The Association of the Body Composition of Children with 24-Hour Activity Composition

Association Between 24-Hour Movement Behaviors and Adiposity in Malaysian Schoolchildren: A Compositional Isotemporal Substitution Analysis

BACKGROUND

Physical activity (PA), sedentary behavior (SB), and sleep are interrelated 24-hour movement behaviors that are important for the growth and well-being of children. This cross-sectional study examined the relationship between 24-hour movement behaviors and adiposity, and predicted changes in adiposity following compositional time reallocations in 7- to 12.9-year-old Malaysian children from the South East Asian Nutrition Surveys II Malaysia.

METHODS

A total of 381 children (mean age 9.7 [1.6] y, 57% girls) provided 24-hour wrist-worn GENEActiv accelerometry data which captured time spent for sleep, SB, light PA and moderate to vigorous PA (MVPA). Indicators of adiposity were derived from anthropometry and bioelectrical impedance analysis: body-mass-index-for-age, waist circumference, waist-to-height ratio, percent body fat, and body mass index. The composition of 4-part movement behaviors was expressed as isometric log-ratio coordinates which were entered into regression models. Isotemporal substitution analysis was used to assess changes in adiposity indicators when reallocating time between movement behaviors.

RESULTS

Relative to other movement behaviors, time spent on MVPA was significantly associated with waist circumference, waist-to-height ratio, percent body fat, and fat mass index. A 15-minute one-to-one reallocation from other movement behaviors to MVPA predicted lower body-mass-index-for-age (-0.03 to -0.11), smaller waist circumference (-0.67 to -1.28 cm), lower waist-to-height ratio (-0.004 to -0.008), percent body fat (-0.87% to -1.47%), and fat mass index (-0.23 to -0.42). Replacing SB and light PA with sleep or MVPA was associated with lower adiposity.

CONCLUSIONS

The overall composition of movement behavior was significantly associated with the adiposity of Malaysian schoolchildren. Promoting MVPA and sleep and reducing SB and light PA are important for prevention of childhood obesity.

A systematic review of research reporting practices in observational studies examining associations between 24-h movement behaviors and indicators of health using compositional data analysis

Background

Compositional data analysis (CoDA) techniques are well suited for examining associations between 24-h movement behaviors (i.e., sleep, sedentary behavior, physical activity) and indicators of health given they recognize these behaviors are co-dependent, representing relative parts that make up a whole day. Accordingly, CoDA techniques have seen increased adoption in the past decade, however, heterogeneity in research reporting practices may hinder efforts to synthesize and quantify these relationships via meta-analysis. This systematic review described reporting practices in studies that used CoDA techniques to investigate associations between 24-h movement behaviors and indicators of health.

Methods

A systematic search of eight databases was conducted, in addition to supplementary searches (e.g., forward/backward citations, expert consultation). Observational studies that used CoDA techniques involving log-ratio transformation of behavioral data to examine associations between time-based estimates of 24-h movement behaviors and indicators of health were included. Reporting practices were extracted and classified into seven areas: (1) methodological justification, (2) behavioral measurement and data handling strategies, (3) composition construction, (4) analytic plan, (5) composition-specific descriptive statistics, (6) model results, and (7) auxiliary information. Study quality and risk of bias were assessed by the National Institutes of Health Quality Assessment Tool for Observational Cohort and Cross-sectional Studies.

Results

102 studies met our inclusion criteria. Reporting practices varied considerably across areas, with most achieving high standards in methodological justification, but inconsistent reporting across all other domains. Some items were reported in all studies (e.g., how many parts the daily composition was partitioned into), whereas others seldom reported (e.g., definition of a day: midnight-to-midnight versus wake-to-wake). Study quality and risk of bias was fair in most studies (85%).

Conclusions

Current studies generally demonstrate inconsistent reporting practices. Consistent, clear and detailed reporting practices are evidently needed moving forward as the field of time-use epidemiology aims to accurately capture and analyze movement behavior data in relation to health outcomes, facilitate comparisons across studies, and inform public health interventions and policy decisions. Achieving consensus regarding reporting recommendations is a key next step.

Supplementary Information

The online version contains supplementary material available at 10.1186/s44167-024-00062-8.

Reallocating just 10 min to moderate-to-vigorous physical activity from other components of 24-hour movement behaviors improves cardiovascular health in adults

BACKGROUND

As components of a 24-hour day, sedentary behavior (SB), physical activity (PA), and sleep are all independently linked to cardiovascular health (CVH). However, insufficient understanding of components' mutual exclusion limits the exploration of the associations between all movement behaviors and health outcomes. The aim of this study was to employ compositional data analysis (CoDA) approach to investigate the associations between 24-hour movement behaviors and overall CVH.

METHODS

Data from 581 participants, including 230 women, were collected from the 2005-2006 wave of the US National Health and Nutrition Examination Survey (NHANES). This dataset included information on the duration of SB and PA, derived from ActiGraph accelerometers, as well as self-reported sleep duration. The assessment of CVH was conducted in accordance with the criteria outlined in Life's Simple 7, encompassing the evaluation of both health behaviors and health factors. Compositional linear regression was utilized to examine the cross-sectional associations of 24-hour movement behaviors and each component with CVH score. Furthermore, the study predicted the potential differences in CVH score that would occur by reallocating 10 to 60 min among different movement behaviors.

RESULTS

A significant association was observed between 24-hour movement behaviors and overall CVH (p < 0.001) after adjusting for potential confounders. Substituting moderate-to-vigorous physical activity (MVPA) for other components was strongly associated with favorable differences in CVH score (p < 0.05), whether in one-for-one reallocations or one-for-remaining reallocations. Allocating time away from MVPA consistently resulted in larger negative differences in CVH score (p < 0.05). For instance, replacing 10 min of light physical activity (LPA) with MVPA was related to an increase of 0.21 in CVH score (95% confidence interval (95% CI) 0.11 to 0.31). Conversely, when the same duration of MVPA was replaced with LPA, CVH score decreased by 0.67 (95% CI -0.99 to -0.35). No such significance was discovered for all duration reallocations involving only LPA, SB, and sleep (p > 0.05).

CONCLUSIONS

MVPA seems to be as a pivotal determinant for enhancing CVH among general adult population, relative to other movement behaviors. Consequently, optimization of MVPA duration is an essential element in promoting overall health and well-being.

Proportion and Correlates of Children in the US-Affiliated Pacific Region Meeting Sleep, Screen Time, and Physical Activity Guidelines

INTRODUCTION

Limited data on 24-hour movement behaviors of children aged 5-8 years exist globally. We describe the prevalence and sociodemographic associations of meeting physical activity (PA), sedentary recreational screen time (ST), and sleep guidelines among children from 11 jurisdictions in the US-Affiliated Pacific region.

METHODS

Cross-sectional representative data from 1192 children aged 5-8 years living in the US-Affiliated Pacific region were drawn from the baseline 2012-2014 Children's Healthy Living Program. Sleep and moderate- to vigorous-intensity PA were calculated from accelerometry. ST and sociodemographic data were collected from caregiver surveys. The percentage of children meeting the Asia-Pacific 24-hour movement guidelines for PA (≥60 min/d of moderate- to vigorous-intensity PA), sleep (≥9 and ≤ 11 h/d) and ST (≤2 h/d) were calculated. Generalized linear mixed models were used to examine associations with adiposity and sociodemographic variables.

RESULTS

Twenty-seven percent (95% confidence interval, 24.6-30.0) of children met integrated guidelines; 98% (96.2-98.0) met PA, 78% (75.4-80.0) met sleep, and 35% (32.6-38.0) met ST guidelines. Females (adjusted odds ratio = 1.40 [95% confidence interval, 1.03-1.91]) and those living in lower-middle-income jurisdictions (2.29 [1.49-3.54]) were more likely to meet ST guidelines. Overweight children (0.62 [0.40-0.96]), those aged 8 years (0.39 [0.22-0.69]), and children with caregivers of an education level of high school or beyond (0.44 [0.29-0.68]) were less likely to achieve ST guidelines. Children from midrange annual household incomes were less likely to meet combined guidelines (0.60 [0.39-0.92]).

CONCLUSIONS

Three-quarters of children are not meeting integrated Asia-Pacific 24-hour movement guidelines. Future strategies for reducing ST and increasing integrated guidelines compliance are needed.

Time Reallocations From Sedentary Behavior to Physical Activity and Cardiovascular Risk Factors in Children and Adolescents: A Systematic Review

BACKGROUND

Recent statistical approaches have allowed consideration of the integrated relationships between sedentary behavior (SB) and physical activity (PA) with different health outcomes. The present paper aimed to systematically review the literature and synthesize evidence about associations between hypothetical reallocations from SB to different PA intensities and cardiovascular risk factors in youth.

METHODS

A systematic search of 8 databases was performed. Observational studies with a population of children and/or adolescents and based on statistical analysis that investigated the associations between time reallocations from SB to PA and cardiovascular risk factors were included.

RESULTS

Twenty-eight studies met the inclusion criteria. Level of evidence (derived from cross-sectional studies) indicated that the reallocation from SB to moderate to vigorous PA was beneficially associated with adiposity, cardiorespiratory fitness, and cardiometabolic biomarkers in youth. Reallocation from SB to light PA was not associated with the analyzed outcomes. Associations derived from longitudinal studies were mostly inconclusive.

CONCLUSION

Cardiovascular risk factors could be improved by increasing moderate to vigorous PA at the expense of time spent in SB in pediatric populations. Prospective studies or studies investigating the effects of reallocating sedentary bouts to PA are needed.

The relative contributions of soft tissue mass components as risk or protective factors of non-alcoholic fatty liver disease in children

BACKGROUND/OBJECTIVE

Several body components are known to be associated with non-alcoholic fatty liver disease (NAFLD) in children. However, the relative contributions of soft tissue mass components as risk or protective factors of NAFLD are largely unknown because measurements of these components are often highly correlated. Therefore, we aimed to estimate levels of association between soft tissue mass components and NAFLD.

SUBJECTS/METHODS

We collected the medical records of 555 Chinese children (aged 3-18 years). Five mutually exclusive and exhaustive components of soft tissue mass were measured using dual energy X-ray absorptiometry. NAFLD was diagnosed with abdominal B-ultrasound scan. We fit Dirichlet regression and multivariate linear regression models wherein age and NAFLD were used as predictors of the proportional measurements of soft tissue mass components.

RESULTS

The proportion of android fat was significantly higher in children with NAFLD than in those without NAFLD (ratio of proportions ranged from 1.18 to 1.30), whereas proportions of trunk lean and limb lean were significantly lower (ratio of proportions ranged from 0.87 to 0.92 for trunk lean and from 0.82 to 0.91 for limb lean). The proportion of gynoid fat was slightly higher in boys with NAFLD than in those without NAFLD (ratio = 1.05), but this proportion was not significantly higher in girls. The association between the proportion of android fat and NAFLD appeared to be somewhat greater than the associations between proportions of trunk lean or limb lean components and NAFLD.

CONCLUSION

Our findings suggest that lowering fat mass and increasing lean mass can both be used to combat NAFLD in children and that more studies are needed to determine the association between gynoid fat and NAFLD.

The association between reallocations of time and health using compositional data analysis: a systematic scoping review with an interactive data exploration interface

BACKGROUND

How time is allocated influences health. However, any increase in time allocated to one behaviour must be offset by a decrease in others. Recently, studies have used compositional data analysis (CoDA) to estimate the associations with health when reallocating time between different behaviours. The aim of this scoping review was to provide an overview of studies that have used CoDA to model how reallocating time between different time-use components is associated with health.

METHODS

A systematic search of four electronic databases (MEDLINE, Embase, Scopus, SPORTDiscus) was conducted in October 2022. Studies were eligible if they used CoDA to examine the associations of time reallocations and health. Reallocations were considered between movement behaviours (sedentary behaviour (SB), light physical activity (LPA), moderate-to-vigorous physical activity (MVPA)) or various activities of daily living (screen time, work, household chores etc.). The review considered all populations, including clinical populations, as well as all health-related outcomes.

RESULTS

One hundred and three studies were included. Adiposity was the most commonly studied health outcome (n = 41). Most studies (n = 75) reported reallocations amongst daily sleep, SB, LPA and MVPA. While other studies reported reallocations amongst sub-compositions of these (work MVPA vs. leisure MVPA), activity types determined by recall (screen time, household chores, passive transport etc.) or bouted behaviours (short vs. long bouts of SB). In general, when considering cross-sectional results, reallocating time to MVPA from any behaviour(s) was favourably associated with health and reallocating time away from MVPA to any behaviour(s) was unfavourably associated with health. Some beneficial associations were seen when reallocating time from SB to both LPA and sleep; however, the strength of the association was much lower than for any reallocations involving MVPA. However, there were many null findings. Notably, most of the longitudinal studies found no associations between reallocations of time and health. Some evidence also suggested the context of behaviours was important, with reallocations of leisure time toward MVPA having a stronger favourable association for health than reallocating work time towards MVPA.

CONCLUSIONS

Evidence suggests that reallocating time towards MVPA from any behaviour(s) has the strongest favourable association with health, and reallocating time away from MVPA toward any behaviour(s) has the strongest unfavourable association with health. Future studies should use longitudinal and experimental study designs, and for a wider range of outcomes.

Combinations of Physical Activity, Sedentary Behavior, and Sleep Duration and Their Associations With Physical, Psychological, and Educational Outcomes in Children and Adolescents: A Systematic Review

We conducted a systematic review to evaluate combinations of physical activity, sedentary behavior, and sleep duration (defined as "movement behaviors") and their associations with physical, psychological, and educational outcomes in children and adolescents. MEDLINE, CINAHL, PsychInfo, SPORTDiscus, PubMed, EMBASE, and ERIC were searched in June 2020. Included studies needed to 1) quantitatively analyze the association of 2 or more movement behaviors with an outcome, 2) analyze a population between 5 and 17 years of age, and 3) include at least an English abstract. We included 141 studies. Most studies included the combination of physical activity and sedentary behavior in their analyses. Sleep was studied less frequently. In combination, a high level of physical activity and a low level of sedentary behavior were associated with the best physical health, psychological health, and education-related outcomes. Sleep was often included in the combination that was associated with the most favorable outcomes. Sedentary behavior had a stronger influence in adolescents than in children and tended to be associated more negatively with outcomes when it was defined as screen time than when defined as overall time spent being sedentary. More initiatives and guidelines combining all 3 movement behaviors will provide benefit with regard to adiposity, cardiometabolic risk factors, cardiorespiratory fitness, muscular physical fitness, well-being, health-related quality of life, mental health, academic performance, and cognitive/executive function.

Associations between 24-h movement behaviours and BMI in Chinese primary- and middle- school students

Purposes

This cross-sectional study aimed to examine the associations between the 24-h movement behaviours and body mass index (BMI) of students from China by using compositional data analysis.

Methods

A total of 389 students aged 6-16 years participated in this study. Accelerometers were used to measure moderate-to-vigorous physical activity (MVPA), light-intensity physical activity (LPA), sedentary behaviour (SED), and sleep. Weight and height were objectively measured. The association between 24-h movement and BMI was analyzed by using compositional data analysis.

Results

Time reallocation using minutes and proportions created major differences to the results. Reallocating 10 min from other movement behaviours to MVPA was associated with decreased BMI z-score of 1.372 to 0.158 among primary-school students. Reallocating 10 min from sleep and SED to MVPA, and from sleep and SED to LPA were associated with decreased BMI z-score of 0.505 to 0.017 among middle-school students. Reallocating 10% of time from all other components to SED and sleep were associated with a higher BMI z-score by 0.148 (95%CI: 0.020; 0.276) and 0.125 (95%CI: 0.046; 0.204), while reallocating time to MVPA was associated with a decrease in BMI z-scores of 0.132 (95%CI: -0.193; -0.070) among primary-school students. Reallocating 10% of time from all other components to SED was associated with a higher BMI z-score of 0.254 (95%CI: 0.165; 0.345), whereas reallocating time to MVPA and LPA was associated with a decrease in BMI z-scores of 0.039 (95%CI: -0.073; -0.005) and 0.093 (95%CI: -0.153; -0.033) among middle-school students.

Conclusion

Research results of 10-min one-to-one reallocation may be treated cautiously due to uneven distribution of time in 24-h movement behaviours. Based on the results of 10% one-to-remaining reallocation, replacing SED with MVPA may be an appropriate target for adiposity intervention in primary-school students, while increasing MVPA or LPA at the expense of SED may be effective in controlling adiposity of middle-school students in China.

Longitudinal associations of movement behaviours with body composition and physical fitness from 4 to 9 years of age: structural equation and mediation analysis with compositional data

BACKGROUND

The associations of movement behaviours (physical activity [PA], sedentary behaviour [SB], and sleep) with body composition and physical fitness from pre-school to childhood, as well as the direction of the associations, could provide important information for healthy lifestyle promotion in children. This study investigated the longitudinal and bidirectional associations of movement behaviours with body composition and physical fitness measured at 4 and 9 years of age.

METHODS

This longitudinal study included baseline (n = 315, 4.5 [SD = 0.1] years) and follow-up data (n = 231, 9.6 [SD = 0.1] years) from the MINISTOP study. Movement behaviours were measured for 7 days using wrist-worn accelerometers, body composition with air-displacement plethysmography, and physical fitness with the ALPHA health-related fitness test battery. Cross-lagged panel models and mediation analyses were performed in combination with compositional data analysis.

RESULTS

We did not observe direct associations of the movement behaviours at 4 years with either body composition or physical fitness at 9 years (all P > 0.05). However, fat mass index at 4 years was negatively associated with vigorous PA (VPA), relative to remaining behaviours (VPA, β = - 0.22, P = 0.002) and light PA (LPA), relative to SB and sleep (β = - 0.19, P = 0.016) at 9 years. VPA (relative to remaining), moderate PA (MPA) (relative to LPA, SB, and sleep), and SB (relative to sleep) tracked from 4 to 9 years (all β ≥ 0.17, all P < 0.002), and these behaviours shared variance with fat mass index (all|β| ≥ 0.19, all P < 0.019), and aerobic, motor, and muscular fitness (all|β| ≥ 0.19, all P < 0.014) at 9 years. Mediation analysis suggested that the tracking of VPA (relative to remaining behaviours) from 4 to 9 years was negatively associated with fat mass index (β ≥ - 0.45, P = 0.012), and positively with aerobic fitness at 9 years (β ≥ 1.64, P = 0.016).

CONCLUSION

PA and SB tracked from the pre-school years into childhood. Fat mass index at 4 years of age was negatively associated with VPA (relative to remaining behaviours) and LPA (relative to SB and sleep) at 9 years of age. The tracking of VPA was associated with lower fat mass index and higher aerobic fitness at 9 years of age. These findings suggest that higher levels of VPA in pre-school age, if maintained throughout childhood, may support the development of healthy body composition and aerobic fitness levels in later childhood.

A 24-h activity profile and adiposity among children and adolescents: Does the difference between school and weekend days matter?

BACKGROUND

Twenty-four-hour movement behaviours are gaining attention in the research community. However, no study has addressed how 24-h activity profiles vary between structured and less structured days and whether an unfavourable activity profile is associated with childhood obesity. We aimed to analyse differences between school day and weekend day 24-h activity profiles and their associations with adiposity indicators among children and adolescents.

METHODS

Participants were 382 children and 338 adolescents who wore wrist accelerometers for 24 hours a day for seven consecutive days. The 24-h activity profile expressed by the average acceleration (AvAcc) and intensity gradient (IG) were estimated from multi-day raw accelerometer data. Adiposity indicators included body mass index (BMI) z-score, fat mass percentage (FM%), fat mass index (FMI), and visceral adipose tissue (VAT). Multiple linear regression of activity profile metrics and adiposity indicators was performed separately for school and weekend days.

RESULTS

Weekend days AvAcc and IG were lower compared to school days in both age groups (p <0.001 for all). Specifically, AvAcc was lower by 9.4% and 11.3% in children and adolescents, respectively. IG on weekend days was lower (more negative) by 3.4% in children and 3.1% in adolescents. Among children, on school days AvAcc and IG were negatively associated with FM%, FMI, and VAT, whilst on weekend days AvAcc was positively associated with BMI z-score, FMI, and VAT (p < 0.05 for all). Among adolescents, negative associations were found between weekend day AvAcc and IG and FM% and FMI (p < 0.05 for all), respectively.

CONCLUSIONS

This study confirms the importance of 24-h activity profile as a potentially protective factor against excess adiposity. The variability of movement behaviours during structured and less structured days should be considered when optimizing the 24-h movement behaviours to prevent childhood obesity.

Physical activity, sedentary behaviour, and sleep in the Thai population: A compositional data analysis including 135,824 participants from two national time-use surveys

PURPOSE

To determine the amounts of time spent in physical activity (PA), sedentary behaviour (SB), and sleep in the Thai population, as well as their sociodemographic correlates and changes over time.

METHODS

We analysed cross-sectional data collected in a population-representative, stratified random sample of 135,824 Thais aged 10 years and over as part of the two most recent Thai National time-use surveys (2009 and 2015). Daily activities reported by the participants were coded using the International Classification of Activities for Time-Use Statistics (ICATUS) and categorised as PA, SB, or sleep.

RESULTS

In the latest survey, participants spent on average the largest amount of time sleeping (geometric mean [g] = 9.44 h/day; 95% confidence interval [CI]: 9.42, 9.47), followed by PA (g = 8.60 h/day; 95% CI: 8.55, 8.64) and SB (g = 5.96 h/day; 95% CI: 5.93, 6.00). The time spent in PA was higher on weekdays, while the amounts of SB and sleep were higher on weekends (p < 0.05). Males, older age groups, and unemployed people spent less time in PA and more time in SB, compared with other population groups (p < 0.05). We found a relatively large increase in SB (mean difference [d] = 39.64 min/day; 95% CI: 36.18, 42.98) and decrease in PA (d = 54.33 min/day; 95% CI: -58.88, -49.30) over time. These findings were consistent across most sociodemographic groups, with the most concerning shifts from active to sedentary lifestyle found among people with a higher education degree and on weekends.

CONCLUSIONS

Our findings revealed a shift to a more sedentary lifestyle in the Thai population. Public health interventions should focus on improving time use among males, older age groups, and unemployed people, while preventing the rapid decrease in PA and increase in SB among those with a higher education degree and on weekends.

iEngage: A digital health education program designed to enhance physical activity in young adolescents

iEngage is a modular health education and behavioural change program designed to help adolescents increase moderate to vigorous physical activity (MVPA). The program is delivered through the iEngage app which integrates activity trackers data (Misfit Ray^©) within 10 interactive learning modules. Key features include guidance to set goals, self-monitor and assess achievements, and experiential learning via the connected activity trackers which allows for continuous steps recording during the program. iEngage was implemented in two schools over 5 weeks with 10–12 years old adolescents (n = 57) and PA outcomes compared to control group (n = 26). Results show that adolescents successfully set goals and self-assessed achievements during the program, progressing toward higher physical activity (PA) levels as shown by the 30% increase in daily steps through the program (+ 2647 steps/day, P < .001) with boys increasing goals and achievements faster than girls. The consistency in days totalling at least 11,000 steps/day increased from 35% at the start to 48% at the end of the program. The increase in PA is confirmed through the assessment of MVPA during schooldays pre- and post- program via research grade wrist accelerometers in both iEngage and control participants. Contrasting with the control group, MVPA was increased in the week following the program (~+5 min/day, P = .023) in short bouts, particularly during lunch time, recess and after school. This study shows that a digital program integrating activity trackers data, health education, goals setting and self-monitoring of PA, helped young adolescents enhance PA goals, improve achievements and increase MVPA.

Sociodemographic differences in 24-hour time-use behaviours in New Zealand children

BACKGROUND

The time that children spend in physical activity, sedentary behaviour, and sleep each day (i.e., 24-h time-use behaviours), is related to physical and mental health outcomes. Currently, there is no comprehensive evidence on New Zealand school-aged children's 24-h time-use behaviours, adherence to the New Zealand 24-h Movement Guidelines, and how these vary among different sociodemographic groups.

METHODS

This study utilises data from the 8-year wave of the Growing Up in New Zealand longitudinal study. Using two Axivity AX3 accelerometers, children's 24-h time-use behaviours were described from two perspectives: activity intensity and activity type. Compositional data analysis techniques were used to explore the differences in 24-h time-use compositions across various sociodemographic groups.

RESULTS

Children spent on average, 31.1%, 22.3%, 6.8%, and 39.8% of their time in sedentary, light physical activity, moderate-to-vigorous physical activity, and sleep, respectively. However, the daily distribution of time in different activity types was 33.2% sitting, 10.8% standing, 7.3% walking, 0.4% running, and 48.2% lying. Both the activity intensity and activity type compositions varied across groups of child ethnicity, gender, and household income or deprivation. The proportion of children meeting each of the guidelines was 90% for physical activity, 62.5% for sleep, 16% for screen time, and 10.6% for the combined guidelines. Both gender and residence location (i.e., urban vs. rural) were associated with meeting the physical activity guideline, whereas child ethnicity, mother's education and residence location were associated with meeting the screen time guideline. Child ethnicity and mother's education were also significantly associated with the adherence to the combined 24-h Movement Guidelines.

CONCLUSIONS

This study provided comprehensive evidence on how New Zealand children engage in 24-h time-use behaviours, adherence to the New Zealand 24-h Movement Guidelines, and how these behaviours differ across key sociodemographic groups. These findings should be considered in designing future interventions for promoting healthy time-use patterns in New Zealand children.

The Physical Behaviour Intensity Spectrum and Body Mass Index in School-Aged Youth: A Compositional Analysis of Pooled Individual Participant Data

We examined the compositional associations between the intensity spectrum derived from incremental acceleration intensity bands and the body mass index (BMI) z-score in youth, and investigated the estimated differences in BMI z-score following time reallocations between intensity bands. School-aged youth from 63 schools wore wrist accelerometers, and data of 1453 participants (57.5% girls) were analysed. Nine acceleration intensity bands (range: 0−50 mg to ≥700 mg) were used to generate time-use compositions. Multivariate regression assessed the associations between intensity band compositions and BMI z-scores. Compositional isotemporal substitution estimated the differences in BMI z-score following time reallocations between intensity bands. The ≥700 mg intensity bandwas strongly and inversely associated with BMI z-score (p < 0.001). The estimated differences in BMI z-score when 5 min were reallocated to and from the ≥700 mg band and reallocated equally among the remaining bands were −0.28 and 0.44, respectively (boys), and −0.39 and 1.06, respectively (girls). The time in the ≥700 mg intensity band was significantly associated with BMI z-score, irrespective of sex. When even modest durations of time in this band were reallocated, the asymmetrical estimated differences in BMI z-score were clinically meaningful. The findings highlight the utility of the full physical activity intensity spectrum over a priori-determined absolute intensity cut-point approaches.

Changes in sedentary behavior patterns during the transition from childhood to adolescence and their association with adiposity: a prospective study based on compositional data analysis

Background

To date, no longitudinal study using a compositional approach has examined sedentary behavior (SB) patterns in relation to adiposity in the pediatric population. Therefore, our aims were to (1) investigate the changes in SB patterns and adiposity from childhood to adolescence, (2) analyze the prospective compositional associations between changes in SB patterns and adiposity, and (3) estimate the changes in adiposity associated with substituting SB with physical activity (PA) of different intensities.

Methods

The study presents a longitudinal design with a 5-year follow-up. A total of 88 participants (61% girls) were included in the analysis. PA and SB were monitored for seven consecutive days using a hip-worn accelerometer. Adiposity markers (fat mass percentage [FM%], fat mass index [FMI], and visceral adiposity tissue [VAT]) were assessed using the multi-frequency bioimpedance analysis. The prospective associations were examined using compositional data analysis.

Results

Over the follow-up period, the proportion of time spent in total SB increased by 154.8 min/day (p < 0.001). The increase in total SB was caused mainly by an increase in middle and long sedentary bouts, as these SB periods increased by 79.8 min/day and 62.0 min/day (p < 0.001 for both), respectively. FM%, FMI, and VAT increased by 2.4% points, 1.0 kg/m², and 31.5 cm² (p < 0.001 for all), respectively. Relative to the remaining movement behaviors, the increase in time spent in middle sedentary bouts was significantly associated with higher FM% (β_ilr1 = 0.27, 95% confidence interval [CI]: 0.02 to 0.53) at follow-up. Lower VAT by 3.3% (95% CI: 0.8 to 5.7), 3.8% (95% CI: 0.03 to 7.4), 3.9% (95% CI: 0.8 to 6.9), and 3.8% (95% CI: 0.7 to 6.9) was associated with substituting 15 min/week spent in total SB and in short, middle, and long sedentary bouts, respectively, with an equivalent amount of time spent in vigorous PA.

Conclusions

This study showed unfavorable changes in SB patterns and adiposity status in the transition from childhood to adolescence. Incorporating high-intensity PA at the expense of SB appears to be an appropriate approach to reduce the risk of excess adiposity in the pediatric population.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13690-021-00755-5.

Relative associations of abdominal and thigh compositions with cardiometabolic diseases in African Caribbean men

BACKGROUND

Regional body compositions are differentially associated with cardiometabolic risk factors. Simultaneous inclusion of both upper and lower body composition predictors in models is not often done, and studies which do include both measures (1) tend to exclude some tissue(s) of potential metabolic relevance, and (2) have used study populations with underrepresentation of individuals with African ancestries. Further, most body composition analyses do not employ compositional data analytic approaches, which may result in spurious associations.

OBJECTIVE

The objective of this analysis was to assess associations of abdominal and thigh adipose (AT) and muscle tissues with hypertension and type 2 diabetes using compositional data analytic methods.

RESEARCH DESIGN AND METHODS

This cross-sectional analysis included 610 African Caribbean men (median age: 62 years; mean BMI: 27.8 kg/m2). Abdominal (three components: subcutaneous [ASAT] and visceral [VAT] AT, 'other' abdominal tissue) and mid-thigh (four components: subcutaneous and intermuscular AT, muscle, bone) compositions were measured by computed tomography; additive log ratio transformations were applied to each composition. Regression models were used to simultaneously assess associations of abdominal and thigh component ratios with continuous risk factors (blood pressures, fasting glucose and insulin, HOMA-IR) and disease categories.

RESULTS

A two-fold increase in ASAT:'Other' ratio was associated with higher continuous risk factors and with odds of being in a higher hypertension (OR: 1.77, 95%CI: 1.10-2.84) or diabetes (OR: 1.81, 95%CI: 1.06-3.10) category. A two-fold increased VAT ratio was only associated with higher log-insulin and log-HOMA-IR (β = 0.10, p < 0.05 for both), while a two-fold increased thigh muscle:bone ratio was associated with a lower diabetes category (OR: 0.37, 95%CI: 0.14-1.01).

CONCLUSIONS

These findings support ASAT as a significant driver of cardiometabolic disease in African Ancestry populations, independent of other abdominal and thigh tissues.

The effect of replacing sedentary behavior by different intensities of physical activity in body composition: a systematic review

Introduction: The isotemporal substitution model (ISM) is a statistical approach that estimates the effects of replacing, in minutes, a block of physical activity or sedentary behavior by another block with different intensity. Previous studies have used the ISM to evaluate the effect of different isotemporal substitutions on body composition. Thus, the ISM can contribute to the understanding of changes in body composition related to distinct lifestyles and, hence, guiding future recommendations for maintaining and/or improving body composition. Objective: To review the effect of replacing sedentary behavior by physical activity on body composition change analyzed through ISM. Methods: Original articles in English were identified from searches in PubMed and Periódicos Capes databases. The search was carried out by two researchers. Last search was performed in October 2020. Results: A total of 17 included articles, which evaluated different applications of ISM in relation to body composition change, mostly obtained by BMI and body fat. The physical activity was mainly assessed by using an accelerometer. Several methodological differences among the included studies limited comparisons between findings, including the sample profile and cut off points for physical activity. Conclusion: Among the studies that evaluate the effect of replacing sedentary behavior for different intensities of physical activity through ISM, replacing sedentary behavior by moderate-to-vigorous physical activity presented a more consistent effect in body composition change in comparison to replacement by other physical activity intensities, even for small blocks of time (five minutes).

The Associations Between Daily Activities and Affect: a Compositional Isotemporal Substitution Analysis

BACKGROUND

Daily activities are associated with affective experiences. A 24-h day can be separated into five mutually exclusive activity types: sleep, awake in bed, moderate-to-vigorous physical activity (MVPA), light-intensity physical activity (LIPA), and sedentary behavior (SB). Most research has examined these activities independently and not collectively, yet increased time in one activity must be offset by decreasing other activities. Using compositional isotemporal substitution analyses, this study examined the associations between time spent in daily activities and affect, including both high and low arousal positive and negative affect.

METHOD

Across three separate studies, daily activities and affect were measured throughout 7-15 days (M_days = 10) in 361 healthy community adults (72.5% females, M_age = 22.79 years). Activities were objectively assessed using accelerometry and self-reported affect was assessed using repeated ecological momentary assessments. Minutes spent in each activity and affect values across the three studies were averaged for each participant.

RESULTS

Longer sleep duration at the expense of time awake in bed was associated with lower high arousal negative affect (e.g., nervousness, b =  - 0.24, p = .007). More MVPA at the expense of LIPA or SB was associated with higher high arousal positive affect (e.g., happiness, b = 0.35, p = .027). Activity composition was not associated with low arousal positive or negative affect (all p ≥ .06).

CONCLUSION

Associations between 24-h activity composition and affect differed based on types of activities, types of affect, and the interrelationships between activities within the composition. Findings can aid interventions to develop integrated guidance on the optimal activity patterns for mental health.

Relationships of physical activity and sedentary behaviour with the previous and subsequent nights' sleep in children and youth: A systematic review and meta-analysis

The interrelationships between sleep and daytime movement behaviours have been examined at interindividual level. Studies of within-person, temporal relationships of daytime physical activity (PA) and sedentary behaviour with the previous and subsequent nights' sleep are increasing. The present systematic review and meta-analysis synthesised the results of studies in school-aged children and youth. Eight databases (MEDLINE, PsycINFO, EMBASE, Global Health, PubMed, Web of Science, SPORTDiscus, and CINAHL) were searched for peer-reviewed articles that examined the association between daytime movement behaviours (including PA, sedentary time, or sedentary recreational screen time) and night-time sleep on the same day, or the association between night-time sleep and daytime movement behaviours the next day, in children and youth. A total of 11 studies comprising 9,622 children and youth aged 5-15 years met the inclusion criteria. Sedentary time was negatively associated with the subsequent night's sleep duration (r = -0.12, 95% confidence interval -0.23 to -0.00; I²  = 93%; p = .04). Positive relationships between PA and the previous or subsequent night's sleep duration were observed only for studies that adjusted for accelerometer wear time. There was some evidence suggesting that a longer sleep duration was associated with less sedentary time and a higher proportion of the daytime spent being physically active and vice versa, although the association was weak and based on a limited number of studies. From a clinical perspective, promotion of either sleep hygiene or daytime PA should be planned with considerations of the virtuous or vicious circle between these behaviours and monitor concurrent effects on the others.

Helping Children with Obesity "Move Well" To Move More: An Applied Clinical Review

ABSTRACT

Children with obesity experience musculoskeletal pain and reduced physical function and well-being, which collectively impact their fitness, strength, motor skills, and even their ability to undertake simple tasks, like walking and climbing stairs. Disrupting obesity-related disability may be critical to increasing children's physical activity. Thus, barriers to movement should be considered by health practitioners to improve the efficacy of prescribed physical activity. This applied clinical review highlights key subjective and objective findings from a hypothetical case scenario, linking those findings to the research evidence, before exploring strategies to enhance movement and increase physical activity.

Cross-Sectional and Longitudinal Associations between 24-Hour Movement Behaviours, Recreational Screen Use and Psychosocial Health Outcomes in Children: A Compositional Data Analysis Approach

It remains unclear whether the time-use composition of 24-h movement behaviours (sleep, sedentary time (ST), physical activity (PA)) and recreational screen use are independently associated with psychosocial health. This study examined the cross-sectional and longitudinal associations between 24-h movement behaviour composition, recreational screen use and psychosocial health outcomes in children. Measures completed at baseline (n = 127; 11.7 years) and follow-up (n = 88; 12.8 years) included accelerometer-based 24-h movement behaviours, self-reported recreational screen use and psychosocial health (Strengths and Difficulties Questionnaire, Kessler’s Psychological Distress Scale). Linear mixed models were used to examine the cross-sectional and longitudinal associations between the 24-h movement behaviour composition and recreational screen use levels with psychosocial health outcomes. Overall, the movement behaviour composition (p < 0.05) and recreational screen use levels (p < 0.01) were both cross-sectionally but not longitudinally associated with psychosocial health outcomes. Relative to other behaviours, sleep was negatively associated, while light-intensity PA was positively associated with internalising problems and total difficulties scores. ST was positively associated with internalising problems. High levels of recreational screen use (>2 h/day) were associated with greater externalising problems, total difficulties scores and psychological distress. These findings reinforce the importance of achieving a balance between different types of movement behaviours over a 24-h period for psychosocial health.

Changes in 24-hour movement behaviours during the transition from primary to secondary school among Australian children

This study examined concurrent changes in all components of 24-h movement behaviours (24-h MB) (sleep, sedentary behaviour [SB] and physical activity [PA]) and compliance with the Australian 24-Hour Movement Guidelines over the primary to the secondary school transition period. The analytical sample included 83 children (60.2% girls) who provided valid accelerometer-measured 24-h MB data during their final year of primary school (T1) and first year of secondary school (T2). Self-reported participation in domain-specific SB and PA, socio-demographic characteristics and weight status were also assessed. Change in 24-h MB composition from T1 to T2 was analysed using a compositional multivariate linear model for repeated measures. The difference in the proportion of meeting the 24-hour integrated movement guidelines was assessed using a McNemar-Bowker test. An unfavourable change was observed in the 24-h MB composition (p < .0001), with increased time spent in SB (+58 min/day) and decreased time in sleep (-13 min/day), Iight-intensity PA (-13 min/day) and moderate- to vigorous-intensity PA (-14 min/day). Domain-specific SB results indicated an increase in recreational screen time (+45 min/day) and out-of-school educational activities (+25 min/day). No significant changes were observed for domain-specific PA. The proportion of children meeting the 24-hour integrated movement guidelines also declined (20.5% vs. 3.6%; p < .0001). Change in 24-h MB was larger on weekdays than weekends (p < .0001); but this was not moderated by socio-demographic characteristics or weight status. These findings suggest that an integrated intervention approach targeting weekdays may be beneficial to promote adherence to healthy 24-h MB during the primary to the secondary school transition period. HighlightsThis study investigated how the 24-hour movement behaviour composition (i.e., time spent in sleep, sedentary behaviour and physical activity) changes and its impact on children's compliance with the 24-hour integrated movement guidelines during the primary to secondary school transition period.There was an unfavourable change in the accelerometer-measured 24-hour movement behaviour composition, with increased time spent in sedentary behaviour and decreased time in sleep, light-intensity physical activity and moderate- to vigorous-intensity physical activity. The change in weekday composition was significantly more prominent than change on weekends.The observed increase in sedentary behaviour may be attributed in part to an increase in recreational screen time and out-of-school educational activities in secondary schools.These behavioural changes were reflected in decreased compliance rates with the individual and integrated 24-hour movement guidelines, with the largest decline observed in the sleep guideline.Our findings highlight the need for an integrated intervention approach to support children to develop and/or maintain healthy movement behaviour habits throughout the school transition period.

Daily Physical Activity in Children and Adolescents with Low Lumbar and Sacral Level Myelomeningocele

PURPOSE

Children with low lumbar and sacral level myelomeningocele are expected to be community ambulators. However, they do not always meet the expected ambulation level by the time they reach adulthood. The purpose of this study is to investigate daily activity energy expenditure and physical activity levels of these patients in daily routine.

MATERIALS AND METHODS

20 patients and 20 healthy peers were included in this case-control study. Omnidirectional accelerometer monitor was used for assessing activity energy expenditure, and daily durations spent in sedentary, light activity, and moderate to vigorous physical activity levels (NCT04186338).

RESULTS

Mean activity energy expenditure and moderate to vigorous physical activity duration were significantly lower in the patient group, while age was positively correlated with sedentary time and negatively correlated with light activity time.

CONCLUSIONS

In patients with myelomeningocele, increasing daily activity energy expenditure and moderate to vigorous physical activity and, especially as age progresses, decreasing the sedentary behavior may assist in providing the expected ambulation level. These patients should be encouraged to partake in regular exercise programs.

Compositional Associations of Sleep and Activities within the 24-h Cycle with Cardiometabolic Health Markers in Adults

PURPOSE

This study aimed to examine how compositions of 24-h time use and time reallocations between movement behaviors are associated with cardiometabolic health in a population-based sample of middle-age Finnish adults.

METHODS

Participants were 3443 adults 46 yr of age from the Northern Finland Birth Cohort 1966 study. Participants wore a hip-worn accelerometer for 14 d from which time spent in sedentary behavior (SB), light-intensity physical activity (LPA), and moderate- to vigorous-intensity physical activity (MVPA) were determined. These data were combined with self-reported sleep to obtain the 24-h time-use composition. Cardiometabolic outcomes included adiposity markers, blood lipid levels, and markers of glucose control and insulin sensitivity. Multivariable-adjusted regression analysis, using a compositional data analysis approach based on isometric log-ratio transformation, was used to examine associations between movement behaviors with cardiometabolic outcomes.

RESULTS

More daily time in MVPA and LPA, relative to other movement behaviors, was consistently favorably associated with all cardiometabolic outcomes. For example, relative to time spent in other behaviors, 30 min·d-1 more MVPA and LPA were both associated with lower 2-h post-glucose load insulin level (-11.8% and -2.7%, respectively). Relative to other movement behaviors, more daily time in SB was adversely associated with adiposity measures, lipid levels, and markers of insulin sensitivity, and more daily time asleep was adversely associated with adiposity measures, blood lipid, fasting plasma glucose, and 2-h insulin. For example, 60 min·d-1 more SB and sleep relative to the remaining behaviors were both associated with higher 2-h insulin (3.5% and 5.7%, respectively).

CONCLUSIONS

Altering daily movement behavior compositions to incorporate more MVPA at the expense of any other movement behavior, or more LPA at the expense of SB or sleep, could help to improve cardiometabolic health in midadulthood.

Balancing time use for children's fitness and adiposity: Evidence to inform 24-hour guidelines for sleep, sedentary time and physical activity

PURPOSE

Daily time spent on one activity cannot change without compensatory changes in others, which themselves may impact on health outcomes. Optimal daily activity combinations may differ across outcomes. We estimated optimal daily activity durations for the highest fitness and lowest adiposity.

METHODS

Cross-sectional Child Health CheckPoint data (1182 11-12-year-olds; 51% boys) from the population-based Longitudinal Study of Australian Children were used. Daily activity composition (sleep, sedentary time, light physical activity [LPA], moderate-to-vigorous physical activity [MVPA]) was from 8-day, 24-hour accelerometry. We created composite outcomes for fitness (VO2max; standing long jump) and adiposity (waist-to-height ratio; body mass index; fat-to-fat-free log-ratio). Adjusted compositional models regressed activity log-ratios against each outcome. Best activity compositions (optimal time-use zones) were plotted in quaternary tetrahedrons; the overall optimal time-use composition was the center of the overlapping area.

RESULTS

Time-use composition was associated with fitness and adiposity (all measures p<0.001). Optimal time use differed for fitness and adiposity. While both maximized MVPA and minimized sedentary time, optimal fitness days had higher LPA (3.4 h) and shorter sleep (8.25 h), but optimal adiposity days had lower LPA (1.0 h) and longer sleep (10.9 h). Balancing both outcomes, the overall optimal time-use composition was (mean [range]): 10.2 [9.5; 10.5] h sleep, 9.9 [8.8; 11.2] h sedentary time, 2.4 [1.8; 3.2] h LPA and 1.5 [1.5; 1.5] h MVPA.

CONCLUSION

Optimal time use for children's fitness and adiposity involves trade-offs. To best balance both outcomes, estimated activity durations for sleep and LPA align with, but for MVPA exceed, 24-h guidelines.

The whole day matters: Understanding 24-hour movement guideline adherence and relationships with health indicators across the lifespan

BACKGROUND

New research suggests that the composition (mix) of movement behaviors within a 24-h period may have important implications for health across the lifespan. Consistent with this integrated movement behavior paradigm, a number of countries across the world have developed and released 24-h movement guidelines for specific age groups. The purpose of this systematic review was to examine the associations between the 24-h time-use composition of movement behaviors, or adherence to 24-h movement guidelines, and multiple health indicators across the lifespan.

METHODS

Five online databases (PsycINFO, PubMed, SPORTDiscus, Web of Science, and Ovid MEDLINE) were searched for relevant peer-reviewed studies published between January 2015 and January 2020 that met the a priori inclusion criteria, with no study design limits. The methodological quality of research evidence for each individual study and for each health indicator was assessed by using a modified version of the Downs and Black checklist.

RESULTS

A total of 51 studies from 20 different countries met the inclusion criteria. A total of 31 studies examined adherence (meeting vs. not meeting) to 24-h movement guidelines, and 20 studies used compositional analyses to explore the 24-h time-use composition of movement behaviors. Findings indicated that meeting the 24-h movement guidelines were (1) not associated with adiposity among toddlers, (2) favorably associated with health-related quality of life, social-cognitive development, and behavioral and emotional problems among preschoolers, (3) favorably associated with global cognition, health-related quality of life, and healthy dietary patterns in children, and (4) favorably associated with adiposity, fitness, and cardiometabolic, mental, social, and emotional health among children and youth. Significant associations were also found between the composition of 24-h movement behaviors and indicators of (1) adiposity and bone and skeletal health among preschoolers, (2) health-related quality of life among children, (3) adiposity, fitness, and cardiometabolic, social, and emotional health among children and youth, (4) cardiometabolic health in adults, (5) adiposity and fitness among adults and older adults, and (6) mental health and risk of mortality among older adults. The quality of the available evidence ranged from poor to good.

CONCLUSION

The current evidence indicates that the composition of movement behaviors within a 24-h period may have important implications for health at all ages and that meeting the current 24-h movement guidelines is associated with a number of desirable health indicators in children and youth. Future studies should employ longitudinal and experimental designs, include valid and reliable measures of 24-h movement behaviors, and examine a wide array of health indicators across all age groups. Such studies would confirm the results from the primarily cross-sectional evidence drawn from studies included in our review and further advance our understanding of the relationships between 24-h movement behaviors and health.

Analysing body composition as compositional data: An exploration of the relationship between body composition, body mass and bone strength

Human body composition is made up of mutually exclusive and exhaustive parts (e.g. %truncal fat, %non-truncal fat and %fat-free mass) which are constrained to sum to the same total (100%). In statistical analyses, individual parts of body composition (e.g. %truncal fat or %fat-free mass) have traditionally been used as proxies for body composition, and have been linked with a range of health outcomes. But analysis of individual parts omits information about the other parts, which are intrinsically co-dependent because of the constant sum constraint of 100%. Further, body mass may be associated with health outcomes. We describe a statistical approach for body composition based on compositional data analysis. The body composition data are expressed as logratios to allow relative information about all the compositional parts to be explored simultaneously in relation to health outcomes. We describe a recent extension to the logratio approach to compositional data analysis which allows absolute information about the total of the compositional parts (body mass) to be considered alongside relative information about body composition. The statistical approach is illustrated by an example that explores the relationships between adults' body composition, body mass and bone strength.

Lean mass accretion in children born very low birth weight is significantly associated with estimated changes from sedentary time to light physical activity

BACKGROUND

Few studies have investigated how lifestyle is associated with body composition in children born very low birth weight (VLBW, <1500 g), a population at increased risk of obesity and metabolic syndrome in later life.

OBJECTIVES

Determine how time spent in physical activity, sedentary time, and sleep are associated with body composition in children born VLBW.

METHODS

In this prospective cohort study of 5.5-year-old children born VLBW, height, weight, body composition (skinfolds, air displacement plethysmography), and 7 days of movement data (logbooks and accelerometers) were collected.

RESULTS

Of 158 participants, 53% were male, and mean (SD) birth weight was 1013 (264) g. Only 52% achieved 60 minutes/day of moderate-to-vigorous physical activity, but 96% achieved sleep recommendations. Reallocating 30 minutes of sedentary time to light physical activity (LPA) was associated with 0.20 kg/m² (95% CI, 0.02 to 0.37) greater fat-free mass index. An equivalent inverse association was found when reallocating LPA to sedentary time. No associations were found for other movement behaviours.

CONCLUSIONS

Promoting LPA and reducing sedentary time may be an important strategy in reducing the elevated risk of obesity and metabolic syndrome amongst those born VLBW by supporting lean mass accretion. Funded by CIHR (FHG 129919) and SickKids Restracomp.

Sedentary behavior patterns and adiposity in children: a study based on compositional data analysis

BACKGROUND

Between-person differences in sedentary patterns should be considered to understand the role of sedentary behavior (SB) in the development of childhood obesity. This study took a novel approach based on compositional data analysis to examine associations between SB patterns and adiposity and investigate differences in adiposity associated with time reallocation between time spent in sedentary bouts of different duration and physical activity.

METHODS

An analysis of cross-sectional data was performed in 425 children aged 7-12 years (58% girls). Waking behaviors were assessed using ActiGraph GT3X accelerometer for seven consecutive days. Multi-frequency bioimpedance measurement was used to determine adiposity. Compositional regression models with robust estimators were used to analyze associations between sedentary patterns and adiposity markers. To examine differences in adiposity associated with time reallocation, we used the compositional isotemporal substitution model.

RESULTS

Significantly higher fat mass percentage (FM%; β_ilr1 = 0.18; 95% CI: 0.01, 0.34; p = 0.040) and visceral adipose tissue (VAT; β_ilr1 = 0.37; 95% CI: 0.03, 0.71; p = 0.034) were associated with time spent in middle sedentary bouts in duration of 10-29 min (relative to remaining behaviors). No significant associations were found for short (< 10 min) and long sedentary bouts (≥30 min). Substituting the time spent in total SB with moderate-to-vigorous physical activity (MVPA) was associated with a decrease in VAT. Substituting 1 h/week of the time spent in middle sedentary bouts with MVPA was associated with 2.9% (95% CI: 1.2, 4.6), 3.4% (95% CI: 1.2, 5.5), and 6.1% (95% CI: 2.9, 9.2) lower FM%, fat mass index, and VAT, respectively. Moreover, substituting 2 h/week of time spent in middle sedentary bouts with short sedentary bouts was associated with 3.5% (95% CI: 0.02, 6.9) lower FM%.

CONCLUSIONS

Our findings suggest that adiposity status could be improved by increasing MVPA at the expense of time spent in middle sedentary bouts. Some benefits to adiposity may also be expected from replacing middle sedentary bouts with short sedentary bouts, that is, by taking standing or activity breaks more often. These findings may help design more effective interventions to prevent and control childhood obesity.

Compositional Data Analysis in Time-Use Epidemiology: What, Why, How

In recent years, the focus of activity behavior research has shifted away from univariate paradigms (e.g., physical activity, sedentary behavior and sleep) to a 24-h time-use paradigm that integrates all daily activity behaviors. Behaviors are analyzed relative to each other, rather than as individual entities. Compositional data analysis (CoDA) is increasingly used for the analysis of time-use data because it is intended for data that convey relative information. While CoDA has brought new understanding of how time use is associated with health, it has also raised challenges in how this methodology is applied, and how the findings are interpreted. In this paper we provide a brief overview of CoDA for time-use data, summarize current CoDA research in time-use epidemiology and discuss challenges and future directions. We use 24-h time-use diary data from Wave 6 of the Longitudinal Study of Australian Children (birth cohort, n = 3228, aged 10.9 ± 0.3 years) to demonstrate descriptive analyses of time-use compositions and how to explore the relationship between daily time use (sleep, sedentary behavior and physical activity) and a health outcome (in this example, adiposity). We illustrate how to comprehensively interpret the CoDA findings in a meaningful way.

Characteristics Associated with Successful Weight Management in Youth with Obesity

OBJECTIVE

To identify the medical, demographic, and behavioral factors associated with a reduction of body mass index percent of the 95th percentile (BMIp95) after 1 year for patients receiving care at a tertiary care obesity management clinic.

STUDY DESIGN

A retrospective review of data from first and 12 ± 3-month follow-up visits of subjects aged 8-17 years with obesity. Data included anthropometrics, demographics, medical/psychological history, reported diet patterns, and participation in moderate/vigorous physical activity. After analyzing factors associated with 1-year follow-up, we used a forward conditional logistic regression model, controlling for subject's sex, to examine associations with a BMIp95 ≥5-point decrease at 1 year.

RESULTS

Of 769 subjects, 184 (23.9%) had 1-year follow-up. Boys more often had follow-up (28.4% vs girls, 19.1%; P = .003). The follow-up sample was 62.0% male, 65.8% Hispanic, and 77.7% with public insurance; 33.2% achieved a ≥5-point decrease in BMIp95. In regression results, the ≥5-point decrease group was more likely to have completed an initial visit in April-September (OR 2.0, 95% CI 1.1-3.9); have increased physical activity by 1-2 d/wk (OR 3.4, 95% CI 1.4-7.8) or increased physical activity by ≥ 3 d/wk at 1 year (OR 2.7, 95% CI 1.1-6.3); and less likely to have been depressed at presentation (OR 0.4, 95% CI 0.2-0.9). Demographic and dietary factors were not significantly associated with BMIp95 group status.

CONCLUSIONS

Strategies improving follow-up rates, addressing mental health concerns, and promoting year-round physical activity are needed to increase the effectiveness of obesity management clinics.