Early predictors of objectively measured physical activity and sedentary behaviour in 8-10 year old children: the Gateshead Millennium Study

Tracking of MVPA across childhood and adolescence

OBJECTIVES

Tracking of physical activity from childhood onwards is an important public health issue, but evidence on tracking is limited. This study quantified the tracking of Moderate-Vigorous Physical Activity (MVPA) across childhood and adolescence in a recent cohort from England.

DESIGN

Longitudinal, with a socio-economically representative sample from North-East England, over an 8-year period.

METHODS

Measures of time spent in MVPA, with an Actigraph GT1M accelerometer, were made at age 7-8y (n = 622, T1), age 9-10y (n = 585, T2), age 12-13y (n = 525, T3) and age 14-16y (n = 361, T4). Tracking of MVPA was assessed using rank order correlations between time spent in MVPA T1-T2, T1-T3, and T1-T4, and by using Cohen's kappa to examine tracking of meeting the MVPA guideline (mean of 60 min/d). We examined whether tracking varied by sex, socio-economic status (SES), initial MVPA, or initial body fatness.

RESULTS

Rank order correlations were all statistically significant at p < 0.01 and moderate: 0.58 between T1 and T2; 0.42 between T1 and T3; 0.41 between T1 and T4. Cohen's kappas for meeting the global MVPA guideline were all significant, weakening from moderate to low over the 8 years. Tracking was stronger in higher SES compared to lower SES groups, and there was some evidence that it was stronger in girls than boys, but the other explanatory variables had little influence on tracking.

CONCLUSIONS

Tracking of MVPA from mid-childhood to mid-adolescence in this cohort was moderate. This study suggests there is a need to establish high MVPA by mid-childhood, and to mitigate the age-related reduction in MVPA which occurs from mid-childhood.

Four-Year Accelerometry Outcomes from a Cluster Randomized Whole of Systems Trial of Prevention Strategies for Childhood Obesity

Background: We investigated the effect of the Whole of Systems Trial of Prevention Strategies for Childhood Obesity (WHO STOPS) intervention on children's objectively measured physical activity and sedentary time (ST). Methods: We conducted a cluster randomized controlled trial with children in grades 4 (∼9-10 years old) and grade 6 (∼11-12 years old) from 10 communities in the Great South Coast region of Victoria, Australia. Communities were randomly allocated (1:1) to receive the WHO STOPS intervention in 2015. WHO STOPS was a whole of community systems-based approach to preventing childhood obesity. Outcome data were collected using a repeat cross-sectional design in 2015, 2017, and 2019. Children were asked to wear a hip-mounted accelerometer for 7 days. Age-specific Axis 1 activity counts were converted into duration (minutes/day) spent engaged in moderate-to-vigorous physical activity (MVPA), light physical activity (LPA), and ST. Linear mixed regression models were fitted to estimate the effects of the intervention on the three activity outcomes across the study period. Results: Analyses were based on valid accelerometer data from 1406 children (intervention n = 745; control n = 661). Results for MVPA, LPA, and ST were nonsignificant. Between 2015 and 2017, there were positive, but nonsignificant, changes in mean MVPA favoring intervention boys [3.7 minutes/day; 95% confidence interval (CI): -5.7 to 13.1] and girls (5.5 minutes/day; 95% CI: -1.5 to 12.6). By 2019, these effects had attenuated. Conclusions: Although the WHO STOPS intervention did not significantly change activity levels, the magnitudes of the effects on MVPA suggest that further research with whole-of-community interventions in larger samples would be worthwhile. Clinical trial registration: Australian New Zealand Clinical Trials Registry (ANZCTR.org.au) identifier 12616000980437.

Gardening in Childcare Centers: A Randomized Controlled Trial Examining the Effects of a Garden Intervention on Physical Activity among Children Aged 3-5 Years in North Carolina

This study examined the effects of a childcare gardening intervention on children's physical activity (PA). Eligible childcare centers were randomly assigned to: (1) garden intervention (n = 5; year 1); (2) waitlist control (n = 5; control year 1, intervention year 2); or (3) control (n = 5; year 2 only) groups. Across the two-year study, PA was measured for 3 days at four data collection periods using Actigraph GT3X+ accelerometers. The intervention comprised 6 raised fruit and vegetable garden beds and a gardening guide with age-appropriate learning activities. The sample included a total of 321 3-5-year-olds enrolled in childcare centers in Wake County, North Carolina, with n = 293 possessing PA data for at least one time point. The analyses employed repeated measures linear mixed models (SAS v 9.4 PROC MIXED), accounting for clustering of the children within the center and relevant covariates (e.g., cohort, weather, outside days, accelerometer wear). A significant intervention effect was found for MVPA (p < 0.0001) and SED minutes (p = 0.0004), with children at intervention centers acquiring approximately 6 min more MVPA and 14 min less sedentary time each day. The effects were moderated by sex and age, with a stronger impact for boys and the youngest children. The results suggest that childcare gardening has potential as a PA intervention.

Evaluating Changes in Perceived Enjoyment throughout a 12-Week School-Based Exergaming Intervention

This study assessed whether a high-intensity exergame represents an enjoyable training tool for children in the elementary school setting. Furthermore, it evaluated whether gender, body mass index (BMI), waist-to-height ratio (WHtR), fitness level, weekly physical activity level, and general interest in sports moderate perceived enjoyment during the 12-week intervention. Thirty fifth- and sixth-grade students (10.5 ± 0.7 years; 50% girls) participated in this study. During baseline assessments, anthropometric measurements and a shuttle run test were conducted. Throughout the intervention period, the students participated in 15−20-min exergaming sessions (ES) in the ExerCube twice a week during school hours. Enjoyment was assessed after an ES in weeks 2 and 12. Additionally, enjoyment was evaluated after a physical education (PE) class in week 2. The results reveal no significant changes in enjoyment (p = 0.164) over time. The modest changes over time were significantly affected by BMI (p = 0.027), WHtR (p = 0.007), and weekly activity level (p = 0.016). Compared to the PE class, enjoyment was significantly higher during the ES (p < 0.001). None of the covariates showed a significant effect. Mean HR during the ES reached 87.1 ± 1.9% of students’ individual maximum HR. In conclusion, the ExerCube provides a promising tool for schools to promote enjoyable moderate-to-vigorous physical activity.

Birth-related and current factors associated with physical inactivity in the leisure time in Brazilian adolescents

Background

To determine whether biological and sociodemographic factors at birth and current factors are associated with insufficient physical activity during leisure among Brazilian adolescents.

Methods

A school-based cross-sectional study with national coverage was conducted involving Brazilian adolescents 12 to 17 years of age in municipalities with more than 100 thousand residents. The sample consisted of 74,589 adolescents who participated in the Study of Cardiovascular Risk in Adolescents. Insufficient leisure-time physical activity was categorized based on total volume (<300 minutes/week = insufficiently active; >300 minutes/week = sufficiently active). Poisson regression models were used to assess associated factors.

Results

Most adolescents were classified as insufficiently active (54.8%; 95%CI: 53.7–55.9). The variables associated with insufficient physical activity during leisure were the female sex (70.4%; 95%CI: 68.8–71.9), age between 15 and 17 years (57.8%; 95%CI: 56.3–59.2), pertaining to the low or middle class (54.5%; 95%CI: 52.8–56.1), and not being overweight (55.9%; 95%CI: 54.6–57.1).

Conclusion

Contrary to our hypothesis, birth related factors (e.g., low birth weight, preterm birth and exclusive breastfeeding until 6 months of age) are not associated with physical inactivity. The prevalence of insufficient physical activity during leisure was high among the adolescents evaluated and was associated with sociodemographic characteristics as well as nutritional status. It is necessary to implement strategies focused on physical activity at schools.

Effects of Movement Behaviors on Overall Health and Appetite Control: Current Evidence and Perspectives in Children and Adolescents

PURPOSE OF REVIEW

To present the definitions and recommendations for movement behaviors in children and adolescents, including physical activity (PA), sedentary behaviors (SB), and sleep, and to provide an overview regarding their impact on health and obesity outcomes from childhood to adulthood, as well as interactions with appetite control.

RECENT FINDINGS

PA represents a variable proportion of daily energy expenditure and one can be active with high SB or vice versa. Studies have described movements across the whole day on a continuum from sleep to SB to varying intensities of PA. More PA, less SB (e.g., less screen time) and longer sleep are positively associated with indicators of physical health (e.g., lower BMI, adiposity, cardiometabolic risk) and cognitive development (e.g., motor skills, academic achievement). However, less than 10% of children currently meet recommendations for all three movement behaviors. Movement behaviors, adiposity, and related cardiometabolic diseases in childhood track into adolescence and adulthood. Furthermore, low PA/high SB profiles are associated with increased energy intake. Recent studies investigating energy balance regulation showed that desirable movement behavior profiles are associated with better appetite control and improved eating habits. Early identification of behavioral phenotypes and a comprehensive approach addressing all key behaviors that directly affect energy balance will allow for individual strategies to prevent or treat obesity and its comorbidities. Investigating exercise as a potential "corrector" of impaired appetite control offers a promising weight management approach.

Inattention and hyperactivity symptoms in childhood predict physical activity in adolescence

BACKGROUND

Physical activity has been documented to influence several aspects of physical and mental health. Growing evidence shows that physical activity can improve attention. Less is known about how symptoms of inattention and hyperactivity / impulsivity in childhood are associated with physical activity in adolescence. We aimed to explore this relationship further.

METHODS

We used a cohort of 3949 Swedish children (1884 boys and 2065 girls) with data collected at ages 9 (or 12) and 15. We investigated the influence of symptoms of inattention and hyperactivity / impulsivity in childhood - age 9/12 (inattention and hyperactivity/impulsivity separately) on self-rated physical activity at age 15, using multiple logistic regression models. We considered potential confounders such as sex, parental education level, physical activity in childhood and neurodevelopmental comorbidity. A cluster robust sandwich estimator was applied to adjust the standard errors for the nested twin data when computing the regression models.

RESULTS

Symptoms of inattention in childhood (9/12) predicted less physical activity in adolescence (age 15) (OR = 0.83 CI = 0.78-0.89), whereas the opposite was true for hyperactivity/impulsivity (OR = 1.08 CI = 1.02-1.10). These associations still remained when taking possible confounders into account including neurodevelopmental and neurodevelopmental related comorbidity.

CONCLUSIONS

These findings support the importance of helping children and adolescents with inattention symptoms to engage in physical activity in suitable settings.

Failure to Launch: Predictors of Unfavourable Physical Activity and Sedentary Behaviour Trajectories from Childhood to Adolescence: The Gateshead Millennium Study

In a previous study based on this cohort, only 15% of the participants belonged to a favourable physical activity/sedentary behaviour trajectory group (characterised by relatively high moderate–vigorous intensity physical activity and relatively low sedentary behaviour across childhood and adolescence). Since this favourable trajectory is protective against obesity, we aimed to identify factors associated with membership of this group. In this longitudinal study, 671 participants were assessed at ages 7, 9, 12 and 15 years. Participants’ demographics, socio-economic status (SES) and physical activity environment such as, sports club participation and commuting school were assessed at ages 7, 9 and 12 and analysed with favourable trajectory membership as an outcome using multinomial logistic regression. Sex (male) and SES (higher) were the non-modifiable factors associated with favourable trajectory group. Of the modifiable factors, commuting to school at age 7, a safe environment to play at age 7 and sports club participation at age 12 were all associated with more than 2.0 times increased probability of being in the most favourable trajectory. Future interventions to promote a favourable trajectory could focus on girls and participants with low SES. Promoting active commuting, safe local spaces to play and sports participation should also help lead to a favourable trajectory for physical activity and sedentary behaviour across childhood and adolescence.

Changes in Families' Leisure, Educational/Work and Social Screen Time Behaviours before and during COVID-19 in Australia: Findings from the Our Life at Home Study

This study aimed to understand differences in leisure, educational/work and social screen time behaviours experienced by parents and children due to COVID-19 lockdown restrictions, which may inform behaviour change strategies and policy in the transition to a COVID-normal life. Participants in the "Our Life at Home" study (n = 218 parents from Australia, 43.4 ± 6.8 years, 88% female) completed a cross-sectional online survey in April/May 2020. Parents recalled their own and their child (8.7 ± 2.0 years, 42% female) or adolescents (15.0 ± 1.5 years, 50% female) participation in nine screen time behaviours in the past month (during lockdown) and retrospectively for February 2020 (pre-lockdown), providing data on 436 individuals. Screen time behaviours included leisure (computer/laptop and tablet/smartphone for leisure, TV/videos/DVDs and game consoles); education/work (computer/laptop and tablet/smartphone for work/education); and social screen time (computer/tablet/smartphone for social communication with friends, family and work (parents only)). Wilcoxon signed-rank tests and effect sizes (r) compared the time spent in each behaviour pre-lockdown and during lockdown. Large differences were observed in social (parents: r = 0.41-0.57; children: r = 0.55-0.65; adolescents: r = 0.28-0.43) and education (children: r = 0.50-0.65 and adolescents: r = 0.25-0.37) behaviours. There were small or no differences in leisure time screen use. COVID-19 lockdown restrictions have impacted parent's and children's screen time, and future research and policy should consider strategies to support families to manage screen time.

Health-Related Quality of Life and Frequency of Physical Activity in Spanish Students Aged 8-14

The study of health-related quality of life (HRQoL) in children and adolescents has important implications in terms of policy, education, and health. Data on the time spent in physical activity (PA) and in sedentary activities in this population are worrying. We aim to analyze possible differences in HRQoL and PA levels between sexes and age groups in Spanish students aged between 8 and 14 years, as well as to assess the relationship between HRQoL and the frequency of PA in this population. A total of 3197 participants (1610 boys and 1587 girls) from 8 to 14 years old were recruited. Mquality and Mapping Child Health Utility instrument (Chu9d) were used as HRQoL indicators. A medium positive association between PA and HRQoL concerning the Spanish school population was found. HRQoL was higher among students aged 8 to 12 than 13 to 14. Moreover, when children start secondary education, both sexes seem to lose the quality of life. Similarly, PA decreases among girls over the years, although it seems to increase among boys. Thus, PA levels and HRQoL are directly associated in Spanish schoolchildren aged between 8 and 14 years. However, this HRQoL decreases in children over the years. Practical implications include the need to support education and physical activity programs to improve HRQoL in children and adolescents.

Moderate-To-Vigorous Intensity Physical Activity and Sedentary Behaviour across Childhood and Adolescence, and Their Combined Relationship with Obesity Risk: A Multi-Trajectory Analysis

The combined role of objectively assessed moderate-vigorous intensity physical activity (MVPA) and sedentary behaviour (SB) is unclear in obesity prevention. This study aimed to identify latent groups for MVPA and SB trajectories from childhood to adolescence and examine their relationship with obesity risk at adolescence. From the Gateshead Millennium Study, accelerometer-based trajectories of time spent in MVPA and SB at ages 7, 9, 12, and 15 were derived as assigned as the predictor variable. Fat mass index (FMI), using bioelectrical impedance at age 15, was the outcome variable. From 672 children recruited, we identified three distinct multiple trajectory groups for time spent in MVPA and SB. The group with majority membership (54% of the cohort) had high MVPA and low SB at childhood, but MVPA declined and SB increased by age 15. One third of the cohort (31%) belonged to the trajectory with low MVPA and high time spent sedentary throughout. The third trajectory group (15% of the cohort) that had relatively high MVPA and relatively low SB throughout had lower FMI (-1.7, 95% CI (-3.4 to -1.0) kg/m2, p = 0.034) at age 15 compared to the inactive throughout group. High MVPA and low SB trajectories when combined are protective against obesity.

Sleep duration, physical activity, and caloric intake are related to weight status in Mexican American children: a longitudinal analysis

BACKGROUND

Obesity is a serious issue, spanning all ages, and, in the U.S., disproportionately affects Latinos and African Americans. Understanding sleep, physical activity and dietary behaviors that may predict childhood obesity can help identify behavioral intervention targets.

METHODS

Data were drawn from a U.S. cohort study of 323 Mexican American 8-10-year-old children and their mothers, who participated in a longitudinal study over a 2-year period. Measures were collected at baseline (BL; child mean age = 8.87, SD = 0.83), year 1 (FU1) and year 2 (FU2). Mothers reported on household income and acculturation at BL. Child height and weight were collected and BMI z-scores (BMIz) were calculated for weight status at BL, FU1, and FU2. Accelerometer-estimated sleep duration (hours) and moderate-to-vigorous physical activity (MVPA; minutes) were collected across 3 days at BL, FU1, and FU2. Two 24-h dietary recalls were performed at each time point; from these, average energy intake (EI, kcals/day) was estimated. Cross-lagged panel analysis was used to examine behavioral predictors on BMIz at each time point and across time.

RESULTS

At BL and FU1, longer sleep duration (β = - 0.22, p < 0.001; β = - 0.17, p < 0.05, respectively) and greater MVPA (β = - 0.13, p < 0.05; β = - 0.20, p < 0.01, respectively) were concurrently related to lower BMIz. At FU2, longer sleep duration (β = - 0.18, p < 0.01) was concurrently related to lower BMIz, whereas greater EI (β = 0.16, p < 0.01) was related to higher BMIz. Longer sleep duration at BL predicted lower BMIz at FU1 (β = - 0.05, p < 0.01).

CONCLUSIONS

Longer sleep duration was concurrently related to lower weight status at each time point from ages 8-10 to 10-12. Higher MVPA was concurrently related to lower weight status in earlier childhood (ages 8-10 and 9-11) and higher EI was concurrently related to higher weight status toward the end of childhood (ages 10-12 years). Furthermore, longer sleep in earlier childhood was protective of children's lower weight status 1 year later. These findings suggest that sleep duration plays a consistent and protective role against childhood obesity; in addition, MVPA and healthy EI remain important independent factors for obtaining a healthy weight.

Objectively Measured Physical Activity Increases Only in Males During a Summer Camp for Obese Children

Childhood obesity is a major public health challenge. Summer camps for children with obesity represent an alternative setting to improve eating and physical activity habits. Here we evaluated if the participation in the camp improves objectively measured physical activity and sedentary behavior and whether there are differences between male and female participants. Twenty-eight children, 13 males and 15 females (body mass index >97° centile, weight excess >30%, Tanner stage I), agreed to participate in an 8-day camp. During the summer camp, children participated in sports-like games and outdoor activities for at least 3 h a day, and the school-camp staff also provided a theoretical nutritional learning plan. Accelerometry-derived physical activity was measured through the SenseWear Mini Armband during a week at home and during the camp experience. Before camping, the participants were far above the minimum daily values of moderate- to vigorous-intensity physical activity (MVPA) to be considered sufficiently active (≥60 min/day), but male participants were more active than females (MVPA: 186.2 ± 94.2, 111.0 ± 64.7; P = 0.020). Male participants increased their MVPA (234.3 ± 114.8, P = 0.020), whereas females not (111.9 ± 52.9, P = 0.020). No difference emerged for the sedentary behavior either before or during the camp. This study suggests that participation in a summer camp for obese children can determine different responses in physical activity levels, depending on the sex of young participants. Thus, summer camps for obese children should put particular attention on female participants, besides reducing sedentary behavior in both males and females.

Volume and accumulation patterns of physical activity and sedentary time: longitudinal changes and tracking from early to late childhood

BACKGROUND

Physical activity (PA) decreases and sedentary time (SED) increases across childhood, with both behaviours tracking. However, no studies have examined how accumulation patterns of PA and SED (i.e., prolonged bouts, frequency of breaks in sedentary time) change and track over time. The aim of this study was to investigate longitudinal changes in and tracking of total volume and accumulation patterns of SED, light-intensity PA (LPA), moderate-intensity PA (MPA), vigorous-intensity PA (VPA) among boys and girls.

METHODS

In 2008/09 (T1), children in HAPPY (3-5y; n = 758) in Melbourne, Australia wore ActiGraph GT1M accelerometers to objectively assess SED, LPA, MPA and VPA. This was repeated at age 6-8y (T2; n = 473) and 9-11y (T3; n = 478). Ten pattern variables were computed: bouts of ≥ 5-, ≥ 10-, ≥ 15- and ≥ 20-min for SED, ≥ 1- and ≥ 5-min for LPA, ≥ 1-min for MPA, ≥ 1- and ≥ 5-min for VPA, and breaks in SED (interruptions of > 25 counts 15 s^- 1). Longitudinal mixed models examined changes from T1-3, controlling for T1 age. Generalized estimating equations assessed tracking over the three time points, controlling for T1 age and time between measurements. Analyses were stratified by sex.

RESULTS

Total volume and bouts of SED and SED breaks increased, while total volume and bouts of LPA decreased for both sexes. There was a small decrease in total volume of MPA for girls, but time spent in ≥ 1-min bouts increased for both sexes. Total volume of VPA increased for both sexes, with time spent in ≥ 1-min bouts increasing for boys only. All volume and pattern variables tracked moderately for boys, except for all SED bouts ≥ 15-min, LPA bouts ≥ 5-min and MPA bouts ≥ 1-min (which tracked weakly). For girls, total SED and SED bouts ≥ 1-min tracked strongly, total volume of LPA, MPA and VPA, ≥ 5- and ≥ 10-min SED bouts, and ≥ 1-min LPA and MPA bouts tracked moderately, and SED breaks, all SED bouts ≥ 15 min, LPA bouts ≥ 5 min and all VPA bouts tracked weakly.

CONCLUSIONS

Patterns of SED and PA change from early to late childhood; with the exception of SED breaks and VPA, changes were detrimental. Total volumes and short bouts tended to track more strongly than longer bouts. Interventions to prevent declines in PA and increases in SED are important from early in life.

The Effect of Season and Neighbourhood-Built Environment on Home Area Sedentary Behaviour in 9-14 Year Old Children

There is little understanding of how the built environment shapes activity behaviours in children over different seasons. This study sought to establish how seasonal weather patterns, in a given year in a mid-western Canadian city, affect sedentary time (SED) in youth and how the relationship between season and SED are moderated by the built environment in their home neighbourhood. Families with children aged 9-14 years were recruited from the prairie city of Saskatoon, Canada. Location-specific, device-based SED was captured in children during three timeframes over a one-year period using GPS-paired accelerometers. Multilevel models are presented. Children accumulated significantly greater levels of SED in spring but significantly less SED in the fall months in comparison to the winter months. Children living in neighbourhoods with the highest density of destinations accumulated significantly less SED while in their home area in comparison to their counterparts, and this effect was more pronounced in the spring and summer months. On weekends, the rise in sedentariness within the home area was completely diminished in children living in neighbourhoods with the greatest number of destinations and highest activity friendliness. These results suggested that increasing neighbourhood amenities can lead to a reduced sedentariness of youth, though more so in the warmers months of the year.

Seasons, weather, and device-measured movement behaviors: a scoping review from 2006 to 2020

BACKGROUND

This scoping review summarized research on (a) seasonal differences in physical activity and sedentary behavior, and (b) specific weather indices associated with those behaviors.

METHODS

PubMed, CINAHL, and SPORTDiscus were searched to identify relevant studies. After identifying and screening 1459 articles, data were extracted from 110 articles with 118,189 participants from 30 countries (almost exclusively high-income countries) on five continents.

RESULTS

Both physical activity volume and moderate-to-vigorous physical activity (MVPA) were greater in summer than winter. Sedentary behavior was greater in winter than either spring or summer, and insufficient evidence existed to draw conclusions about seasonal differences in light physical activity. Physical activity volume and MVPA duration were positively associated with both the photoperiod and temperature, and negatively associated with precipitation. Sedentary behavior was negatively associated with photoperiod and positively associated with precipitation. Insufficient evidence existed to draw conclusions about light physical activity and specific weather indices. Many weather indices have been neglected in this literature (e.g., air quality, barometric pressure, cloud coverage, humidity, snow, visibility, windchill).

CONCLUSIONS

The natural environment can influence health by facilitating or inhibiting physical activity. Behavioral interventions should be sensitive to potential weather impacts. Extreme weather conditions brought about by climate change may compromise health-enhancing physical activity in the short term and, over longer periods of time, stimulate human migration in search of more suitable environmental niches.

An Evaluation of the Implementation of a UK School-Based Running Program

The adoption of school-based running programs has rapidly increased over the last five years in the UK and globally. However, there is currently a lack of information on how these initiatives are implemented, and whether they are generalizable and/or sustainable. This study evaluated the implementation (including reach, fidelity, and dose) of a school-based running program over seven months to inform future delivery. This observational study used a mixed-method, single-group, before-and-after design strengthened by multiple interim measurements to evaluate the implementation of an optional school-based running program. Five state-funded primary schools in Leicestershire, UK, participated, with 17 teachers and 189 (81 boys (47.4%) and 90 girls (52.6%)) Year 5 pupils (aged 9-10 years) from eight classes. During the 2016/2017 academic year, data were collected via several measures (including interviews, focus groups, observations, questionnaires, and teacher implementation logs) at multiple levels (i.e., school and individual) and at multiple time points during implementation. Follow up qualitative data were also collected during 2017/2018. The school-based running program achieved good reach, with 100% of pupils opting to participate at some point during the academic year. All schools implemented the program with good fidelity, although the level of implementation varied between schools and over time. The average number of sessions held per week ranged from 0.94-3.89 with the average distance accumulated per pupil per week ranging from 0.02 to 2.91 kilometers and boys being more likely than girls to be classed as high-level participators. Despite an initial drop off in participation over time, all schools remained engaged in the program and continued to implement it until the end of the school year. Contextual features (e.g., staff capacity and resources) differed between schools and influenced the quality of implementation and the frequency of delivery. The school-based running program is simple, inexpensive, and versatile and can be implemented by schools with relative ease. However, schools are diverse settings, with unique challenges to ongoing delivery. Thus, planned adaptations, specific to each school's context, are likely necessary to sustain participation in the longer term and should be considered prior to implementation.

Sedentary Behaviors of a School Population in Brazil and Related Factors

Background. Overweight and obesity arise from a complex range of genetic, environmental, behavioral, educational, and socioeconomic factors. The present study explored the sedentary practices and some life habits related to health among children from the school population of Uruguaiana (Rio Grande do Sul, Brazil). Methods: A cross-sectional descriptive study was conducted to characterize the life habits of the school boys and girls from fourth grade (9-10 years old). Results: A total of 470 fourth-grade boys and girls (9-10 years old) participated in the study. As regards the variables linked to habits, 24% of the boys and girls answered they had not had breakfast the day they completed the questionnaire and 51.8% stated they did not have breakfast any given day of the week. Regarding sedentary habits, 25.3% of children watched TV or played video games five or more hours a day and 9% rarely played sports with their parents or caregivers. Statistical significance was recorded between "number of hours watching TV and playing video games" and "playing sports with parents or caregivers" (p < 0.05). Conclusions: Association between the times spent watching TV or playing video games and the practice of physical exercise in the family proves once again the importance of the family in education for the health of children. The school provides direct access to schoolchildren and their parents to launch numerous health education programs.

Pre- and post-natal factors and physical activity in childhood: The Norwegian Mother, Father and Child Cohort study

Few studies have examined the possibility that pre- and post-natal factors may be non-linearly associated with later physical activity. We used data from the Norwegian Mother, Father and Child Cohort study (MoBa) and the Medical Birth Registry of Norway (MBRN), including 48 672 children with available data on leisure time physical activity (LTPA) at child's age 7 years. Restricted cubic and linear splines or linear regression was used to examine the associations between maternal pre-pregnancy BMI, birth weight for gestational age, and infant weight gain from birth to 1 year with LTPA (frequency/wk) in 7-year-old children. The results suggest no associations between maternal pre-pregnancy BMI, birth weight, and infant weight gain on subsequent LTPA in girls. Maternal pre-pregnancy BMI and birth weight may be non-linearly associated with LTPA in 7-year-old boys. Infant weight gain (change in weight z-score from birth to 1 year) may be weakly linearly associated with LTPA in boys. Pre- and post-natal factors may therefore influence LTPA in childhood differently in boys and girls. Maternal pre-pregnancy BMI and birth weight are positively associated with LTPA at the lower ends of the maternal pre-pregnancy BMI and birth weight continuums in boys. The negative associations at the higher ends of the continuums and the positive association between infant weight gain and LTPA in boys may not be important and needs further replication.

Genetic risk score predicts risk for overweight and obesity in Finnish preadolescents

Common genetic variants predispose to obesity with varying contribution by age. We incorporated known genetic variants into genetic risk scores (GRSs) and investigated their associations with overweight/obesity and central obesity in preadolescents. Furthermore, we compared GRSs with lifestyle factors, and tested if they predict the change in body size and shape in a 4-year follow-up. We utilized 1142 subjects from the Finnish Health in Teens (Fin-HIT) cohort. Overweight and obesity were defined with age- and gender-specific body mass index (BMI) z-score (BMIz), while central obesity by the waist-to-height ratio (WHtR). Background data on parental language, eating habits, leisure-time physical activity (LTPA) and sleep duration were included. Genotyping was performed with the Metabochip platform. Weighted, standardized GRSs were derived. Of the11-year-old children, 25.5% were at least overweight and 90.8% had Finnish speaking background. BMI-GRS was associated with higher risk for overweight with odds ratio (95% confidence interval) of 1.39 (1.20; 1.60) and obesity 1.41 (1.08; 1.83), but not with central obesity. BMI-GRS was weakly and inversely associated with the changes in BMIz and WHtR in the 4-year follow-up. Waist-to-hip ratio-GRS was not related to any obesity measures at baseline nor in the follow-up. The effect of BMI-GRS is similar to that of low LTPA on overweight. An interaction between parental language and BMI-GRS was noted (P = .019): BMI-GRS associated more strongly with overweight in Swedish than in Finnish speakers. We further identified two suggestive genetic variants near LOC101926977 and LOC105369677 associated with BMIz in preadolescents which were replicated in the adult population. In preadolescents, known genetic predisposing factors induce a risk for overweight comparable to low LTPA. However, the GRS was poor in predicting short-term changes in BMI or WHtR.

Bidirectional Associations Between Adiposity, Sedentary Behavior, and Physical Activity: A Longitudinal Study in Children

BACKGROUND

Previous studies have reported on the associations between obesity and sedentary behavior (SB) or physical activity (PA) in children. This study examined longitudinal and bidirectional associations between adiposity and SB and PA in children.

METHODS

Participants were 356 children in England. PA was measured at 7 and 9 years of age using accelerometry. Outcome and exposures were time in SB and PAs and concurrent body mass index z score and fat index (FI).

RESULTS

Adiposity at baseline was positively associated with changes in SB (β = 0.975 for FI) and negatively associated with changes in moderate to vigorous PA (β = -0.285 for body mass index z score, β = -0.607 for FI), vigorous PA (β = -0.095 for FI), and total PA (β = -48.675 for FI), but not vice versa. The changes in SB, moderate to vigorous PA, and total PA for children with overweight/obesity were significantly more adverse than those for children with healthy weight.

CONCLUSIONS

A high body mass index z score or high body fatness at baseline was associated with lower moderate to vigorous PA and vigorous PA after 2 years, but not vice versa, which suggests that in this cohort adiposity influenced PA and SB, but the associations between adiposity and SB or PA were not bidirectional.

Investigating Motor Competence in Association with Sedentary Behavior and Physical Activity in 7- to 11-Year-Old Children

Children's motor competence (MC) has declined in the past decades, while sedentary behavior (SB) has increased. This study examined the association between MC and physical activity (PA) levels among primary schoolchildren. Demographics, body height and weight, MC (Athletic Skills Track), and PA levels (ActiGraph, GT3X+) were assessed among 595 children (291 boys, mean age = 9.1 years, SD = 1.1). MC was standardized into five categories: from very low to very high. PA levels were classified into SB, light PA (LPA), and moderate-to-vigorous PA (MVPA). Mixed-model analyses were conducted with PA levels as dependent variables and MC as the independent variable, while adjusting for age, gender, and body mass index (BMI) z-score on the individual level. A negative association between MC and SB and a positive association between MC and MVPA were found. The strength of both associations increased as children expressed lower or higher levels of MC. MC is an important correlate of both SB and MVPA, particularly for children with very high or low MC. Developing and improving children's MC may contribute to spending less time in SB and more time in MVPA, particularly for high-risk groups, i.e., children with low MC. Moreover, addressing MC development and PA promotion simultaneously might create positive feedback loops for both children's MC and PA levels.

Relationship Among Changes in Sedentary Time, Physical Activity, and Body Mass Index in Young Schoolchildren: A 3-Year Longitudinal Study

PURPOSES

To examine the association between sedentary time (ST) and light physical activity (LPA), moderate- to vigorous-intensity physical activity (MVPA), and body mass index (BMI), and to track these behaviors over a 3-year follow-up in young schoolchildren.

METHODS

The final sample was 64 children (female: n = 36 or 56.3%), enrolled in schools in Porto, Portugal. Height and mass of children were measured by standard methods, and BMI was then calculated. ST, LPA, and MVPA were measured by accelerometer. Changes (Δ) and relative changes (Δ%) between 2009/2010 and 2012/2013 of ST, LPA, MVPA, and BMI were computed. Multiple linear regression analyses were fit to predict Δ%ST (outcome variable), by Δ%LPA, Δ%MVPA, and Δ%BMI (exposure variables).

RESULTS

ST increased and LPA decreased significantly for whole sample (both Ps < .05). No statistically significant difference was found for MVPA over time. There were no differences for ΔST, ΔLPA, ΔMVPA, and ΔBMI between boys and girls. The Δ%LPA and Δ%MVPA were negatively associated with Δ%ST, whereas Δ%BMI was positively associated. Tracking coefficients varied from moderate to strong.

CONCLUSIONS

Time spent in ST increases due to displacement of time in LPA. This reinforces public health measures and suggests the need for interventions focusing on offsetting the decline ST and increasing MVPA during childhood.

In Search of Consistent Predictors of Children's Physical Activity

Physical activity is pivotal for children's health and well-being, yet participation declines across teenage years. Efforts to increase physical activity need to be strengthened to combat this, however, evidence for the design and planning of physical activity promotion in children is lacking. The aim was to identify predictors of physical activity that were relatively consistent across three different measures of physical activity, in pre- and early adolescent South Australians. This is the first study to compare correlates of physical activity across three measures of physical activity in a single sample, in this age group. Children (n = 324) aged 9-13 years and their parents were surveyed on personal, interpersonal and environmental correlates of physical activity. Child physical activity was objectively measured using pedometers (7 days). Self-reported physical activity was determined from organised sport participation and the Physical Activity Questionnaire for Adolescents. Regression models were used to identify consistent predictors of three physical activity measures. Consistent predictors across multiple physical activity measures were: parent support for physical activity, having appropriate clothing for sport, enjoyment of physical activity and perceived availability of sporting clubs. These predictors identify potential avenues for directing intervention efforts to increase physical activity in early adolescents.

Equity effects of children's physical activity interventions: a systematic scoping review

BACKGROUND

Differential effects of physical activity (PA) interventions across population sub-groups may contribute to inequalities in health. This systematic scoping review explored the state of the evidence on equity effects in response to interventions targeting children's PA promotion. The aims were to assess and summarise the availability of evidence on differential intervention effects of children's PA interventions across gender, body mass index, socioeconomic status, ethnicity, place of residence and religion.

METHODS

Using a pre-piloted search strategy, six electronic databases were searched for controlled intervention trials, aiming to increase PA in children (6-18 years of age), that used objective forms of measurement. Screening and data extraction were conducted in duplicate. Reporting of analyses of differential effects were summarized for each equity characteristic and logistic regression analyses run to investigate intervention characteristics associated with the reporting of equity analyses.

RESULTS

The literature search identified 13,052 publications and 7963 unique records. Following a duplicate screening process 125 publications representing 113 unique intervention trials were included. Although the majority of trials collected equity characteristics at baseline, few reported differential effects analyses across the equity factors of interest. All 113 included interventions reported gender at baseline with 46% of non-gender targeted interventions reporting differential effect analyses by gender. Respective figures were considerably smaller for body mass index, socioeconomic status, ethnicity, place of residence and religion. There was an increased likelihood of studying differential effects in school based interventions (OR: 2.9 [1.2-7.2]) in comparison to interventions in other settings, larger studies (per increase in 100 participants; 1.2 [1.0 - 1.4]); and where a main intervention effect on objectively measured PA was reported (3.0 [1.3-6.8]).

CONCLUSIONS

Despite regularly collecting relevant information at baseline, most controlled trials of PA interventions in children do not report analyses of differences in intervention effect across outlined equity characteristics. Consequently, there is a scarcity of evidence concerning the equity effects of these interventions, particularly beyond gender, and a lack of understanding of subgroups that may benefit from, or be disadvantaged by, current intervention efforts. Further evidence synthesis and primary research is needed to effectively understand the impact of PA interventions on existing behavioural inequalities within population subgroups of children.

TRIAL REGISTRATION

PROSPERO (PROSPERO 2016: CRD42016034020 ).

Effect of Sex and Body Mass Index on Children's Physical Activity Intensity during Free Play at an Indoor Soft Play Center: An Exploratory Study

Background: Indoor soft play can provide a safe but exciting physical activity opportunity regardless of environmental conditions. Relatively little is known about the quality or quantity of physical activity engaged in by children during indoor free soft play. The aim of this study was to evaluate the contribution indoor free soft play can make in enabling children to meet physical activity guidelines and to evaluate the effects of sex and body mass index category. Methods: Seventy-two boys and girls aged five to 10 years engaged in un-controlled indoor free soft play with a mean duration of 120.7 (27.1) min, during which physical activity was monitored using Actigraph accelerometers. Results: Children spent an average of 61.7 (24.2) min engaging in moderate to vigorous physical activity (MVPA) and 51.4% (n = 37) achieved the recommended 60 min of MVPA through the single visit to the indoor soft play center. Boys (68.3 (25.7) min) engaged in significantly (p < 0.05) more MVPA than girls (55.8 (21.4) min). Normal weight (65.7 (23.3) min) children engaged in significantly more MVPA than overweight children (48.0 (18.9) min). Conclusions: Attendance at a soft play indoor center has the potential to support children to engage in sufficient MVPA and overcome environmental factors that can restrict physical activity opportunities.

Different healthy habits between northern and southern Spanish school children

AIM

Healthy habits are influenced by several factors such as geographical location. The aims of this study were to describe and compare healthy habits within two populations of sixth-grade primary school children (aged 11-12 years) from northern and southern Spain.

SUBJECTS AND METHODS

A cross-sectional study using two representative samples of school children was conducted. Participants came from Logroño (n = 329) in the north and Granada (n = 284) in the south of Spain. Socio-demographic and anthropometric variables, adherence to the Mediterranean diet, aerobic fitness, and healthy lifestyles were recorded.

RESULTS

Boys reported a higher level of physical activity and aerobic fitness than girls (p = 0.000). Southern school children reported significantly higher adherence to the Mediterranean diet (♀: p = 0.041; ♂: p = 0.008), lower aerobic fitness (♀: p = 0.000; ♂: p = 0.042) and hours of nightly sleep (♀: p = 0.008, ♂: p = 0.007) than northern school children. Southern boys also reported lower levels of physical activity (p = 0.013). There were slight or moderate correlations among all habits measured (physical activity, diet, screen and sleep time). Additionally, the physical activity level was inversely related to weight status. Overweight and obese northern boys reported less physical activity than healthy-weight northern boys (p = 0.020) and overweight and obese southern girls reported less physical activity than healthy-weight southern girls (p = 0.024).

CONCLUSIONS

Results showed differences in physical activity, eating and sleep habits, and aerobic fitness according to geographical location. The relationships found among lifestyle habits indicate the need for health promotion interventions nationally and considering the differences discussed here.

Timing of the decline in physical activity in childhood and adolescence: Gateshead Millennium Cohort Study

Background and aim

There is a widely held and influential view that physical activity begins to decline at adolescence. This study aimed to identify the timing of changes in physical activity during childhood and adolescence.

Methods

Longitudinal cohort study (Gateshead Millennium Study) with 8 years of follow-up, from North-East England. Cohort members comprise a socioeconomically representative sample studied at ages 7, 9, 12 and 15 years; 545 individuals provided physical activity data at two or more time points. Habitual total volume of physical activity and moderate-to-vigorous intensity physical activity (MVPA) were quantified objectively using the Actigraph accelerometer over 5–7 days at the four time points. Linear mixed models identified the timing of changes in physical activity across the 8-year period, and trajectory analysis was used to identify subgroups with distinct patterns of age-related changes.

Results

Four trajectories of change in total volume of physical activity were identified representing 100% of all participants: all trajectories declined from age 7 years. There was no evidence that physical activity decline began at adolescence, or that adolescent declines in physical activity were substantially greater than the declines during childhood, or greater in girls than boys. One group (19% of boys) had relatively high MVPA which remained stable between ages 7 and15 years.

Conclusions

Future policy and research efforts to promote physical activity should begin well before adolescence, and should include both boys and girls.

The Association of Birth Weight and Infant Growth with Energy Balance-Related Behavior - A Systematic Review and Best-Evidence Synthesis of Human Studies

BACKGROUND

Suboptimal prenatal and early postnatal growths are associated with obesity in later life, but the underlying mechanisms are unknown. The aim of this study was to systematically review the literature that reports on the longitudinal association of (i) birth size or (ii) infant growth with later (i) energy intake, (ii) eating behaviors, (iii) physical activity or (iv) sedentary behavior in humans.

METHODS

A comprehensive search of MEDLINE, EMBASE, PsycINFO and The Cochrane Library was conducted to identify relevant publications. We appraised the methodological quality of the studies and synthesized the extracted data through a best-evidence synthesis.

RESULTS

Data from 41 publications were included. The quality of the studies was high in three papers, moderate in 11 and low in the large majority (n = 27) of papers appraised. Our best-evidence synthesis indicates that there is no evidence for an association of birth weight with later energy intake, eating behavior, physical activity or sedentary behavior. We found moderate evidence for an association of extreme birth weights (at both ends of the spectrum) with lower physical activity levels at a later age. Evidence for the association of infant growth with energy balance-related behavior was generally insufficient.

CONCLUSIONS

We conclude that current evidence does not support an association of early-life growth with energy balance-related behaviors in later life, except for an association of extreme birth weights with later physical activity.

Development of sedentary behavior across childhood and adolescence: longitudinal analysis of the Gateshead Millennium Study

Background

In many parts of the world policy and research interventions to modify sedentary behavior of children and adolescents are now being developed. However, the evidence to inform these interventions (e.g. how sedentary behavior changes across childhood and adolescence) is limited. This study aimed to assess longitudinal changes in sedentary behavior, and examine the degree of tracking of sedentary behavior from age 7y to 15y.

Methods

Participants were part of the Gateshead Millennium Study cohort. Measures were made at age 7y (n = 507), 9y (n = 510), 12y (n = 425) and 15y (n = 310). Participants were asked to wear an ActiGraph GT1M and accelerometer epochs were defined as sedentary when recorded counts were ≤25 counts/15 s. Differences in sedentary time and sedentary fragmentation were examined using the Friedman test. Tracking was examined using Spearman’s correlation coefficients and trajectories over time were assessed using multilevel linear spline modelling.

Results

Median daily sedentary time increased from 51.3 % of waking hours at 7y to 74.2 % at 15y. Sedentary fragmentation decreased from 7y to 15y. The median number of breaks/hour decreased from 8.6 to 4.1 breaks/hour and the median bout duration at 50 % of the cumulative sedentary time increased from 2.4 min to 6.4 min from 7y to 15y. Tracking of sedentary time and sedentary fragmentation was moderate from 7y to 15y however, the rate of change differed with the steepest increases/decreases seen between 9y and 12y.

Conclusion

In this study, sedentary time was high and increased to almost 75 % of waking hours at 15y. Sedentary behavior became substantially less fragmented as children grew older. The largest changes in sedentary time and sedentary fragmentation occurred between 9y to 12y, a period which spans the transition to secondary school. These results can be used to inform future interventions aiming to change sedentary behavior.

Prenatal, birth and early life predictors of sedentary behavior in young people: a systematic review

BACKGROUND

Our aim was to systematically summarize the evidence on whether prenatal, birth and early life factors up to 6 years of age predict sedentary behavior in young people (≤18 years).

METHODS

PRISMA guidelines were followed, and searches were conducted in PubMed, SPORTDiscus, EMBASE and Web of Science up to December 1, 2015. We included observational (non-intervention) and longitudinal studies, that reported data on the association between one or more of the potential predictors and objectively or subjectively measured sedentary behavior. Study quality was assessed using a formal checklist and data extraction was performed using standardized forms independently by two researchers.

RESULTS

More than 18,000 articles were screened, and 16 studies, examining 10 different predictors, were included. Study quality was variable (0.36-0.95). Two studies suggest that heritability and BMI in children aged 2-6 years were significant predictors of sedentary behavior later in life, while four and seven studies suggest no evidence for an association between gestational age, birth weight and sedentary behavior respectively. There was insufficient evidence whether other prenatal, birth and early life factors act as predictors of later sedentary behavior in young people.

CONCLUSION

The results suggest that heritability and early childhood BMI may predict sedentary behavior in young people. However, small number of studies included and methodological limitations, including subjective and poorly validated sedentary behavior assessment, limits the conclusions.

TRIAL REGISTRATION

The systematic review is registered in the International Prospective Register of Systematic Reviews, PROSPERO, 17.10.2014 ( CRD42014014156 ).

Objectively measured sedentary behavior and physical activity of Finnish 7- to 14-year-old children- associations with perceived health status: a cross-sectional study

Background

Regular physical activity (PA) forms the basis for healthy growth and development. High volume of sedentary behavior (SB) on the other hand is harmful for health. The purpose of the study was to describe objectively measured PA and SB in Finnish school children. Furthermore, the study aimed at analyzing the association between PA, SB and perceived health status.

Methods

The participants of this cross-sectional study were 7- to 14-year-old girls and boys (n = 1029), whose PA and SB during waking hours were measured with Hookie AM 20-accelerometer (Traxmeet Ltd, Espoo, Finland) for seven days. Perceived health status was assessed by a questionnaire. Association between PA, SB and health status was analyzed by logistic regression analysis using SPSS (Inc, Chicago IL).

Results

Participants (age 10.3 ± 1.9, 52 % girls) with sufficient accelerometer data (at least 4 days with ≥ 10 h/day) were included into the study (n = 851, 88 %). The average measurement time was 13 h 27 min per day.

Participants spent on average 54 % (7 h 18 min) of waking hours sedentary, mainly sitting. They stood still on average 9 % of the time (1 h 15 min). Light PA covered on average 18 % (2 h 24 min) and moderate-to-vigorous PA 19 % (2 h 30 min). Younger participants and boys were more active than the older ones and girls.

Most (63 %) of the participants perceived their health status as excellent. In an adjusted logistic regression analysis greater sedentary time decreased the odds for excellent perceived health status (p = 0.001). In contrast higher number of steps per day (p = 0.019) increased the odds.

Conclusions

Participants spent over half of their waking hours sedentary. Less SB and more steps were associated with excellent perceived health. There is a need for dose-response analyses between objectively measured PA and SB and specific health outcomes in children and adolescents. Also patterns of objectively measured PA and SB should be studied in more detail.

Why Are Girls Less Physically Active than Boys? Findings from the LOOK Longitudinal Study

Background

A gender-based disparity in physical activity (PA) among youth, whereby girls are less active than boys is a persistent finding in the literature. A greater understanding of the mechanisms underlying this difference has potential to guide PA intervention strategies.

Methods

Data were collected at age 8 and 12 years (276 boys, 279 girls) from 29 schools as part of the LOOK study. Multilevel linear models were fitted separately for boys and girls to examine effects of individual, family and environmental level correlates on pedometer measured PA. Cardio-respiratory fitness (multi-stage run), percent fat (DEXA), eye-hand coordination (throw and catch test) and perceived competence in physical education (questionnaire) were used as individual level correlates. At the family level, parent’s support and education (questionnaire) were used. School attended and extracurricular sport participation were included as environmental level correlates.

Results

Girls were 19% less active than boys (9420 vs 11360 steps/day, p<0.001, 95%CI [1844, 2626]). Lower PA among girls was associated with weaker influences at the school and family levels and through lower participation in extracurricular sport. School attended explained some of the variation in boys PA (8.4%) but not girls. Girls compared to boys had less favourable individual attributes associated with PA at age 8 years, including 18% lower cardio-respiratory fitness (3.5 vs 4.2, p<0.001, CI [0.5,0.9]), 44% lower eye-hand coordination (11.0 vs 17.3, p<0.001, CI [5.1,9.0]), higher percent body fat (28% vs 23%, p<0.001, CI [3.5,5.7]) and 9% lower perceived competence in physical education (7.7 vs 8.4, p<0.001, CI [0.2,0.9]). Participation in extracurricular sport at either age 8 or 12 years was protective against declines in PA over time among boys but not girls.

Conclusion

Girls PA was less favourably influenced by socio-ecological factors at the individual, family, school and environmental levels. These factors are potentially modifiable suggesting the gap in PA between boys and girls can be reduced. Strategies aiming to increase PA should be multicomponent and take into consideration that pathways to increasing PA are likely to differ among boys and girls.

Determinants of changes in sedentary time and breaks in sedentary time among 9 and 12 year old children

The current study aimed to identify the determinants of objectively measured changes in sedentary time and sedentary fragmentation from age 9- to age 12 years. Data were collected as part of the Gateshead Millennium Birth Cohort study from September 2008 to August 2009 and from January 2012 to November 2012. Participants were 9.3 (± 0.4) years at baseline (n = 508) and 12.5 (± 0.3) years at follow-up (n = 427). Sedentary behaviour was measured using an ActiGraph GT1M accelerometer. Twenty potential determinants were measured, within a socio-ecological model, and tested for their association with changes in sedentary time and the extent to which sedentary behaviour is prolonged or interrupted (fragmentation index). Univariate and multivariate linear regression analyses were conducted. Measurements taken during winter and a greater decrease in moderate-to-vigorous intensity physical activity (MVPA) over time were associated with larger increases in sedentary time (seasonality β: - 3.03; 95% CI: - 4.52, - 1.54; and change in MVPA β: - 1.68; 95% CI: - 1.94, - 1.41). Attendance at sport clubs was associated with smaller increases in sedentary time (- 1.99; - 3.44, - 0.54). Girls showed larger decreases in fragmentation index (- 0.52; - 1.01, - 0.02). Interventions aimed at decreasing the decline in MVPA and increasing/maintaining sport club attendance may prevent the rise in sedentary time as children grow older. In addition, winter could be targeted to prevent an increase in sedentary time and reduction in sedentary fragmentation during this season.

Association between maternal education and objectively measured physical activity and sedentary time in adolescents

Background

Investigating socioeconomic variation in physical activity (PA) and sedentary time is important as it may represent a pathway by which socioeconomic position (SEP) leads to ill health. Findings on the association between children's SEP and objectively assessed PA and/or sedentary time are mixed, and few studies have included international samples.

Objective

Examine the associations between maternal education and adolescent's objectively assessed PA and sedentary time.

Methods

This is an observational study of 12 770 adolescents (10–18 years) pooled from 10 studies from Europe, Australia, Brazil and the USA. Original PA data were collected between 1997 and 2009. The associations between maternal education and accelerometer variables were examined using robust multivariable regression, adjusted for a priori confounders (ie, body mass index, monitor wear time, season, age and sex) and regression coefficients combined across studies using random effects meta-analyses. Analyses were conducted in March 2014.

Results

Adolescents of university educated mothers spent more time sedentary (9.5 min/day, p=0.005) and less time in light activity (10 min/day, p<0.001) compared with adolescents of high school educated mothers. Pooled analysis across two studies from Brazil and Portugal (analysed separately because of the different coding of maternal education) showed that children of higher educated mothers (tertiary vs primary/secondary) spent less time in moderate to vigorous PA (MVPA) (6.6 min/day, p=0.001) and in light PA (39.2 min/day: p<0.001), and more time sedentary (45.9 min/day, p<0.001).

Conclusions

Across a number of international samples, adolescents of mothers with lower education may not be at a disadvantage in terms of overall objectively measured PA.

Associations between socioeconomic position and correlates of sedentary behaviour among youth: a systematic review

Existing research evidence indicates that children and adolescents of parents with a low socioeconomic position spend more time on sedentary behaviour than their counterparts. However, the mechanisms driving these differences remain poorly understood. The main aim of this systematic review was to summarize the evidence regarding the association between socioeconomic position and correlates of sedentary behaviour among youth (0-18 years) from developed countries. The literature search was conducted using MEDLINE, Embase, CINAHL and PsycINFO. A total of 37 studies were included. All but three studies examined screen-based sedentary behaviours only. Methodological quality ranged from low to moderate. Education was the most commonly used indicator of socioeconomic position, followed by income. Socioeconomic position was inversely related to the presence of a TV in the child's bedroom, parental modelling for TV viewing, parental co-viewing and eating meals in front of the TV. We found no/indeterminate evidence for an association between socioeconomic position and rules and regulations about screen time. The findings suggest possible factors that could be targeted in future intervention studies to decrease screen-based sedentary behaviour in lower socioeconomic groups in particular.

Cross-sectional and prospective associations between moderate to vigorous physical activity and sedentary time with adiposity in children

BACKGROUND

Physical activity (PA) and sedentary time (SED) have both been suggested as potential risk factors for adiposity in children. However, there is paucity of data examining the temporal associations between these variables.

OBJECTIVE

This study aimed to analyze the cross-sectional and prospective associations between PA, SED and body composition in children.

METHODS

A total of 510 children (age at baseline 10.1±0.8, age at follow-up 11.8±0.9) from six Portuguese schools from the Oeiras Municipality participated in this study. PA and SED were measured by accelerometry and trunk fat mass (TFM) and body fat mass (BFM) were measured by dual energy X-ray absorptiometry. Fat mass index (FMI) was calculated as BFM divided by height squared. Several regression models adjusted for age, sex, maturity status, follow-up duration, baseline levels of the outcome variable and SED or moderate to vigorous PA (MVPA) were performed.

RESULTS

MVPA (min per day) was cross-sectionally inversely associated with adiposity indexes (FMI, TFM and BFM). Adiposity indexes were inversely associated with time in MVPA. In prospective analyses, MVPA was associated with a lower levels of FMI (β=-0.37, 95% confidence interval (CI): -0.49 to -0.26, P<0.001), TFM (β=-0.20, 95% CI: -0.29 to -0.10, P<0.001) and BFM (β=-0.37, 95% CI: -0.49 to -0.26, P<0.001). When the model was adjusted for age, sex, maturity status and for baseline levels of the outcome variables MVPA remained a significant predictor of lower adiposity indexes (FMI: β=-0.09, 95% CI: -0.16 to -0.01, P<0.05; TFM: β=-0.08, 95% CI: -0.15 to -0.01, P<0.05; BFM: β=-0.07, 95% CI: -0.15 to 0.00, P<0.05). Adiposity was not associated with MVPA when modeled as the exposure in prospective analyses. SED was not related with adiposity indexes, except for the relationship with FMI.

CONCLUSIONS

In cross-sectional and prospective analyses, MVPA is associated with lower adiposity independent of covariates and SED. Results suggest that promoting MVPA is important for preventing gain in adiposity in healthy children.

Longitudinal changes in objectively measured sedentary behaviour and their relationship with adiposity in children and adolescents: systematic review and evidence appraisal

This review aimed to determine longitudinal changes in objectively measured overall sedentary behaviour, and to examine their associations with adiposity in children and adolescents. A search for longitudinal studies was performed using several electronic databases. Of 161 potentially eligible papers, 10 for change in sedentary behaviour and 3 for longitudinal associations with change in adiposity were included. Weighted mean increase in daily sedentary behaviour per year was 5.7% for boys and 5.8% for girls. Only one paper included preschool children, and it showed a decrease in sedentary behaviour. Nine studies were from Western countries. Null associations were reported between sedentary behaviour and adiposity in two studies, the other found that increases in sedentary behaviour were associated with increases in adiposity, but only in those with body mass index above the 50th percentile. There was consistent evidence that sedentary behaviour increases with age in school-age children and adolescents, by approximately 30 min extra daily sedentary behaviour per year. There was little evidence on the influence of changes in sedentary behaviour on changes in adiposity. There is a need for more longitudinal research, for more evidence from outside the Western world, and for more studies that examine 'dose-response' associations between changes in sedentary behaviour and changes in adiposity.

Longitudinal effects of parental, child and neighborhood factors on moderate-vigorous physical activity and sedentary time in Latino children

Background

Moderate-vigorous physical activity (%MVPA) confers beneficial effects on child musculoskeletal health, cardiovascular fitness, and psychosocial well-being; in contrast, sedentary time (%SED) is emerging as a risk factor for health. This study aimed to identify parental, child and neighborhood factors influencing longitudinal assessments of body mass index (BMI) and activity patterns among Latino children, and to estimate lagged and cross-lagged effects between child BMI, %MVPA and %SED.

Methods

A longitudinal design with assessments at baseline, 1 and 2 years follow-up (FU) was used to evaluate the effects of maternal and paternal factors (BMI, age, education level, acculturation, household income and household size), child factors (gender, age, BMI, pubertal status) and neighborhood factors (disorder, victimization) on child BMI, %MVPA and %SED, expressed as a percent of awake time, in 282 Latino children ages 8–10 y and their parents. This study was restricted to families with a mother and biological father or father figure in the child’s life.

Results

Across time, total daily accelerometer counts (p = 0.04) and steps decreased (p = 0.0001), %SED increased (p = 0.0001), and %MVPA decreased (p = 0.02). Moderate lagged effects or tracking was seen for %MVPA and %SED (p = 0.001). %MVPA varied by gender (5.5% higher in boys than girls, p = 0.0001); child age (−0.4% per year, p = 0.03), and child BMI in boys only (−0.22%, p = 0.0002). Negative effects of paternal age, maternal education and maternal changes in BMI on %MVPA also were seen. %SED increased with child age (2.5% higher per year, p = 0.0001). Positive effects of paternal acculturation, maternal change in BMI, paternal age, and negative effects of household size on %SED were observed. A cross-lagged positive effect of BMI at FU1 on %SED at FU2 was observed for boys and girls (p = 0.03). Neighborhood disorder and victimization were not significant predictors of child BMI, %MVPA or %SED.

Conclusion

The major child determinants of physical activity (age, gender and BMI) and minor parental influences (maternal BMI and education, paternal age and acculturation) should be considered in designing interventions to promote %MVPA and reduce %SED among Latino children as they approach adolescence.

Preschools' friendliness toward physical activity: item battery and two scores developed by mixed methods

BACKGROUND

Previous work suggests that many context-level characteristics of preschools are associated with increased physical activity (PA) in children.

PURPOSE

To facilitate assessment of preschools' friendliness toward PA, an item battery as well as comprehensive and short rating scores were developed based on mixed methods with validity and reliability tested.

METHODS

Organizational and contextual characteristics of 24 German preschools were assessed by direct observation and semi-structured interviews (September 2008 to April 2009; analyzed in 2012). Twenty-seven items across seven domains of friendliness toward PA were rated independently by two researchers as being limited (0); adequate (1); or extraordinarily (2) friendly toward PA. Values were summed to a comprehensive rating score value (RS-c). To increase feasibility, a short score (RS-s) was developed using an item subset identified by both item-item correlations and positive association with moderate to vigorous PA. Validity of items and scores was tested by their association with preschoolers' accelerometer-measured PA (n=405) in covariate-adjusted multilevel models. Reliability was tested by inter-rater reliability coefficients.

RESULTS

Nine of 27 items were included in the RS-s. In the multilevel model, four single items and both the RS-c and RS-s were positively associated with children's moderate to vigorous PA (RS-c: β=0.5 minutes, p=0.003, explained variance=9%; RS-s: β=1.3 minutes, p<0.001, variance=23%), but not with light activity or sedentary behavior. Inter-rater reliability was 0.80 (RS-c) and 0.88 (RS-s).

CONCLUSIONS

There is potential value for mixed methods in assessing preschools' friendliness toward PA.

Separating bedtime rest from activity using waist or wrist-worn accelerometers in youth

Recent interest in sedentary behavior and technological advances expanded use of watch-size accelerometers for continuous monitoring of physical activity (PA) over extended periods (e.g., 24 h/day for 1 week) in studies conducted in natural living environment. This approach necessitates the development of new methods separating bedtime rest and activity periods from the accelerometer recordings. The goal of this study was to develop a decision tree with acceptable accuracy for separating bedtime rest from activity in youth using accelerometer placed on waist or wrist. Minute-by-minute accelerometry data were collected from 81 youth (10-18 years old, 47 females) during a monitored 24-h stay in a whole-room indirect calorimeter equipped with a force platform covering the floor to detect movement. Receiver Operating Characteristic (ROC) curve analysis was used to determine the accelerometer cut points for rest and activity. To examine the classification differences, the accelerometer bedtime rest and activity classified by the algorithm in the development group (n = 41) were compared with actual bedtime rest and activity classification obtained from the room calorimeter-measured metabolic rate and movement data. The selected optimal bedtime rest cut points were 20 and 250 counts/min for the waist- and the wrist-worn accelerometer, respectively. The selected optimal activity cut points were 500 and 3,000 counts/min for waist and wrist-worn accelerometers, respectively. Bedtime rest and activity were correctly classified by the algorithm in the validation group (n = 40) by both waist- (sensitivity: 0.983, specificity: 0.946, area under ROC curve: 0. 872) and wrist-worn (0.999, 0.980 and 0.943) accelerometers. The decision tree classified bedtime rest correctly with higher accuracy than commonly used automated algorithm for both waist- and wrist-warn accelerometer (all p<0.001). We concluded that cut points developed and validated for waist- and wrist-worn uniaxial accelerometer have a good power for accurate separation of time spent in bedtime rest from activity in youth.

School year versus summer differences in child weight gain: a narrative review

The causes of the current high prevalence of overweight and obesity among children are not clearly known. Schools have been implicated in the causal chain to high child obesity prevalence. Recent studies have compared school year versus summertime changes (herein called seasonal differences) in child adiposity or related phenomena. The most common seasonal pattern in six longitudinal descriptive studies was that overweight and obese children experienced accelerated gain in weight or some BMI indicator during the summer, whereas healthy weight children gained less or not at all. Four physical activity (PA) intervention studies demonstrated that school year fitness improvements were lost during the summer. One study showed that PA declined across the summer. Another study provided conflicting results of lower total energy expenditure in the summer, but no seasonal difference in total energy expenditure after adjusting for fat-free mass. This pattern of fairly rapid seasonal differences suggests that PA is the primary factor contributing to seasonal differences in weight or BMI, but the documented seasonal pattern in PA (i.e., higher in summer) does not support this relationship. Sleep duration has also been inversely related to child adiposity. Seasonal patterns in adiposity, PA, and sleep need to be clearly established separately for overweight and healthy weight children in further longitudinal research to provide a clear focus for national policy.

Fatores associados ao comportamento sedentário em escolares de 9-12 anos de idade

São recentes os estudos que investigaram impactos do comportamento sedentário (CS) sobre a saúde, principalmente em crianças. O objetivo foi investigar fatores associados ao CS em escolares do município de Uberaba, MG. Trata-se de estudo epidemiológico, transversal, com amostra probabilística (n = 649). Foram coletadas e consideradas variáveis independentes: medidas antropométricas, pressão arterial, exames bioquímicos, tempo gasto em atividade física (AF). CS foi considerado variável dependente, caracterizado pelo tempo de tela (TT), e verificado fatores associados pela regressão de Poisson. Meninas apresentaram valores maiores de dobras cutâneas, triglicerídeos e HDL-c e meninos, maior concentração de glicose sanguínea, atenderam mais à recomendação de 60 min de AF/dia e maior CS. O TT > 2 h/dia foi prevalente em 76,9 % da amostra. CS não foi associado a variáveis sociodemográficas, de saúde e comportamentais em crianças de 9-12 anos de idade. Mais pesquisas são necessárias para elucidar as inter-relações complexas entre TT e fatores associados.

Children's and adolescents' sedentary behaviour in relation to socioeconomic position

BACKGROUND

Sedentary behaviour is an emerging cardiometabolic risk factor in young people. Little is known about how socioeconomic position (SEP) and sedentary behaviour are associated in children and adolescents. This study examines associations between SEP and sedentary behaviour in school-age children and adolescents.

METHODS

The core sample comprised 3822 Health Survey for England 2008 participants aged 5-15 years with complete information on SEP (household income, head of household occupational social class and area deprivation) and self-reported sedentary time (television viewing and other sitting during non-school times). Accelerometer-measured total sedentary time was measured in a subsample (N=587). We examined multivariable associations between SEP (including a composite SEP score) and sedentary time using generalised linear models, adjusting for age, sex, body mass index, physical activity, accelerometer wear time and mutually adjusting for the other SEP indicators.

RESULTS

Participants in the highest SEP category spent 16 min/day less (95% CI 6 to 25, p=0.003) watching TV than participants in the lowest SEP category; yet they spent 7 (2 to 16, p=0.010) and 17 (5 to 29, p<0.000) min/day more in non-TV sitting and total (accelerometry-measured) sedentary time, respectively. Associations across individual SEP components varied in strength. Area deprivation was not associated with sedentary time.

CONCLUSIONS

Low SEP is linked with higher television times but with lower total (accelerometer-measured) sedentary time, and non-TV sitting during non-school time in children and adolescents. Associations between sedentary time and SEP differ by type of sedentary behaviour. TV viewing is not a good proxy for total sedentary time in children.

Study protocol: the relation of birth weight and infant growth trajectories with physical fitness, physical activity and sedentary behavior at 8-9 years of age - the ABCD study

BACKGROUND

Low birth weight and accelerated infant growth have been identified as independent risk factors for childhood and adult obesity and cardiovascular disease. This led to the 'Developmental Origins of Health and Disease' (DOHaD) hypothesis, stating that environmental factors during pregnancy and early postnatal life affect disease risk in later life. There is growing evidence that perinatal factors may influence adult health through the programming of energy balance regulation, including sedentary behavior and physical activity. The present study focuses on the influence of birth weight and infant growth on physical fitness, physical activity and sedentary behavior in 8-9 year old children, as this might partly explain the higher obesity and cardiovascular risk associated with low birth weight and accelerated infant growth. In addition, this study provides the opportunity for a validation study of a linguistic and cross-cultural translated physical activity questionnaire compared to accelerometer data. This article describes the study protocol for this study.

METHODS/DESIGN

This is a study embedded in the Amsterdam Born Children and their Development (ABCD) birth cohort. In 200 children of Dutch ethnicity, physical fitness, physical activity and sedentary behavior were assessed at age 8-9. We measured aerobic fitness using the 20 meter multistage shuttle run test, and neuromuscular fitness using the standing broad jump and handgrip strength test. Sedentary behavior and physical activity levels were measured using accelerometry. All children also completed a translated physical activity questionnaire, the scores of which will be compared to accelerometry data to assess the construct validity of the questionnaire in Dutch school-aged children.

DISCUSSION

This study will be the first population-based prospective cohort study to address the association of both prenatal and postnatal growth with physical fitness and objectively-assessed physical activity and sedentary behavior. This will contribute to a better understanding of the way perinatal growth relate to lifestyle and obesity in later life. The results may guide both future studies in the field of DOHaD, and public health strategies in the prevention of childhood obesity.