Health risks, correlates, and interventions to reduce sedentary behavior in young people

Sedentary and 21 gastrointestinal disorders: A Mendelian randomization study

Sedentary behavior (SB) has been linked in the past by observational studies to gastrointestinal illnesses, although the exact cause of the link is still unknown. To deal with this problem, we carried out a Mendelian randomization (MR) study to thoroughly examine the connection between SB and common gastrointestinal illnesses. We selected instrumental variables representing the SB from the UK Biobank study, including watching television viewing, playing computer, and driving. In addition, we obtained genetic associations of 21 common gastrointestinal disorders from the FinnGen research. After adjusting for common risk factors associated with gastrointestinal diseases, we analyzed the independent association between genetic. Furthermore, we used the inverse-variance weighted (IVW) method in conjunction with complementing techniques like MR-Egger (Mendelian randomization based on Egger Regression) and weighted median to assure the accuracy and dependability of the results. Our findings suggest that genetic susceptibility to prolonged television viewing is significantly associated with an increased risk of 9 out of 21 gastrointestinal disorders. Specifically, these disorders include gastroesophageal reflux disease, chronic gastritis, cholelithiasis, acute pancreatitis, chronic pancreatitis, gastroduodenal ulcer, fatty liver, irritable bowel syndrome, and acute appendicitis. These associations remained significant even after correcting for potential confounding factors. The replication analysis confirms the same conclusion. The results of this study demonstrate a causal relationship between cachexia and genetically predicted SB. To further understand the underlying pathogenic mechanisms at play, more study is required.

Standing power wheelchairs and their use by children and youth with mobility limitations: an interrupted time series

Standing power wheelchairs (PWSDs) expand positioning and mobility options for individuals with motor impairments. Although more available, little is known about how PWSDs are used in everyday life.

PURPOSE

to describe children's use of PWSDs in the first three months post-wheelchair delivery and the impacts on satisfaction with participation in daily life.

MATERIALS AND METHODS

An interrupted time series of purposefully sampled children aged 5-18 years who were receiving a PWSD. The Wheelchair Outcome Measure for Young People (WhOM-YP) documented satisfaction with patient-reported meaningful participation outcomes. Data loggers objectively measured wheelchair mobility outcomes including distance travelled, bouts of mobility, and duration. Data were measured over two sessions pre-wheelchair-delivery and at one week, one month and three months post-wheelchair-delivery.

RESULTS

Six children aged 7-18 years participated, four diagnosed with cerebral palsy, two with spina bifida. Analyses of individual data illustrated positive change in overall WhOM-YP satisfaction scores after PWSD provision though change varied across time, as did, distance, bouts of mobility and duration of use. Participants identified 14 in-home and 16 out-of-home unique participation outcomes, although several commonalities existed.

CONCLUSION

PWSDs hold promise for increasing children's satisfaction with participation in daily life, in addition to possibly increasing mobility outcomes. IMPLICATIONS FOR REHABILITATIONFor children with mobility limitations, PWSDs may promote participation in daily life and increased mobility.Data logger technology provides valuable information about children's PWSD use and how this varies over time.Benefits and challenges exist with implementing PWSD and data logger technologies.When implementing PWSD use, it is critical to consider context, training and support needs of clients and caregivers.

Reference Values in the 6-Minute Walk Test in Chilean Children Aged 3-10 Years and Relationship With Cardiometabolic Risk

PURPOSE

The aim of this study was to evaluate the performance of healthy Chilean children aged 3-10 years in the 6-minute walking test (6MWT) and cardiometabolic risk variables and to determine sex- and age-specific reference values.

METHODS

This study involved 1165 healthy children (age = 6.36 [1.70] y old). The 6MWT was used to evaluate exercise performance. Furthermore, anthropometric measures were collected, like weight, height, body mass index, waist circumference, and skin folds. Resting heart rate and blood pressure (BP) were also evaluated.

RESULTS

The prevalence of overweight and obesity was 35.0% and 25.4% in preschoolers and 29.0% and 36.2% in school-age children, respectively, showing significant differences (P < .05) between age groups. The distance walked (6-min walk distance) increased significantly year on year at ages from 3 to 10 years. According to the regression analysis, 6MWT performance was positively related to age, systolic BP, and height, whereas it was negatively related to ∑4 skinfold fat, resting heart rate, diastolic BP, and waist circumference.

CONCLUSIONS

This study provides a reference equation and an age- and sex-adjusted percentile curve to assess the predicted 6MWT performance in a cohort of prepubertal Chilean children. The 6-minute walk distance depends mainly on age; however, other variables, such as resting heart rate, BP, skinfold fat, and waist circumference, add significant information and should be taken into account.

Attitudes towards Exercise, Leisure Activities, and Sedentary Behavior among Adults: A Cross-Sectional, Community-Based Study in Saudi Arabia

Background: Sedentary behavior has received increased attention as a threat to public health all around the world. A global effort has been made to avoid the spread of noncommunicable diseases (NCDs) that are associated with poor lifestyle practices, which rely on public awareness. As a result, the purpose of this study was to analyze the attitudes toward exercise, leisure activities, and sedentary behaviour among adults in Saudi Arabia. Methods: A cross-sectional study was conducted among individuals living in the Riyadh Region in Saudi Arabia. The questionnaire (26 items) used in this study was divided into four sections, and the first section comprised demographic and basic information of the respondents (6 items). The second section asked the respondents about the time spent exercising and sedentary time spent (6 items), the third section of the study comprised eight questionnaires about the frequency of sedentary activity performed during their leisure time, and the last section was about the attitude towards sedentary behavior (6 items). Descriptive and analytical statistics were done to describe the study findings. Data were analyzed using SPSS version 27. Results: The current findings revealed that 44% (n = 305) of the respondents performed exercise 1-2 days a week, and 16.7% (n = 116) never performed any exercise. Furthermore, a considerable percentage of the respondents spent >4 h in a day as sedentary. Most of the sedentary time was spent on work relating activities 62% (n = 430), followed by time spent on coffee 36.4% (n = 252), business relating activity 22.5% (n = 156), and social media 8.9% (n = 62). In this study, most of the respondents agreed that sitting for a prolonged time might negatively impact their health. Most of the respondents showed positive attitudes towards sedentary behavior. Males were statistically more likely than females to exercise 1-2 days per week (p < 0.001). Being male and being married were both significantly associated with sedentary behavior (p < 0.001). In addition, there was a significant association between participants' sleeping status and physical activity per week, where those who slept 5-6 h often performed physical activity, indicating a significant difference (p < 0.001) than respondents who slept 7-8 or >8 h. The participant's age was also found to have a significant association with engaging in physical exercise (p < 0.001). Conclusions: The results of this study showed that Saudi adults are highly sedentary and inactive, though knowing the harmful consequences of inactivity. Therefore, a national active living policy must be adopted to discourage inactivity and being sedentary and encourage active living in Saudi Arabia.

Secular trends in motor performance in Swiss children and adolescents from 1983 to 2018

Introduction

Environmental changes, including globalization, urbanization, social and cultural changes in society, and exposure to modern digital technology undoubtedly have an impact on children’s activity and lifestyle behavior. In fact, marked reductions in children’s physical activity levels have been reported over the years and sedentary behavior has increased around the world. The question arises whether these environmental changes had an impact on general motor performance in children and adolescents. The study aimed to investigate secular trends of motor performance in Swiss children and adolescents, aged between 7 and 18 years, over a period of 35 years from 1983 to 2018.

Methods

Longitudinal data on the five motor components of the Zurich Neuromotor Assessment (ZNA) – pure motor (PM), fine motor (FM), dynamic balance (DB), static balance (SB), and contralateral associated movements (CAM) – were pooled with cross-sectional data on PM and FM from eight ZNA studies between 1983 and 2018. Regression models were used to estimate the effect of the year of birth on motor performance and body mass index (BMI) measurements. Models were adjusted for age, sex, and socioeconomic status.

Results

The secular trend estimates in standard deviation scores (SDS) per 10 years were − 0.06 [−0.33; 0.22, 95% Confidence Interval] for PM, −0.11 [−0.41; 0.20] for FM, −0.38 [−0.66; −0.09] for DB (−0.42 when controlled for BMI), −0.21 [−0.47; 0.06] for SB, and − 0.01 [−0.32; 0.31] for CAM. The mean change in BMI data was positive with 0.30 SDS [0.07; 0.53] over 10 years.

Discussion

Despite substantial societal changes since the 1980s, motor performance has remained relatively stable across generations. No secular trend was found in FM, PM, SB, and CAM over a period of 35 years. A secular trend in DB was present independent of the secular trend in body mass index.

Associations between socioeconomic status and screen time among children and adolescents in China: A cross-sectional study

Background

Socioeconomic status (SES) is an important determinant of screen time (ST) in children and adolescents, however, the association between SES and ST is not fully understood in China. This study aimed to investigate the association between SES and ST (operationalized as meeting the ST guidelines; no more than 2 hours per day) in Chinese children and adolescents.

Methods

Cross-sectional data of 2,955 Chinese children and adolescents aged 8 to 17(53.4% girls) were used. SES was measured using indicators of parental education and perceived family wealth. ST was assessed with detailed items from the Health Behaviour School-aged Children survey questionnaires. Descriptive statistics and a Chi-square test were used to report the sample characteristics and analyse ST differences across different sociodemographic groups. A binary logistic regression was then applied to analyse the association of SES indicators with ST in children and adolescents.

Results

Overall, 25.3% of children and adolescents met the ST guidelines. Children and adolescents with higher parental education levels were 1.84 [95% CI 1.31–2.57; father] and 1.42 [95% CI 1.02–1.98; mother] times more likely to meet the ST guidelines than those with lower parental education levels. Associations between SES and ST varied across sex and grade groups. Moreover, the associations of SES with ST on weekdays and weekends were different.

Conclusions

This study demonstrated the association between SES and ST in children and adolescents, highlighting the importance of targeting children and adolescents with low SES levels as an intervention priority. Based on our findings, specific interventions can be tailored to effectively reduce ST. Future studies are encouraged to use longitudinal or interventional designs to further determine the association between SES and ST.

Sedentary Behavior Patterns of the Hungarian Adult Population

BACKGROUND AND AIM

Nowadays, a high level of sedentary behavior (SB) is an important health issue. Many studies have focused on evaluating the physical activity (PA) level, while evaluation of SB has received less attention. The main goal of the present study is to describe the sedentary lifestyle of the Hungarian adult population and identify the vulnerable groups with high amount of sitting time and the patterns of SB. Another aim of this study is to compare the two types of questionnaires (International Physical Activity Questionnaire-IPAQ and Sedentary Behavior Questionnaire-SBQ) related to sitting time.

METHODS

This study analyzed cross-sectional primary data using self-reported questionnaires collected by a Hungarian research market company among the adult population in Hungary. The final sample of this study consisted of 1295 participants with a mean age of 45.9 years (SD = 15.2). Analysis of variance (ANOVA) test with post-hoc (Tukey) analysis were used to analyze the link between sitting time and socio-demographic variables (sex, age, BMI, settlement type, education level, marital status, work category, working hours, employment status, sport activity) and body mass index (BMI).

RESULTS AND CONCLUSIONS

According to the SBQ, on average, Hungarians sit for 469.53 min per day (7.81 h) on weekdays and 421.25 min per day (7.01 h) on weekends, which suggested a significant difference compared to IPAQ data: 287.82 min per day (4.79 h) on weekdays and 224.30 min per day (3.73 h) on weekends. Young people (aged between 18 and 29) were reported to have the highest average sitting time, i.e., 545 min per day (more than 9 h), and are showing the highest prevalence (53%) of sitting at least 480 min (8 h) per day. Sitting workers also had a high average sitting time, i.e., 514.82 min per day, and a high prevalence (49.3%) of sitting at least 480 min (8 h) per day. People who live in the capital city had higher sitting time, especially on working days. Men sat longer than woman, i.e., 19 min on working days and 45 min on weekends. The most frequent sedentary activities are: working on computer (126 min) on working days and watching TV (130 min) on weekends. Our results clearly show that the self-report single-item measure (IPAQ) significantly underestimates sedentary time compared to the multi-item questionnaire (SBQ). We identified vulnerable groups with high sitting times: men, young adults, inhabitants of the capital city and sitting workers. Consequently, these groups should be continuously surveyed, and requires specific interventions and strategies that particularly counteract the increased sitting time.

Correlates of Sedentary Time Among Children and Adolescents in Ethiopia: A Cross-Sectional Study

PURPOSE

To assess the correlates of sedentary time among children and adolescents in Ethiopia.

METHODS

The study was conducted in representative samples of children and adolescents in the capital city of Ethiopia, Addis Ababa. Multivariable logistic regression models were used to determine associations of sedentary time and predictor variables.

RESULTS

The mean sedentary time was 4.61 (95% confidence interval [CI], 4.35-4.86) hours per day. Overall, the prevalence of high sedentary time (>3 h/d) was 68.2% (95% CI, 64.2-72.2). Results of multivariable logistic regression analyses showed a statistically significant association between high sedentary time and female household head (adjusted odds ratio [AOR] = 0.50; 95% CI, 0.32-0.80), literate mothers (AOR = 1.98; 95% CI, 1.26-3.11), child attending public school (AOR = 1.79; 95% CI, 1.12-2.85), children who belonged to the poor and rich household wealth tertiles compared with medium wealth tertile (AOR = 2.30; 95% CI, 1.42-3.72 and AOR = 2.04; 95% CI, 1.14-3.65, respectively), and those families that did not have adequate indoor play space for children (AOR = 0.45; 95% CI, 0.29-0.72).

CONCLUSION

The study found that time spent sedentary was high in the study area as compared with other studies of similar settings. Several modifiable factors were identified that can be targeted in interventions to reduce sedentary time in the study setting.

Physical activity and sedentary behaviour among children and adolescents with intellectual disabilities during the COVID-19 lockdown in China

BACKGROUND

In the wake of the COVID-19 pandemic, preliminary research has reported a significant decline in physical activity (PA) and an increase in sedentary behaviour (SB) among typically developed children and adolescents. Limited research has looked at the current situation of PA and SB during this pandemic among children and adolescents with intellectual disabilities (ID). This study investigated the situations about PA and SB among school-aged children and adolescents with ID on China's mainland during the COVID-19 outbreak.

METHODS

In total, 837 parents of children and adolescents (ages 6-18 years) with ID from 15 special education schools of Shandong Province in China were recruited through convenience sampling in the study. Parents reported PA and SB among children and adolescents with ID through the Children's Leisure Activities Study Survey-Chinese version (CLASS-C) online questionnaires.

RESULTS

From parents' reports, Chinese children and adolescents with ID during the COVID-19 pandemic participated in approximately 10 min of moderate-to-vigorous physical activity, and engaged in approximately 530 min of SB every day. Meanwhile, only 17.4% of children and adolescents with ID were able to achieve the recommendation of 60 min of daily moderate-to-vigorous physical activity and 76.1% of children and adolescents with ID spent more than 2 h on SB per day. Additionally, the problems of decrease PA and excessive SB were more prominent in older adolescents with ID compared with younger children with ID.

CONCLUSION

In China, the low level of PA and high level of SB is particularly evident in children and adolescents with ID during the outbreak of COVID-19. The great majority of children and adolescents with ID did not meet the recommended amount of PA while undergoing excessive SB under the long-term home quarantine environment. Therefore, immediate attention and great effort should be made to deal with this severe situation among this vulnerable population in the mainland of China.

Effects of using standing desks for 45 minutes on the stress and executive function of elementary school students

Studies have presented data regarding the effects of short-term (weeks) and long-term (one year) use of standing desks in classrooms on children’s health, cognition, and musculoskeletal symptoms. However, no previous study has examined such effects in an extremely short-term period such as one classroom lesson. This study aimed to examine the effects of using standing desks for 45 minutes on elementary school students’ stress and executive function. For this experiment, 56 students were recruited from public elementary schools in Setagayaku, Tokyo, Japan. There were three conditions involving the use of standing desks (standing, sitting, and mixed), and all students performed tasks for 45 minutes in each condition. Measurements of stress and executive function were performed before and after the students engaged with each condition. Stress levels did not differ between the sitting and standing conditions for the full 45 minutes. The number of correct answers in the Stroop test, an interference task, was higher in the standing and mixed conditions (switching between standing and sitting) than in the sitting condition (interaction: F_(1,37) = 3.340, p = 0.04, η² = 0.05). These results indicate that using standing desks for 45 minutes improved the ‘inhibition’ of executive function without excessively increasing stress levels.

Comprehensive cardiac evaluation to maximal exercise in a contemporary population of prepubertal children

BACKGROUND

Heart rate (HR) is a biomarker used to measure physiological function, health status and cardiovascular autonomic function. The purpose of this study was to determine sex- and age-specific reference values for cardiac autonomic function at rest, during maximal exercise and the recovery phase in prepubertal children.

METHODS

Five hundred and twelve healthy children 7-11 years of age performed a Léger test. A heart RR-interval monitor recorded the heart data and a specific software analysed the cardiac autonomic response through HR and HR variability (HRV). It analysed HR before the test (resting HR, RHR), during the test (HR_peak) and HR recovery (HRR) in the first minute (HRR1) and the fifth minute (HRR5). The values are mean ± SD.

RESULTS

Collectively, 91.2% of girls and 92.3% of boys were within the recommended ranges regarding RHR. The average HR_peak was 199 ± 10.83 b.p.m. and 96.8% of girls and 95.3% of boys were within the minimum threshold value recommended (180 b.p.m.). Boys showed lower values of RHR than girls (p < 0.001) and larger values of HRR 1 and HRR5 (p < 0.001).

CONCLUSIONS

This study comprehensively provides a reference set of data for the most important HR variables that can be obtained during exercise testing in prepubertal children regarding age and sex and in a field setting.

IMPACT

This is the first study to provide reference values of autonomic cardiac function at rest, during maximal exercise and during the recovery period in prepubertal children aged 7-11 years. Despite the early age of participants, cardiorespiratory fitness, RHR and HRR are different according to sex. Aerobic performance and HR_peak have a negative correlation with body mass index and cardiometabolic risk.

Time-Varying Associations Between Device-Based and Ecological Momentary Assessment-Reported Sedentary Behaviors and the Concurrent Affective States Among Adolescents: Proof-of-Concept Study

BACKGROUND

Previous studies on affective state-sedentary behavior (SB) associations have not accounted for their potentially time-varying nature and have used inconsistent SB measurement modalities. We investigated whether the strength of the associations between affective states and SB varied as a function of the time of day and by SB measurement modality (device-measured SB vs ecological momentary assessment-reported screen-based SB) in youth.

OBJECTIVE

This study aimed to establish a proof of concept that SB-affective state associations may not be static during the day. In addition, we aimed to inform the methodology of future work, which may need to model associations as functions of the time of day and carefully consider how SB is operationalized or measured.

METHODS

A total of 15 adolescents (age: mean 13.07, SD 1.03 years; 10/15, 67% female; 6/15, 40% Hispanic; 10/15, 67% healthy weight) wore thigh-mounted activPAL accelerometers and simultaneously reported their screen-based SBs and concurrent positive and negative affective states via ecological momentary assessment for 7 to 14 days (N=636 occasions). Time-varying effect models (varying slopes) examined how each measure of SB was associated with concurrent affective states from 7 AM to 8 PM.

RESULTS

Time-varying effect model plots revealed that these associations varied in strength throughout the day. Specifically, device-based SB was related to greater concurrent negative affect only after approximately 5 PM and was unrelated to concurrent positive affect. Screen-based SB was related to greater concurrent negative affect only from 7 AM to approximately 9 AM. This was also related to greater concurrent positive affect from 7 AM to approximately 9:30 AM and from approximately 3 PM to approximately 7 PM.

CONCLUSIONS

We provide preliminary evidence to suggest that future confirmatory studies investigating the SB-affective state relationship should consider the time-varying nature of these associations and SB measurement modality. There may be critical time windows when specific types of SBs co-occur with affect, suggesting that interventions may need tailoring to the time of day and type of SB if future studies using similar methodologies can replicate our findings.

Influence of Sit-Stand Tables in Classrooms on Children's Sedentary Behavior and Teacher's Acceptance and Feasibility: A Mixed-Methods Study

Children spend over 70% of their school day sitting, most of the time in the classroom. Even when meeting physical activity guidelines but sitting for long uninterrupted periods, children are at risk of poorer health outcomes. With an approach to create an active learning environment through the implementation of sit-stand tables, this exploratory mixed-methods study aims to evaluate a holistic concept for reducing sedentary time in schools by implementing sit-stand tables as well as to examine the feasibility and didactic usability in classroom settings. Children from eight German schools aged 7 to 10 in primary schools and 11 to 13 in secondary schools (n = 211), allocated into control and intervention groups, were included in the study, as well as teachers (n = 13). An accelerometer was used as a quantitative measure to assess sitting and standing times and sport motoric tests were taken. Qualitative interviews were performed with teachers regarding feasibility and acceptance of the sit-stand tables. Independent t-test analysis adjusted for age, sex and school type found that sitting times of children in the intervention group could be reduced (by 30.54 min per school day of 6 h, p < 0.001) within all school and age levels. Overall, implementing sit-stand tables in classrooms serves as a feasible and effective opportunity to reduce sedentary behaviour and create an active learning environment.

Fitness, Fatness, and Academic Attainment in Male Schoolchildren from a Soccer Academy

This investigation explored the association between anthropometric measures, fitness, and academic attainment (mathematics and science grade point average [GPA]) in male schoolchildren from a soccer academy. Thirty-one males (age: 10.3 ± 1.19 years; body mass: 41.7 ± 6.5 kg; height: 1.43 ± 0.07 m; body mass index (BMI): 20.2 ± 2.8 kg/m2) participated. Body mass, body fat percentage (%BF), and BMI were used as measures of anthropometry. The Yo-Yo Intermittent Recovery Test (level 1), squat and counter-movement jumps (SJ and CMJ), static balance, 10 and 15 m sprint, and a T-half test for change-of-direction (CoD) performance were used to measure fitness parameters. The GPA of mathematics and science determined academic attainment. All physical performance tests showed excellent relative reliability. ICC was between 0.87 (10 m sprint) and 1.00 (15 m sprint, CMJ). Regarding correlations between fatness and academic attainment, we found three correlations of practical value (r > 0.5), but only for mathematics (BMI: r = 0.540, subscapular skinfold: r = 0.589, body fat: r = 0.560). Mathematics was relevantly correlated with 15 m sprint (r = 0.574) and Yo-Yo IR1 test (r = 0.770). Only static balance (r = 0.428) did not reach the relevance criteria (r > 0.5). Science only showed large correlations with static balance (r = 0.620) and Yo-Yo IR1 test (r = 0.730). In conclusion, fatness and fitness are related to academic attainment in schoolchildren. In addition, except for static balance, all physical performance parameters were relevantly (r > 0.5) correlated with mathematics.

Patterns of Screen Time Parenting Practices among Parent-Adolescent Dyads Who Participated in a Cross-Sectional Internet-Based Study

Background: Little is known about the simultaneous use of screen time (ST) parenting practices in children. Hence, study objectives were to determine patterns of ST parenting practices and associations with demographic, anthropometric, and sedentary behavior measures in parents and their adolescent children (12-17 years). Methods: Dyadic survey data from Family Life, Activity, Sun, Health, and Eating, a cross-sectional, internet-based study, conducted in 2014 were analyzed using latent class analysis on six ST parenting practices-permissive, rules/limits, monitoring, modeling, accessibility, and negotiated rules. Self-report model covariates included adolescent age and parent and adolescent sex, body weight category, and sedentary behavior. Results: Based on 1200 parent-adolescent dyads, five latent classes were identified representing a continuum of practice use (high to low)-Complete Influencers (16%, reference class), Disagreeing Influencers (18%), Positive Influencers (24%), Negative Influencers (23%), and Indifferent Influencers (20%). Disagreeing, Indifferent, and Negative Influencers were 50%-81% and 45%-49% less likely to contain younger adolescent dyads and male adolescent dyads, respectively. Dyads with adolescent overweight/obesity had twice the odds of belonging to one of the other four classes. Odds of belonging to one of the other four classes were 3%-9% lower for every 1 minute/day increase in adolescent sedentary behavior. Conclusions: Parents utilize distinct patterns of ST practices, which are differentially associated with adolescent age, sex, weight, and sedentary behavior. Advocating for parental use of combinations of practices, like rules/limits and monitoring, to decrease their adolescents' ST may prove more beneficial than no practice use.

Time spent in different sedentary activity domains across adolescence: a follow-up study

OBJECTIVE

This longitudinal study aimed to verify possible changes in the time spent in sedentary activities occurring as screen-time, educational, cultural, social, and transportation domains in a sample of Brazilian adolescents between 2015 and 2017.

METHODS

It is a longitudinal prospective study with 586 adolescents from 12 to 15 years old at the Baseline (2015) enrolled in 14 public schools from Curitiba, Brazil. The Adolescent Sedentary Activity Questionnaire assessed the time spent in sedentary activities in five domains (recreational screen-time, educational, cultural, social, and transportation). A series of linear random effects regressions analyzed changes in the sedentary time between 2015 and 2017, with p < .05.

RESULTS

Overall, 323 adolescents dropped out of the study resulting in a retention rate of 44.9%. The overall sedentary time remained stable from 2015 to 2017 (-3.98 min/day, 95%CI: -15.39; 7.42). The screen-time decreased (-22.22 min/day, 95%CI: -30.30; -14.15), and educational (8.29 min/day, 95% CI: 3.52; 13.06), cultural (3.41 min/day, 95% CI: 0.66; 6.15) and social sedentary activities (8.20 min/day, 95% CI: 2.06; 14.34) increased from 2015 to 2017.

CONCLUSION

Significant reductions in screen-time were evidenced along with increases in time spent on other sedentary activities of educational, cultural, and social nature. KeywordsSedentary behavior, Adolescent health, Longitudinal studies.

The Antecedents and Consequences of Interpersonal Communication during a School-based Health Intervention

School-based health interventions often have limited and inconsistent effects. Although interpersonal communication likely is important, hardly any studies have investigated interpersonal communication of students with their friends, classmates, and parents about the health programs and health behaviors in school-based health interventions. In a two-wave prospective study of 389 adolescents focusing on three health behaviors (i.e., alcohol use, snack intake, and exercise), we addressed two aims. Our first aim was to investigate how student evaluations of a school-based health intervention influenced interpersonal communication about health behaviors (i.e., valence and frequency of conversations). Findings showed that positively evaluating a school-based health intervention increased how often students talked about the intervention with friends, classmates, and parents, as well as how they discussed the three health behaviors. Our second aim was to investigate the influence of interpersonal communication with friends, classmates, and parents on predictors of health behaviors. We found for conversational frequency that frequently discussing health behaviors resulted in healthier (more positive) predictors of exercise, but also in unhealthier (more positive) predictors of snacking and drinking. Furthermore, findings showed that positively discussing exercising, and negatively discussing snacking and drinking, resulted in healthier predictors of these behaviors. Our findings show that it is important to understand the impact of post-intervention communication and that post-intervention communication with peers and parents about health behaviors are predictors of health behavior.

Examining 24-Hour Activity and Sleep Behaviors and Related Determinants in Latino Adolescents and Young Adults With Obesity

Background. Few studies have examined 24-hour activity and sleep behaviors and their contribution to type 2 diabetes (T2D) in Latino adolescents and young adults with obesity. Aim. This study included quantitative data on T2D risk and 24-hour activity and sleep behaviors and qualitative data on individual, social, and environmental behavioral determinants. Method. A 7 day, 24-hour, wrist-worn accelerometer protocol assessed moderate-to-vigorous physical activity (PA), sedentary behaviors (SB), sleep, and sleep regularity, in adolescents (N = 38; 12-16 years) and young adults (N = 22; 18-22 years). T2D-related outcomes included adiposity (BMI, BF%, waist circumference), fasting, and 2-hour glucose. A subsample of participants (N = 16 adolescents, N = 15 young adults) completed interviews to identify behavioral determinants. Results. High levels of PA were observed among adolescents (M = 103.8 ± 67.5 minutes/day) and young adults (M = 96.8 ± 78.8 minutes/day) as well as high levels of SB across both age groups (≥10 hours/day). Sleep regularity was negatively associated with adiposity (all ps < .05) in both age groups as well as fasting and 2-hour glucose in young adults (all ps < .05). Social support was associated with PA in both age groups as well as SB in younger youth. Auditory noises, lights, and safety inhibited sleep in both age groups. Conclusion. PA is critical for disease reduction, yet reducing SB and improving sleep are also important targets for reducing T2D risk in Hispanic adolescents and young adults. Future health promotion and disease prevention strategies should leverage qualitative findings regarding behavioral determinants.

Associations between physical activity, sedentary time and cardiovascular risk factors among Dutch children

Introduction

Physical activity (PA) plays an important role in the prevention of cardiovascular diseases, especially in children. Previous studies which investigated the role of PA and sedentary time (ST) in cardiovascular disease used different measurements and found inconsistent results. The current study used recommended standardized measures and provides an overview of PA and ST among Dutch primary school children and their associations with cardiovascular risk factors.

Methods

503 children (55% girls, mean age (± SD) 10 ± 1y) were included. PA (total PA, lightPA and moderate to vigorous PA (MVPA)) and ST were measured with the Actigraph GT3X accelerometer. PA in different domains was measured with the BAECKE questionnaire. Cardiovascular risk factors included BMI z-score, waist circumference, blood pressure (z-score) and estimated cardiorespiratory fitness (CRF) as measured with the 20 meter shuttle run test.

Results

Children spent 57 ± 20 min/day (8%) on MVPA and 42% of the children reached the MVPA guideline of 60 min/day. Total PA and MVPA (h/day) were negatively associated with BMI z-score (B = -0.452, p = 0.011) and waist circumference (B = -3.553, p = 0.011) and positively associated with CRF (B = 2.527, p = <0.001). ST was positively associated with BMI z-score (B = 0.108, p = 0.048) and waist circumference (B = 0.920, p = 0.033). No significant associations were found between total PA or PA intensities and blood pressure.

Conclusion

This study used standardized measures of PA and therefore created an accurate overview of PA, ST and their associations with cardiovascular risk factors. PA and ST were associated with BMI z-score, waist circumference and CRF. The findings emphasize the importance of promoting MVPA in children, but also highlight the potential benefits of reducing ST to improve cardiovascular risk factors.

Trial registration

ClinicalTrials.gov NCT03440580.

Generational Status, Language Use, Parental Limit Setting, and Screen Time in US Latinx Children

Latinx children engage in excessive screen time and are disproportionately affected by obesity. We examined the effect of generational status and language use on screen time in 6- to 11-year-old Latinx children and whether parental limit setting mediated that relationship. Participants included 3127 children (aged 9.2 ± 2.0 years; 54% male) from the 2011-2012 National Survey of Children's Health. Spanish language use was associated with 14.0 more minutes per day of screen time (P = .038); parental limit setting partially mediated this relationship (11.4%). Future research should explore the protective role of parental limit setting in reducing screen time in Latinx children.

International Physical Activity and Built Environment Study of adolescents: IPEN Adolescent design, protocol and measures

INTRODUCTION

Only international studies can provide the full variability of built environments and accurately estimate effect sizes of relations between contrasting environments and health-related outcomes. The aims of the International Physical Activity and Environment Study of Adolescents (IPEN Adolescent) are to estimate the strength, shape and generalisability of associations of the community environment (geographic information systems (GIS)-based and self-reported) with physical activity and sedentary behaviour (accelerometer-measured and self-reported) and weight status (normal/overweight/obese).

METHODS AND ANALYSIS

The IPEN Adolescent observational, cross-sectional, multicountry study involves recruiting adolescent participants (ages 11-19 years) and one parent/guardian from neighbourhoods selected to ensure wide variations in walkability and socioeconomic status using common protocols and measures. Fifteen geographically, economically and culturally diverse countries, from six continents, participated: Australia, Bangladesh, Belgium, Brazil, Czech Republic, Denmark, Hong Kong SAR, India, Israel, Malaysia, New Zealand, Nigeria, Portugal, Spain and USA. Countries provided survey and accelerometer data (15 countries), GIS data (11), global positioning system data (10), and pedestrian environment audit data (8). A sample of n=6950 (52.6% female; mean age=14.5, SD=1.7) adolescents provided survey data, n=4852 had 4 or more 8+ hours valid days of accelerometer data, and n=5473 had GIS measures. Physical activity and sedentary behaviour were measured by waist-worn ActiGraph accelerometers and self-reports, and body mass index was used to categorise weight status.

ETHICS AND DISSEMINATION

Ethical approval was received from each study site's Institutional Review Board for their in-country studies. Informed assent by adolescents and consent by parents was obtained for all participants. No personally identifiable information was transferred to the IPEN coordinating centre for pooled datasets. Results will be communicated through standard scientific channels and findings used to advance the science of environmental correlates of physical activity, sedentary behaviour and weight status, with the ultimate goal to stimulate and guide actions to create more activity-supportive environments internationally.

Are associations between home environment and preschool children's sedentary time influenced by parental educational level in a cross-sectional survey?

Background

Childhood obesity is a major public health concern, especially in low socioeconomic groups. Sedentary time (SED) is an important predictor of obesity. To be able to diminish SED it is important to find modifiable predictors of sedentary behavior. The home environment associated with children’s SED may vary by parental socioeconomic status. This study aims to clarify the association between parental educational level (PEL) and the home environment of 3–6-year-old children, and to examine how home environment associates with children’s SED, and whether PEL modifies these associations.

Methods

A cross-sectional Increased health and wellbeing in preschools (DAGIS) study was conducted in 2015–2016 in Finland. The parents (n = 809) filled in questionnaires assessing PEL, and the home physical and social environment related to children’s SED. Children’s SED was measured with accelerometers, which the children (n = 745) wore for 1 week.

Results

High PEL was associated with a home environment restraining sedentary behaviour compared with low PEL. Stricter descriptive norms about screen time, considering it important to limit the child’s screen time, and satisfaction about the child’s screen time associated with children’s lower SED. The association with parental psychological control and SED was influenced by PEL. In the PEL stratified analyses, however, the associations between psychological control and SED did not reach statistical significance.

Conclusions

Future interventions aiming to decrease SED should pay attention to relevant factors in children’s sedentary behaviour home environment. It is important to acknowledge the possible PEL differences in these factors.

Electronic Devices as Correlates of Sedentary Behavior and Screen Time Among Diverse Low-Income Adolescents During the School Year and Summer Time

Excessive screen time among adolescents increases risk for overweight and obesity. Having electronic devices in the adolescent's bedroom is associated with more screen time. The present study expanded on previous studies by also examining portable personal electronic devices and social media membership as correlates of screen time use and total sedentary time in the school year and summer among diverse low-income adolescents. Adolescents aged 10-17 years were recruited from lower-income areas; n=150 (34 African Americans, 23 American Indians, 16 Asian/Pacific Islanders, 39 Latinos, and 38 White/non-Hispanics) completed surveys and wore accelerometers in both the school year and summer. Total sedentary time was computed from accelerometers. Recreational screen time was assessed with a 3-item validated scale. Adolescents reported the presence of 6 electronic devices in their bedrooms, ownership of 4 portable devices, and social media membership. General linear modeling was conducted for both time periods, with demographic covariates and interactions with sex and race/ethnicity. More electronic devices in bedrooms were related to more screen time during the school year and summer, and to more total sedentary time in summer. Personal electronics were related only to more screen time in the school year. Social media membership was related to more total sedentary time in summer, but only among African Americans, American Indians, and non-Hispanic Whites. Electronic devices in bedrooms was confirmed as a risk factor for sedentary behavior among low-income adolescents of color. Social media membership and use should be further studied with diverse adolescents.

Objectively measured sedentary behaviour in overweight and obese prepubertal children: challenging the school

Sedentary lifestyle is associated with unfavourable health outcomes; however, few studies have analysed the daily fluctuations of sedentary behaviour in children. The aim was to characterise sedentary behaviour in low active, overweight/obese prepubertal children and to examine whether there were daily, age- or gender-based differences. In this observational study free-living movement was measured by accelerometry for one week. Eighty-eight low active, overweight/obese children (8- to 12-year-olds) were included. Analysis was conducted for weekends, weekdays, school time and non-school time on weekdays. Participants spent half of their waking hours engaged in sedentary behaviour (48.1%). Short sedentary bouts (1-4 min) accounted for 86% of sedentary time. Sedentary time was similar on weekends and non-school time, while it was highest during school time. Interventions for the management of childhood obesity should include strategies for shifting sedentary time to physical activity on weekends and non-school time and implementing more activity-permissive classroom lessons.

COVID-19 Impact on Behaviors across the 24-Hour Day in Children and Adolescents: Physical Activity, Sedentary Behavior, and Sleep

In the wake of the COVID-19 pandemic, social restrictions to contain the spread of the virus have disrupted behaviors across the 24-h day including physical activity, sedentary behavior, and sleep among children (5–12 years old) and adolescents (13–17 years old). Preliminary evidence reports significant decreases in physical activity, increases in sedentary behavior, and disrupted sleep schedules/sleep quality in children and adolescents. This commentary discusses the impact of COVID-19-related restrictions on behaviors across the 24-h day in children and adolescents. Furthermore, we suggest recommendations through the lens of a socio-ecological model to provide strategies for lasting behavior change to insure the health and well-being of children and adolescents during the COVID-19 pandemic.

Association between sedentary behavior and bone mass in adolescents

The effects of sedentary behavior on adolescents' bone health are controversial because, even in normal weight individuals, the excessive time spent in some specific types of these behaviors appears to have no negative effect on bone health.

PURPOSE

To analyze the relationship between sedentary behaviors and bone mass in adolescents.

METHODS

One hundred four adolescent boys and girls, aged 10 to 14 years, were divided into normal weight and overweight according to weight status. Specific sedentary behaviors (time spent on the Internet for school and non-school purposes, using the computer, watching television, and playing videogames) were assessed by questionnaire, and the total sedentary behavior time by accelerometry. Bone parameters were collected using X-ray absorptiometry, using total and lumbar bone mineral density (BMD) and total and lumbar bone mineral content (BMC) values.

RESULTS

In both groups, the time spent on the Internet for non-school purposes was positively correlated to the total and lumbar BMD. Also, while in the overweight group, the time spent using the computer was negatively correlated to lumbar BMD, and the time spent on the Internet for non-school purposes was positively correlated to the total and lumbar BMC, and in the normal weight group, the time spent on the Internet for non-school purposes was positively correlated to lumbar BMC.

CONCLUSIONS

Adolescents who spend more time in sedentary behavior, especially using the Internet for non-school purposes, have higher BMD and BMC, while normal weight adolescents who spend more time on the computer have lower BMD.

Are neighborhood characteristics associated with sedentary behavior in adolescents? A systematic review

Sedentary behavior (SB) has emerged as a potential risk factor for chronic diseases. SB includes activities requiring low energy expenditure (≤1.5 metabolic equivalents) performed in a sitting or reclining posture. Our study aimed to gather evidence on the association between SB outcomes in adolescents (10-19 years) and neighborhood characteristics. This systematic review (PROSPERO registration number: CRD42018076877) examined studies indexed in PubMed Central®, LILACS, ScienceDirect, and SPORTDiscus databases. Sixteen articles were included. Insecurity during daytime hours, crime incidence, physical and social disorders, a higher neighborhood socioeconomic level, and time spent with peers were associated with higher levels of SB. Traffic, availability of a favorable environment for physical activity, and higher residential density were associated with lower levels of SB. Despite great variability in the SB cutoff points and methodology used for evaluating SB and neighborhood characteristics among studies, the evidence suggests that adolescent SB might be influenced by neighborhood characteristics.

A novel bamboo sheet chair and its influence on sitting comfort

Background

In today’s economy, workers spend increasingly more time in seated positions, leading to a growing scientific interest in chair design. In this study we used body pressure distribution tests to compare a novel bamboo chair with unique structural features to other commonly-used chairs. We studied the bamboo sheet chair’s physical characteristics and comfort to provide a scientific theoretical basis for common use seat design.

Methods

A total of 25 (14 male and 11 female) subjects participated in the study. Subjects were divided into six groups according to their body characteristics parameters included stature, weight, shoulder breadth, hip breadth, waist width, popliteal height, buttocks-popliteal length, and buttock-abdomen depth, with three groups for males and three groups for females. Each subject was required to complete specified body pressure tests for three different experimental chairs for three minutes and subjective comfort evaluations were also administered. The pressure indexes were measured from the seat pan and backrest and calculated with MATLAB 2015b, which mainly included maximum pressure (Pm), average pressure (Pa), pressure exponent (Pe) and contact area index (P_AI). Three pressure threshold limits of 0.67 kPa, 4.00 kPa and 9.33 kPa and four contact surface indexes were used in the experiment to reflect the contact area between human and chair.

Results

The contact areas in the backrest (52.96 ± 32.94 cm²) and seat pan (307.75 ± 90.31 cm²) in the middle-to-high threshold pressure range, and the contact areas of the backrest (4.34 ± 5.95 cm²) in the high threshold pressure range of bamboo sheet chair were smaller than the corresponding indexes of the common office chair (81.430 ± 45.04 cm², p = 0.00; 394.39 ± 98.99 cm², p = 0.02; 13.54 ± 12.00 cm², p = 0.00, respectively). The pressure index (2.68 ± 0.88 kPa), maximum pressure (6.66 ± 2.05 kPa), and average pressure (2.42 ± 0.59 kPa) values of the bamboo sheet chair backrest were also found to be lower than those of the office chair (4.32 ± 1.62 kPa, p = 0.00; 10.50 ± 3.88 kPa, p = 0.00; 3.43 ± 0.97 kPa, p = 0.00, respectively). The average pressure on the seat pan was greater than 4 kPa for all subjects, while the average pressure on the seat pan was greater than 9.33 kPa for male subjects with a body mass index (BMI) of 27.48.

Discussion

The bamboo sheet chair’s contact areas within the middle-to-high and high-pressure threshold ranges of the backrest and seat pan were smaller than those of the office chair, indicating that the bamboo sheet chair is effective at relieving pressure. Human body characteristics must be considered in the design of seat functional size. Buttocks-popliteal length, weight, body mass index, body shape and weight distribution, all have important effects on the distribution of body pressure at the human-chair interface.

Study protocol of the Health4Life initiative: a cluster randomised controlled trial of an eHealth school-based program targeting multiple lifestyle risk behaviours among young Australians

INTRODUCTION

Lifestyle risk behaviours, including alcohol use, smoking, poor diet, physical inactivity, poor sleep (duration and/or quality) and sedentary recreational screen time ('the Big 6'), are strong determinants of chronic disease. These behaviours often emerge during adolescence and co-occur. School-based interventions have the potential to address risk factors prior to the onset of disease, yet few eHealth school-based interventions target multiple behaviours concurrently. This paper describes the protocol of the Health4Life Initiative, an eHealth school-based intervention that concurrently addresses the Big 6 risk behaviours among secondary school students.

METHODS AND ANALYSIS

A multisite cluster randomised controlled trial will be conducted among year 7 students (11-13 years old) from 72 Australian schools. Stratified block randomisation will be used to assign schools to either the Health4Life intervention or an active control (health education as usual). Health4Life consists of (1) six web-based cartoon modules and accompanying activities delivered during health education (once per week for 6 weeks), and a smartphone application (universal prevention), and (2) additional app content, for students engaging in two or more risk behaviours when they are in years 8 and 9 (selective prevention). Students will complete online self-report questionnaires at baseline, post intervention, and 12, 24 and 36 months after baseline. Primary outcomes are consumption of sugar-sweetened beverages, moderate-to-vigorous physical activity, sleep duration, sedentary recreational screen time and uptake of alcohol and tobacco use.

ETHICS AND DISSEMINATION

This study has been approved by the University of Sydney (2018/882), NSW Department of Education (SERAP no. 2019006), University of Queensland (2019000037), Curtin University (HRE2019-0083) and relevant Catholic school committees. Results will be presented to schools and findings disseminated via peer-reviewed journals and scientific conferences. This will be the first evaluation of an eHealth intervention, spanning both universal and selective prevention, to simultaneously target six key lifestyle risk factors among adolescents.

TRIAL REGISTRATION NUMBER

Australian New Zealand Clinical Trials Registry (ACTRN12619000431123), 18 March 2019.

Associations between self-efficacy and sedentary behaviour: a meta-analysis

Objective: The study sought to synthesize research on the relationship between time spent engaged in sedentary behaviours (SB) and self-efficacy. Analyses investigated whether such associations are moderated by age, conceptualization of self-efficacy, conceptualization of SB, and/or SB measurement.Design and Main Outcome Measures: The review was registered with PROSPERO (no. CRD42018086899). Studies including associations between self-efficacy and SB were identified through a systematic search of six databases. Inclusion criteria were met by k = 26 original studies.Results: A random effect meta-analysis showed that higher levels of self-efficacy were associated with lower levels of SB (r = -.158, 95% CI [-.220, -.094]). Moderator analyses indicated that associations between self-efficacy and SB may be similar in strength across age groups, the conceptualizations of self-efficacy or SB and SB measurements.Conclusion: The findings provide preliminary guidance for future interventions targeting reduction of SB, although more longitudinal research is needed to draw causal inferences.

Social inequalities in traditional and emerging screen devices among Portuguese children: a cross-sectional study

BACKGROUND

Children are often exposed to too much screen time but few studies have explored the use of old and new digital media among young children. This study assesses screen time, including traditional and mobile devices, in pre-school and elementary school-aged children, according to their gender, age, and socioeconomic position (SEP).

METHODS

A total of 8430 children (3 to 10 years; 50.8% boys) from the north, center and south-central Portugal were included in the present study. Data was collected by a parental questionnaire during 2016/2017. Children's screen time (by media device, weekdays and at the weekend; calculated by mean minutes per day) were reported by parents. Analysis were carried to compare screen time by children's age, gender and family SEP (classified using father's educational degree).

RESULTS

Daily screen time was high both in children aged 3 to 5 and 6 to 10 years - 154 min/day (95% CI: 149.51-158.91) and 200.79 min/day (95% CI: 197.08-204.50), respectively - and the majority of children, independently of their gender, exceed the recommended 2 h/day of screen viewing. Children are still primarily engaging in screen time through television but the use of mobile devices, particularly tablets, were already high among 3 year-old children and increased with age. SEP was a negative predictor of screen time in the linear regression analysis, including after adjustment.

CONCLUSIONS

Considering the negative health impacts of excessive screen time, recognizing subgroups at risk of excessive screen time and identifying how each device is used according to age is fundamental to enable appropriate future interventions. The screen time in children aged 3-10 years is longer than the recommended, particularly among boys and in those children from lower SEP. Parents and policymakers should have in mind that children spend most of their screen time watching television but mobile devices are becoming extremely popular starting at a young age.

Correlates of screen time and mediators of differences by parental education among adolescents

Background

Existing literature shows that there is an inverse association between socioeconomic position and screen time among adolescents. What is less known is the mechanism behind these differences. The study aimed to explore individual, interpersonal and neighborhood environmental correlates of total screen time (TST) among adolescents and to assess their mediating role in the association between parental education and TST.

Methods

A cross-sectional study including 706 adolescents (mean age of 13.6 (SD = 0.3)) was used to collect data at schools through an online questionnaire. Multiple regression analyses were used to explore factors associated with TST. Mediation analyses were conducted to assess whether these factors mediated the association between parental education and TST.

Results

Multiple linear regression analyses, adjusted for gender and age, showed that parental modelling of TV and movie streaming, TV/movie streaming during dinner and access to screens were positively related to TST. Self-efficacy towards limiting TV and movie streaming, self-efficacy towards limiting computer/electronic game use, and the perceived opportunities for physical activity in the neighborhood were inversely related to total screen time. All of these factors except self-efficacy towards limiting TV and movie streaming mediated the association between parental education and TST.

Conclusions

The study identified several modifiable factors at the individual, interpersonal and neighborhood environmental levels that can be targeted in interventions aimed at decreasing screen time among youth in general and among those with a low socioeconomic position in particular.

Latin American interventions in children and adolescents' sedentary behavior: a systematic review

OBJECTIVE To identify and evaluate the effects of community-based interventions on the sedentary behavior (SB) of Latin American children and adolescents. METHODS A systematic review on community-based trials to reduce and/or control SB in Latin American countries (Prospero: CRD42017072157). Five databases (PubMed, Web of Science, Scopus, SciELO and Lilacs) and a reference lists were searched. RESULTS Ten intervention studies met the eligibility criteria and composed the descriptive synthesis. These studies were conducted in Brazil (n=5), Mexico (n=3), Ecuador (n=1) and Colombia (n=1). Most interventions were implemented in schools (n=8) by educational components, such as meetings, lessons, and seminars, on health-related subjects (n=6). Only two studies adopted specific strategies to reduce/control SB; others focused on increasing physical activity and/or improving diet. Only one study used an accelerometer to measure SB. Seven studies investigated recreational screen time. Eight studies showed statistically significant effects on SB reduction (80%). CONCLUSIONS Latin America community-based interventions reduced children and adolescents' SB. Further studies should: define SB as a primary outcome and implement strategies to reduce such behaviour; focus in different SBs and settings, other than recreational screen time or at-home sitting time; and use objective tools together with questionnaires to measure sedentary behaviour in.

Social correlates of sedentary behavior in young people: The UP&DOWN study

PURPOSE

The aim of the present study was to analyze the associations of youths' sedentary behavior (SB) with parents' and siblings' SB and physical activity (PA), as well as the associations of youths' coparticipation with parents, siblings, and friends in PA and SB with youths' SB.

METHODS

The sample consisted of 1543 youths (12.02 ± 2.51 years; 788 boys) enrolled in the baseline cohort of the UP&DOWN study. SB was assessed by accelerometry and questionnaire. Participants reported the time spent by their parents and siblings watching television, playing videogames, surfing the Internet, sitting/resting, and doing PA. Further, participants reported coparticipation with parents, siblings, and friends in these activities. Linear mixed models, including school and city as random effects, were performed.

RESULTS

Parents' television time was positively associated with youths' screen-based SB. Coparticipation with friends in playing videogames (in boys) and in surfing the Internet (in girls) showed a positive association with screen-based SB and a negative association with educational-based SB. Moreover, coparticipation with siblings and friends in PA was inversely associated with accelerometer-based SB in boys and girls.

CONCLUSION

Our results emphasize the important role of social modeling in the development of sedentary lifestyles in youths. Interventions aimed at reducing health risk behaviors in youths could be more effective if they are oriented from a social perspective that involves their families and networks of their closest friends.

mHealth Research Applied to Regulated and Unregulated Behavioral Health Sciences

Behavioral scientists are developing new methods and frameworks that leverage mobile health technologies to optimize individual level behavior change. Pervasive sensors and mobile apps allow researchers to passively observe human behaviors "in the wild" 24/7 which supports delivery of personalized interventions in the real-world environment. This is all possible because these technologies contain an incredible array of sensors that allow applications to constantly record user location and can contextualize current environmental conditions through barometers, thermometers, and ambient light sensors and can also capture audio and video of the user and their surroundings through multiple integrated high-definition cameras and microphones. These tools are a game changer in behavioral health research and, not surprisingly, introduce new ethical, regulatory/legal and social implications described in this article.

Sleeping Time, BMI, and Body Fat in Chinese Freshmen and Their Interrelation

INTRODUCTION

In the past two decades, urbanization in many Asian countries has led to sedentary lifestyle and overnutrition, which has set the stage for the epidemic of obesity. Those who have obesity during adolescence usually have obesity into adulthood, which causes many medical and psychological issues that can result in premature death. Recent data suggest that short sleep duration may contribute to the risk of obesity, opening a new avenue for potential intervention. The aim of this study was to describe the prevalence of sleeping time, body mass index (BMI), and fat mass in Chinese freshmen and to indicate the relationship among them.

METHODS

We conducted a cross-sectional study consisting of 1,938 freshmen aged from 18 to 24 years, including 684 (35.3%) men and 1,254 (64.7%) women. BMI, sleeping time, and other potential related variables were collected by questionnaire. Obesity and overweight were defined as BMI ≥28.0 and ≥24.0, respectively. All students were divided into three groups according to the tertiles of body fat percentage (Fat%), which were measured by bioelectrical impedance analysis. Sleeping time was divided into 3 categories based on the duration, <6, 6-8, and >8 h per day.

RESULTS

Participants who slept longer had lower BMI and Fat%. Sex, diet control, and maternal obesity were all significantly associated with BMI or Fat% after adjustment. There were significant differences between sleeping time <6 and >8 h in both overweight group and Fat% tertiles independent of adjustment used. The significant difference between sleeping time 6-8 and >8 h only existed in overweight group, while irrelevant relation was observed in both models of obesity group.

CONCLUSION

Longer sleeping time was associated with a lower BMI in Chinese freshmen, even after adjustment for multiple confounders. The overweight stage is a critical period of weight management intervention by changing sleeping time. If adolescents have entered the obesity stage, the effect size of lifestyle intervention might be significantly limited.

Association of cardiorespiratory fitness, physical activity level, and sedentary behavior with overweight in adolescents

Abstract Physical activity and sedentary behavior promote opposite effects on overweight and obesity, in adolescents; however little is known of their combined impact on these outcomes. We aimed to investigate if there were any associations between overweight, and physical activity level, cardiorespiratory fitness, and sedentary behavior, both as isolated variables and in combination. Data of 1,015students from two public and four private schools from the metropolitan area of Rio de Janeiro, Brazil were analyzed. Overweight was classified according to body mass index, whereas physical activity level was assessed by the International Physical Activity Questionnaire (IPAQ), cardiorespiratory fitness by a 9-minute test (T9), and sedentary behavior by a self-completed questionnaire, considering the time spent watching television as the main indicator. Associations were examined by binary logistic regression analysis. Odds ratios (ORs) and 95% confidence intervals (95%CIs) were used to measure the magnitude of the associations. IBM SPSS Statistics version 20 was used for all statistical analyses. Adolescents with poor cardiorespiratory fitness (OR=3.71; 95%CI=1.30-10.6) and a high degree of sedentary behavior (OR=1.73; 95%CI=1.24-2.42) had a bigger chance of being overweight. However the combination of these two categories in the same individual was not statistically associated with overweight. The study indicates that both sedentary behavior and poor performance on cardiorespiratory fitness test are significantly independent associated with overweight in adolescents.

The Acute Effects of a "Reduced Sitting Preschool Day" on Executive Function and Musculoskeletal Health in Preschoolers: A Randomized Cross-Over Study

PURPOSE

To examine the acute effects of a reduced sitting day on executive function (EF) and musculoskeletal health in preschoolers.

METHODS

A sample of 29 children (54% boys; 4-5 y) participated in a randomized cross-over trial. Each child completed 2 protocols, which simulate a day at childcare in random order for 2.5 hours; a typical preschool day (50% sitting) and a reduced preschool day (25% sitting) where most sitting activities were replaced with standing activities. Sitting, standing, and stepping time were objectively assessed using an activPAL accelerometer. EF was evaluated using tablet-based EF assessments (inhibition, working memory, and task shifting). Musculoskeletal health was assessed using a handheld dynamometer and goniometer.

RESULTS

Compared with the typical preschool day, the reduced sitting day showed no significant differences for EF scores. Effect sizes for inhibition (d = 0.04), working memory (d = 0.02), and shifting (d = 0.11) were all small. For musculoskeletal health, no significant differences were reported after the reduced preschool day. The effect sizes for the hip extension force, hamstring flexibility, gastrocnemius length, and balancing on 1 leg were all small (d = 0.21, d = 0.25, d = 0.28, and d = 0.28).

CONCLUSIONS

This study suggests that reducing sitting time is unlikely to result in acute changes in EF and musculoskeletal health among preschoolers.

Sedentary Behaviors in Today's Youth: Approaches to the Prevention and Management of Childhood Obesity: A Scientific Statement From the American Heart Association

This scientific statement is about sedentary behavior and its relationship to obesity and other cardiometabolic outcomes in youth. A deleterious effect of sedentary behavior on cardiometabolic health is most notable for screen-based behaviors and adiposity; however, this relation is less apparent for other cardiometabolic outcomes or when sedentary time is measured with objective movement counters or position monitors. Increasing trends of screen time are concerning; the portability of screen-based devices and abundant access to unlimited programming and online content may be leading to new patterns of consumption that are exposing youth to multiple pathways harmful to cardiometabolic health. This American Heart Association scientific statement provides an updated perspective on sedentary behaviors specific to modern youth and their impact on cardiometabolic health and obesity. As we reflect on implications for practice, research, and policy, what emerges is the importance of understanding the context in which sedentary behaviors occur. There is also a need to capture the nature of sedentary behavior more accurately, both quantitatively and qualitatively, especially with respect to recreational screen-based devices. Further evidence is required to better inform public health interventions and to establish detailed quantitative guidelines on specific sedentary behaviors in youth. In the meantime, we suggest that televisions and other recreational screen-based devices be removed from bedrooms and absent during meal times. Daily device-free social interactions and outdoor play should be encouraged. In addition, parents/guardians should be supported to devise and enforce appropriate screen time regulations and to model healthy screen-based behaviors.

Sitting and Screen Time Outside School Hours: Correlates in 6- to 8-Year-Old Children

BACKGROUND

Although there is increasing evidence regarding children's screen time, little is known about children's sitting. This study aimed to determine the correlates of screen time and sitting in 6- to 8-year-old children.

METHODS

In 2011-2012, parents in the Healthy Active Preschool and Primary Years (HAPPY) study (n = 498) reported their child's week/weekend day recreational screen time and potential correlates. ActivPALs™ measured children's nonschool sitting. In model 1, linear regression analyses were performed, stratified by sex and week/weekend day and controlling for age, clustered recruitment, and activPAL™ wear time (for sitting analyses). Correlates significantly associated with screen time or sitting (P < .05) were included in model 2.

RESULTS

Children (age 7.6 y) spent 99.6 and 119.3 minutes per day on week and weekend days engaging in screen time and sat for 119.3 and 374.6 minutes per day on week and weekend days, respectively. There were no common correlates for the 2 behaviors. Correlates largely differed by sex and week/weekend day. Modifiable correlates of screen time included television in the child's bedroom and parental logistic support for, encouragement of, and coparticipation in screen time. Modifiable correlates of sitting included encouragement of and coparticipation in physical activity and provision of toys/equipment for physical activity.

CONCLUSIONS

Interventions may benefit from including a range of strategies to ensure that all identified correlates are targeted.

Sedentary Thresholds for Accelerometry-Based Mean Amplitude Deviation and Electromyography Amplitude in 7-11 Years Old Children

We investigated the ability of energy expenditure, movement sensing, and muscle activity to discriminate sedentary and non-sedentary activities in children. Thirty-five 7–11-year-old children participated in the study. Simultaneous assessment of oxygen uptake (V̇O₂), triaxial accelerometry, and thigh muscle electromyography (EMG) were performed during eight different sedentary and non-sedentary activities including lying down, sitting-, standing-, and walking-related activities, which were performed in a random order. Mean values of V̇O₂, accelerometry, and EMG from the concurrent 2 min epochs during each activity were computed. Resting energy expenditure (REE) was measured during 30 min supine rest. Directly measured metabolic equivalent of tasks (METs, V̇O₂ in activities/V̇O₂ in REE) were calculated for each activity. Mean amplitude deviation (MAD) was computed for accelerometry. EMG was normalized for mean muscle activity during self-paced walking. The classification accuracy of METs, MAD, and EMG to discriminate sedentary activities from physical activities was investigated by receiver operating characteristic curves and optimal cut-offs based on maximal sensitivity and specificity. Mean (SD) REE was 5.0 ± 0.8 ml/kg/min. MET, MAD, and EMG values ranged from 1.0 to 4.9, 0.0020 to 0.4146 g, and 4.3 to 133.9% during lying down and walking at 6 km/h, respectively. Optimal cut-offs to discriminate sedentary activities from non-sedentary activities were 1.3 for METs (sensitivity = 82%, specificity = 88%), 0.0033 g for MAD (sensitivity = 80%, specificity = 91%), and 11.9% for EMG (sensitivity = 79%, specificity = 92%). In conclusion, this study provides applicable thresholds to differentiate sitting and standing and sedentary and non-sedentary activities based on METs, MAD, and EMG in young children.

Physical Activity Trends in Separate Contexts Among South Australian Older Children (10-12 Y) and Early Adolescents (13-15 Y) From 1985 to 2013

PURPOSE

To assess trends in South Australian children's physical activity between 1985 and 2003 and 2013 in the contexts of school active transport, organized sport, physical education, and school break times.

METHOD

The 1985 Australian Health and Fitness Survey was administered in South Australian schools in 2004 (8 schools) and 2013 (9 schools) and was demographically matched to the 10 South Australian schools in the Australian Health and Fitness Survey. Ordinal logistic modeling was used to identify trends, stratified by older children (10-12 y) and early adolescent (13-15 y) subgroups.

RESULTS

School active transport generally declined for males and older female children (19 and 20 percentage points per decade, respectively), whereas early adolescent females increased in walking to school (11 percentage points per decade). School sport participation declined for early adolescents, and club sport participation declined in early adolescent females (23 percentage points per decade). Moderate to vigorous physical activity participation during school break times (particularly lunchtime) generally declined (16-26 percentage points per decade). Observed changes in most contexts occurred between 2004 and 2013.

CONCLUSION

There was evidence of context-specific declines in children's physical activity participation over this time span. Early adolescent females were the subgroup of most concern, experiencing declines in most contexts.

High sedentary time in children is not only due to screen media use: a cross-sectional study

Background

Sedentary behaviour has become a growing public health concern. Currently, it is a common belief that screen time (SCT) is a key factor in high overall sedentary time (ST) and is often used as a primary outcome. However, the evidence is lacking. Therefore, this study investigated the association of objectively assessed total ST with SCT among children. Further, SCT was investigated separately for sedentary level, weight status, gender, and migration background.

Methods

For 198 primary school children (7.1 ± 0.7 years, boys: 43.9%) ST was assessed objectively using a multi-sensor device (Actiheart®; CamNtech, Cambridge, UK). The sample was split into three groups (tertiles) to investigate SCT of children with low, medium and high ST. SCT and socio-demographic parameters, such as migration background, were assessed using a parental questionnaire; anthropometric data was collected at schools.

Results

Absolut SCT did not differ significantly among the three sedentary groups: Daily average of SCT was 83.8 ± 55.0 min (27.4% of ST) for children with high ST, 82.8 ± 50.5 min (39.8% of ST) for children with medium ST, and 77.2 ± 59.4 min (71.3% of ST) for those with low ST. However, relatively the SCT percentage of total ST was significantly higher among children with low ST (p < 0.01). Significantly higher SCT was found in children with migration background (p < 0.01), while underweight children had significantly less SCT (p < 0.05). An association of total SCT and overall ST was found for the whole sample (B = 17.11, [2.75; 31.48], p = 0.02), but did not remain when analysis were separated for the groups, except for normal weight children (B = 15.97, [0.13; 31.81], p = 0.05).

Conclusions

The amount of SCT is the same among high, low and medium sedentary children, and high ST is largely independent of SCT. Therefore, SCT cannot be the key contributor to high ST and should not solely be used for predicting or changing children’s sedentary behaviour. Moreover, children’s weight status to classify activity levels and the role of possible compensation mechanisms should be considered in future research and when trying to intervene on ST.

Trial registration

German Clinical Trials Register (DRKS), DRKS-ID: DRKS00000494 DATE: 25/08/2010.

Validity and reliability of an instrument to measure factors associated with screen time in Brazilian students

This study analyzed the validity and reliability of an instrument with scales measuring factors associated with screen time in adolescents. Two cross-sectional studies included students for analyses of validity and internal consistency (n=1138, 51.5% boys) and test-retest reproducibility (n=194, 56.2% boys). Individual (attitude, self-efficacy and expectations), social (behaviors, rules, beliefs and family support and support of school members) and physical environmental (home and bedroom equipment) factors of screen time were evaluated. All the scales of the instrument met the statistical criteria of the validity of the exploratory factorial analysis (p<0.001). The exploratory factorial analysis indicated five one-dimensional and three two-factor scales (self-efficacy, expectations and familiar behavior), with factorial loads of 0.56 to 0.88. There were significant correlations between the scores of almost all the scales and the reported screen time (p<0.05). Eight of nine scales/subscales showed Cronbach's α value being higher than 0.70, and ICC ranged from 0.63 to 0.83. In conclusion, the instrument presented scales with acceptable validity and reliability and can be used to measure factors associated with screen time in Brazilian students.

Associations of Class-Time Sitting, Stepping and Sit-to-Stand Transitions with Cognitive Functions and Brain Activity in Children

Previous research showed that children’s physical activity is positively related to executive functions, whilst screen time shows negative associations. However, it is unclear how school-based sitting time and transitions from sitting to standing relate to cognition. We investigated the relationship between class time sitting/stepping/sit-to-stand transitions and cognitive functions in Grade 1–2 children. Overall, 149 children (7.7 ± 0.6 years old, 54% boys) participated. Measures included class time sitting/stepping/sit-to-stand transitions and: (i) response inhibition (i.e., response time and accuracy); (ii) lapses of attention; (iii) working memory; and (iv) brain activity (cortical haemodynamic response). Linear mixed-models, adjusting for age, sex, and clustering at the classroom level, found that more sitting time was associated with higher lapses of attention (β = 0.12, p < 0.05). Children who stepped more had quicker inhibition response time (β = −0.95, p < 0.01); however, they were less accurate in their responses (β = −0.30, p < 0.05) and this was also observed with sit-to-stand transitions (β = −0.26, p < 0.05). No associations were found with brain activity. In conclusion, reducing and breaking up sitting may help keep children focused, but the evidence regarding response inhibition is unclear.

Associations between family structure and young people's physical activity and screen time behaviors

Background

Identifying factors that can influence young peoples’ physical activity and sedentary behaviors is important for the development of effective interventions. The family structure in which children grow up may be one such factor. As the prevalence of single parent and reconstituted families have increased substantially over the last decades, the objective of this study was to examine whether these family structures are differentially associated with young people’s MVPA, participation in organized sports and screen-time activities (screen-based passive entertainment, gaming, other screen-based activities) as compared to traditional nuclear families.

Methods

The data stem from the 2013/2014 “Health Behaviour in School- aged Children (HBSC) study”. A large Norwegian sample of 11–16 years old students (n = 4509) participated. Cluster-adjusted regression models were estimated using full information maximum likelihood with robust standard errors (MLR).

Results

After adjusting for covariates, living with a single parent was negatively associated with days/week with 60 min MVPA (b = −.39, 95%CI: −.58, −.20), and positively associated with hours/weekday of total screen time (b = .50, 95%CI: .08, .93). Young people living with a single parent were also more likely to report no participation in organized sports (OR = 1.40, 95%CI: 1.09, 1.79). Living in a reconstituted family was negatively associated with days/week with 60 min MVPA (b = −.31, 95%CI: −.53, −.08), and positively associated with hours/weekday of total screen time (b = .85, 95%CI: .37, 1.33). For all outcomes, the interaction effects of family structure with sex, and with having siblings were not statistically significant. For material affluence, a significant interaction effect was found for participation in organized sports (χ² [4] =13.9, p = .008). Those living in a reconstituted family with low or high material affluence had an increased risk for not participating in organized sports whereas those with medium material affluence did not.

Conclusion

This study suggests that living with a single parent or in reconstituted families was unfavorably associated with physical activity, sport participation and screen-based behaviors among Norwegian youth. The findings indicate that family structure could be an important factor to take into account in the development and testing of interventions. More in-depth research is needed to identify the mechanisms involved.

Longitudinal Sedentary Time Among Females Aged 17 to 23 Years

INTRODUCTION

Time spent in sedentary behaviors is a newer risk factor for poor cardiometabolic health. This study examined longitudinal correlates of sedentary time among a cohort of females from about age 17 to age 23 years.

METHODS

The cohort included females originally participating in the Trial of Activity for Adolescent Girls Maryland site who had assessments in 2009 and 2015 (n=431). Percentage daily time in sedentary behaviors was determined from accelerometers. Sociodemographics, psychosocial factors, and health behaviors were assessed by questionnaire. Lasso variable selection identified potential variables included in linear mixed effects models. As a secondary analysis, a k-means algorithm for longitudinal data identified homogeneous clusters of individual sedentary time trajectories.

RESULTS

Percentage daily sedentary time did not change over time (67% to 68%). Not of black race (p=0.04), higher father's education (p<0.001), more weekday computer hours (p<0.001), more weekend TV hours (p=0.01), more physical activity barriers (p=0.003), fewer days per week driving (p=0.01), and more vehicles in the household (p=0.02) were associated with greater sedentary time. Cluster analysis resulted in two patterns: more (70%) versus less (60%) time being sedentary. The more sedentary individuals were more likely to be college graduates (p<0.001), have a higher income (p=0.03), and work fewer hours (p=0.009). They were also less likely to be married or in a common-law relationship (p=0.05) or in a parenting role (p=0.02).

CONCLUSIONS

Time spent in sedentary behaviors remained stable. Factors associated with sedentary time were significant across the socioecologic framework and included several factors indicating higher SES.

How Can Physical Activity Be Promoted Among Children and Adolescents? A Systematic Review of Reviews Across Settings

Introduction: A vast majority of children and adolescents are physically inactive. As a result, high obesity rates and related diseases have made physical activity promotion a politically relevant topic. In order to form the basis for political decision making, evidence is required regarding the efficacy and effectiveness of interventions for physical activity promotion. In contrast to previous research, this systematic review of reviews targets three key settings (family and home, childcare, school), and is among the largest to have been conducted. Methods: A systematic review of reviews was conducted as part of a large-scale project to develop national recommendations for physical activity promotion in Germany. Six electronic databases were searched and inclusion criteria were defined. Two independent reviewers screened the titles and abstracts of potentially relevant literature. 213 reviews were identified and categorised by target group. A total of 74 reviews were identified dealing with children and adolescents. Each review underwent a quality assessment. Results: 39 reviews with the highest quality and relevance were analysed. Three reviews focused on the family and home setting, 4 on the childcare setting, 28 on the school setting and 4 on other settings. Evidence revealed the key role played by parents in promoting physical activity in children within each setting. Furthermore, evidence pointed toward the efficacy of multi-component interventions in the childcare and school setting. Several evidence-based intervention strategies were identified for childcare facilities and schools. Discussion: The review of reviews identified a number of promising strategies for PA promotion among children and adolescents. Among reviews, multi-component interventions in childcare facilities and schools stand out prominently. At the same time, the review of reviews indicated that there is still a lack of studies on the efficacy of interventions that go beyond the individual level. We recommend that future research should also target community and policy level interventions and interventions other than the school setting. In order to make more specific recommendations regarding the scale-up of promising intervention strategies, further knowledge about the effectiveness, health equity and cost effectiveness of interventions is needed.

Heart Rate Kinetics Response of Pre-Pubertal Children during the Yo-Yo Intermittent Endurance Test-Level 1

This study analyzed heart rate (HR) kinetics during the Yo-Yo Intermittent Endurance Test—level 1 (Yo-Yo IE1) in children. At the middle of the school year, 107 boys (7–10 years old) performed the Yo-Yo IE1. Individual HR curves during the Yo-Yo IE1 were analyzed to detect an inflection point between an initial phase of fast rise in HR, and a second phase in which the rise of HR is slower. The 7^th shuttle of the test was established as the inflection point. Engagement with extra-school sports practice was identified. Percentile groups (P₁, P₂ and P₃) were created for body weight and physical fitness data composite (PF_composite). Differences were found between the slopes of P₁ and P₃ on phase 1 for body weight (12.5 ± 2.7 vs. 13.7 ± 2.0 bpm/shuttle; p = 0.033; d = 0.50) and PF_composite (14.2 ± 2.5 vs. 12.5 ± 2.0 bpm/shuttle; p = 0.015; d = 0.75). Time spent >95% of peak HR was longer for the children engaged with extra-school sports practice (335 ± 158 vs. 234 ± 124 s; p < 0.001; d = 0.71); differences were also detected for PF_composite (P₁, P₂ and P₃: 172 ± 92, 270 ± 109, and 360 ± 157 s, respectively; p < 0.05; d = 0.66–1.46). This study indicates that physical fitness and body weight influence HR kinetics during the Yo-Yo IE1 in pre-pubertal boys.