Objectively Measured Sedentary Time in Children and Their Parents

Does light-intensity physical activity moderate the relationship between sitting time and adiposity markers in adolescents?

BACKGROUND

While the relationship between sedentary time and adiposity markers may be independent of moderate-to-vigorous intensity physical activity (MVPA) among adolescents, little is known about the role of light-intensity physical activity (LIPA) in this relationship. The aim of this cross-sectional study was to examine whether device-measured LIPA and MVPA moderate the associations between objectively measured sitting time and adiposity markers (body mass index (BMI)) and waist circumference (WC)) among adolescents.

METHODS

This study included accelerometer and inclinometer data obtained from 219 adolescents (age = 14.9 ± 1.6 years, mean ± SD), collected during 2014 and 2015 in Melbourne, Australia. ActiGraph GT3X accelerometers were used to determine time spent in total-LIPA (101 counts/min to 3.99 metabolic equivalents (METs)) was dichotomized into low-LIPA (101-799 counts/min) and high LIPA (800 counts/min to 3.99 METs), and MVPA (≥ 4 METs). The average time spent sitting was obtained from activPAL inclinometers. Anthropometric measures were assessed by trained staff. Interactions between sitting and total-LIPA, low-LIPA, high-LIPA, and MVPA on BMI z-score (zBMI) and WC z-score (zWC), respectively, were examined using linear regression, adjusting for age and sex; and moderation by total-LIPA, low-LIPA, high-LIPA, and MVPA were examined by adding interaction terms. Significant interaction effects were probed by comparing associations at the mean and at 1 SD below and above the mean.

RESULTS

Total-LIPA significantly moderated the association between sitting time and zBMI, and low-LIPA significantly moderated the association between sitting time and zBMI and zWC. No other associations were found for total-LIPA, high-LIPA, or MVPA. Specifically, at high levels of total-LIPA (+1 SD), there is a negative association between sitting time and zBMI. In addition, at high levels of low-LIPA (+1 SD), there is a negative association between sitting time and zBMI and zWC.

CONCLUSION

Associations between sitting and adiposity depended on time spent in total-LIPA and low-LIPA, but not high-LIPA or MVPA. Results suggest that increasing time spent in LIPA may provide protection from the deleterious effects of sitting on adiposity markers among adolescents. Experimental evidence is needed to support these conclusions.

Determinants of High Fat Mass Index in Preschoolers Living in Brazilian Urban Areas

OBJECTIVE

Determine the social, environmental, and personal factors associated with high fat mass index in preschoolers.

DESIGN

A quantitative, exploratory, and cross-sectional study.

SETTING AND PARTICIPANTS

Fifty-one Brazilian preschoolers from public schools living in urban areas.

MAIN OUTCOME MEASURE(S)

The preschoolers' fat mass index was determined using dual-energy radiological absorptiometry. The quality of home and school environments were accessed using the Early Childhood Home Observation for Measurement of the Environment and Early Childhood Environment Rating Scales. The physical activity levels were recorded by accelerometers. The daily energy intake was recorded and sociodemographic data using the Brazilian Economic Classification criterion. Data on exposure time to screens and parental obesity were collected according to the parents' reports.

ANALYSIS

Data analyses were performed using simple and multiple regressions models.

RESULTS

Parental obesity (β, 0.516; 95% confidence interval [CI], 2.078-5.133), high quality of environmental stimulation of home (β, 0.429; 95% CI, 1.294-4.023), and high exposure time to screens (β, 0.256; 95% CI, 0.215-2.554) explained 43% of preschoolers' high fat mass index.

CONCLUSIONS AND IMPLICATIONS

Identification of parental obesity, high quality of environmental stimulation of home, and high exposure time to screens as the most important determinants of the high fat mass index in preschoolers from Brazilian urban areas.

The Impact of Online-Schooling during COVID-19 on Device-Measured 24-Hour Movement Behaviours among High School Students: A Compositional Data Analysis

The COVID-19 measures have unfavourably affected the movement behaviours of youth. The aim of this study was to explore the impact of online-schooling during COVID-19 on device-measured sleep (SL), sedentary behaviour (SB), light physical activity (LPA), and moderate–vigorous physical activity (MVPA) among high school students. A total of 51 students (26 female) from Slovenia wore an activity monitor activPAL4 during the weekdays of onsite-schooling and during the weekdays of online-schooling. Data on movement behaviours were analysed using compositional data analysis. During the onsite-schooling (and online-schooling), students spent on average 432 min/day (469 min/day) in SL, 731 (755) in SB, 253 (202) in LPA, and 25 (15) in MVPA. Repeated measures multivariate analysis of variance confirmed significantly more time was spent in SL (log ratio 0.29; 95% CI 0.20, 0.37)) and SB (log ratio 0.23; 95% CI 0.13, 0.32) and less time in MVPA (log ratio −0.44; 95% CI −0.66, −0.23) during the online-schooling weekdays. Students spent significantly more time in SB during leisure (log ratio 0.20; 95% CI 0.06, 0.35) as well as during lecture time (log ratio 0.45; 95% CI 0.32, 0.58). Our results indicate that online-schooling significantly contributed to the unfavourable changes in students’ movement behaviours during COVID-19. Future studies should focus on developing physical activity interventions suitable for the circumstances of the epidemic.

Children's and Families' Determinants of Health-Related Behaviors in an Italian Primary School Sample: The "Seven Days for My Health" Project

Childhood obesity is an established health problem, and there is a growing need for health promotion interventions focused on healthy behaviors in collaboration with parents and schools. The Mediterranean diet (MD) could help to tackle obesity, but it is essential to maintain a good level of physical activity (PA) and limit time spent in sedentary activities (ST). To explore family determinants, adherence to the MD and PA levels as potential predictors of a child’s health-related behaviors, we performed a cross-sectional analysis of 368 Italian primary school children with a mean age of 8.95 years (SD = 1.43). Data were collected from May to June 2017 using a weekly diary, an interactive tool to assess the child’s and parents’ lifestyle. The child’s degree of adherence to the MD was calculated using the KIDMED index. Adherence to the MD was high, medium and poor in 5.2%, 62.5% and 32.3% of children, respectively. Higher maternal educational level was positively associated with children’s MD and PA (p < 0.05) and negatively correlated to ST. Maternal fruit and vegetable consumption was positively related to the MD and negatively related to ST (p < 0.05). Maternal PA was positively associated with the MD (p < 0.001). Paternal PA, and fruit and vegetable consumption, were positively associated with children’s PA (p < 0.05). Our results underline the need for future studies, mainly focused on school-based and family-based interventions, to promote healthy lifestyles and nutritional habits.

Familial Correlates of Leisure Time Activities among Polish Early School-Age Children: A Cross-Sectional Study

The after-school period may play a critical role in the accumulation of children’s physical activity and sedentary time. The study aimed to characterize familial correlates of early school-age children’s leisure time activities. A cross-sectional study was conducted among a group of 223 children (mean age 8.7 ± 0.5) and their parents. The percentage of children with daily leisure time physical activity (LTPA) >1 h was 23.32%, and with daily screen time <2 h was 32.74%. The average children’s leisure time physical activity was significantly higher on weekend days than on weekdays (114.85 vs. 89.43 min, p = 0.005). Similarly, the average screen time was higher on weekend days than on weekdays (95.50 vs. 66.10 min, p < 0.001). The multivariate regression analysis revealed that independent predictors of children’s leisure time physical activity were the father’s education level and the father’s occupational status, whereas at least one parent with higher education correlated negatively with children’s longer screen time. The study showed that children’s leisure time activities are associated with parental education and differ significantly between weekdays and weekend days. These findings underline the need for screening for unfavorable health behaviors among early school-age children, and indicate that health promotion programs should be oriented on both parents and children aiming to improve parental health consciousness, reduce screen time and increase physical activity, especially during the weekend.

The Influence of Role Models on the Sedentary Behaviour Patterns of Primary School-Aged Children and Associations with Psychosocial Aspects of Health

BACKGROUND

High levels of sedentary behaviour (SB) are associated with poor health outcomes in children, but the effects on mental health are less clear. This study explored the relationship between SB and psychosocial aspects of health in children, and what influence key role models, including parents and schoolteachers, have on the SB levels of children.

METHODS

Physical activity (PA) and SB were measured using accelerometery in 101 children, 113 parents and 9 teachers. Children were aged 9 or 10 years old and in fourth grade. Child psychosocial outcomes were assessed using the Rosenberg Self-Esteem Scale and the Strengths and Difficulties Questionnaire.

RESULTS

Children engaged in a high volume of SB (9.6 h/day) but interrupted SB often. They accumulated less than 11,000 steps per day, and thus, many may not meet the recommended daily levels of PA. No associations were found between child SB and teacher SB during the school day or child SB and parent SB during the after-school period. No association was found between SB and self-esteem, although children with a higher body mass index had a higher number of emotional and behavioural difficulties.

CONCLUSIONS

Although there was no indication that children's SB was linked to that of parents and teachers, or that SB was associated with self-esteem or behavioural problems, school children were highly sedentary and insufficiently physically active. Therefore, there is a need to explore school practices and curriculum delivery methods, as well as school and home environments, to reduce the volume of SB children engage in.

activPAL-measured sitting levels and patterns in 9-10 years old children from a UK city

BACKGROUND

There is insufficient evidence of sitting time in UK children from validated objective measures. This study explored sitting patterns in primary school children from Bradford, UK, using the validated activPAL inclinometer.

METHODS

Overall, 79 children (9.8 (SD 0.3) years old, 52% boys; 70% South Asian) wore activPALs for 7 days. Total sitting time, sitting time accumulated in different bout lengths, and the proportion of wear time spent in these variables were explored and compared across different periods of the week.

RESULTS

Children spent 614 ± 112 (median ± IQR) min/day on school days and 690 ± 150 min/day on weekend days sitting. The proportion of time spent sitting was significantly higher on weekend days compared to school days (mean±SD: 74 ± 10% versus 68 ± 8%,P < 0.001), as was the proportion of time accumulated in >30 min sitting bouts (mean±CI: 28 ± 27-33% versus 20 ± 20-22%, P < 0.001). The proportion of time spent sitting after school was significantly higher than during school time (mean±SD: 70 ± 8.4% versus 63 ± 8.3%,P < 0.001), as was the proportion of time spent in prolonged (>30 min) sitting bouts (mean±CI: 19 ± 16-22% versus 11 ± 10-14%, P < 0.001).

CONCLUSIONS

Children spent large proportions of their waking day sitting, often accumulated in prolonged uninterrupted bouts and particularly after school and on weekends. Interventions to reduce sitting time in children are urgently needed.

Sit–stand desks to reduce sedentary behaviour in 9- to 10-year-olds: the Stand Out in Class pilot cluster RCT

Background

Sedentary behaviour (sitting) is a highly prevalent negative health behaviour, with individuals of all ages exposed to environments that promote prolonged sitting. The school classroom represents an ideal setting for environmental change through the provision of sit–stand desks.

Objectives

The aim of this study was to undertake a pilot cluster randomised controlled trial of the introduction of sit–stand desks in primary school classrooms, to inform a definitive trial. Objectives included providing information on school and participant recruitment and retention, acceptability of the intervention, and outcome measures. A preliminary estimate of the intervention’s effectiveness on the proposed primary outcome (change in weekday sitting time) for inclusion in a definitive trial was calculated, along with a preliminary assessment of potential cost-effectiveness. A full process evaluation was also undertaken.

Design

A two-armed pilot cluster randomised controlled trial with economic and qualitative evaluations. Schools were randomised on a 1 : 1 basis to the intervention (n = 4) or control (n = 4) trial arms.

Setting

Primary schools in Bradford, West Yorkshire, UK.

Participants

Children in Year 5 (i.e. aged 9–10 years).

Intervention

Six sit–stand desks replaced three standard desks (sitting six children) in the intervention classrooms for 4.5 months. Teachers were encouraged to ensure that all pupils were exposed to the sit–stand desks for at least 1 hour per day, on average, using a rotation system. Schools assigned to the control arm continued with their usual practice.

Main outcome measures

Trial feasibility outcomes included school and participant recruitment and attrition, acceptability of the intervention, and acceptability of and compliance with the proposed outcome measures [including weekday sitting measured using activPAL™ (PAL Technologies Ltd, Glasgow, UK) accelerometers, physical activity, adiposity, blood pressure, cognitive function, musculoskeletal comfort, academic progress, engagement and behaviour].

Results

Thirty-three per cent of schools approached and 75% (n = 176) of eligible children took part. At the 7-month follow-up, retention rates were 100% for schools and 97% for children. Outcome measure completion rates ranged from 63% to 97%. A preliminary estimate of intervention effectiveness, from a weighted linear regression model (adjusting for baseline sitting time and wear time) revealed a mean difference in change in sitting of –30.6 minutes per day (95% confidence interval –56.42 to –4.84 minutes per day) between the intervention and control trial arms. The process evaluation revealed that the intervention, recruitment and evaluation procedures were acceptable to teachers and children, with the exception of minor issues around activPAL attachment. A preliminary within-trial economic analysis revealed no difference between intervention and control trial arms in health and education resource use or outcomes. Long-term modelling estimated an unadjusted incremental cost-effectiveness ratio of Stand Out in Class of £78,986 per quality-adjusted life-year gained.

Conclusion

This study has provided evidence of the acceptability and feasibility of the Stand Out in Class intervention and evaluation methods. Preliminary evidence suggests that the intervention may have a positive direction of effect on weekday sitting time, which warrants testing in a full cluster randomised controlled trial. Lessons learnt from this trial will inform the planning of a definitive trial.

Trial registration

Current Controlled Trials ISRCTN12915848.

Funding

This project was funded by the National Institute for Health Research (NIHR) Public Health Research programme and will be published in full in Public Health Research; Vol. 8, No. 8. See the NIHR Journals Library website for further project information.

Exploring when and how adolescents sit: cross-sectional analysis of activPAL-measured patterns of daily sitting time, bouts and breaks

BACKGROUND

This study describes patterns of adolescents' objectively-measured sitting volume, sitting bouts, and breaks in sitting during different days and periods of the day, and explored differences by sex and weekdays versus weekend days.

METHODS

ActivPAL™ data were collected in August 2014-December 2015 from adolescents attending secondary government schools in Melbourne Australia. Eight periods (early morning, mid-morning, morning break, late morning, lunch, early afternoon, late-afternoon and evening) were extracted for each day. School time, class time and out-of-school time were also extracted for weekdays. The percentage of time sitting, percentage of each hour in prolonged sitting (sitting bout ≥10 min), and number of sitting breaks/hour were calculated for each period. Differences by sex, and week and weekend days were determined using t-tests.

RESULTS

Participants (n = 297, 15.4 ± 1.6 years) spent 68% of their day sitting; ~ 30% of each hour in prolonged sitting and 3.1 sitting breaks/hour. Sitting time was greater during class time (75%) and school (70%) compared to out-of-school time (65%). Sitting patterns differed between week and weekend days for all periods except the evening period. Girls had higher proportion of sitting during class than boys (76% vs 72% respectively) and school hours (72% vs 67%), more prolonged sitting during school hours (27% vs 23%), and more sitting breaks per hour during out-of-school time (2.6 vs 2.4), but fewer during class (2.5 vs 3.3) and school hours (2.7 vs 3.3). Sitting patterns did not differ by sex on weekend days.

CONCLUSIONS

Adolescents spent two-thirds of their waking hours sitting, with distinct patterns on weekdays and weekend days. Even though boys and girls were exposed to the same school day routine, girls spent more time sitting and had fewer sitting breaks. Class times, school breaks and the evening period were identified as key intervention periods. Further research is needed to understand the behavioural differences, and guide future intervention design.

Ethnic differences in sedentary behaviour in 6-8-year-old children during school terms and school holidays: a mixed methods study

BACKGROUND

Sedentary behaviour (SB) in childhood is a major public health concern. Little is known about ethnic differences in SB during school and holiday weeks among White British (WB) and South Asian (SA) children, which this study aims to address through investigating inclinometer measured SB and exploring reasons for child engagement in SB.

METHODS

A mixed methods study, comprising of a quantitative investigation with 160, 6-8 years old children and a qualitative study with a subsample of 18 children, six parents and eight teachers was undertaken. Children of WB and SA ethnicity in three schools were invited to wear inclinometers for seven school terms (summer/winter/spring) and seven holidays (winter/spring) days during July 2016-May 2017. Total SB, SB accumulated in bouts > 30 min and breaks in SB were explored using multivariate linear mixed effects models which adjusted for wear time, sex, deprivation, overweight status, season, term, weekday and school. Nine focus groups and two interviews were carried out using the Theoretical Domains Framework to explore SB perceptions among parents, teachers and children. Data were analysed using the Framework Approach.

RESULTS

104/160 children provided 836 valid days of data. Children spent on average eight hours of SB/day during term time and holidays, equating to 60% of their awake time, and had on average 111 SB breaks /day. SA children had 25 fewer SB breaks/ day when compared to WB (p < 0.001). Perceived reasons for engagement in SB included: boredom, enjoyment of screen activities (by children), parenting practices, curriculum pressures (by teachers), the need to sit down and learn, and child's preference for screen activities (by parents).

CONCLUSIONS

Children spent 60% of their awake time being sedentary, regardless of ethnicity or school term. There were no significant ethnic differences for any of the SB outcomes except for breaks in SB. Interventions aimed at reducing SB should consider involving parents and teachers and should focus on increasing breaks in SB, especially for SA children, who are at a higher risk of cardio metabolic ill health.

Subjectively and Objectively Assessed Behavioral, Social, and Physical Environmental Correlates of Sedentary Behavior in Preschoolers

OBJECTIVE

To investigate associations between preschoolers' objective leisure-time sedentary behavior and a comprehensive set of subjective and objective potential correlates of sedentary behavior across the behavioral, social, and physical environmental domains on both the family and community level.

STUDY DESIGN

In 3- to 6-year-old preschoolers (n = 738) from 52 preschools in Southern Germany, leisure time spent in sedentary behavior was assessed by accelerometry in 2008-2009. Family- and community-level potential correlates of sedentary behavior from different domains (behavioral, social, and physical environmental) were subjectively (ie, by parent-proxy report) and objectively (ie, by routine administrative data) assessed.

RESULTS

None of the objective social and physical environmental correlates showed associations with sedentary behavior. Leisure-time sedentary behavior decreased with greater levels of moderate-to-vigorous physical activity (both weekends and weekday afternoons), participation in organized sports, parental leisure-time physical activity, as well as greater parental traffic safety perceptions (weekends only).

CONCLUSIONS

Targeting multiple health behaviors at the same time (ie, physical activity and sedentary behavior) and focusing on the entire family (ie, preschoolers, parents, and potentially older siblings) might be useful opportunities to reduce sedentary behaviors in preschoolers.