Prevalence of high screen time in English youth: association with deprivation and physical activity

Associations between socioeconomic position and young people's physical activity and sedentary behaviour in the UK: a scoping review

OBJECTIVE

To examine the evidence on the associations between socioeconomic position and young people's physical activity and sedentary behaviours in the UK.

DESIGN

Scoping review.

DATA SOURCES

PubMed, SCOPUS and Web of Science databases were searched for articles published up to and including January 2021.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Observational studies in children and adolescents (aged 5-18 years) from the UK that had assessed associations between at least one indicator of socioeconomic position and at least one outcome of physical activity and/or sedentary behaviour.

DATA EXTRACTION AND SYNTHESIS

Data were extracted by one reviewer and 20% were double checked. Indicators of socioeconomic position were tabulated with domains of physical activity and sedentary behaviour.

RESULTS

Fifty-seven publications were included in the review; 37 publications from 19 studies (k=23) of children and 21 publications from 15 studies (k=23) of adolescents. Most studies were cross-sectional. 63% of studies of children, and 40% of studies of adolescents assessed Index of Multiple Deprivation. Eighteen studies measured physical activity in children, 13 measured sedentary behaviour. Eleven studies of adolescents included a measure of physical activity, 10 included a measure of sedentary behaviour. Among children and adolescents, the association between socioeconomic position and measures of either physical activity or sedentary behaviour was highly variable depending on the measure of both socioeconomic position used and the behavioural outcome, with the exception of higher family affluence which was consistently associated with higher reported physical activity among adolescents.

CONCLUSION

Physical activity and sedentary behaviours of children and adolescents in the UK are complex and influenced by multiple indicators of socioeconomic position that are, in most cases, different across age stages, outcomes examined and measurement tools. Greater consistency in the use and measures of socioeconomic position as well as outcomes of behaviour are required for robust country-specific meta-analyses.

The Cut-Off Value for Classifying Active Italian Children Using the Corresponding National Version of the Physical Activity Questionnaire

The present study aimed to determine a cut-off value following the filling in of a questionnaire (PAQ-C-It) to identify active Italian children. One-hundred-twenty-nine primary school children (5 Piedmont schools; 47.3% female; mean age = 10 ± 1 years) wore an accelerometer (Actigraph wGT3X-BT) to objectively quantify individual moderate-to-vigorous physical activity during one week. Afterwards, the PAQ-C-It was filled in by participants. A ROC curve procedure was applied to obtain an active/non-active cut-off point. Spearman’s correlation coefficient was also applied to establish the relationship between the two parameters. According to the ROC analysis, the PAQ-C-It cut-off point value is identifiable at >2.75 to indicate active children (area under the curve = 0.62; standard error = 0.05; p = 0.025; coefficient intervals = 0.518−0.716; sensitivity = 0.592, specificity = 0.382), determining that 65 participants (55%) were non-active (mean PAQ-C-It value = 2.3 ± 0.4; active mean PAQ-C-It value = 3.3 ± 0.4). Spearman’s correlation coefficient results were significant but with a small effect size (rho = 0.214; p = 0.008). In conclusion, the present results suggest that the PAQ-C-It can be cautiously used as tool to practically classify active Italian children because of a non-solid relationship between respective accelerometer data and MVPA daily data.

Impact of school closures on the health and well-being of primary school children in Wales UK: a routine data linkage study using the HAPPEN Survey (2018-2020)

OBJECTIVES

This study aimed to explore the relationship between initial school closures and children's health by comparing health and well-being outcomes collected during school closures (April-June 2020) via HAPPEN (the Health and Attainment of Pupils in a Primary Education Network) with data from the same period in 2019 and 2018 via the HAPPEN Survey.

SETTING

The study was conducted online with 161 primary schools across Wales involved in the 'HAPPEN At Home' Survey.

PARTICIPANTS

Data were collected via the 'HAPPEN At Home' Survey capturing the typical health behaviours of children aged 8-11 years from 1333 participants across Wales. These data were compared with data in 2018 and 2019 also collected between April and June, from HAPPEN (2019 (n=1150) and 2018 (n=475)).

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary outcomes included validated measures of physical activity, screen time, diet and dental health, as well as well-being, competency and autonomy. Free school meal (FSM) status was used as a proxy for socioeconomic deprivation. Analyses were repeated stratifying by FSM.

RESULTS

Comparing responses between April-June in 2020 (n=1068), 2019 (n=1150) and 2018 (n=475), there were improvements in physical activity levels, sleep time, happiness and general well-being for children during school closures compared with previous years. However, children on FSM ate fewer fruits and vegetables (21% less at five or more portions of fruits and vegetables (95% CI: 5.7% to 37%)) and had lower self-assessed school competence compared with 2019. Compared with those not on FSM, they also spent less time doing physical activity (13.03%, 95% CI: 3.3% to 21.7%) and consumed more takeaways (16.3%, 95% CI: 2% to 30%) during school closures.

CONCLUSIONS

This study suggests that schools are important in reducing inequalities in physical health. The physical health (eg, physical activity and diet) of children eligible for FSM may be affected by prolonged school closures.

Relationship Between the Practice of Physical Activity and Physical Fitness in Physical Education Students: The Integrated Regulation As a Mediating Variable

The practice of physical activity (PA) contributes to the prevention of chronic diseases such as obesity, metabolic syndrome or cardiovascular diseases, being also directly related to the individual’s physical fitness. Therefore, it is necessary to measure and monitoring the levels of PA in childhood and adolescence, since it may be useful to describe their current health status and the association with physical fitness, as well as to reveal putative consequences in the future. Within the educational field, it has been shown that physical education (PE) classes are a favorable context for the creation of healthy physical-sports habits and self-determined motivation could be a key for explaining the level of PA practice. For this reason, the purpose of this research was to study the mediating role of integrated regulation (IR) on the relationship between PA and physical fitness in children and adolescents. A total of 325 students between 11 and 14 years old participated in the study. The level of PA was estimated through the specific Physical Activity Questionnaire for Children (PAQ-C), while motivation and IR were measured by using the Perceived Locus of Causality scale (PLOC-2). In addition, physical fitness was measured through the Eurofit fitness battery of tests, composed of three body composition measures and seven tests of different physical capacities. The physical fitness score showed no differences when genders were compared. After regression analysis, the resulting models revealed a good adjustment and correlation between PA practice and physical fitness (β = 0.173; p < 0.001), being established through the macro Process that this relationship is partially conditioned by the IR (β = 0.122; p = 0.03). ROC curve analysis estimated the score of 5.88 as a cut-off point to discriminate between levels of IR for students, classified as physically active or not (AUC = 0.67; p < 0.001). The conclusions from these main and other complementary analyses reporting complete mediations, suggest that the IR could be decisive in predicting and explaining the relationship between the practice of PA and physical fitness at these ages, highlighting its importance for a greater adherence to the practice.

"In my day…"- Parents' Views on Children's Physical Activity and Screen Viewing in Relation to Their Own Childhood

Physical activity and screen viewing are associated with cardio-metabolic risk factors, psychological wellbeing, and academic performance among children. Across the last generation, children’s physical activity and screen viewing behaviours have changed, coinciding with changes to the home and neighbourhood environment. This study aimed to qualitatively explore parents’ views on their 8–9-year-old child’s childhood and how this compares to experiences from their own childhood, with a specific focus on physical activity and screen viewing behaviours. Semi-structured telephone interviews were conducted with 51 parents (mean age = 41.2 years, range 31.5 to 51.5 years), between July and October 2016. Inductive and deductive content analyses were used to explore parents’ perceptions of their child’s physical activity and screen viewing behaviours in comparison to their own childhood behaviours. Interview data revealed that compared to the relative freedom they recalled as children, parents restrict their children’s independent mobility and outdoor play due to concerns about safety. Despite their children having greater access to structured activities than they did as children, parents feel their children are “missing out,” and perceived their own childhood as better with regards to maximising independent and outdoor play and limiting screen viewing. Innovative strategies are needed to change the social norms surrounding children’s independent mobility and outdoor play.

Socioeconomic Correlates of Sedentary Behavior in Adolescents: Systematic Review and Meta-Analysis

Background

The body of evidence on associations between socioeconomic status (SES) and sedentary behaviors in adolescents is growing.

Objectives

The overall aims of our study were to conduct a systematic review and meta-analysis of this evidence and to assess whether (1) the associations between SES and sedentary behavior are consistent in adolescents from low-middle-income and from high-income countries, (2) the associations vary by domain of sedentary behavior, and (3) the associations vary by SES measure.

Methods

We performed a systematic literature search to identify population-based studies that investigated the association between SES and sedentary behavior in adolescents (aged 10–19 years). Only studies that presented risk estimates were included. We conducted meta-analyses using random effects and univariate meta-regression and calculated pooled effect sizes (ES).

Results

Data from 39 studies were included; this provided 106 independent estimates for meta-analyses. Overall, there was an inverse association between SES and sedentary behavior (ES 0.89; 95 % confidence interval [CI] 0.81–0.98). However, the direction of the association varied: in high-income countries, SES was inversely associated with sedentary behavior (ES 0.67; 95 % CI 0.62–0.73), whereas in low-middle-income countries, there was a positive association between SES and sedentary behavior (ES 1.18; 95 % CI 1.04–1.34). In high-income countries, the associations were strongest for screen time (ES 0.68; 95 % CI 0.62–0.74) and television (TV) time (ES 0.58; 95 % CI 0.49–0.69), whereas in low-middle-income countries, the associations were strongest for ‘other’ screen time (i.e., computer, video, study time, but not including TV time) (ES 1.38; 95 % CI 1.07–1.79). All indicators of SES were negatively associated with sedentary behavior in high-income countries, but only resources (income and assets indexes) showed a significant positive association in low-middle-income countries.

Conclusion

The associations between SES and sedentary behavior are different in high- and low-middle-income countries, and vary by domain of sedentary behavior. These findings suggest that different approaches may be required when developing intervention strategies for reducing sedentary behavior in adolescents in different parts of the world.

Electronic supplementary material

The online version of this article (doi:10.1007/s40279-016-0555-4) contains supplementary material, which is available to authorized users.

Cross-sectional and prospective associations between sleep, screen time, active school travel, sports/exercise participation and physical activity in children and adolescents

BACKGROUND

The aim of this study was to investigate how sleep, screen time, active school travel and sport and/or exercise participation associates with moderate-to-vigorous physical activity (MVPA) in nationally representative samples of Norwegian 9- and 15-y-olds, and whether these four behaviors at age nine predict change in MVPA from age nine to 15 years.

METHOD

We pooled cross-sectional accelerometer and questionnaire data from 9- (n = 2366) and 15-y-olds (n = 1554) that participated in the first (2005/06) and second (2011/12) wave of the Physical Activity among Norwegian Children Study to investigate cross-sectional associations. To investigate prospective associations, we used data from a sub-sample that participated in both waves (at age nine and 15 years, n = 517).

RESULTS

Cross-sectional analyses indicated a modest, inverse association between screen time and MVPA among 9- (- 2.2 min/d (95% CI: -3.1, - 1.3)) and 15-y-olds (- 1.7 min/d (95% CI: -2.7, - 0.8)). Compared to their peers with 0-5 min/d of active travel to school, 9- and 15-y-olds with ≥16 min/d accumulated 7.2 (95% CI: 4.0, 10.4) and 9.0 (95% CI: 3.8, 14.1) more min/d of MVPA, respectively. Nine-y-old boys and 15-y-olds reporting ≥8 h/week of sports and/or exercise participation accumulated 14.7 (95% CI: 8.2, 21.3) and 17.9 (95% CI: 14.0, 21.8) more min/d of MVPA, respectively, than those reporting ≤2 h/week. We found no cross-sectional association between sleep duration and MVPA in either age group. None of the four behaviors predicted change in MVPA from age nine to 15 years (p ≥ 0.102).

CONCLUSION

Active travel to school and sport/exercise participation may be important targets for future interventions aimed at increasing MVPA in children and adolescents. However, future studies are needed to determine causality.

Cumulative Effect of Obesogenic Behaviours on Adiposity in Spanish Children and Adolescents

OBJECTIVE

Little is known about the cumulative effect of obesogenic behaviours on childhood obesity risk. We determined the cumulative effect on BMI z-score, waist-to-height ratio (WHtR), overweight and abdominal obesity of four lifestyle behaviours that have been linked to obesity.

METHODS

In this cross-sectional analysis, data were obtained from the EnKid sudy, a representative sample of Spanish youth. The study included 1,614 boys and girls aged 5-18 years. Weight, height and waist circumference were measured. Physical activity (PA), screen time, breakfast consumption and meal frequency were self-reported on structured questionnaires. Obesogenic behaviours were defined as <1 h PA/day, ≥2 h/day screen time, skipping breakfast and <3 meals/day. BMI z-score was computed using age- and sex-specific reference values from the World Health Organization (WHO). Overweight including obesity was defined as a BMI > 1 SD from the mean of the WHO reference population. Abdominal obesity was defined as a WHtR ≥ 0.5.

RESULTS

High screen time was the most prominent obesogenic behaviour (49.7%), followed by low physical activity (22.4%), low meal frequency (14.4%), and skipping breakfast (12.5%). Although 33% of participants were free of all 4 obesogenic behaviours, 1, 2, and 3 or 4 behaviours were reported by 44.5%, 19.3%, and 5.0%, respectively. BMI z-score and WHtR were positively associated (p < 0.001) with increasing numbers of concurrent obesogenic behaviours. The odds of presenting with obesogenic behaviours were significantly higher in children who were overweight (OR 2.68; 95% CI 1.50; 4.80) or had abdominal obesity (OR 2.12; 95% CI 1.28; 3.52); they reported more than 2 obesogenic behaviours. High maternal and parental education was inversely associated (p = 0.004 and p < 0.001, respectively) with increasing presence of obesogenic behaviours. Surrogate markers of adiposity increased with numbers of concurrent presence of obesogenic behaviours. The opposite was true for high maternal and paternal education.

'Life in the age of screens': parent perspectives on a 24-h no screen-time challenge

Screens have become ubiquitous in modern society. Their use frequently underlies sedentary behaviour, a well-established determinant of obesity. As part of a family oriented clinic offering a 2-year lifestyle program for obese children and youth, we explored parents' experiences with a 24-h no screen-time challenge, an intervention designed to raise awareness of screen-time habits and to help families develop strategies to limit their use. In total, 15 parents representing 13 families participated. A focus group with nine parents and six phone interviews with those who could not join in person were conducted. Interviews were transcribed verbatim and analysed qualitatively. Key elements to successful completion of the 24-h no screen-time challenge emerged, namely: clear rules about permitted activities during the 24-h period; togetherness, i.e. involving all family members in the challenge; and busyness, i.e. planning a full schedule in order to avoid idleness and preclude the temptation to use screens. Our findings suggest that practitioners aiming to increase awareness of screen-time or to limit their use may be more likely to succeed if they include all family members, offer concrete alternatives to screen-based activities and provide tailored strategies to manage discretionary time.

Media device ownership and media use: Associations with sedentary time, physical activity and fitness in English youth

The aim of this study was to determine whether ownership and use of electronic media were associated with sedentary time and cardiorespiratory fitness (fitness) in youth. We also aimed to determine if associations were independent of physical activity (PA).

Fitness was measured using the 20 m shuttle-run. PA, sedentary time, ownership of media devices and media use were self-reported.

Participants (n = 678, age 10–15 years) reported daily sedentary time of 620 (± 210) min. Forty-one percent of participants had low PA and 50.4% had low fitness.

Higher weekend sedentary time was associated with low fitness in girls (p = 0.005) and boys (p < 0.001) and remained significant when adjusted for PA in the latter (p = 0.006). Using social media was associated with higher sedentary time in both sexes and low fitness in girls. High sedentary time was more likely (OR = 5.3, 95%CI: 2.0–14.4) in boys who owned game consoles. Low fitness was more likely in boys who owned digital/satellite TV receivers (OR = 1.8, 95%CI: 1.8–3.2).

Schoolchildren spent > 10 h or ~ 85% of each waking day sedentary. Use of social media was associated with higher sedentary time in both sexes and with low fitness in girls. Reducing social media use in youth offers one potential target for intervention. Behaviours associated with sedentary time differed from predictors of low fitness. The complex and often sex-specific interactions identified between sedentary time, PA and fitness suggest the need for carefully targeted interventions to reduce sedentary time and improve fitness in English youth.

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English schoolchildren spend most of their waking time engaged in sedentary behaviours.

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Physical activity and sedentary time are independently associated with low fitness in boys.

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Owning a game console is associated with higher sedentary time in boys.

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Use of social media is associated with higher sedentary time in boys and girls.

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Owning a digital/satellite TV receiver doubles the risk of low cardiorespiratory fitness in boys.

Association of screen time with self-perceived attention problems and hyperactivity levels in French students: a cross-sectional study

OBJECTIVE

To investigate whether high levels of screen time exposure are associated with self-perceived levels of attention problems and hyperactivity in higher education students.

DESIGN

Cross-sectional study among participants of the i-Share cohort.

SETTING

French-speaking students of universities and higher education institutions.

PARTICIPANTS

4816 graduate students who were at least 18 years old.

EXPOSURE

Screen time was assessed by self-report of the average time spent on five different screen activities on smartphone, television, computer and tablet and categorised into quartiles.

MAIN OUTCOME MEASURE

We used the Attention Deficit Hyperactivity Disorder Self-Report Scale (ASRS-v1.1) concerning students' behaviour over the past 6 months to measure self-perceived levels of attention problems and hyperactivity. Responses were summarised into a global score as well as scores for attention problems and hyperactivity.

RESULTS

The 4816 participants of this study had a mean age of 20.8 years and 75.5% were female. Multivariable ordinary regression models showed significant associations of screen time exposure with quintiles of the total score of self-perceived attention problems and hyperactivity levels as well as the individual domains. Compared to the lowest screen time exposure category, the ORs (95% CI) were 1.58 (1.37 to 1.82) for each increasing level of quintiles of the global score, 1.57 (1.36 to 1.81) for increasing quintiles of attention levels and 1.25 (1.09 to 1.44) for increasing quartiles of hyperactivity.

CONCLUSIONS

Results of this large cross-sectional study among French university and higher education students show dose-dependent associations between screen time and self-perceived levels of attention problems and hyperactivity. Further studies are warranted to evaluate whether interventions could positively influence these associations.

Conceptual framework of a simplified multi-dimensional model presenting the environmental and personal determinants of cardiometabolic risk behaviors in childhood

Clinical manifestations of cardiometabolic risk (CMR) may be set early in childhood due to unfavorable behaviors or lifestyle patterns related to diet and physical activity. Several factors may determine the adoption of such lifestyle-related behaviors, which researchers have tried to cluster under certain frameworks or models. In this context, the framework developed and proposed by this review gathers all the present knowledge regarding these determining factors to date and groups them into three main categories related to personal characteristics and the social and physical environment. Based on the proposed framework, a large variety of personal, social and physical environmental factors can positively or negatively influence CMR-related behaviors (either directly or indirectly via their interrelations), thus leading to decreased or increased risk, respectively. This framework could be of great value to public health policy makers and legislators for designing and implementing interventional programs tailored to the needs of susceptible population groups who are most in need for such initiatives. Targeting the correlates as potential determinants of CMR-related behaviors, and not just on the behaviors themselves, has been shown previously to be the most effective approach for tackling health issues related to CMR starting from early life stages.

Social deprivation as a risk factor for fractures in childhood

Paediatric fractures are common and can cause significant morbidity. Socioeconomic deprivation is associated with an increased incidence of fractures in both adults and children, but little is known about the epidemiology of paediatric fractures. In this study we investigated the effect of social deprivation on the epidemiology of paediatric fractures. We compiled a prospective database of all fractures in children aged < 16 years presenting to the study centre. Demographics, type of fracture, mode of injury and postcode were recorded. Socioeconomic status quintiles were assigned for each child using the Scottish Index for Multiple Deprivation (SIMD). We found a correlation between increasing deprivation and the incidence of fractures (r = 1.00, p < 0.001). In the most deprived group the incidence was 2420/100 000/yr, which diminished to 1775/100 000/yr in the least deprived group. The most deprived children were more likely to suffer a fracture as a result of a fall (odds ratio (OR) = 1.5, p < 0.0001), blunt trauma (OR = 1.5, p = 0.026) or a road traffic accident (OR = 2.7, p < 0.0001) than the least deprived. These findings have important implications for public health and preventative measures.

Delayed bedtime due to screen time in schoolchildren: importance of area deprivation

BACKGROUND

Sleep duration is an important predictor of obesity and health. This study evaluated the association between late bedtime and screen time, and the role of geographical deprivation in English schoolchildren.

METHODS

We collected bedtime and waking time, screen time, sociodemographic data and measured body mass index in a cross-section of 1332 11-15-year-old schoolchildren (45.7% female) participating in the East of England healthy heart study. Logistic regression was used to determine the likelihood of late bedtime in schoolchildren with different screen time and from a different geographic location. Mean differences were assessed either on ANOVA or t-test.

RESULTS

Approximately 42% of boys went to bed late at night compared with 37% of girls. When compared to those with <2 h of daily screen time, schoolchildren with 2-4 h of screen time were more likely [odds ratio (OR) = 1.50, 95% confidence interval (CI): 1.07-2.09] to go to bed late at night while those with >4 h of daily screen time were most likely to go to sleep late at night (OR, 1.97; 95%CI: 1.34-2.89). Late bedtime was associated with deprivation in schoolchildren.

CONCLUSIONS

High screen time and deprivation may explain lateness in bedtime in English schoolchildren. This explanation may vary according to area deprivation and geographic location. Family-centered interventions and parental support are important to reduce screen time, late bedtime and increase sleep duration.

Media Use, Sports Participation, and Well-Being in Adolescence: Cross-Sectional Findings From the UK Household Longitudinal Study

Objectives. We investigated the relationship between selected types of screen-based media (SBM) use, total SBM use, sports participation, and markers of well-being. Methods. Data came from the youth panel (n = 4899) of Understanding Society, the UK Household Longitudinal Study, conducted in 2009. Well-being was measured by the Strengths and Difficulties Questionnaire and markers of happiness in different life domains. Results. The majority of young people used multiple types of SBM for at least 1 hour per day; only 30% participated in sports every day. Overall, young people with heavy SBM use were less happy than moderate users and more likely to have socioemotional difficulties. Chatting on social networking Web sites and game console use were associated with higher odds of socioemotional problems. Higher total SBM use was associated with lower odds of happiness and higher odds of socioemotional difficulties. Greater participation in sports was associated with higher odds of happiness and lower odds of socioemotional difficulties. Conclusions. Further longitudinal research could inform future interventions to reduce sedentary behavior and encourage healthy lifestyles among young people.

Associations between showering behaviours following physical education, physical activity and fitness in English schoolchildren

We aimed to describe the frequency of showering after physical education (PE) in English high-school pupils. We examined differences in physical activity (PA) and cardiorespiratory fitness according to showering behaviours and examined predictors of showering. We measured PA and cardiorespiratory fitness of n = 3921 pupils (11-16 years, 53.5% males) from eight high schools. Pupils self-reported showering behaviour and parental PA levels. We calculated deprivation and distance travelled to school from their home postcode. Overall, 53% of boys and 68% of girls said they never shower after PE. Pupils who did not shower after PE were less physically active and engaged in fewer team sports. Girls who did not shower also had lower cardiorespiratory fitness than those who did. Showering behaviour varied greatly by school, so we adjusted for clustering at the school level. Pupils were more likely to shower if they were active with their parents [odds ratio (OR) = 1.72; 95% CI: 1.43, 2.07] and less likely to shower if they were from deprived areas (OR = 0.68; 95% CI: 0.52, 0.88). Showering after PE is relatively rare in English schoolchildren, particularly girls. While we cannot infer causality regarding the relationships found here, the low rates of showering and the lower PA and cardiorespiratory fitness (in girls) observed in schoolchildren who do not shower suggest research is needed to determine whether showering is a barrier to being physically active during PE.

Physical activity and screen time in adolescents transitioning out of compulsory education: a prospective longitudinal study

BACKGROUND

Within the UK context, it is unclear whether physical activity and screen time changes between completing compulsory education and the period afterwards, and the factors associated with any change.

METHODS

A prospective population-based longitudinal design among adolescents (n = 2204 at baseline) was adopted. A self-report questionnaire was administered at baseline (final year of compulsory education) and follow-up (i.e. post compulsory education) to measure physical activity over the previous 7 days and screen time (weekday and weekend) in relation to recommended guidelines. Magnitude of change in physical activity and screen time and key influencing variables associated with changes were analysed.

RESULTS

For physical activity, there was a significant change in participants meeting guidelines at baseline but not meeting guidelines at follow-up with 81.0% not meeting guidelines at baseline and follow-up. For screen time, there was no significant change between baseline and follow-up, with 70.6% not meeting guidelines at baseline and follow-up. Gender was associated with the change in physical activity with a decline less likely in females.

CONCLUSIONS

Findings reinforce the importance of reducing physical inactivity and sedentary behaviour during this transition. Factors associated with changes in physical inactivity and sedentary behaviour need further investigation.

Physical Activity Questionnaire for children and adolescents: English norms and cut-off points

BACKGROUND

The Physical Activity Questionnaire for Children and Adolescents (PAQ-C/-A) provides general estimates of physical activity levels. Following recent expert recommendations for using the PAQ for population surveillance, the aim of this paper was twofold: first, to describe normative PAQ data for English youth; and second, to determine a criterion-referenced PAQ-score cut-off point.

METHODS

Participants (n = 7226, 53% boys, 10-15 years) completed an anglicized version of the PAQ. Peak oxygen uptake (VO2peak ) was predicted from PACER lap count according to latest FITNESSGRAM standards and categorized into "at-risk" and "no-risk" for metabolic syndrome. ROC curves were drawn for each age-sex group to identify PAQ scores, which categorized youth into "sufficiently active" versus "low-active" groups, using cardiorespiratory fitness as the criterion-referenced standard.

RESULTS

PAQ scores were higher in boys than in girls and declined with age. Mean PAQ score was a significant, albeit relatively weak (area under the curve < 0.7) discriminator between "at-risk" and "no-risk." PAQ scores of ≥2.9 for boys and ≥2.7 for girls were identified as cut-off points, although it may be more appropriate to use lower, age-specific PAQ scores for girls of 13, 14 and 15 years (2.6, 2.4, 2.3, respectively).

CONCLUSION

The normative and criterion-referenced PAQ values may be used to standardize and categorize PAQ scores in future youth population studies.

Independence of physical activity and screen time as predictors of cardiorespiratory fitness in youth

BACKGROUND

Screen time (ST) is associated with physical activity (PA) levels. We aimed to investigate the relationship between ST and fitness.

METHODS

We assessed fitness and daily ST in 7,466 10-16-y-old schoolchildren from the east of England. The differences in fitness between ST groups, and the association between ST and fitness were assessed.

RESULTS

ST was negatively associated with fitness in boys of all ages (P < 0.001) and girls in grades 6-9 (P < 0.005). Boys were less likely to be fit if they reported >2 h/d ST (odds ratio (OR): 0.70, 95% confidence interval (CI): 0.58-0.85) or >4 h/d (OR: 0.45, 95% CI: 0.35-0.57) ST, as were girls reporting >4 h/d ST (OR: 0.58, 95% CI: 0.43-0.78). Controlling for PA levels attenuated these odds in boys reporting >2 h/d ST (OR: 0.81, 95% CI: 0.66-0.91) or >4 h/d ST (OR: 0.65, 95% CI: 0.50-0.84) and in girls reporting >4 h/d ST (OR: 0.68, 95% CI: 0.50-0.93).

CONCLUSION

These first data from English children show a negative association between ST and fitness in youth. Of note, very high levels of daily ST (>4 h) are associated with poor fitness. Some of the associations were mediated by PA levels. Our data support international recommendations to limit ST to <2 h/d; we believe such guidance should be issued in the United Kingdom.

Prevalence of elevated mean arterial pressure and how fitness moderates its association with BMI in youth

OBJECTIVE

Cardiorespiratory fitness is known to be cardioprotective and its association with the components of the metabolic syndrome in children is becoming clearer. The aim of the present study was to examine the extent to which cardiorespiratory fitness may offset the weight-related association with mean arterial pressure (MAP) in schoolchildren.

DESIGN

Cross-sectional study.

SETTINGS

Schoolchildren from the East of England, U.K.

SUBJECTS

A total of 5983 (48% females) schoolchildren, 10 to 16 years of age, had height, weight and blood pressure measured by standard procedures and cardiorespiratory fitness assessed by the 20 m shuttle-run test. Participants were classified as fit or unfit using internationally accepted fitness cut-off points; and as normal weight, overweight or obese based on BMI, again using international cut-off points. Age-adjusted ANCOVA was used to determine the main effects and interaction of fitness and BMI on MAP Z-score. Logistic regression models were used to estimate odds ratios of elevated MAP.

RESULTS

Prevalence of elevated MAP in schoolchildren was 14.8% overall and 35.7% in those who were obese-unfit. Approximately 21% of participants were overweight and 5% obese, while 23% were classified as unfit. MAP generally increased across BMI categories and was higher in the aerobically unfit participants. Obese-fit males had lower MAP compared with obese-unfit males (P < 0.001); this trend was similar in females (P = 0.05).

CONCLUSIONS

Increasing fitness level may have a positive impact on the weight-related elevations of MAP seen in obese and overweight schoolchildren.

Temporal relationships between screen-time and physical activity with cardiorespiratory fitness in English schoolchildren: a 2-year longitudinal study

OBJECTIVE

To determine the temporal relationships screen-time and physical activity have with cardiorespiratory fitness.

METHOD

Measures were made over two years (2008-2010) in 1500 participants aged 11.5 (SD 0.5) years at baseline.

RESULTS

Tracking coefficients were low-to-moderate for all measures. At follow-up, 25% of participants moved from having low (<2h) to high (≥ 2 h) daily screen-time and 6% became unfit according to FITNESSGRAM standards. Baseline screen-time was the strongest univariate predictor of becoming unfit. Multivariate analysis controlling for decimal age, BMI and deprivation confirmed baseline screen-time as the strongest independent predictor of becoming unfit over the 2-year study period (OR 2.4; 95%CI:1.4-4.0). Current (OR 2.3; 95%CI:1.3-4.0) and previous (OR 1.7; 95%CI:1.0-2.9) physical activity levels also independently predicted becoming unfit.

CONCLUSION

There is currently no guidance for limiting screen-time in UK children. These longitudinal data add to the cross-sectional evidence of lower physical activity and fitness in children reporting ≥ 2 h daily screen-time. More importantly, these data demonstrate that high screen-time during childhood is an independent predictor of lower cardiorespiratory fitness in adolescence.