Changes in sedentary behavior among adolescent girls: a 2.5-year prospective cohort study

Trends of physical activity and recreational screen time among Chinese children and adolescents: a national study from 2017 to 2019

BACKGROUND

The prevalence of physical inactivity and sedentary behavior among children and adolescents is a growing public health concern. This study aims to examine the trends in Physical Activity (PA) and Recreational Screen Time (RST) amongst children and adolescents in China, considering variations in genders, school levels, areas (urban versus rural), and regions (north versus south). The findings provide a foundation to guide policy and strategy making for future health promotion and development.

METHODS

An annual national cross-sectional survey was conducted in China from 2017 to 2019 cumulatively involving 52,503 (48% female) children and adolescents from grades 4 to 12 (aged 12.72 ± 2.12). Data on PA and RST were collected through self-administered questionnaires. Weighted least squares regression was used to analyze the trends and differences in PA and RST among the participants' profiles.

RESULTS

There was an annual decreased in PA compliance rate of approximately 3.43% (95% CI: 0.79-6.08%) for primary school students, primarily among males residing in rural areas, and in northern regions. Middle school students experienced a yearly decrease of about 5.23% (95% CI: 2.55-7.92%) in PA compliance across all genders, regions, and urban areas. Similarly, the RST compliance rates for primary school students declined by approximately 3.18% (95% CI: 1.57-4.78%) annually for all genders and areas, but only in the northern regions.

CONCLUSIONS

This research highlights a downward trend in PA and RST compliance amongst Chinese children and adolescents, with variations based on school level, gender, area, and region. Urgent policies and interventions are imperative to promote PA while mitigating excessive RST within these populations.

Physical activity, screen time and body composition in 13-year-old adolescents: The Generation R Study

BACKGROUND

Body composition between prepubertal children and adolescents varies, and it is unclear how physical activity and sedentary behaviour affect adolescent body composition.

OBJECTIVES

This study aimed to examine the associations of physical activity and screen time with overall and specific fat depots in the general adolescent population.

METHODS

In a population-based prospective cohort study, among 3258 adolescents aged 13 years, physical activity and screen time were assessed via self-report questionnaires. Body mass index, dual-energy X-ray absorptiometry-based measures (i.e. fat mass and lean body mass) and magnetic resonance imaging-based measures (i.e. abdominal subcutaneous and visceral fat mass) were obtained.

RESULTS

After adjusting for social-demographic and growth-related factors, each additional hour of daily physical activity was associated with lower fat mass, abdominal visceral fat mass and higher lean body mass (all p < 0.05). However, these associations were not observed in the longitudinal analyses. Each additional hour of daily screen time was associated with higher body mass index, fat mass, abdominal subcutaneous and visceral fat mass (all p < 0.05), which were consistent with the longitudinal analyses.

CONCLUSION

Adolescents with higher physical activity and lower screen time had lower levels of adiposity both at the general and visceral levels.

Physical activity and eating behaviors patterns associated with high blood pressure among Chinese children and adolescents

BACKGROUND

Physical activity and eating behavior are associated with hypertension in children and adolescents. Revealing the associations between physical activity patterns, eating behavior patterns and high blood pressure (HBP) could help improve the problem of hypertension from the actual children's physical activities and eating behaviors.

METHODS

A total of 687 students aged 8-15 years were selected from two nine-year primary and secondary schools using stratified cluster random sampling method. The students' body height, weight, systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured, and their physical activity time and eating behaviors were surveyed by using CLASS questionnaire and self-made eating behavior questionnaire, respectively. Exploratory factor analysis (EFA) was used to extract moderate to vigorous physical activity factor (MVPAF), sedentary activity factor (SAF), healthy eating behavior factor (HEBF), unhealthy eating behavior factor (UHEBF). MVPAF ≥ SAF was defined as moderate to vigorous physical activity pattern (MVPAP), MVPAF < SAF was defined as sedentary activity pattern (SAP). HEBF ≥ UHEBF was defined as healthy eating behavior pattern (HEBP), while the opposite was defined as unhealthy eating behavior pattern (UHEBP). Lifestyles includes physical activity patterns and eating behavior patterns.

RESULTS

The overall prevalence of hypertension was 5.8% (40/687), and was 5.69% (21/369) in boys and 5.97% (19/318) in girls, respectively. The MVPAF and UHEBF in boys were significantly higher than those in girls (P < 0.01), while the SAF in girls was significantly higher than that in boys (P < 0.05). The SAF was positively correlated with SBP in girls (β(SE) = 0.14 (0.50), P = 0.016), and was positively correlated with SBP (β(SE) = 0.21 (1.22), P = 0.000 and DBP (β(SE) = 0.14 (0.49), P = 0.006) in boys. The MVPAF was negatively correlated with DBP (β(SE)=-0.11 (0.40), P = 0.022) in boys. In boys, the SAP increased the risks of HBP (OR (95% CI):3.34 (1.30-8.63)) and high DBP (OR (95% CI):3.08 (1.02-9.34)) compared with MVPAP.

CONCLUSION

Compared with the boys with MVPAP, boys with SAP may increase the risks of HBP and high DBP. The SAF may be positively associated with SBP in boys and girls, while the MVPAF may be negatively associated with DBP in boys.

The influence of specialization and the level of physical activism on leisure options for students of the Faculty of Physical Education and Sports

Leisure activities, their dynamics in ontogenesis and the way of managing the time allocated to them are a topic that is frequently researched. Purpose: to investigate students' attitudes, aiming at aspects related to forms of leisure, depending on specialization and level of physical activism, by applying a questionnaire. Material and method: The research took place in the academic year 2019-2020, on a number of 180 students of the Faculty of Physical Education and Sports in Galați. The differences for the pairs of independent specialty variables (PES / physical education and sport and PT / physical therapy), respectively physical activity (HLPA / high level of physical activity, and LLPA / low level of physical activity were analyzed, by applying the techniques of MANOVA and ANOVA calculation. Results: Multivariate analysis indicates significant effects of the physical activity variable on the items of the questionnaire for leisure budget factors, preferred leisure activities, leisure sports activities, and for the specialty variable significant effects are determined only at leisure sports activities, so the level of physical activism will generate more differences between the opinions expressed compared to the specialization of students. Univariate test results indicate significant F values (P <0.05) for a number of items, with weaker values, dominant for PT and LLPA groups. Sports activities and socializing on the internet (defining variant of young people) are at the top, so they do not exclude each other. Conclusion: the students from the PES and HLPA groups stand out through a better organization of free time, high satisfaction of its capitalization, a greater involvement in the variants of active leisure and superior socialization, and those from the PT and LLPA groups allocate more time to watching on TV and using the internet. Keywords: physical activism, specialization, questionnaire, active and passive leisure options, opinions

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 INFLUENCE OF BODY INDEX MASS ON THE LEISURE TYPES FOR THE STUDENTS OF THE FACULTY OF PHYSICAL EDUCATION AND SPORTS

The study aims to investigate the ways of spending free time for a group of 180 students of the Faculty of Physical Education and Sports in Galati (years 1, 2 and 3 of cycle 1 / bachelor’s degree studies, with an average age of 22.34 ± 5.79 years.), by using a questionnaire-based survey, structured on 4 distinct factors: leisure time budget, causes limiting leisure time, favorite leisure activities and leisure sports activities. The purpose of the research is to determine the perception of students of the Faculty of Physical Education and Sports on how to spend free time and determine differences of opinion, depending on BMI / body mass index, by dividing them into 3 groups (underweight, normal weight or overweight). Results: The analysis of variance (ANOVA) indicates significant influences of the independent variable on the response values for the following items (F <.05): inaccessibility of going out with friends, stress generated by shopping, limiting free time to help others, spending free time with entourage and life partner, spending holidays in the country, etc. Socializing on the internet, physical sports activities, TV, internet and computer games, going out with friends are the preferred options for students, and reading gets low scores. The differences between groups (in most cases insignificant) however, signal that normal weight students watch TV and the Internet the least, but waste more time with commuting and household activities and have high scores when involved in most sports. Overweight people have low scores for time spent on favorite activities, are most dissatisfied with time management, work more overtime, spend less time with those around them, but prefer to spend time with their life partner or alone, have slightly better scores for reading and music auditions, get the lowest scores for involvement in most sports activities, but have high satisfaction generated by physical effort. Underweight students perceive the inaccessibility of going out with friends more strongly, are more affected by difficult homework, have a higher level of stress for reading, but perceive most other activities as less stressful, socialize more on the internet, prefer jogging and cycling / rollerblading as sports activities. Swimming is selected by all groups as indicated for optimizing health and ensuring body harmony, even if its practice is deficient, and contact / combat sports are indicated as the most risky for physical integrity. Keywords: active and passive leisure, lifestyle, physical and mental health, opinions, accessibility

Characterizing Changes in Screen Time During the COVID-19 Pandemic School Closures in Canada and Its Perceived Impact on Children With Autism Spectrum Disorder

The COVID-19 pandemic has led to an increase in screen time for children and families. Traditionally, screen time has been associated with negative physical and mental health outcomes, and children with autism spectrum disorder (ASD) are at increased risk of these outcomes. The primary objectives of this study were to (1) characterize the change in screen time during COVID-19 school closures for children with ASD, and (2) examine the parent perceived impact of screen time on mental health and quality of life of children and their families. Canadian parents and caregivers of children 19 years of age and younger were eligible to participate in an anonymous, online survey study. This survey was available in English, consisted of 28 questions, took ~10-min to complete, and was available for 6 weeks (May 22 through July 6, 2020). The total sample consisted of 414 responses (ASD: n = 127, mean age = 11.7 ± 4.06 years; community sample: n = 287, mean age = 9.4 ± 4.26 years). Seventy-one respondents were missing responses to our primary question and removed from the analyses (final sample n = 344). Compared to the community sample, the ASD group had a significantly higher screen time use before and during the COVID-19 pandemic school closures [weekdays: difference = 1.14 (SE = 0.18), t = 6.56, p < 0.0001; weekends: difference = 1.41 (SE = 0.20), t = 6.93, p < 0.0001]. Mean total screen time during the pandemic was 6.9 h (95% CI 6.49, 7.21) on weekdays and 6.3 h (95% CI 5.91, 6.63) on weekends for the ASD group, and 5.6 h (95% CI 5.28, 5.92) on weekdays and 5.0 h (95% CI 4.70, 5.34) on weekends for the community sample. There was a significant increase in screen time during the COVID-19 pandemic as compared to before the pandemic period in the ASD group [weekdays: mean difference = 3.8 h (95% CI 3.35-4.25), p < 0.0001; weekends: mean difference = 1.5 h (95% CI 1.17-1.92), p < 0.0001]. Gender was a significant predictor of parent perceived mental health and quality of life, with male gender associated with a higher likelihood of negative impact [quality of life (child/family) OR = 1.8 (95% CI 1.1-2.9), corrected p = 0.040; mental health OR = 1.9 (95% CI 1.1-3.1), corrected p = 0.0028]. Parents' most frequently endorsed emotions toward screen time were guilt, frustration, and worry. Results of this survey study revealed that children with ASD were less likely to benefit from screen time to cope with social isolation, and screen time resulted in significantly more lost time on social interactions than the community sample, which may exacerbate difficulties in social domains. Given the unprecedented circumstances of the COVID-19 pandemic and the novel context of technology use, the findings of this study highlight the need for revision of screen time recommendations to reflect the current needs of children and families.

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.

Effects of physical activity interventions on cognitive outcomes and academic performance in adolescents and young adults: A meta-analysis

The aim was to provide a meta-analysis of studies investigating the effects of physical activity interventions on cognitive outcomes and academic performance in adolescents or young adults. A systematic review with meta-analysis was performed using the following databases: Embase, ERIC, MEDLINE, PsycINFO and Web of Science. Studies had to meet the following criteria: controlled study design, investigating the effects of physical activity interventions on cognitive outcomes and academic performance in healthy adolescents or young adults (12-30 years). Results showed that acute interventions (n=44) significantly improved processing speed (ES=0.39), attention (ES=0.34) and, inhibition (ES=0.32). In a subsequent meta-regression, shorter duration of intervention was significantly associated with greater improvements in attention (β=-0.02) and cognitive flexibility (β=-0.04), whereas age, percentage of boys, intensity and dose were not. Chronic interventions (n=27) significantly improved processing speed (ES=0.30), attention (ES=0.50), cognitive flexibility (ES=0.19), working memory (ES=0.59) and language skills (ES=0.31). In the meta-regression, higher percentage of boys was significantly associated with greater improvements in attention (β=0.02) and working memory (β=0.01) whereas age, duration, frequency, dose and load were not. In conclusion, acute and chronic physical activity interventions might be a promising way to improve several cognitive outcomes and language skills in adolescents and young adults.

The Role of Recreational Online Activities in School-Based Screen Time Sedentary Behaviour Interventions for Adolescents: A Systematic and Critical Literature Review

Sedentary behaviours are highly associated with obesity and other important health outcomes in adolescence. This paper reviews screen time and its role within school-based behavioural interventions targeting adolescents between the years 2007 and 2019. A systematic literature review following PRISMA guidelines was conducted across five major databases to identify interventions targeting screen time—in addition to TV/DVD viewing. The review identified a total of 30 papers analysing 15 studies across 16 countries aiming at addressing reduction of recreational screen time (internet use and gaming) in addition to television/DVD viewing. All of the interventions focused exclusively on behaviour change, targeting in the majority both reduction of sedentary behaviours along with strategies to increase physical activity levels. A mix of intervention effects were found in the reviewed studies. Findings suggest aiming only for reduction in time spent on screen-based behaviour within interventions could be a limited strategy in ameliorating excessive screen use, if not targeted, in parallel, with strategies to address other developmental, contextual and motivational factors that are key components in driving the occurrence and maintenance of adolescent online behaviours. Additionally, it raises the need for a differential treatment and assessment of each online activity within the interventions due to the heterogeneity of the construct of screen time. Recommendations for enhancing the effectiveness of school-based sedentary behaviour interventions and implications for public policy are discussed.

Active Gaming Prevalence and Correlates by Type of Day in Spanish Youth

BACKGROUND

Active gaming has emerged as a new option to foster physical activity in youth. The aim of this study was to estimate the prevalence of active gaming in adolescents, to determine differences between active and nonactive gamers by type of day, and to examine predictors of being an active gamer.

METHODS

A cross-sectional study was conducted with 3095 Spanish adolescents aged 12 to 18 years who self-reported their involvement in moderate to vigorous physical activity, sedentary behaviors, and active gaming. Those engaging in active gaming for at least 10 minutes per day were considered active gamers. Student's 2-tailed t tests, chi-square test, and binomial logistic regression were performed.

RESULTS

About 25.9% of the adolescents were active gamers. They were younger, had higher body mass index, and spent more time on moderate to vigorous physical activity, television viewing, and sedentary video games with computer/console than nonactive gamers. There were more active gamers on weekends than on weekdays. On weekdays, more males than females were active gamers. Adolescents who did not meet sleep time guidelines were more likely to be active gamers on weekdays, whereas on weekends, being a girl, overweight/obese, and having a high socioeconomic status were predictors of being an active gamer.

CONCLUSION

Because active gaming may contribute to meeting physical activity guidelines, the present findings could enable better targeting of physical activity promotion programs.

Personal Network Characteristics as Predictors of Change in Obesity Risk Behaviors in Early Adolescence

The potential for peers to influence obesity risk behavior increases in adolescence, yet there are knowledge gaps of how behaviors are modified in response to peers over time. This study examined how personal friendship network characteristics were associated with obesity-related behaviors from late childhood to early adolescence. Two waves of friendship, physical activity, screen time, and dietary recall data were collected from 11- to 13-year-old students (99% retention) in Australia (n = 308) over a five- to eight-month period. Regression models identified friendship network characteristics that predicted later health behaviors which varied by gender and behavior type, such as the number of friends positively associated with physical activity intensity (males) and screen time (females). The need for considering context to influence behavior change is discussed.

Screen time and moderate-to-vigorous physical activity changes and displacement in adolescence: A prospective cohort study

BACKGROUND

This paper determines longitudinal changes in the time Spanish adolescents devote to moderate-to-vigorous physical activity (MVPA) and screen media activity (SMA). Moreover, it examines the displacement hypothesis between time spent on SMA and MVPA.

METHODS

A cohort of 755 adolescents participated in a prospective cohort study over a three-year period. Repeated measures ANOVA to highlight interaction effects among all variables and Structural Equation Modeling (SEM) techniques were employed.

RESULTS

Age and gender-related variations in longitudinal changes in time spent on MVPA and SMA evolved in the inverse direction (decreased on MVPA/increased on SMA) according to the ANOVA. The potential displacement between time spent on SMA and MVPA from Wave I to Wave II was analysed via SEM. The first model, estimated in the overall sample, showed no evidence for the displacement hypothesis. Subsequently, a multigroup sequence of panel models was performed and a partial displacement was observed only in boys. Hence, boys who spent more time on SMA were more likely to devote less time to MVPA three years later.

CONCLUSION

This study confirms the opposite trend on the time spent on MVPA and SMA over a three-year period, being clearly higher in SMA. Further SEM analyses reveal a deferred displacement hypothesis between SMA and MVPA only in boys. This partial gendered displacement may be linked to the different uses adolescents make of screen media. The incursion of new technological devices (smartphones or tablets) and their wide range of possibilities for social networking or gaming could explain this displacement.

Association Between Sitting, Screen Time, Fitness Domains, and Fundamental Motor Skills in Children Aged 5-16 Years: Cross-Sectional Population Study

BACKGROUND

To examine the associations between school-age children's sedentary behavior, screen time, and 3 physical activity attributes: muscular strength, cardiorespiratory endurance (CRE), and fundamental movement skills.

METHODS

Cross-sectional survey of 2734 children in years 2 and 4 and 3671 adolescents in years 6, 8, and 10. Total sitting time, 6 screen time behaviors, and physical activity were measured by self-report. Muscular strength was assessed by standing broad jump; CRE by 20-m shuttle run test; and fundamental movement skills by process-oriented checklists. Associations between incremental sitting and screen time (in hours) and meeting the healthy zone of physical activity attributes were examined using logistic regression.

RESULTS

After adjusting for covariates and physical activity, children had lower odds of achieving the healthy zone for muscular strength and CRE for each hour of week (but not weekend) screen time. For adolescents, each hour of screen time per day was associated with lower odds of achieving the healthy fitness zone for CRE, locomotor skills, and overall healthy zone, and each hour of weekend screen time was associated with lower odds of achieving the healthy zone for most attributes and overall healthy zone. The associations were slightly stronger among adolescent girls than boys. The findings were similar for total sitting time.

CONCLUSIONS

Screen time was associated with a lower likelihood to achieve healthy zones of physical activity attributes, and the effect was more consistent and slightly stronger among adolescents than children. This may suggest that the negative effects of screen time are incremental, emerging during adolescence.

The 3-Year Longitudinal Impact of Sedentary Behavior on the Academic Achievement of Secondary School Students

BACKGROUND

Sedentary behavior is linked to many adverse health outcomes; however, its relationship with academic achievement is less understood. We examined sedentary behavior's impact on academic achievement over 3 years in 4408 adolescents from the COMPASS study.

METHODS

Sedentary behavior (screen-based: watching/streaming television shows/movies, video/computer games, surfing the internet; communication-based: texting/messaging/emailing, talking on the phone; and doing homework) and academic achievement (overall math and English marks) were self-reported.

RESULTS

Holding time fixed, moving from the lowest quartile (Q1) to Q2, Q3, or Q4 of watching/streaming television shows/movies (Q2: OR = 0.90; 95%CI: 0.84-0.97, Q3: OR = 0.85; 95%CI: 0.74-0.98, Q4: OR = 0.74; 95%CI: 0.64-0.85) or to Q2 of surfing the internet (Q2: OR = 0.87; 95%CI: 0.78-0.97) decreased the likelihood of surpassing English standards. Moving from Q1 to Q2 of communication-based sedentary behavior (OR = 0.90; 95%CI: 0.82-0.99) decreased the likelihood of surpassing math standards. Moving from Q1 to Q4 (OR = 1.31; 95%CI: 1.15-1.50) of watching/streaming television shows/movies increased the likelihood of surpassing math standards. Moving from Q1 to Q4 of doing homework (OR = 1.16; 95%CI: 1.02-1.31) increased the likelihood of surpassing English standards.

CONCLUSIONS

Predicting academic achievement from total sedentary behavior is challenging. Targeting specific types of sedentary behavior should be considered for improving math and English achievement.

Review of Short-Form Questions for the Evaluation of a Diet, Physical Activity, and Sedentary Behaviour Intervention in a Community Program Targeting Vulnerable Australian Children

Childhood obesity is associated with low socioeconomic status in developed countries, and community programs can deliver cost-effective obesity interventions to vulnerable children and adolescents at scale. Evaluating these programs in a low-cost, time-efficient, and culturally appropriate way with valid and reliable measures is essential to determining their effectiveness. We aimed to identify existing valid and reliable short-form instruments (≤50 items for diet, ≤15 items for physical activity) suitable for the assessment of change in diet, physical activity, and sedentary behaviour in an Australian obesity intervention program for children and adolescents aged 7⁻13 years from low socioeconomic groups, with a focus on Aboriginal and Torres Strait Islander children. Relevant electronic databases were searched, with a focus on Australian literature. Validity and/or reliability studies using diet instruments (5), physical activity/sedentary behaviour instruments (12), and diet and physical activity/sedentary behaviour instruments used with Aboriginal and Torres Strait Islander (3) children were identified. Seven questions on diet, one question on physical activity, and no questions on sedentary behaviour were recommended. These questions can be used for evaluation in community-based obesity programs among Australian children and adolescents, including those from low socioeconomic groups and Aboriginal and Torres Strait Islander children.

Systematic Review of Childhood Sedentary Behavior Questionnaires: What do We Know and What is Next?

BACKGROUND

Accurate measurement of child sedentary behavior is necessary for monitoring trends, examining health effects, and evaluating the effectiveness of interventions.

OBJECTIVES

We therefore aimed to summarize studies examining the measurement properties of self-report or proxy-report sedentary behavior questionnaires for children and adolescents under the age of 18 years. Additionally, we provided an overview of the characteristics of the evaluated questionnaires.

METHODS

We performed systematic literature searches in the EMBASE, PubMed, and SPORTDiscus electronic databases. Studies had to report on at least one measurement property of a questionnaire assessing sedentary behavior. Questionnaire data were extracted using a standardized checklist, i.e. the Quality Assessment of Physical Activity Questionnaire (QAPAQ) checklist, and the methodological quality of the included studies was rated using a standardized tool, i.e. the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) checklist.

RESULTS

Forty-six studies on 46 questionnaires met our inclusion criteria, of which 33 examined test-retest reliability, nine examined measurement error, two examined internal consistency, 22 examined construct validity, eight examined content validity, and two examined structural validity. The majority of the included studies were of fair or poor methodological quality. Of the studies with at least a fair methodological quality, six scored positive on test-retest reliability, and two scored positive on construct validity.

CONCLUSION

None of the questionnaires included in this review were considered as both valid and reliable. High-quality studies on the most promising questionnaires are required, with more attention to the content validity of the questionnaires. PROSPERO registration number: CRD42016035963.

Do Young People Ever Sit Still? Variations in Accelerometer Counts, Muscle Activity and Heart Rate across Various Sedentary Activities in Youth

Evidence of adverse health effects of TV viewing is stronger than for overall sedentary behaviour in youth. One explanation may be that TV viewing involves less body movement than other sedentary activities. Variations in body movement across sedentary activities are currently unknown, as are age differences in such variations. This study examined body movement differences across various sedentary activities in children and adolescents, assessed by hip-, thigh- and wrist-worn accelerometers, muscle activity and heart rate. Body movement differences between sedentary activities and standing were also examined. Fifty-three children (aged 10–12 years) and 37 adolescents (aged 16–18 years) performed seven different sedentary activities, a standing activity, and a dancing activity (as a control activity) in a controlled setting. Each activity lasted 10 minutes. Participants wore an Actigraph on their hip and both wrists, an activPAL on their thigh and a heart rate monitor. The muscle activity of weight-bearing leg muscles was measured in a subgroup (n = 38) by surface electromyography. Variations in body movement across activities were examined using general estimation equations analysis. Children showed significantly more body movement during sedentary activities and standing than adolescents. In both age groups, screen-based sedentary activities involved less body movement than non-screen-based sedentary activities. This may explain the stronger evidence for detrimental health effects of TV viewing while evidence for child sedentary behaviour in general is inconsistent. Differences in body movement during standing and sedentary activities were relatively small. Future research should examine the potential health effects of differences in body movement between screen-based versus non-screen based and standing versus sedentary activities.

Sedentary behavior during leisure time, physical activity and dietary habits as risk factors of overweight among school children aged 14-15 years: case control study

OBJECTIVE

To determine the risk of sedentary behavior during leisure time, physical activity and dietary habits on overweight among school children aged 14-15 years in Kalutara District, Sri Lanka.

RESULTS

School based case-control study was conducted during September to November 2013 including 176 overweight children as cases and 704 children with normal weight as controls. Cases were defined as body mass index for age and sex of ≥ +1SD and controls as those in the range of -2SD to +1SD. Validated instruments were used for data collection. Multiple logistic regression was applied and results were expressed with adjusted odds ratios (OR) and 95% confidence intervals (CI). Risk factors for overweight were insufficient physical activity (OR 1.6, 95% CI 1.1-2.4), watching video/DVD ≥ 2 h (OR 3.1, 95% CI 1.8-5.3), watching television ≥ 2 h (OR 2.6, 95% CI 1.7-3.8) and doing homework ≥ 2 h, (OR 1.8, 95% CI 1.2-2.7). Consuming meat (OR 1.9, 95% CI 1.2-3.1), fish or other sea foods (OR 1.6, 95% CI 1.1-2.8), fast food/fried rice/oily foods (OR 1.9, 95% CI 1.2-2.9), carbonated drinks or sugary drinks (OR 1.9, 95% CI 1.2-2.8), sweets, cookies or ice cream (OR 1.8, 95% CI 1.2-2.9) were dietary risk factors for overweight. Consuming legumes and seeds (OR 0.50, 95% CI 0.3-0.7), vegetables and fruits (OR 0.6, 95% CI 0.4-0.9) were protective factors for overweight.

Reliability and validity of the Youth Leisure-time Sedentary Behavior Questionnaire (YLSBQ)

OBJECTIVES

To develop a questionnaire able to assess time spent by youth in a wide range of leisure-time sedentary behaviors (SB) and evaluate its test-retest reliability and criterion validity.

DESIGN

Cross-sectional observational.

METHODS

The reliability sample included 194 youth, aged 10-18 years, who completed the questionnaire twice, separated by one-week interval. The validity study comprised 1207 participants aged 8-18 years. Participants wore an accelerometer for 7 consecutive days. The questionnaire was designed to assess the amount of time spent in twelve different SB during weekdays and weekends, separately. In order to avoid usual phenomenon of time over reporting, values were adjusted to real available leisure-time (LT) for each participant. Reliability was assessed by using Intraclass Correlation Coefficients (ICC) and weighted (quadratic) kappa (k), and validity was assessed by using Pearson correlation and Bland-Altman plots.

RESULTS

The reliability of questionnaire showed a moderate-to-substantial agreement for the most (91%) of items (k=0.43-0.74; ICC=0.41-0.79) with three items (4%) reaching an almost perfect agreement (ICC=0.82-0.83). Only 'sitting and talking' evidenced fair-to-moderate reliability (k=0.27-0.39; ICC=0.34-0.46). The relationship between average sedentary time assessed by the questionnaire and accelerometry was moderate (r=0.36; p<0.001). Systematic biases were not found between questionnaire and accelerometer sedentary time for average day (r=0.05; p=0.11) but Bland-Altman plots suggest moderate discrepancies between both methods of SB measurement (mean=19.86; limits of agreement=-280.04 to 319.76).

CONCLUSIONS

The questionnaire showed moderate to good test-retest reliability and a moderate level of validity for assessing SB in youth, similar or slightly better to previously published in this population.

Trajectories of maternal leisure-time physical activity and sedentary behavior during adolescence to young adulthood and offspring birthweight

PURPOSE

The objectives of the study were to determine the extent to which trajectories of maternal preconception leisure-time physical activity (LTPA) and leisure-time sedentary behavior (LTSB) during adolescence and young adulthood are associated with offspring birth weight (BW) and to test if these associations differ by offspring sex or maternal pre-pregnancy overweight-obese status.

METHODS

Participants with one or more birth (n = 1408) were identified from the National Longitudinal Study of Adolescent to Adult Health. Group-based trajectory modeling was used to characterize trajectories of LTPA (frequency/week) and LTSB (hours/week) which were measured, on average, over 7 years between age 15 and 22 years. Weighted regression and Wald tests were used to estimate and test mean differences and odds ratios for BW, small for gestational age, and large for gestational age (LGA).

RESULTS

Three trajectories were identified for LTPA and five for LTSB. Associations differed by offspring sex for continuous BW and LGA (interaction P = .10 and .008, respectively). Among female offspring, participants with high followed by decreasing LTPA delivered offspring with 90 g greater BW (95% confidence interval [CI]: -4 to 184) and 72% greater risk of LGA (95% CI: 0.94-3.14), compared with participants with low LTPA. Among male offspring, LTPA patterns were not associated with BW. A pattern of high then decreasing LTPA among normal weight, but not overweight-obese women, was associated with 2.03 times greater risk of LGA (95% CI: 1.06-3.88). LTSB trajectories were not associated with BW.

CONCLUSIONS

Associations of preconception trajectories of LTPA with offspring BW may differ by offspring sex and maternal pre-pregnancy overweight-obese status.

Why Do Children Engage in Sedentary Behavior? Child- and Parent-Perceived Determinants

Todays children spend a large amount of their time sedentary. There is limited evidence on the determinants of sedentary behavior in children, and qualitative studies are especially lacking. Therefore, this study aimed to explore determinants of children’s sedentary behavior from the child- and parent perspective. Qualitative data were collected during concept mapping sessions with four groups of 11–13 years old children (n = 38) and two online sessions with parents (n = 21). Children and parents generated sedentary behavior motives, sorted related motives, and rated their importance in influencing children’s sedentary time. Next, multidimensional scaling and hierarchical cluster analysis was performed to create clusters of motives resulting in a concept map. Finally, the researchers named the clusters in the concept map. Concept maps of children yielded eight to ten perceived determinants, and concept maps of parents six to seven. Children and parents identified six similar potential determinants, and both rated as important: Sitting because… “it is the norm (I have to)”, and “I can work/play better that way”. In addition, children rated “there is nobody to play with” as an important potential determinant for engaging in sedentary behavior. The most important child- and parent perceived determinants were related to the social/cultural and physical environment, indicating that these are promising targets for future interventions.

Parental Expectations and Child Screen and Academic Sedentary Behaviors in China

INTRODUCTION

This study examined sociodemographic patterns of parental expectations for academic performance, terminal degree, and future occupation for middle school students in China, and how these expectations influence students' screen-based and academic-related sedentary behaviors through parenting control practices.

METHODS

Based on data collected in 2013-2014 from 19,487 Chinese middle school students, bivariate logistic regressions tested associations between sociodemographic variables and parental expectations; structural equation models tested associations between parental expectations and students' self-reported daily time on TV/Internet/homework, with parental controls as potential mediators. Analyses were performed in October 2015.

RESULTS

Chinese students spent 0.96 (SD=1.44) hours/day on TV, 0.56 (SD=1.20) on Internet use, and 2.79 (SD=2.07) on homework. Girls spent more hours/day on homework (2.98 [SD=2.07] vs 2.62 [SD=2.04]) than boys but less on TV (0.90 [SD=1.37] vs 1.02 [SD=1.50]) and Internet (0.42 [SD=0.98] vs 0.69 [SD=1.36]). More than 30% of students were expected by parents to reach the top five of their class, almost 90% were expected to earn a college degree or higher, and >80% were expected to have a professional occupation. Students in rural areas, with siblings, and with lower parental SES tended to bear lower parental expectations. Children experiencing higher parental expectations spent more time on homework but less time on TV/Internet, partially explained by stricter parental homework and screen control.

CONCLUSIONS

High parental expectations suppress screen use but promote academic-related sedentary behaviors for Chinese children. Interventions should attend to academic-related sedentary behaviors and call for broader policies addressing sociocultural factors fueling high parental expectations.

Stress and adolescent hippocampal neurogenesis: diet and exercise as cognitive modulators

Adolescence is a critical period for brain maturation. Deciphering how disturbances to the central nervous system at this time affect structure, function and behavioural outputs is important to better understand any long-lasting effects. Hippocampal neurogenesis occurs during development and continues throughout life. In adulthood, integration of these new cells into the hippocampus is important for emotional behaviour, cognitive function and neural plasticity. During the adolescent period, maturation of the hippocampus and heightened levels of hippocampal neurogenesis are observed, making alterations to neurogenesis at this time particularly consequential. As stress negatively affects hippocampal neurogenesis, and adolescence is a particularly stressful time of life, it is important to investigate the impact of stressor exposure at this time on hippocampal neurogenesis and cognitive function. Adolescence may represent not only a time for which stress can have long-lasting effects, but is also a critical period during which interventions, such as exercise and diet, could ameliorate stress-induced changes to hippocampal function. In addition, intervention at this time may also promote life-long behavioural changes that would aid in fostering increased hippocampal neurogenesis and cognitive function. This review addresses both the acute and long-term stress-induced alterations to hippocampal neurogenesis and cognition during the adolescent period, as well as changes to the stress response and pubertal hormones at this time which may result in differential effects than are observed in adulthood. We hypothesise that adolescence may represent an optimal time for healthy lifestyle changes to have a positive and long-lasting impact on hippocampal neurogenesis, and to protect against stress-induced deficits. We conclude that future research into the mechanisms underlying the susceptibility of the adolescent hippocampus to stress, exercise and diet and the consequent effect on cognition may provide insight into why adolescence may be a vital period for correct conditioning of future hippocampal function.

Is sleep education an effective tool for sleep improvement and minimizing metabolic disturbance and obesity in adolescents?

The prevalence of childhood obesity has increased significantly in recent years. Obesity is associated with a range of adverse physiological, psychological and social outcomes and places a huge economical burden on healthcare systems around the world. Insufficient sleep duration is common in adolescents and exacerbated by contemporary lifestyles, but may be a contributor to obesity onset and metabolic disruption. We briefly review the current evidence surrounding the associations between sleep and obesity as well as diabetes. Sleep improvement programs have been suggested as a potential avenue to raise awareness of the importance of sleep and ultimately enhance sleep behaviors/routines. A review of the current literature supporting the efficacy of such programs is tentative. Furthermore, very few studies have investigated if sleep enhancement has downstream positive effects on metabolic function or body weight in adolescents. We highlight biological and social factors that intensify sleep loss in adolescents and recommend that these be targeted components in future interventions aimed at improving adolescent sleep.

Prospective Associations between Depression and Obesity for Adolescent Males and Females- A Systematic Review and Meta-Analysis of Longitudinal Studies

Adolescent obesity and depression are increasingly prevalent and are currently recognised as major public health concerns worldwide. The aim of this study is to evaluate the bi-directional associations between obesity and depression in adolescents using longitudinal studies. A systematic literature search was conducted using Pubmed (including Medline), PsycINFO, Embase, CINAHL, BIOSIS Preview and the Cochrane Library databases. According to the inclusion criteria, 13 studies were found where seven studies evaluated depression leading to obesity and six other studies examined obesity leading to depression. Using a bias-adjusted quality effects model for the meta-analysis, we found that adolescents who were depressed had a 70% (RR 1.70, 95% CI: 1.40, 2.07) increased risk of being obese, conversely obese adolescents had an increased risk of 40% (RR 1.40, 95% CI: 1.16, 1.70) of being depressed. The risk difference (RD) of early adolescent depression leading to obesity is 3% higher risk than it is for obesity leading to depression. In sensitivity analysis, the association between depression leading to obesity was greater than that of obesity leading to depression for females in early adulthood compared with females in late adolescence. Overall, the findings of this study suggest a bi-directional association between depression and obesity that was stronger for female adolescents. However, this finding also underscores the importance of early detection and treatment strategies to inhibit the development of reciprocal disorders.

Does Sedentary Behavior Predict Academic Performance in Adolescents or the Other Way Round? A Longitudinal Path Analysis

This study examined whether adolescents' time spent on sedentary behaviors (academic, technological-based and social-based activities) was a better predictor of academic performance than the reverse. A cohort of 755 adolescents participated in a three-year period study. Structural Equation Modeling techniques were used to test plausible causal hypotheses. Four competing models were analyzed to determine which model best fitted the data. The Best Model was separately tested by gender. The Best Model showed that academic performance was a better predictor of sedentary behaviors than the other way round. It also indicated that students who obtained excellent academic results were more likely to succeed academically three years later. Moreover, adolescents who spent more time in the three different types of sedentary behaviors were more likely to engage longer in those sedentary behaviors after the three-year period. The better the adolescents performed academically, the less time they devoted to social-based activities and more to academic activities. An inverse relationship emerged between time dedicated to technological-based activities and academic sedentary activities. A moderating auto-regressive effect by gender indicated that boys were more likely to spend more time on technological-based activities three years later than girls. To conclude, previous academic performance predicts better sedentary behaviors three years later than the reverse. The positive longitudinal auto-regressive effects on the four variables under study reinforce the 'success breeds success' hypothesis, with academic performance and social-based activities emerging as the strongest ones. Technological-based activities showed a moderating effect by gender and a negative longitudinal association with academic activities that supports a displacement hypothesis. Other longitudinal and covariate effects reflect the complex relationships among sedentary behaviors and academic performance and the need to explore these relationships in depth. Theoretical and practical implications for school health are outlined.

A systematic review of determinants of sedentary behaviour in youth: a DEDIPAC-study

Sedentary behaviour (SB) has emerged as a potential risk factor for metabolic health in youth. Knowledge on the determinants of SB in youth is necessary to inform future intervention development to reduce SB. A systematic review was conducted to identify predictors and determinants of SB in youth. Pubmed, Embase, CINAHL, PsycINFO and Web of Science were searched, limiting to articles in English, published between January 2000 and May 2014. The search strategy was based on four key elements and their synonyms: (a) sedentary behaviour, (b) determinants, (c) types of sedentary behaviours, (d) types of determinants. The full protocol is available from PROSPERO (PROSPERO 2014:CRD42014009823). Cross-sectional studies were excluded. The analysis was guided by the socio-ecological model. 37 studies were selected out of 2654 identified papers from the systematic literature search. Most studies were conducted in Europe (n = 13), USA (n = 11), and Australia (n = 10). The study quality, using the Qualsyst tool, was high with a median of 82 % (IQR: 74–91 %). Multiple potential determinants were studied in only one or two studies. Determinants were found at the individual, interpersonal, environmental and policy level but few studies examined a comprehensive set of factors at different levels of influences. Evidence was found for age being positively associated with total SB, and weight status and baseline assessment of screen time being positively associated with screen time (at follow-up). A higher playground density and a higher availability of play and sports equipment at school were consistently related to an increased total SB, although these consistent findings come from single studies. Evidence was also reported for the presence of safe places to cross roads and lengthening morning and lunch breaks being associated with less total SB. Future interventions to decrease SB levels should especially target children with overweight or obesity and should start at a young age. However, since the relationship of many determinants with SB remains inconsistent, there is still a need for more longitudinal research on determinants of SB in youth.

Impact of social norms and social support on diet, physical activity and sedentary behaviour of adolescents: a scoping review

The prevalence of non-communicable diseases (NCDs) in adulthood is rapidly increasing, and it is essential that risk factors for NCDs be addressed in adolescence, both for the health of individuals during adolescence and for their health in later life. These risk factors include diet, physical activity and sedentary behaviour. No literature has been published that comprehensively summarizes the impact of social norms and social support on these behaviours among adolescents. Therefore, a scoping review was conducted to determine the extent of recent (since 2000) literature available on this topic. A comprehensive search strategy was used to search PubMed and EMBASE for eligible reviews. Review papers (narrative reviews, systematic and non-systematic reviews) published in English in peer-reviewed journals from 2000 to February 2013 were included in the overview. Two of the authors screened the titles and abstracts of the search results independently. Thirty reviews were included in the scoping review. This scoping review has shown sufficient evidence for parental influences, and especially the positive impact of an authoritative parenting style, on healthy behaviours of adolescents, although the evidence is somewhat more compelling for diet than for physical activity and sedentary behaviour. More research is needed to investigate parental and family influences on physical activity and sedentary behaviour. And the effect of peer influences on diet, physical activity and sedentary behaviour of adolescents requires further investigation. The evidence presented affirms the consideration of social norms and social support in the development of interventions to address these behaviours in adolescents. The evidence regarding parenting style provides some concrete guidance for such interventions.

Leisure time computer use and adolescent bone health--findings from the Tromsø Study, Fit Futures: a cross-sectional study

OBJECTIVES

Low levels of physical activity may have considerable negative effects on bone health in adolescence, and increasing screen time in place of sporting activity during growth is worrying. This study explored the associations between self-reported screen time at weekends and bone mineral density (BMD).

DESIGN

In 2010/2011, 1038 (93%) of the region's first-year upper-secondary school students (15-18 years) attended the Tromsø Study, Fit Futures 1 (FF1). A follow-up survey (FF2) took place in 2012/2013. BMD at total hip, femoral neck and total body was measured as g/cm(²) by dual X-ray absorptiometry (GE Lunar prodigy). Lifestyle variables were self-reported, including questions on hours per day spent in front of television/computer during weekends and hours spent on leisure time physical activities. Complete data sets for 388/312 girls and 359/231 boys at FF1/FF2, respectively, were used in analyses. Sex stratified multiple regression analyses were performed.

RESULTS

Many adolescents balanced 2-4 h screen time with moderate or high physical activity levels. Screen time was positively related to body mass index (BMI) in boys (p=0.002), who spent more time in front of the computer than girls did (p<0.001). In boys, screen time was adversely associated with BMDFF1 at all sites, and these associations remained robust to adjustments for age, puberty, height, BMI, physical activity, vitamin D levels, smoking, alcohol, calcium and carbonated drink consumption (p<0.05). Screen time was also negatively associated with total hip BMD(FF2) (p=0.031). In contrast, girls who spent 4-6 h in front of the computer had higher BMD than the reference (<2 h).

CONCLUSIONS

In Norwegian boys, time spent on screen-based sedentary activity was negatively associated with BMD levels; this relationship persisted 2 years later. Such negative associations were not present among girls. Whether this surprising result is explained by biological differences remains unclear.

Systematic review shows only few reliable studies of physical activity intervention in adolescents

Introduction. Several studies have pointed to the high prevalence of low levels of physical activity in adolescents, suggesting the need for more effective interventions for this group. The aim of this study was to present evidence of intervention programs for efficacy of physical activity for adolescents. Methods. Surveys in PubMed, SportDiscus, LiLacs, and SciELO databases were conducted using keywords to identify population, intervention, and outcome, as well as DeCS and MeSH terms in English, Portuguese, and Spanish, whenever appropriate. The review included observational studies with minimal intervention of six months, minimum sample size of 100 adolescents, written in any language, and those who have reached STROBE score greater than 70%. Results. Only seven studies met all inclusion criteria. Of these, five were pre- and postintervention and two had n > 2000 participants. Interventions were of several types, durations, and strategies for physical activity implementation. Behavior change was assessed in 43% of studies and three reported success in some way. Conclusion. Due to heterogeneity in their contents and methodologies, as well as the lack of jobs that accompany adolescents after the intervention period, one cannot draw conclusions about the actual effects of the intervention programs of physical activity on the behavior of young people.

Application of Intervention Mapping to develop a community-based health promotion pre-pregnancy intervention for adolescent girls in rural South Africa: Project Ntshembo (Hope)

BACKGROUND

South Africa (SA) is undergoing multiple transitions with an increasing burden of non-communicable diseases and high levels of overweight and obesity in adolescent girls and women. Adolescence is key to addressing trans-generational risk and a window of opportunity to intervene and positively impact on individuals' health trajectories into adulthood. Using Intervention Mapping (IM), this paper describes the development of the Ntshembo intervention, which is intended to improve the health and well-being of adolescent girls in order to limit the inter-generational transfer of risk of metabolic disease, in particular diabetes risk.

METHODS

This paper describes the application of the first four steps of IM. Evidence is provided to support the selection of four key behavioural objectives: viz. to eat a healthy, balanced diet, increase physical activity, reduce sedentary behaviour, and promote reproductive health. Appropriate behaviour change techniques are suggested and a theoretical framework outlining components of relevant behaviour change theories is presented. It is proposed that the Ntshembo intervention will be community-based, including specialist adolescent community health workers who will deliver a complex intervention comprising of individual, peer, family and community mobilisation components.

CONCLUSIONS

The Ntshembo intervention is novel, both in SA and globally, as it is: (1) based on strong evidence, extensive formative work and best practice from evaluated interventions; (2) combines theory with evidence to inform intervention components; (3) includes multiple domains of influence (community through to the individual); (4) focuses on an at-risk target group; and (5) embeds within existing and planned health service priorities in SA.

Screen media usage, sleep time and academic performance in adolescents: clustering a self-organizing maps analysis

Screen media usage, sleep time and socio-demographic features are related to adolescents' academic performance, but interrelations are little explored. This paper describes these interrelations and behavioral profiles clustered in low and high academic performance. A nationally representative sample of 3,095 Spanish adolescents, aged 12 to 18, was surveyed on 15 variables linked to the purpose of the study. A Self-Organizing Maps analysis established non-linear interrelationships among these variables and identified behavior patterns in subsequent cluster analyses. Topological interrelationships established from the 15 emerging maps indicated that boys used more passive videogames and computers for playing than girls, who tended to use mobile phones to communicate with others. Adolescents with the highest academic performance were the youngest. They slept more and spent less time using sedentary screen media when compared to those with the lowest performance, and they also showed topological relationships with higher socioeconomic status adolescents. Cluster 1 grouped boys who spent more than 5.5 hours daily using sedentary screen media. Their academic performance was low and they slept an average of 8 hours daily. Cluster 2 gathered girls with an excellent academic performance, who slept nearly 9 hours per day, and devoted less time daily to sedentary screen media. Academic performance was directly related to sleep time and socioeconomic status, but inversely related to overall sedentary screen media usage. Profiles from the two clusters were strongly differentiated by gender, age, sedentary screen media usage, sleep time and academic achievement. Girls with the highest academic results had a medium socioeconomic status in Cluster 2. Findings may contribute to establishing recommendations about the timing and duration of screen media usage in adolescents and appropriate sleep time needed to successfully meet the demands of school academics and to improve interventions targeting to affect behavioral change.

A comparison of physical activity and sedentary behaviour in 9-11 year old British Pakistani and White British girls: a mixed methods study

BACKGROUND

Previous studies suggest that British children of South Asian origin are less active and more sedentary than White British children. However, little is known about the behaviours underlying low activity levels, nor the familial contexts of active and sedentary behaviours in these groups. Our aim was to test hypotheses about differences between British Pakistani and White British girls using accelerometry and self-reports of key active and sedentary behaviours, and to obtain an understanding of factors affecting these behaviours using parental interviews.

METHODS

Participants were 145 girls (70 White British and 75 British Pakistani) aged 9-11 years and parents of 19 of the girls. Accelerometry data were collected over 4 days and girls provided 24-hour physical activity interviews on 3 of these days. Multilevel linear regression models and generalised linear mixed models tested for ethnic differences in activity, sedentary time, and behaviours. Semi-structured interviews were conducted with parents.

RESULTS

Compared to White British girls, British Pakistani girls accumulated 102 (95% CI 59, 145) fewer counts per minute and 14 minutes (95% CI 8, 20) less time in moderate to vigorous physical activity per day. British Pakistani girls spent more time (28 minutes per day, 95% CI 14, 42) sedentary. Fewer British Pakistani than White British girls reported participation in organised sports and exercise (OR 0.22 95% CI 0.08, 0.64) or in outdoor play (OR 0.42 95% CI 0.20, 0.91). Fewer British Pakistani girls travelled actively to school (OR 0.26 95% CI 0.10, 0.71). There was no significant difference in reported screen time (OR 0.88 95% CI 0.45, 1.73). Parental interviews suggested that structural constraints (e.g. busy family schedules) and parental concerns about safety were important influences on activity levels.

CONCLUSIONS

British Pakistani girls were less active than White British girls and were less likely to participate in key active behaviours. Sedentary time was higher in British Pakistani girls but reported screen-time did not differ, suggesting that British Pakistani girls engaged more than White British girls in other sedentary behaviours. Interviews highlighted some differences between the groups in structural constraints on activity, as well as many shared constraints.

Conceptual understanding of screen media parenting: report of a working group

Screen media (television, computers, and videogames) use has been linked to multiple child outcomes, including obesity. Parents can be an important influence on children's screen use. There has been an increase in the number of instruments available to assess parenting in feeding and physical activity contexts, however few measures are available to assess parenting practices regarding children's screen media use. A working group of screen media and parenting researchers convened at the preconference workshop to the 2012 International Society for Behavioral Nutrition and Physical Activity (ISBNPA) annual meeting, "Parenting Measurement: Current Status and Consensus Reports," to identify and prioritize issues in assessing screen media parenting practices. The group identified that screen media use can pose different risks for children, depending on their age and developmental stage, across physiologic, psychosocial, and development outcomes. With that in mind, a conceptual framework of how parents may influence their child's screen-viewing behaviors was proposed to include the screen media content, context of viewing, and amount viewed. A research agenda was proposed to prioritize a validation of the framework and enhance the ability of researchers to best assess parenting influences across the three domains of content, context and amount of children's screen media use.

5-year changes in afterschool physical activity and sedentary behavior

BACKGROUND

The afterschool period holds promise for the promotion of physical activity, yet little is known about the importance of this period as children age.

PURPOSE

To examine changes in physical activity of children aged 5-6 years and 10-12 years and their sedentary time in the afterschool period over 3 and 5 years, and to determine the contribution of this period to daily physical activity and sedentary behavior over time.

METHODS

Data from two longitudinal studies conducted in Melbourne, Australia, were used. Accelerometer data were provided for 2053 children at baseline (Children Living in Active Neighbourhoods Study [CLAN]: 2001; Health, Eating and Play Study [HEAPS]: 2002/2003); 756 at 3-year follow-up (time point 2 [T2]); and 622 at 5-year follow-up (T3). Light (LPA), moderate (MPA) and vigorous (VPA) physical activity were determined using age-adjusted cut-points. Sedentary time was defined as ≤ 100 counts/minute. Multilevel analyses, conducted in April 2012, assessed change in physical activity and sedentary time and the contributions of the afterschool period to overall levels.

RESULTS

Afterschool MPA and VPA decreased among both cohorts, particularly in the younger cohort, who performed less than half of their baseline levels at T3 (MPA: T1=24 minutes; T3=11 minutes; VPA: T1=12 minutes; T3=4 minutes). LPA also declined in the older cohort. Afterschool sedentary time increased among the younger (T1=42 minutes; T3=64 minutes) and older cohorts (T1=57 minutes; T3=84 minutes). The contribution of the afterschool period to overall MPA and VPA increased in the older cohort from 23% to 33% over 5 years. In the younger cohort, the contribution of the afterschool period to daily MPA and VPA decreased by 3% over 5 years.

CONCLUSIONS

The importance of the afterschool period for children's physical activity increases with age, particularly as children enter adolescence.

The health indicators associated with screen-based sedentary behavior among adolescent girls: a systematic review

PURPOSE

Evidence suggests sitting time is independently associated with a range of health issues in adults, yet the relationship between sedentary behavior and health indicators in young people is less clear. Age-related increases in sedentary behavior are well-documented; the behavioral patterns of adolescent girls are of particular concern. More than one third of adolescent girls' sedentary behavior time is accumulated through use of recreational screen-based behaviors. The objective of this review was to investigate the association between recreational screen-based sedentary behavior and the physical, behavioral, and psychosocial health indicators for adolescent girls. A secondary objective was to identify studies that have adjusted sedentary behavior indicators for physical activity.

METHODS

A structured electronic search of all publication years (through December 2011) was conducted to identify studies in: CINAHL, Communications and Mass Media Complete, ERIC, MEDLINE with Full Text, PsycINFO, and SPORTDiscus with Full Text. Included publications were observational and interventional studies involving adolescent girls (12-18 years) that examined associations between screen-based, sedentary behavior and health indicators (physical, psychosocial, and/or behavioral). The search identified 33 studies that evaluated health indicators of screen-based sedentary behaviors among adolescent girls.

RESULTS

Strong evidence for a positive association between screen-based sedentary behavior and weight status was found. A positive association was observed between screen-time and sleep problems, musculoskeletal pain and depression. Negative associations were identified between screen time and physical activity/fitness, screen time and psychological well-being, and screen time and social support. The relationship between screen-based sedentary behavior and diet quality was inconclusive. Less than half of the studies adjusted sedentary behavior indicators for physical activity.

CONCLUSIONS

Screen-based sedentary behavior is associated with a range of adverse health consequences, but additional longitudinal studies are needed to better understand the health impacts. In addition, screen-time guidelines for youth should be regularly revised and updated to reflect rapid technological changes.

Longitudinal sedentary behavior changes in adolescents in Ho Chi Minh City

BACKGROUND

Sedentary behavior is associated with increased risk of chronic disease and sedentary behavior is increasing among adolescents. Data on changes in sedentary behavior in developing countries are limited.

PURPOSE

To describe 5-year longitudinal changes in nonschool sedentary hours among urban adolescents in Ho Chi Minh City, and to identify correlates with this change.

METHODS

This is a 5-year longitudinal cohort with systematic random sampling of 759 students from 18 junior high schools. All measures were taken annually between 2004 and 2009. Sedentary behavior was assessed by self-report and accelerometry. Generalized linear latent and mixed models were used to analyze the data in 2011.

RESULTS

Between 2004 and 2009, self-reported time spent in nonschool sedentary behavior increased from 498 to 603 minutes/day. In the 5th survey year, boys and girls (aged 16 years) were, respectively, 3.6 times (95% CI=2.3, 6.0) and 3.1 times (95% CI= 1.8, 5.0) more likely to spend ≥2 hours/day on screen time compared with baseline (aged 12 years). Accelerometer data adjusted for wearing time revealed that boys and girls aged 16 years had, respectively, 78 minutes/day (95% CI=48, 104) and 69 minutes/day (95% CI=34, 95) more nonschool sedentary time than those at the first accelerometer assessment (at age 13 years). Girls in the highest socioeconomic quartile spent an additional 90 minutes/day in sedentary behavior compared with girls in the lowest quartile (95% CI=52, 128).

CONCLUSIONS

Nonschool sedentary behavior increased among Vietnamese adolescents with age. The largest increase was in recreational screen time (28%), which would be the most obvious target for preventive health strategies.

School-based physical activity programs for promoting physical activity and fitness in children and adolescents aged 6 to 18

BACKGROUND

The World Health Organization (WHO) estimates that 1.9 million deaths worldwide are attributable to physical inactivity and at least 2.6 million deaths are a result of being overweight or obese. In addition, WHO estimates that physical inactivity causes 10% to 16% of cases each of breast cancer, colon, and rectal cancers as well as type 2 diabetes, and 22% of coronary heart disease and the burden of these and other chronic diseases has rapidly increased in recent decades.

OBJECTIVES

The purpose of this systematic review was to summarize the evidence of the effectiveness of school-based interventions in promoting physical activity and fitness in children and adolescents.

SEARCH METHODS

The search strategy included searching several databases to October 2011. In addition, reference lists of included articles and background papers were reviewed for potentially relevant studies, as well as references from relevant Cochrane reviews. Primary authors of included studies were contacted as needed for additional information.

SELECTION CRITERIA

To be included, the intervention had to be relevant to public health practice (focused on health promotion activities), not conducted by physicians, implemented, facilitated, or promoted by staff in local public health units, implemented in a school setting and aimed at increasing physical activity, included all school-attending children, and be implemented for a minimum of 12 weeks. In addition, the review was limited to randomized controlled trials and those that reported on outcomes for children and adolescents (aged 6 to 18 years). Primary outcomes included: rates of moderate to vigorous physical activity during the school day, time engaged in moderate to vigorous physical activity during the school day, and time spent watching television. Secondary outcomes related to physical health status measures including: systolic and diastolic blood pressure, blood cholesterol, body mass index (BMI), maximal oxygen uptake (VO2max), and pulse rate.

DATA COLLECTION AND ANALYSIS

Standardized tools were used by two independent reviewers to assess each study for relevance and for data extraction. In addition, each study was assessed for risk of bias as specified in the Cochrane Handbook for Systematic Reviews of Interventions. Where discrepancies existed, discussion occurred until consensus was reached. The results were summarized narratively due to wide variations in the populations, interventions evaluated, and outcomes measured.

MAIN RESULTS

In the original review, 13,841 records were identified and screened, 302 studies were assessed for eligibility, and 26 studies were included in the review. There was some evidence that school-based physical activity interventions had a positive impact on four of the nine outcome measures. Specifically positive effects were observed for duration of physical activity, television viewing, VO2 max, and blood cholesterol. Generally, school-based interventions had little effect on physical activity rates, systolic and diastolic blood pressure, BMI, and pulse rate. At a minimum, a combination of printed educational materials and changes to the school curriculum that promote physical activity resulted in positive effects.In this update, given the addition of three new inclusion criteria (randomized design, all school-attending children invited to participate, minimum 12-week intervention) 12 of the original 26 studies were excluded. In addition, studies published between July 2007 and October 2011 evaluating the effectiveness of school-based physical interventions were identified and if relevant included. In total an additional 2378 titles were screened of which 285 unique studies were deemed potentially relevant. Of those 30 met all relevance criteria and have been included in this update. This update includes 44 studies and represents complete data for 36,593 study participants. Duration of interventions ranged from 12 weeks to six years.Generally, the majority of studies included in this update, despite being randomized controlled trials, are, at a minimum, at moderate risk of bias. The results therefore must be interpreted with caution. Few changes in outcomes were observed in this update with the exception of blood cholesterol and physical activity rates. For example blood cholesterol was no longer positively impacted upon by school-based physical activity interventions. However, there was some evidence to suggest that school-based physical activity interventions led to an improvement in the proportion of children who engaged in moderate to vigorous physical activity during school hours (odds ratio (OR) 2.74, 95% confidence interval (CI), 2.01 to 3.75). Improvements in physical activity rates were not observed in the original review. Children and adolescents exposed to the intervention also spent more time engaged in moderate to vigorous physical activity (with results across studies ranging from five to 45 min more), spent less time watching television (results range from five to 60 min less per day), and had improved VO2max (results across studies ranged from 1.6 to 3.7 mL/kg per min). However, the overall conclusions of this update do not differ significantly from those reported in the original review.

AUTHORS' CONCLUSIONS

The evidence suggests the ongoing implementation of school-based physical activity interventions at this time, given the positive effects on behavior and one physical health status measure. However, given these studies are at a minimum of moderate risk of bias, and the magnitude of effect is generally small, these results should be interpreted cautiously. Additional research on the long-term impact of these interventions is needed.

Exploring the paradox: double burden of malnutrition in rural South Africa

BACKGROUND

This article is a review of the PhD thesis by Elizabeth Kimani-Murage that explores the double burden of malnutrition in rural South Africa. This is in the context of a worryingly rapid increase in obesity and obesity-related diseases in low- and middle-income countries (LMICs) including South Africa, and in the wake of on-going nutrition transition and lifestyle changes in these countries.

OBJECTIVE

To understand the profiles of malnutrition among children and adolescents in a poor, high HIV prevalent, transitional society in a middle-income country.

METHODS

A cross-sectional growth survey was conducted in 2007 targeting 4,000 children and adolescents aged 1-20 years. In addition, HIV testing was carried out on children aged 1-5 years and Tanner pubertal assessment among adolescents aged 9-20 years.

RESULTS

The study shows stunting at an early age and adolescent obesity, particularly among girls, that co-exists in the same socio-geographic population. The study also shows that HIV is an independent modifiable risk factor for poor nutritional outcomes in children and makes a significant contribution to nutritional outcomes at the individual level. Significant predictors of undernutrition at an early age, documented at individual, household, and community levels, include child's HIV status, age and birth weight, maternal age, age of household head, and area of residence. Significant predictors of overweight/obesity and risk for metabolic disease during adolescence, documented at individual and household levels include child's age, sex, and pubertal development, household-level food security, socio-economic status, and household head's highest education level.

CONCLUSIONS

The combination of early stunting and adolescent obesity raises critical concerns in the wake of the rising public health importance of metabolic diseases in LMICs. This is because, both paediatric obesity and adult short stature are risk factors for metabolic syndrome and metabolic diseases in adulthood. Clearly, policies and interventions to address malnutrition in this and other transitional societies need to be double-pronged and gender-sensitive.

Overweight and obese teenagers: why is adolescence a critical period?

This paper discusses the critical period of adolescence and its potential role in the development and persistence of obesity. The adolescent years are characteristic of changes in body composition (location and quantity of body fat), physical fitness and decreased insulin sensitivity during puberty. This period of growth and maturation is also marked with behavioural changes in diet, physical activity, sedentary behaviour and psychological health. Physical activity and sport participation decline during adolescence especially in teenage girls, while sedentary behaviour, risk for depression and body esteem issues increase during the teenage years. These physiological and behavioural changes during adolescence warrant the attention of health practitioners to prevent the onset and continuation of obesity throughout the lifespan.

"Peers, parents and phones"--Swedish adolescents and health promotion

Many unhealthy behaviors are created during adolescence and follow the individual into adulthood. In addition, health behaviors often occur in clusters as those who are inactive are more likely to eat unhealthy food and smoke. This makes the early foundation of healthy behaviors vital. The aim was to describe and develop an understanding of adolescents' awareness and experiences concerning health promotion. Data was collected using focus groups with a total of 28 seventh graders and was analysed with latent qualitative content analysis. One main theme was identified; being competent, ambivalent and creative at the same time. The following three subthemes also emerged: being a digital native for better and for worse, knowing what is healthy, and sometimes doing it, and considering change and having ideas of how change could be supported. The main theme elucidates how the majority of students were informed and able but they did not always prioritize their health. The concept of health promotion relies upon the engagement of the individual; however, although the students had clear ideas about how they would like to change their own behaviors, they felt a need for support. Interestingly, the students were able to make several suggestions about the kind of support that would make a difference to their adoption to more healthy modes of living. They suggested information and communication technology (ICT), for example encouraging text messages (SMS), and social support, for example parents setting rules and peers inspiring them to adhere to a healthy behavior. The knowledge gained from this study echoes our view of inclusion and this could be helpful for those who encounter the challenge of promoting health among adolescents.

Television watching from adolescence to adulthood and its association with BMI, waist circumference, waist-to-hip ratio and obesity: a longitudinal study

OBJECTIVE

To examine the prospective association of television (TV) watching from adolescence to young adulthood with BMI, waist circumference (WC), waist-to-hip ratio (WHR) and obesity.

DESIGN

A community-based longitudinal cohort study.

SETTING

Mater-University of Queensland Study of Pregnancy (MUSP) Cohort, Brisbane, Australia.

SUBJECTS

A sub-sample of 2439 children was followed up at ages 14 years and 21 years as part of a population-based birth cohort. Offspring reported the number of TV viewing hours each day at 14 and 21 years. BMI, WC and WHR were measured at 21 years.

RESULTS

In the adjusted model, offspring who watched TV for <3 h/d at 14 years but for ≥ 3 h/d at 21 years, or who watched TV for ≥ 3 h/d at 14 and 21 years, had greater BMI, WC and WHR at 21 years. Offspring who watched TV for ≥ 3 h/d at 14 years but for <3 h/d at 21 years had similar mean BMI, WC and WHR at 21 years to those who watched TV for <3 h/d at 14 and 21 years. Those offspring who reduced their TV watching hours to <3 h/d during the transition from adolescence into young adulthood were at less risk of becoming obese and those who continued or increased their TV watching to ≥ 3 h/d were at greater risk of becoming obese. This association remained independent of the potential confounding factors considered.

CONCLUSIONS

The present findings suggest that our efforts to decrease obesity by reducing TV watching hours among adults should consider interventions to reduce TV time among adolescents.

Childhood obesity and the media

This article assesses the role played by media in contributing to the current epidemic of childhood obesity. Electronic media use, often referred to as screen time, is significantly correlated with child adiposity. Although the causal mechanism that accounts for this relationship is unclear, it is well established that reducing screen time improves weight status. Media advertising for unhealthy foods contributes to obesity by influencing children's food preferences, requests, and diet. Industry efforts have failed to improve the nutritional quality of foods marketed on television to children, leading public health advocates to recommend government restrictions on child-targeted advertisements for unhealthy foods.

Children, adolescents, and the media: health effects

The media can be a powerful teacher of children and adolescents and have a profound impact on their health. The media are not the leading cause of any major health problem in the United States, but they do contribute to a variety of pediatric and adolescent health problems. Given that children and teens spend >7 hours a day with media, one would think that adult society would recognize its impact on young people's attitudes and behaviors. Too little has been done to protect children and adolescents from harmful media effects and to maximize the powerfully prosocial aspects of modern media.

Childhood obesity prevention in rural settings: background, rationale, and study design of '4-Health,' a parent-only intervention

Background

Childhood obesity in rural communities is a serious but understudied problem. The current experiment aims to assess a wide range of obesity risk factors among rural youth and to offer an 8-month intervention program for parents to reduce obesity risk in their preteen child.

Methods/Design

A two-group, repeated measures design is used to assess the effectiveness of the 4-Health intervention program. Assessments include anthropometric measures, child self-evaluations, parent self-evaluations, and parent evaluations of child. County Extension agents from 21 rural Montana counties recruit approximately 150 parent–child dyads and counties are semi-randomly assigned to the active intervention group (4-Health Educational Program) or a “best-practices” (Healthy Living Information) control group.

Discussion

This study will shed light on the effectiveness of this parent-only intervention strategy in reducing obesity risk factors among rural preteens. The 4-Health program is designed to provide information and skills development for busy rural parents that will increase healthy lifestyles of their preteen children and improve the parents’ ability to intervene effectively in the lives of their families during this critical developmental period.

Trial registration

ClinicalTrials.gov ID: NCT01510587

Obesity-related factors in Turkish school children

OBJECTIVE

To determine the prevalence of obesity and its risk factors in Turkish children.

METHOD

This cross-sectional survey was conducted on students including 1271 boys and 1206 girls selected from 20 secondary schools in Samsun, Turkey. A predesigned questionnaire was used to elicit the information on individual characteristics. The height and weight of students were measured in their classroom. Obesity was defined as body mass index at or above the 95th percentile for age of the sex-specific CDC growth charts.

RESULT

The mean age was 12.8 ± 0.9 years, and the prevalence of obesity was found at 10.3%. There were higher numbers of obese students in boys than in girls (X(2) = 53.4; P < 0.001). The prevalence of obesity was 10.0% and 16.8% in public and private school students, respectively. The percentage of obese children in students who skipped breakfast was found to be higher than that in the group that consumed 3 meals a day regularly. There was no difference at time spent in sedentary behavior except watching TV, and prevalence of obesity in the group of students watching television over 3 hours per day was higher than that in their counterparts (X(2) = 13.6; P < 0.01). The time of engagement in sports was lower in obese group statistically (F = 8.9; P < 0.001).

CONCLUSION

In order to prevent childhood obesity, monitoring children's lifestyle by parents is necessary.

Rethinking passive transport: bus fare exemptions and young people's wellbeing

Much recent public health research has emphasised the health impacts for young people of 'active travel' modes, typically defined as walking and cycling. Less research has focused on public transport modes. Drawing on qualitative data, we examine the links between bus travel and wellbeing in London, where young people currently have free bus travel. Our findings indicate that bus travel can be both a physically and socially active experience for young people. We suggest a more nuanced understanding of 'active travel' is now needed, alongside greater attention to urban public transport networks as key sites that impact on important determinants of wellbeing such as independent mobility and social inclusion.