and during weekend days.

Conclusions

Coinciding with the introduction of smartphones, tablets and near-universal internet access, total daily ST and ST accumulated in prolonged sedentary bouts increased between 2005 and 2018 in children and adolescents.

Variation in Child Serum Cholesterol and Prevalence of Familiar Hypercholesterolemia: The Health Oriented Pedagogical Project (HOPP)

Early stages of atherosclerosis may develop in childhood due to hyperlipidemia. The aims are to investigate the prevalence of familiar hypercholesterolemia in 6 to 12-year-old children and to study the deviation in cholesterol measures. Anthropometric data and venous blood were collected from children participating in the Health Oriented Pedagogical Project (HOPP). Out of 18 children with TC > 6.0 mmol/L, 15 were tested genetically and none diagnosed with FH. The prevalence of TC > 6.0 mmol/L declined from 1.3% in 2015 to 0.5% in 2016. The mean TC was 4.30 mmol/L both years, which is lower than in earlier studies. Usage of a single TC measurement and a threshold of TC > 6.0 mmol/L in screening children for FH, may not be a good screening strategy. While lipid values have a good reliability across 2 measurements, there are variations in individual TC levels across 1 year.

Childhood obesity: an ecological perspective

OBJECTIVE

To describe the participation of the environment in the childhood obesity epidemic, since childhood obesity currently represents a great challenge, with high prevalence worldwide, including in Brazil.

DATA SOURCE

Survey of articles published in the last 10 years in PubMed, evaluating the interface between the environment and childhood obesity.

DATA SYNTHESIS

Recent studies show that the environment is very important in the etiopathogenesis of obesity and its comorbidities. Therefore, factors such as air pollution, exposure to chemical substances that interfere with the metabolism, excessive consumption of ultra-processed foods, changes in the intestinal microbiota, and sedentary lifestyle are associated with increased obesity, insulin resistance, type 2 diabetes, and changes in lipid metabolism. These factors have a greater impact on some stages of life, such as the first thousand days, as they affect the expression of genes that control the adipogenesis, energy expenditure, and the mechanisms for hunger/satiety control.

CONCLUSIONS

Environmental aspects must be taken into account in the prevention and treatment of childhood obesity, both from the individual and the population point of view, with adequate and comprehensive public health policies.

Joint associations between objectively measured physical activity volume and intensity with body fatness: the Fenland study

BACKGROUND/OBJECTIVES

Physical activity energy expenditure (PAEE) represents the total volume of all physical activity. This can be accumulated as different underlying intensity profiles. Although volume and intensity have been studied in isolation, less is known about their joint association with health. We examined this association with body fatness in a population-based sample of middle-aged British adults.

METHODS

In total, 6148 women and 5320 men from the Fenland study with objectively measured physical activity from individually calibrated combined heart rate and movement sensing and DXA-derived body fat percentage (BF%) were included in the analyses. We used linear and compositional isocaloric substitution analysis to examine associations of PAEE and its intensity composition with body fatness. Sex-stratified models were adjusted for socio-economic and dietary covariates.

RESULTS

PAEE was inversely associated with body fatness in women (beta = -0.16 (95% CI: -0.17; -0.15) BF% per kJ day-1 kg-1) and men (beta = -0.09 (95% CI: -0.10; -0.08) BF% per kJ day-1 kg-1). Intensity composition was significantly associated with body fatness, beyond that of PAEE; the reallocation of energy to vigorous physical activity (>6 METs) from other intensities was associated with less body fatness, whereas light activity (1.5-3 METs) was positively associated. However, light activity was the main driver of overall PAEE volume, and the relative importance of intensity was marginal compared to that of volume; the difference between PAEE in tertile 1 and 2 in women was associated with 3 percentage-point lower BF%. Higher vigorous physical activity in the same group to the maximum observed value was associated with 1 percentage-point lower BF%.

CONCLUSIONS

In this large, population-based cohort study with objective measures, PAEE was inversely associated with body fatness. Beyond the PAEE association, greater levels of intense activity were also associated with lower body fatness. This contribution was marginal relative to PAEE. These findings support current guidelines for physical activity which emphasise that any movement is beneficial, rather than specific activity intensity or duration targets.

Association between Metabolic Syndrome Diagnosis and the Physical Activity-Sedentary Profile of Adolescents with Obesity: A Complementary Analysis of the Beta-JUDO Study

Metabolic syndrome (MetS) is highly prevalent in children and adolescents with obesity and places them at an increased risk of cardiovascular-related diseases. However, the associations between objectively measured movement-related behaviors and MetS diagnosis remain unexplored in youths with obesity. The aim was to compare profiles of sedentary (SED) time (more sedentary, SED+ vs. less sedentary, SED−), moderate to vigorous physical activity (MVPA) time (more active, MVPA+ vs. less active, MVPA−) and combinations of behaviors (SED−/MVPA+, SED−/MVPA−, SED+/MVPA+, SED+/MVPA−) regarding the MetS diagnosis. One hundred and thirty-four adolescents with obesity (13.4 ± 2.2 years) underwent 24 h/7 day accelerometry, waist circumference (WC), blood pressure (BP), high-density lipoprotein-cholesterol (HDL-c), triglycerides (TG) and insulin-resistance (IR) assessments. Cumulative cardiometabolic risk was assessed by using (i) MetS status (usual dichotomic definition) and (ii) cardiometabolic risk z-score (MetScore, mean of standardized WC, BP, IR, TG and inverted HDL-c). SED− vs. SED+ and MVPA+ vs. MVPA− had lower MetS (p < 0.01 and p < 0.001) and MetScore (p < 0.001). SED−/MVPA+ had the lowest risk. While SED and MVPA times were lower in SED−/MVPA− vs. SED+/MVPA+ (p < 0.001), MetScore was lower in SED−/MVPA− independently of body mass index (BMI) (p < 0.05). MVPA, but not SED, time was independently associated with MetS diagnosis (p < 0.05). Both MVPA (p < 0.01) and SED times (p < 0.05) were associated with MetScore independently of each other. A higher MVPA and lower SED time are associated with lower cumulative cardiometabolic risk.

Six-week behaviour change intervention to reduce sedentary behaviour in people with chronic obstructive pulmonary disease: a randomised controlled trial

INTRODUCTION

This study aimed to determine whether a 6-week behaviour change intervention was more effective than a sham intervention for reducing sedentary behaviour (SB) in people with chronic obstructive pulmonary disease (COPD).

METHODS

People with stable COPD on the waitlist for entry into pulmonary rehabilitation were recruited to this multicentre trial with randomisation (independent, concealed allocation) to either an intervention group or sham group, assessor blinding and intention-to-treat (ITT) analysis. The behaviour change intervention consisted of once weekly sessions for 6 weeks with a physiotherapist to reduce SB through education, guided goals setting and real-time feedback on SB. The sham intervention consisted of once weekly phone calls for 6 weeks to monitor health status. SB was measured continuously over 7 days using thigh-worn accelerometry (activPAL3 micro). The primary outcome was time spent in SB. Participants with at least 4 days of ≥10 hours waking wear time were included in the ITT analysis and those who reported achieving ≥70% of goals to reduce SB or who completed all sham calls were included in a per-protocol analysis.

RESULTS

70 participants were recruited and 65 completed the study (mean±SD age 74±9 years, mean FEV₁ 55%±19% predicted, 49% male). At 6 weeks, no between-group differences in time spent in SB were observed in the ITT analysis (mean difference 5 min/day, 95% CI -38 to 48) or per-protocol analysis (-16 min/day, 95% CI -80 to 48).

DISCUSSION

A 6-week behaviour change intervention did not reduce time in SB compared with a sham intervention in people with stable moderate-to-severe COPD prior to pulmonary rehabilitation.

Associations of fitness, motor competence, and adiposity with the indicators of physical activity intensity during different physical activities in children

We investigated the associations of peak oxygen uptake (V̇O2peak), ventilatory threshold (VT), muscle strength, motor competence (MC), and adiposity with the indicators of PA intensity during different physical activities used to create absolute PA intensity cut-offs among 35 children 7-11-years-of-age. V̇O2peak was defined as the highest V̇O2 achieved in the maximal cardiopulmonary exercise test (CPET) on a cycle ergometer, self-paced running, or running on a treadmill at 8 km/h. VT was defined from the CPET data. Peak isometric knee extensor and flexor strength was assessed by a dynamometer, MC by the Körperkoordination test für Kinder tests, and body composition by the bioelectrical impedance analysis. PA intensity was assessed using V̇O2 as a % of V̇O2reserve or V̇O2 at VT, mean amplitude deviation (MAD) measured by accelerometry, metabolic equivalent of task (MET), and muscle activity measured by textile electromyography during walking or running on a treadmill at 4, 6, and 8 km/h, playing hopscotch, walking up and down the stairs, self-paced walking, and self-paced running. Children with lower V̇O2peak, V̇O2 at VT, and MC operated at higher intensity level during given physical task than their peers with higher fitness and MC when PA intensity was expressed using relative PA intensity using V̇O2 as a % of V̇O2reserve or V̇O2 at VT (p < 0.05). MAD and METs during different tasks were not able to discriminate PA intensity between children with varying levels of physical fitness or MC. Traditionally used absolute measures of PA intensity based on accelerometry or MET underestimated PA intensity in children with lower V̇O2peak, V̇O2 at VT, and MC.

Cross-Sectional and Longitudinal Associations between Non-School Time Physical Activity, Sedentary Time, and Adiposity among Boys and Girls: An Isotemporal Substitution Approach

This study investigated the cross-sectional and longitudinal associations of the substitution of non-school time light physical activity (LPA), moderate-to-vigorous physical activity (MVPA), and sedentary time (ST) with adiposity in boys and girls. Boys (n = 65, baseline Mage= 9.93 ± 0.86 years) and girls (n = 77, baseline Mage = 10.17 ± 0.95 years) wore waist-worn accelerometers (ActiGraph GT3X) at baseline and at a 30-month follow-up, from which non-school time LPA, MVPA, ST, and total device wear were quantified. Body mass index (BMI) and waist-to-height-ratio (WHR) were measured at baseline and follow-up. Body fat percent (BF%) was obtained at follow-up only. Isotemporal substitution models assessed the cross-sectional and longitudinal associations of reallocating non-school time activity with BMI, WHR and BF%. In boys, replacing 30 min/day of LPA with MVPA was cross-sectionally (β = −8.26, p < 0.05) associated with a lower BF%. Replacing 30 min/day of ST with MVPA was cross-sectionally (β = −6.02, p < 0.05) associated with a lower BF% in boys. Longitudinally in boys, replacing 30 min of change in LPA with MVPA (β = −7.42, p < 0.10) and replacing 30 min of change in MVPA with ST (β = 5.78, p < 0.10) over 30 months was marginally associated with less BF%. Associations were null in girls (p > 0.05). These results may support targeting activity reallocation during non-school time for the purposes of adiposity improvement in boys. A multi-behavioral approach may be more appropriate for girls, as non-school time activity may not be driving adiposity status.

Physical activity and sedentary time in children and adolescents with asthma: A systematic review and meta-analysis

The influence of asthma on physical activity (PA) in youth remains equivocal. This review synthesizes the evidence regarding the influence of asthma on PA and sedentary time and evaluates the role of key moderators for this relationship. In accordance with PRISMA guidelines, six electronic databases and gray literature were searched. Primary studies in English were included if they reported device-assessed PA in youth with and without asthma. Random effects meta-analyses examined the effect of asthma on PA and, separately, sedentary time. Mixed-effect meta-regression analyses were conducted using age and sex as moderators, with sub-group comparisons for study quality and asthma diagnosis criteria. Overall, of 3944 citations retrieved, 2850 were screened after the removal of supplication and 2743 citations excluded. Of the 107 full-text publications reviewed, 16 were included in data extraction and analysis, with 15 and five studies included in the PA and sedentary time meta-analyses, respectively. The robust effect size estimate for the influence of asthma on PA and sedentary time was -0.04 [95% CI = -0.11, 0.03] and -0.09 [95% CI = -0.12, -0.06], indicating a non-significant and significant trivial effect, respectively. The effect of asthma on PA levels or sedentary time was not associated with age or sex. Youth with controlled asthma are equally physically (in)active as their healthy peers, with asthma associated with less sedentary time. However, methodological limitations and a paucity of clear methodological reporting temper these conclusions. More rigorous device-based assessments, with a particular focus on sedentary time, and more robust diagnoses of asthma, especially with regard to severity, are needed.

Association of mentally-passive and mentally-active sedentary behaviors with device-measured bouts and breaks of sedentary time in adolescents

Background: Our aim was to analyze the association of self-reported mentally-passive and mentally-active sedentary behaviors with different patterns (bouts and breaks) of device-measured sedentary time in adolescents.

Methods: This was a cross-sectional study conducted among 375 adolescents (177 boys) aged 1015 years. Total time, bouts and breaks of sedentary time were measured through accelerometers. Self-reported sedentary behavior in different activities was summed and divided into mentally-active (playing electronic games, studying and reading) and mentally-passive (watching TV, watching DVD, and using computer for leisure). Bayesian linear regression models were used for association analyses.

Results: Only mentally-passive sedentary behaviors were positively associated with longer bouts [1-4 minutes: mean posterior distribution: -0.431 (95% credible interval: -0.745 to -0.114); =15 minutes: 0.641 (0.122 to 1.222)] and lower number of breaks [-0.138 (-0.228 to -0.044)] of device-measured sedentary time.

Conclusion: Self-reported mentally-passive sedentary behaviors are associated with longer bouts and lower breaks of device-measured sedentary time.

Comparative effectiveness of school-based interventions targeting physical activity, physical fitness or sedentary behaviour on obesity prevention in 6- to 12-year-old children: A systematic review and meta-analysis

A systematic search of the literature was performed to compare the effects of interventions that targeted sedentary behaviours or physical activity (PA) or physical fitness on primary prevention of obesity in 6- to 12-year-old children. The search identified 146 reports that provided relevant data for meta-analysis. Point estimates in % body fat were higher for fitness interventions compared with PA interventions (standardized mean difference = -0.11%; 95% CI = -0.26 to 0.04, and -0.04%; 95% CI = -0.15 to 0.06, respectively). Including sedentary behaviour to a PA- or fitness-oriented intervention was not accompanied by an increase in intervention effectiveness, as the point estimates were slightly smaller compared with those for PA- or fitness-only interventions. Overall, the effects tended to be larger in girls than in boys, especially for PA + sedentary behaviour interventions. There was some evidence for inequality, as the effects on body mass index were seen when interventions were delivered in the general population (standardized mean difference = -0.05, 95% CI = -0.07 to -0.02), but not in groups of disadvantaged children (standardized mean difference = -0.01, 95% CI = -0.29 to 0.19). In conclusion, school-based PA interventions appear to be an effective strategy in the primary prevention of childhood obesity among 6- to 12-year-old children, but targeting sedentary behaviour in addition to PA or fitness does not increase the effectiveness of the intervention.

Associations of age, body size, and maturation with physical activity intensity in different laboratory tasks in children

We investigated the associations of age, sex, body size, body composition, and maturity with measures of physical activity (PA) intensity in children. PA intensity was assessed using VO₂ as % of VO_2reserve or VO₂ at ventilatory threshold (VT), muscle activity measured by textile electromyography, mean amplitude deviation (MAD) measured by accelerometry, and metabolic equivalent of task (MET) during laboratory activities.Age, stature, and muscle mass were inversely associated with VO2 as % of VO_2reserve and % of VT, during walking or running on a treadmill for 4, 6, and 8 km/h (Spearman r = -0.645 to -0.358). Age was inversely associated with MAD during walking on treadmill for 4 km/h (r = -0.541) and positively associated with MAD during running on a treadmill for 8 km/h, playing hopscotch, and during self-paced running (r = 0.368 to 0.478). Fat mass was positively associated with VO2 as % of VO_2reserve and VO2 as % of VO2 at VT and waist circumference was positively associated with VO2 as a % of VO_2reserve and muscle activity during stair climbing (r = 0.416 to 0.519).Fixed accelerometry cut-offs used to define PA intensities should be adjusted for age, sex, body size, and body composition.

Factors Associated with Primary Hypertension in Pediatric Patients: An Up-to-Date

BACKGROUND

Arterial hypertension in children is considered a common alteration nowadays, mainly because obesity is a growing worldwide problem closely related to increased blood pressure. Childhood hypertension can be classified as primary or secondary, depending on the etiology. Primary or essential hypertension still has its pathophysiology not fully elucidated, and there is no consensus in the literature on most underlying mechanisms. In this review, genetic and environmental factors, including sodium and potassium intake, socioeconomic status, ethnicity, family structure, obesity, sedentary lifestyle, prematurity and low birth weight, prenatal and postnatal exposures are highlighted.

OBJECTIVE

The present study aimed to perform an update on primary hypertension in childhood, providing clinicians and researchers an overview of the current state of the literature regarding the influence of genetic and environmental factors.

METHODS

This integrative review searched for articles on genetic and environmental factors related to primary hypertension in pediatric patients. The databases evaluated were PubMed and Scopus.

RESULTS

The studies have provided insights regarding many genetic and environmental factors, in addition to their association with the pathophysiology of primary hypertension in childhood. Findings corroborated the idea that primary hypertension is a multifactorial disease. Further studies in the pediatric population are needed to elucidate the underlying mechanisms.

CONCLUSION

The study of primary hypertension in pediatrics has utmost importance for the adoption of preventive measures and the development of more efficient treatments, therefore reducing childhood morbidity and the incidence of cardiovascular diseases and other health consequences later in life.

World Health Organization 2020 guidelines on physical activity and sedentary behaviour

OBJECTIVES

To describe new WHO 2020 guidelines on physical activity and sedentary behaviour.

METHODS

The guidelines were developed in accordance with WHO protocols. An expert Guideline Development Group reviewed evidence to assess associations between physical activity and sedentary behaviour for an agreed set of health outcomes and population groups. The assessment used and systematically updated recent relevant systematic reviews; new primary reviews addressed additional health outcomes or subpopulations.

RESULTS

The new guidelines address children, adolescents, adults, older adults and include new specific recommendations for pregnant and postpartum women and people living with chronic conditions or disability. All adults should undertake 150-300 min of moderate-intensity, or 75-150 min of vigorous-intensity physical activity, or some equivalent combination of moderate-intensity and vigorous-intensity aerobic physical activity, per week. Among children and adolescents, an average of 60 min/day of moderate-to-vigorous intensity aerobic physical activity across the week provides health benefits. The guidelines recommend regular muscle-strengthening activity for all age groups. Additionally, reducing sedentary behaviours is recommended across all age groups and abilities, although evidence was insufficient to quantify a sedentary behaviour threshold.

CONCLUSION

These 2020 WHO guidelines update previous WHO recommendations released in 2010. They reaffirm messages that some physical activity is better than none, that more physical activity is better for optimal health outcomes and provide a new recommendation on reducing sedentary behaviours. These guidelines highlight the importance of regularly undertaking both aerobic and muscle strengthening activities and for the first time, there are specific recommendations for specific populations including for pregnant and postpartum women and people living with chronic conditions or disability. These guidelines should be used to inform national health policies aligned with the WHO Global Action Plan on Physical Activity 2018-2030 and to strengthen surveillance systems that track progress towards national and global targets.

The multivariate physical activity signature associated with metabolic health in children and youth: An International Children's Accelerometry Database (ICAD) analysis

There is solid evidence for an association between physical activity and metabolic health outcomes in children and youth, but for methodological reasons most studies describe the intensity spectrum using only a few summary measures. We aimed to determine the multivariate physical activity intensity signature associated with metabolic health in a large and diverse sample of children and youth, by investigating the association pattern for the entire physical intensity spectrum. We used pooled data from 11 studies and 11,853 participants aged 5.8-18.4 years included in the International Children's Accelerometry Database. We derived 14 accelerometry-derived (ActiGraph) physical activity variables covering the intensity spectrum (from 0-99 to ≥8000 counts per minute). To handle the multicollinearity among these variables, we used multivariate pattern analysis to establish the associations with indices of metabolic health (abdominal fatness, insulin sensitivity, lipid metabolism, blood pressure). A composite metabolic health score was used as the main outcome variable. Associations with the composite metabolic health score were weak for sedentary time and light physical activity, but gradually strengthened with increasing time spent in moderate and vigorous intensities (up to 4000-5000 counts per minute). Association patterns were fairly consistent across sex and age groups, but varied across different metabolic health outcomes. This novel analytic approach suggests that vigorous intensity, rather than less intense activities or sedentary behavior, are related to metabolic health in children and youth.

World Health Organization 2020 guidelines on physical activity and sedentary behaviour

OBJECTIVES

To describe new WHO 2020 guidelines on physical activity and sedentary behaviour.

METHODS

The guidelines were developed in accordance with WHO protocols. An expert Guideline Development Group reviewed evidence to assess associations between physical activity and sedentary behaviour for an agreed set of health outcomes and population groups. The assessment used and systematically updated recent relevant systematic reviews; new primary reviews addressed additional health outcomes or subpopulations.

RESULTS

The new guidelines address children, adolescents, adults, older adults and include new specific recommendations for pregnant and postpartum women and people living with chronic conditions or disability. All adults should undertake 150-300 min of moderate-intensity, or 75-150 min of vigorous-intensity physical activity, or some equivalent combination of moderate-intensity and vigorous-intensity aerobic physical activity, per week. Among children and adolescents, an average of 60 min/day of moderate-to-vigorous intensity aerobic physical activity across the week provides health benefits. The guidelines recommend regular muscle-strengthening activity for all age groups. Additionally, reducing sedentary behaviours is recommended across all age groups and abilities, although evidence was insufficient to quantify a sedentary behaviour threshold.

CONCLUSION

These 2020 WHO guidelines update previous WHO recommendations released in 2010. They reaffirm messages that some physical activity is better than none, that more physical activity is better for optimal health outcomes and provide a new recommendation on reducing sedentary behaviours. These guidelines highlight the importance of regularly undertaking both aerobic and muscle strengthening activities and for the first time, there are specific recommendations for specific populations including for pregnant and postpartum women and people living with chronic conditions or disability. These guidelines should be used to inform national health policies aligned with the WHO Global Action Plan on Physical Activity 2018-2030 and to strengthen surveillance systems that track progress towards national and global targets.

Adiposity, cardiovascular, and health-related quality of life indicators and the reallocation of waking movement behaviors in preschool children with overweight and obesity: An isotemporal data analysis

Background

Isotemporal substitution evaluates hypothetical time replacement scenarios of physical movement on health, with few studies conducted among ethnically diverse preschool-aged populations. This study examines the reallocation of waking movement behaviors on adiposity, cardiovascular, and quality of life indicators among low-income, majority Hispanic preschool-aged youth (2–5 years) with overweight.

Methods

Participants wore an ActiGraph monitor (waist) and completed adiposity, cardiovascular, and health-related quality of life health assessments. Covariates included age, sex, ethnicity, and socioeconomic status. The isotemporal substitution approach was employed to address study aims.

Results

Complete data were available for 131 preschoolers. For boys, reallocating 5 minutes of stationary time with light intensity, moderate to vigorous intensity, or total physical activity showed a relation with beneficial reductions in adiposity indicators; for girls, these relations were statistically null. For boys and girls, reallocating 5 minutes of stationary time [-2.2 (95% CI: -3.7, -0.7) mmHg], light intensity [-2.1 (95% CI: -3.7, -0.7) mmHg], or moderate intensity activity [-2.7 (95% CI: -5.0, -0.4) mmHg] to vigorous intensity activity was related to favorable systolic blood pressure. Reallocating 5 minutes of stationary time to moderate to vigorous intensity activity [0.6 (95% CI: -1.0, -0.1) mmHg] or total physical activity [-0.2 (95% CI: -0.3, -0.01) mmHg] was related to lowered systolic blood pressure. Reallocating 5 minutes of stationary time to moderate to vigorous intensity activity [0.6 (95% CI: -1.1, -0.02) bpm] was related to lowered resting heart rate. No significant results for quality of life were found.

Conclusion

Reallocation of time from stationary time to other movement behaviors is associated with several favorable adiposity and cardiovascular health outcomes among preschool children with overweight and obesity.