Systematic review of sedentary behaviour and health indicators in school-aged children and youth

Television time among Brazilian adolescents: correlated factors are different between boys and girls

Objective. The aim of this study was to identify the prevalence of excess television time and verify correlated factors in adolescent males and females. Methods. This cross-sectional study included 2,105 adolescents aged from 13 to 18 years from the city of Aracaju, Northeastern Brazil. Television time was self-reported, corresponding to the time spent watching television in a typical week. Several correlates were examined including age, skin color, socioeconomic status, parent education, physical activity level, consumption of fruits and vegetables, smoking status, alcohol use, and sports team participation. Results. The prevalence excess television time (≥2 hours/day) in girls and boys was 70.9% and 66.2%, respectively. Girls with low socioeconomic status or inadequate consumption of fruits and vegetables were more likely to have excess television time. Among boys, those >16 years of age or with black skin color were more likely to have excess television time. Conclusions. Excess television time was observed in more than two-thirds of adolescents, being more evident in girls. Correlated factors differed according to sex. Efforts to reduce television time among Brazilian adolescents, and replace with more active pursuits, may yield desirable public health benefits.

Levels and patterns of objectively-measured physical activity volume and intensity distribution in UK adolescents: the ROOTS study

BACKGROUND

Few studies have quantified levels of habitual physical activity across the entire intensity range. We aimed to describe variability in total and intensity-specific physical activity levels in UK adolescents across gender, socio-demographic, temporal and body composition strata.

METHODS

Physical activity energy expenditure and minutes per day (min/d) spent sedentary and in light, moderate, and vigorous intensity physical activity were assessed in 825 adolescents from the ROOTS study (43.5% boys; mean age 15.0 ± 0.30 years), by 4 days of individually calibrated combined heart rate and movement sensing. Measurement days were classified as weekday or weekend and according to the three school terms: summer (April-July), autumn (September-December), and spring (January-March). Gender and age were self-reported and area-level SES determined by postcode data. Body composition was measured by anthropometry and bio-electrical impedance. Variability in physical activity and sedentary time was analysed by linear multilevel modelling, and logistic multilevel regression was used to determine factors associated with physical inactivity (<60 min moderate-to-vigorous intensity physical activity/d).

RESULTS

During awake hours (15.8 ± 0.9 hrs/d), adolescents primarily engaged in light intensity physical activity (517 min/d) and sedentary time (364 min/d). Boys were consistently more physically active and less sedentary than girls, but gender differences were smaller at weekends, as activity levels in boys dropped more markedly when transitioning from weekday to weekend. Boys were more sedentary on both weekend days compared to during the week, whereas girls were more sedentary on Sunday but less sedentary on Saturday. In both genders light intensity physical activity was lower in spring, while moderate physical activity was lower in autumn and spring terms, compared to the summer term; sedentary time was also higher in spring than summer term. Adolescents with higher fatness engaged in less vigorous intensity physical activity. Factors associated with increased odds of physical inactivity were female gender, both weekend days in boys, and specifically Sunday in girls.

CONCLUSIONS

Physical activity components vary by gender, temporal factors and body composition in UK adolescents. The available data indicate that in adolescence, girls should be the primary targets of interventions designed to increase physical activity levels.

Physical activity, sedentary time and adiposity during the first two decades of life

High amounts of time spent sedentary and low levels of physical activity have been implicated in the process of excessive adiposity gains in youth. The aim of this review is to discuss the role of physical activity, sedentary time and behaviour (i.e. television (TV)-viewing) in relation to adiposity during the first two decades of life with a specific focus on whether the association between sedentary time, and behaviour and adiposity is independent of physical activity. We identified nine cohort studies (three prospective) whether sedentary time was associated with adiposity independent of physical activity. Eight of these studies suggested that sedentary time was unrelated to adiposity when physical activity was taken into account. Results from studies (n 8) examining the independent association between TV-viewing and adiposity independent of physical activity were mixed. Those that observed a positive association between TV-viewing and adiposity independent of physical activity discussed that the association may be due to residual confounding. A few additional studies have also challenged the general notion that low levels of physical activity leads to fatness and suggested that higher baseline fatness may be predictive of a decline in physical activity. It appears unlikely that higher levels of sedentary time are associated with or predictive of, higher levels of adiposity when physical activity is controlled for in youth. Specific sedentary behaviours such as TV-viewing may be associated with adiposity independent of physical activity but the results may be explained by residual confounding.

A socio-ecological approach promoting physical activity and limiting sedentary behavior in adolescence showed weight benefits maintained 2.5 years after intervention cessation

Background:

Obesity in youth remains a major public health issue. Yet no effective long-term preventive strategy exists. We previously showed that a school-based socio-ecological approach targeting behavior and social/environmental influences on physical activity (PA) prevented 4-year excessive weight gain in 12-year olds. In this study, we investigated if this efficacy persists 30 months after intervention cessation.

Methods and Findings:

The program targeted students, family, school and the living environment to promote/support PA and prevent sedentary behavior (SB). A total of 732 students from eight randomized middle schools completed the 4-year trial. At the 30-month post-trial follow-up, body mass index (BMI), fat mass index (FMI), leisure PA (LPA), home/school/workplace active commuting, TV/video time (TVT), and attitudes toward PA were measured in 531 adolescents. The beneficial effects of the intervention on the excess BMI increase (+0.01 vs +0.34 kg m⁻² in the intervention and control groups, respectively) and on the overweight incidence in initially non-overweight students (4.3% vs 8.6% odds ratio=0.48 (95% confidence interval: 0.23–1.01)) were maintained at the post-trial follow-up. LPA was not maintained at the level achieved during the trial. However, we still observed a prevention of the age-related decrease of the adolescents' percentage reporting regular LPA (−14.4% vs −26.5%) and a higher intention to exercise in the intervention group. The intervention promoted lower TVT (−14.0 vs +13.6 min per day) and higher active commuting changes (+11.7% vs −4.8%). Trends in higher BMI reduction in students with high initial TVT and in the least wealthy group were noted. TVT changes throughout the follow-up predicted excess BMI and FMI changes.

Conclusions:

Long-term multilevel approach targeting PA and SB prevents excessive weight gain up to 30 months after intervention cessation. The efficacy may be higher in the most sedentary and least wealthy adolescents. Healthy PA-related behavior inducing long-lasting weight effects can be promoted in youth providing that an ecological approach is introduced in the prevention strategy.

Sedentary time in children: influence of accelerometer processing on health relations

PURPOSE

Accelerometry is increasingly being used to assess sedentary time in epidemiological studies, yet the most appropriate means of processing these data remains uncertain. This cross-sectional study examined the influence of selected accelerometer cut points and nonwear criteria on associations of sedentary time with adiposity and clustered metabolic risk.

METHODS

Data were from the European Youth Heart Study, which included assessment of sedentary time by accelerometer. Sixteen sedentary time variables were constructed based on combinations of frequently used cut points (100, 500, 800, and 1100 counts per minute) and nonwear criteria (10-, 20-, 60-, and 100-min consecutive zeros). Adiposity was assessed by sum of four skinfold thickness measures. A clustered metabolic risk score was calculated as the mean of standardized metabolic syndrome components, including blood pressure, insulin resistance, and inverted fasting HDL-cholesterol. Analyses were conducted using multilevel cross-sectional time series regression, adjusted for overall physical activity (accelerometer counts per minute). Meta-analysis was used to obtain pooled estimates of the exposure-outcome association over all processing protocols; meta-regression was used to determine the influence of nonwear and cut point protocol on observed associations.

RESULTS

Sedentary time follows a power law with cut point (exponent = 0.27) and zero string (exponent = 0.03), and it was positively associated with clustered metabolic risk (β = 0.0051; 95% confidence interval = 0.0018-0.0085). The association was moderated by cut point, with higher cut points typically producing stronger associations. No significant association between sedentary time and adiposity was observed.

CONCLUSIONS

The choice of accelerometer cut point may moderate the association between sedentary time and clustered metabolic risk, suggesting that direct comparisons of associations between studies using different cut points must be made with caution.

Adolescent television viewing and unhealthy snack food consumption: the mediating role of home availability of unhealthy snack foods

OBJECTIVE

To examine whether home availability of energy-dense snack foods mediates the association between television (TV) viewing and energy-dense snack consumption among adolescents.

DESIGN

Cross-sectional.

SETTING

Secondary schools in Victoria, Australia.

SUBJECTS

Adolescents (n 2984) from Years 7 and 9 of secondary school completed a web-based survey, between September 2004 and July 2005, assessing their energy-dense snack food consumption, school-day and weekend-day TV viewing and home availability of energy-dense snack foods.

RESULTS

School-day and weekend-day TV viewing were positively associated with energy-dense snack consumption among adolescent boys (β = 0·003, P < 0·001) and girls (β = 0·03, P < 0·001). Furthermore, TV viewing (school day and weekend day) were positively associated with home availability of energy-dense snack foods among adolescent boys and girls and home availability of energy-dense snack foods was positively associated with energy-dense snack food consumption among boys (β = 0·26, P < 0·001) and girls (β = 0·28, P < 0·001). Home availability partly mediated the association between TV viewing and energy-dense snack consumption.

CONCLUSIONS

The results of the present study suggest that TV viewing has a significant role to play in adolescent unhealthy eating behaviours. Future research should assess the efficacy of methods to reduce adolescent energy-dense snack food consumption by targeting parents to reduce home availability of energy-dense foods and by reducing TV viewing behaviours of adolescents.

Family-based interventions for reducing sedentary time in youth: a systematic review of randomized controlled trials

Family involvement in interventions to reduce sedentary time may help foster appropriate long-term screen-based habits in children. This review systematically synthesized evidence from randomized controlled trials of interventions with a family component that targeted reduction of sedentary time, including TV viewing, video games and computer use, in children. MEDLINE, PubMed, PsycInfo, CINAHL and Embase were searched from inception through March 2012. Seventeen articles were considered eligible and included in the review. Studies were judged to be at low-to-moderate risk of bias. Despite inconsistent study results, level of parental involvement, rather than the setting itself, appeared an important determinant of intervention success. Studies including a parental component of medium-to-high intensity were consistently associated with statistically significant changes in sedentary behaviours. Participant age was also identified as a determinant of intervention outcomes; all three studies conducted in pre-school children demonstrated significant decreases in sedentary time. Finally, TV exposure appeared to be related to changes in energy intake rather than physical activity. Future studies should assess the effects of greater parental involvement and child age on success of sedentary behaviour interventions. More research is required to better understand the relationship between screen time and health behaviours, particularly energy intake.

Health-enhancing physical activity in children with cerebral palsy: more of the same is not enough

Physical activity is important for young people's health. The emphasis over the last 2 decades has been on moderate to vigorous exercise when designing activity and exercise programs for children and adolescents with cerebral palsy (CP). Emerging evidence suggests that sedentary behavior is distinctly different from a lack of moderate to vigorous physical activity and has independent and different physiological mechanisms. The concept of concurrently increasing moderate to vigorous physical activity and replacing sedentary behavior with light physical activity may be beneficial for children and adolescents with CP. This article is a summary of the evidence for what works and what does not work for improving the physical activity of children and adolescents with CP. It also discusses what is known about sedentary behavior of children and adolescents with CP and what research directions are needed to build foundational knowledge in this area with this population.

Insulin secretion and its association with physical activity, fitness and screen time in children

OBJECTIVES

To determine the independent associations of moderate to vigorous physical activity (MVPA), fitness, screen time, and adiposity with insulin secretion in children.

DESIGN AND METHODS

Caucasian youth (n = 423/630), 8-10 years old, with at least one obese biological parent, were studied (QUALITY cohort). Insulin secretion was measured using HOMA2-%B, area under the curve (AUC) of insulin to glucose over the first 30 minutes (AUC I/G(t30min)) of the OGTT and AUC I/G(t120min) over 2 hours. Fitness was measured by VO₂peak ; percent fat mass (PFM) by DXA; 7-day MVPA by accelerometry; self-reported screen time included television, video game, or computer use. Models were adjusted for age, sex, season, puberty, PFM, and insulin sensitivity [IS] (HOMA2-IS, Matsuda-ISI).

RESULTS

PFM was strongly associated with insulin secretion, even after adjustment for IS: for every 1% increase in PFM, insulin secretion increased from 0.3% to 0.8% across indices. MVPA was negatively associated with HOMA2-%B (P < 0.05), but not with OGTT-derived measures. Fitness was negatively associated with AUC I/G(t120min) (P < 0.05). Screen time showed a trend toward higher HOMA2-%B in girls (P = 0.060).

CONCLUSIONS

In children with an obese parent, lower insulin secretion is associated with lower adiposity, higher MVPA, better fitness, and possibly reduced screen time.

The clustering of diet, physical activity and sedentary behavior in children and adolescents: a review

Diet, physical activity (PA) and sedentary behavior are important, yet modifiable, determinants of obesity. Recent research into the clustering of these behaviors suggests that children and adolescents have multiple obesogenic risk factors. This paper reviews studies using empirical, data-driven methodologies, such as cluster analysis (CA) and latent class analysis (LCA), to identify clustering patterns of diet, PA and sedentary behavior among children or adolescents and their associations with socio-demographic indicators, and overweight and obesity. A literature search of electronic databases was undertaken to identify studies which have used data-driven methodologies to investigate the clustering of diet, PA and sedentary behavior among children and adolescents aged 5–18 years old. Eighteen studies (62% of potential studies) were identified that met the inclusion criteria, of which eight examined the clustering of PA and sedentary behavior and eight examined diet, PA and sedentary behavior. Studies were mostly cross-sectional and conducted in older children and adolescents (≥9 years). Findings from the review suggest that obesogenic cluster patterns are complex with a mixed PA/sedentary behavior cluster observed most frequently, but healthy and unhealthy patterning of all three behaviors was also reported. Cluster membership was found to differ according to age, gender and socio-economic status (SES). The tendency for older children/adolescents, particularly females, to comprise clusters defined by low PA was the most robust finding. Findings to support an association between obesogenic cluster patterns and overweight and obesity were inconclusive, with longitudinal research in this area limited. Diet, PA and sedentary behavior cluster together in complex ways that are not well understood. Further research, particularly in younger children, is needed to understand how cluster membership differs according to socio-demographic profile. Longitudinal research is also essential to establish how different cluster patterns track over time and their influence on the development of overweight and obesity.

Physical activity and sedentary behavior among adolescents in rural South Africa: levels, patterns and correlates

BACKGROUND

Physical inactivity is increasing among children and adolescents and may be contributing to the increasing prevalence of overweight and obesity. This study examines physical activity and sedentary behavior patterns, and explores associations with individual, maternal, household, and community factors amongst rural South African adolescents.

METHODS

In 2009, 381 subjects, stratified by ages 11-12-years and 14-15-years, were randomly selected from 3511 children and adolescents who had participated in a growth survey two years previously. Weight and height were measured and self-reported Tanner pubertal stage was collected. A questionnaire quantifying frequency and duration of physical activity (PA) domains and sedentary time for the previous 12 months was administered. Moderate-vigorous physical activity (MVPA mins/wk) was calculated for time spent in school and club sport. Socio-demographic and other related data were included from the Agincourt health and socio-demographic system (HDSS). The Agincourt HDSS was established in 1992 and collects prospective data on the community living in the Agincourt sub-district of Mpumalanga Province in rural north-east South Africa.

RESULTS

Puberty, maternal education and socio-economic status (SES) contributed significantly to the mulitiple linear regression model for sedentary behavior (R2 = 0.199; adjusted R2 = 0.139; p < 0.000), and sex, SES and maternal education contributed to the tobit regression model for school and club sport MVPA (p < 0.000). MVPA, calculated from school and club sport, was higher in boys than girls (p < 0.001), and informal activity was lower (boys: p < 0.05 and girls: p < 0.01) while sedentary time was higher (girls: p < 0.01) in the older than the younger groups. Ninety-two percent (92%) of the sample reported walking for transport.

CONCLUSIONS

In this study of rural South African adolescent boys and girls, SES at the maternal, household and community level independently predicted time spent in sedentary behaviors, and school and club MVPA. This study provides local data that can be used to develop health promotion strategies specific to this community, and other similar communities in developing countries.

Does participation in physical education reduce sedentary behaviour in school and throughout the day among normal-weight and overweight-to-obese Czech children aged 9-11 years?

Participation of 9 to 11-year-old children in physical education lessons (PEL) contributes to a significantly higher duration of moderate-to-vigorous physical activity (MVPA) during the school day and, in overweight/obese girls and normal-weight boys, to an increase in overall daily MVPA as shown by previous research. However, it is not known whether this increase in MVPA is at the expense of light physical activity (LPA) or sedentary behaviour (SED). SED, LPA, and MVPA were assessed in 338 schoolchildren aged 9–11 years (50.3% girls; 29.6% overweight/obese) over two school days (with and without a PEL) using a triaxial accelerometer during various segments of the school day. SED, LPA, and MVPA were quantified based on the duration of the activity (minutes). Participation in PEL led to significantly higher school MVPA in the overweight/obese and normal-weight girls and boys (p < 0.005) compared to MVPA of those children on the school day without PEL. Participation in PEL led to a significantly higher overall daily MVPA duration compared to that during the day without PEL for the overweight/obese girls (p < 0.05), normal-weight girls (p < 0.05) and boys (p < 0.005). Participation in PEL contributed not only to significantly higher LPA in the normal-weight girls and boys (p < 0.01) during the school day but also reduced school-time SED in the overweight/obese children (p < 0.01) and normal-weight girls (p < 0.005). Moreover, participation in PEL significantly reduced the overall daily SED in the normal-weight children and overweight/obese boys (p < 0.05). Adding one PEL to the daily school routine appears to be a promising strategy for effectively reducing SED in children.

Associations between family eating behaviours and body composition measures in peri-adolescents: results from a community-based study of school-aged children

OBJECTIVES

To identify key eating behaviours in children and their parents and to determine the associations between these behaviours and measures of body composition in children.

METHODS

Data were collected on a sample of 431 peri-adolescent children (12.4±0.3 years) and their parents from the Niagara Region. Body composition was assessed by trained research assistants. Eating behaviours were assessed using a revised version of the Family Eating and Activity Habits Questionnaire. Principal component analyses were used to identify key eating behaviours among children, mothers and fathers. Linear regression models were used to assess their associations with body mass index (BMI), waist-to-height ratio, waist-to-hip ratio, waist girth, and hip girth measures in children.

RESULTS

Emotional/uncontrolled eating and eating by the television in children and their mothers were positively associated with measures of body composition in children. Other eating behaviours that were associated with larger measures of body composition in children included low frequency of eating meals with parents, frequent sweet beverage consumption and snacking and eating "on-the-go" in children, eating "on-the-go" in mothers, and emotional eating and eating by the television/late at night in fathers.

CONCLUSIONS

The eating behaviours of children and mothers, and to a lesser degree fathers, are important predictors of children's body composition. Public health interventions designed to help mothers and children reduce the frequency of emotional/uncontrolled eating and eating by the television may be effective means of facilitating positive weight outcomes in children.

Field assessments for obesity prevention in children and adults: physical activity, fitness, and body composition

Nutrition and health educators work in community settings implementing lifestyle programs focused on obesity prevention and chronic disease risk reduction. These programs typically focus on improving diet and physical activity (PA) behaviors. Many nutrition educators may not be confident in their ability to select, administer, and interpret PA assessments to effectively evaluate their PA or lifestyle programs. This report will assist educators in identifying and selecting appropriate field-based assessments for measurement of PA, physical fitness, and body composition for children and adults. Specific guidelines, references, and resources are given for selecting assessment methods and test within these 3 areas.

Risk factors associated with high blood pressure in two-to five-year-old children

BACKGROUND

Over recent decades, the prevalence of high blood pressure (BP) has increased among children. Several risk factors are involved in the genesis of high BP during childhood, and their early identification can prevent the development of that disease.

OBJECTIVES

To assess the prevalence of high BP and associated factors in children.

METHODS

Cross-sectional, population-based study, carried out at the household. This study included 276 two- to five-year-old children in the city of Goiânia, state of Goiás, and assessed their BP, sociodemographic characteristics, birth weight, high BP family history, passive smoking, maternal breastfeeding, dietary habits, sedentary lifestyle and nutritional status. Poisson regression was used to assess the association between risk factors and high BP.

RESULTS

Their mean age was 3.1 ± 0.79 years, and high BP and overweight were observed in 19.9% and 11.2% of the children, respectively. Direct association of high BP was identified with age [prevalence ratio (PR) = 2.3; 95%CI: 1.2 - 4.8; p = 0.017] and overweight (PR = 2.0; 95%CI: 1.2 - 3.6; p = 0.014). No other variable associated with high BP.

CONCLUSIONS

The prevalence of high BP in children was high. Overweight and younger children had greater prevalence of high BP.

Interventions designed to reduce sedentary behaviours in young people: a review of reviews

BACKGROUND

Leisure time is increasingly spent in sedentary pursuits such as screen-viewing (eg, television/DVD viewing and computer use), motorised travel, school/work and sitting-based socialising (eg, social media and chatting). Sedentary screen time, particularly TV, appears to play an important role in the aetiology of obesity due to its co-occurrence with other unhealthy behaviours such as snacking on energy-dense foods, low levels of physical activity and inadequate sleep. More information is needed on how to reduce sedentary behaviours. Most interventions have focused on young people and a number of systematic reviews exist on this topic.

OBJECTIVE

To synthesise systematic reviews and meta-analyses of interventions aimed at decreasing sedentary behaviours among children and adolescents.

METHODS

Papers were located from computerised and manual searches. Included articles were English language systematic reviews or meta-analyses of interventions aiming at reducing sedentary behaviour in children (<11 years) and adolescents (12-18 years).

RESULTS

Ten papers met the inclusion criteria and were analysed. All reviews concluded some level of effectiveness in reducing time spent in sedentary behaviour. When an effect size was reported, there was a small but significant reduction in sedentary time (highest effect size=-0.29; CI -0.35 to -0.22). Moderator analyses showed a trend favouring interventions with children younger than 6 years. Effective strategies include the involvement of family, behavioural interventions and electronic TV monitoring devices.

CONCLUSIONS

Results from systematic reviews and meta-analyses show that interventions to reduce children's sedentary behaviour have a small but significant effect. Future research should expand these findings examining interventions targeting different types of sedentary behaviours and the effectiveness of specific behaviour change techniques across different contexts and settings.

Bedroom media, sedentary time and screen-time in children: a longitudinal analysis

BACKGROUND

Having electronic media in the bedroom is cross-sectionally associated with greater screen-time in children, but few longitudinal studies exist. The aim of this study was to describe longitudinal patterns of ownership and examine cross-sectional and longitudinal associations of bedroom media with children's sedentary behaviour.

METHODS

Data are from the Sport, Physical activity and Eating behaviour: Environmental Determinants in Young people (SPEEDY) study, collected at 3 time-points: baseline (2007, T0; age 10.3 ± 0.3 years), 1-year (T1y) and 4-year (T4y) follow-up. For each assessment, 1512 (44.9% male), 715 (41.0% male), and 319 (48.3% male) participants provided valid accelerometer data. Outcome variables were accelerometer-assessed sedentary time and self-reported screen-time. The presence of a television or computer in the bedroom was self-reported by participants and a combined bedroom media score calculated as the sum of such items. Cross-sectional and longitudinal associations between bedroom media and each outcome were examined using multi-level linear regression.

RESULTS

Bedroom TV ownership fell from 70.9% at T0 to 42.5% at T4y. Having a TV in the bedroom (beta; 95% CI*100, T0: -1.17; -1.88, -0.46. T1y: -1.68; -2.67, -0.70) and combined bedroom media (T0: -0.76; -1.26, -0.27. T1y: -0.79; -1.51, -0.07) were negatively associated with objectively measured weekly sedentary time at T0 and T1y. Having a computer in the bedroom (beta; 95% CI, T0: 0.15; 0.02, 0.29. T4y: 0.35; 0.10, 0.60) and combined bedroom media (T0: 0.09: 0.01, 0.18. T4y: 0.20; 0.05, 0.34) were positively associated with screen-time at T0 and T4y. Relative to participants without a computer throughout the study, children that had a computer in their bedroom at T0 but not at T4y (beta; 95% CI for change in screen-time: -8.02; -12.75, -3.29) reported smaller increases in screen-time.

CONCLUSIONS

The bedroom media environment changes with age and exhibits a complex relationship with children's sedentary behaviour. Modifying children's bedroom media environment may impact upon screen-time but appears unlikely to influence overall sedentary time.

Screen-based media use clusters are related to other activity behaviours and health indicators in adolescents

Background

Screen-based media (SBM) occupy a considerable portion of young peoples’ discretionary leisure time. The aim of this paper was to investigate whether distinct clusters of SBM use exist, and if so, to examine the relationship of any identified clusters with other activity/sedentary behaviours and physical and mental health indicators.

Methods

The data for this study come from 643 adolescents, aged 14 years, who were participating in the longitudinal Western Australian Pregnancy Cohort (Raine) Study through May 2003 to June 2006. Time spent on SBM, phone use and reading was assessed using the Multimedia Activity Recall for Children and Adults. Height, weight, muscle strength were measured at a clinic visit and the adolescents also completed questionnaires on their physical activity and psychosocial health. Latent class analysis (LCA) was used to analyse groupings of SBM use.

Results

Three clusters of SBM use were found; C1 ‘instrumental computer users’ (high email use, general computer use), C2 ‘multi-modal e-gamers’ (both high console and computer game use) and C3 ‘computer e-gamers’ (high computer game use only). Television viewing was moderately high amongst all the clusters. C2 males took fewer steps than their male peers in C1 and C3 (-13,787/week, 95% CI: -4619 to -22957, p = 0.003 and -14,806, 95% CI: -5,306 to -24,305, p = 0.002) and recorded less MVPA than the C1 males (-3.5 h, 95% CI: -1.0 to -5.9, p = 0.005). There was no difference in activity levels between females in clusters C1 and C3.

Conclusion

SBM use by adolescents did cluster and these clusters related differently to activity/sedentary behaviours and both physical and psychosocial health indicators. It is clear that SBM use is not a single construct and future research needs to take consideration of this if it intends to understand the impact SBM has on health.

A systematic review of the psychological and social benefits of participation in sport for adults: informing development of a conceptual model of health through sport

Background

The definition of health incorporates the physical, social and mental domains, however the Physical Activity (PA) guidelines do not address social health. Furthermore, there is insufficient evidence about the levels or types of PA associated specifically with psychological health. This paper first presents the results of a systematic review of the psychological and social health benefits of participation in sport by adults. Secondly, the information arising from the systematic review has been used to develop a conceptual model of Health through Sport.

Methods

A systematic review of 14 electronic databases was conducted in June 2012, and studies published since 1990 were considered for inclusion. Studies that addressed mental and/or social health benefits from participation in sport were included.

Results

A total of 3668 publications were initially identified, of which 11 met the selection criteria. There were many different psychological and social health benefits reported, with the most commonly being wellbeing and reduced distress and stress. Sport may be associated with improved psychosocial health in addition to improvements attributable to participation in PA. Specifically, club-based or team-based sport seems to be associated with improved health outcomes compared to individual activities, due to the social nature of the participation. Notwithstanding this, individuals who prefer to participate in sport by themselves can still derive mental health benefits which can enhance the development of true-self-awareness and personal growth which is essential for social health. A conceptual model, Health through Sport, is proposed. The model depicts the relationship between psychological, psychosocial and social health domains, and their positive associations with sport participation, as reported in the literature. However, it is acknowledged that the capacity to determine the existence and direction of causal links between participation and health is limited by the cross-sectional nature of studies to date.

Conclusion

It is recommended that participation in sport is advocated as a form of leisure-time PA for adults which can produce a range of health benefits. It is also recommended that the causal link between participation in sport and psycho-social health be further investigated and the conceptual model of Health through Sport tested.

Clustering of health-related behaviors, health outcomes and demographics in Dutch adolescents: a cross-sectional study

Background

Recent studies show several health-related behaviors to cluster in adolescents. This has important implications for public health. Interrelated behaviors have been shown to be most effectively targeted by multimodal interventions addressing wider-ranging improvements in lifestyle instead of via separate interventions targeting individual behaviors. However, few previous studies have taken into account a broad, multi-disciplinary range of health-related behaviors and connected these behavioral patterns to health-related outcomes. This paper presents an analysis of the clustering of a broad range of health-related behaviors with relevant demographic factors and several health-related outcomes in adolescents.

Methods

Self-report questionnaire data were collected from a sample of 2,690 Dutch high school adolescents. Behavioral patterns were deducted via Principal Components Analysis. Subsequently a Two-Step Cluster Analysis was used to identify groups of adolescents with similar behavioral patterns and health-related outcomes.

Results

Four distinct behavioral patterns describe the analyzed individual behaviors: 1- risk-prone behavior, 2- bully behavior, 3- problematic screen time use, and 4- sedentary behavior. Subsequent cluster analysis identified four clusters of adolescents. Multi-problem behavior was associated with problematic physical and psychosocial health outcomes, as opposed to those exerting relatively few unhealthy behaviors. These associations were relatively independent of demographics such as ethnicity, gender and socio-economic status.

Conclusions

The results show that health-related behaviors tend to cluster, indicating that specific behavioral patterns underlie individual health behaviors. In addition, specific patterns of health-related behaviors were associated with specific health outcomes and demographic factors. In general, unhealthy behavior on account of multiple health-related behaviors was associated with both poor psychosocial and physical health. These findings have significant meaning for future public health programs, which should be more tailored with use of such knowledge on behavioral clustering via e.g. Transfer Learning.

Sedentary behaviors in fifth-grade boys and girls: where, with whom, and why?

BACKGROUND

An understanding of the context surrounding screen- and non-screen-based sedentary behavior would facilitate efforts to reduce children's overall sedentary behavior. This study examined the prevalence of specific types of sedentary behavior in children, the social and physical contexts surrounding these behaviors, and differences by gender.

METHODS

Participants included 686 fifth graders participating in the Transitions and Activity Changes in Kids Study (TRACK). The Physical Activity Choices instrument measured child participation in seven sedentary behaviors, the social (i.e., with whom) and physical (i.e., where) contexts, and perceptions (i.e., why) of those behaviors. Analysis included mixed-model regression adjusted for race/ethnicity, BMI, and socioeconomic status.

RESULTS

Children participated in both screen- and non-screen-based sedentary behaviors at very high frequencies. The most popular activities included watching television or videos, listening to music, playing video games (boys only), and talking on the phone or texting (girls only). Children engaged in sedentary behaviors most often at home, at school, or in their neighborhood. In general, the patterns of social context for the behaviors were similar for boys and girls, with the exception of video game playing. Girls perceived listening to music and talking on the phone or texting to be more fun than boys; children did not differ in their other perceptions (i.e., how much choice or how important) of the behaviors.

CONCLUSIONS

Multi-level interventions that target reducing sedentary behavior in the home, neighborhood, and school context may be most effective; however, the approach needed will likely differ by gender.

Active Screen Time Among U.S. Youth Aged 9-18 Years, 2009

OBJECTIVE

This study documented the prevalence of active screen time (i.e., screen time that includes active games, exercise or dance videos, or TV exercise programs) and identified characteristics associated with it among youth 9-18 years of age.

SUBJECTS AND METHODS

This cross-sectional study was conducted on a convenience sample of 1,165 youth using the 2009 Styles Surveys; data were weighted to approximate the Current Population Survey. We calculated descriptive statistics and conducted multivariable logistic regression to identify characteristics associated with active screen time by estimating adjusted odds ratio (aOR) and 95 percent confidence intervals (CIs).

RESULTS

The sample comprised 51.4 percent boys, and almost 60 percent were non-Hispanic white. The prevalence of active screen time ≥1 hour/day was 31.2 percent on a typical school day and 41.6 percent on a typical weekend day. Logistic regression revealed youth with physical activity of 3-5 days/week had higher odds of active screen time ≥1 hour/day compared with youth with no physical activity (aOR school day=2.8, 95 percent CI 1.5-5.2; aOR weekend day=2.3, 95 percent CI 1.4-3.9). Certain characteristics (i.e., sex, age group, race/ethnicity, income, and sedentary screen time) were significantly associated with active screen time ≥1 hour/day, but associations were inconsistent for school and weekend days.

CONCLUSIONS

Three in 10 youth are engaging in at least 1 hour of active screen time on school days, and about 4 in 10 youth are engaging in at least one hour on weekend days. Understanding the use of active screen time and associated characteristics are important for developing interventions addressing screen time and physical activity.

Adiposity and different types of screen time

OBJECTIVE

Few prospective studies have examined separate forms of screen time in relation to adiposity. Our objective was to assess independent relations of television, electronic games (video/computer), and digital versatile disc (DVD)/videos and total screen time with change in adolescent BMI.

METHODS

Using data from the 2004, 2006, and 2008 waves of the ongoing Growing up Today Study II, we assessed baseline and 2-year change in reported screen time in relation to concurrent change in BMI among 4287 girls and 3505 boys aged 9 to 16 years in 2004. Gender-specific models adjusted for previous BMI, age, race/ethnicity, growth/development, months between questionnaires, and physical activity.

RESULTS

Among girls and boys, each hour per day increase in reported television viewing was associated with a 0.09 increase in BMI (Ps < .001), and each hour per day increase in total screen time was associated with a 0.07 increase among girls and 0.05 increase among boys (Ps < .001). Among girls only, greater baseline television, games, and total screen time and change in DVDs/videos were associated with gains in BMI (Ps < .05). BMI gains associated with change in television and total screen time were stronger among overweight girls than lean girls (Ps-heterogeneity < .001).

CONCLUSIONS

Television, which remains the steadiest source of food advertising, was most consistently associated with BMI gains. Among girls, electronic games and DVDs/videos were also related to increased BMI, possibly due to influences of product placements and advergames on diet and/or distracted eating. Adolescents, especially overweight adolescents, may benefit from reduced time with multiple types of media.

Paediatricians' awareness of, agreement with and use of the new Canadian Physical Activity and Sedentary Behaviour Guidelines for children and youth zero to 17 years of age

OBJECTIVE

To examine the awareness of, agreement with and use of the new Canadian Physical Activity and Sedentary Behaviour Guidelines for children and youth zero to 17 years of age in a sample of Canadian paediatricians.

METHODS

The findings are based on responses from 331 paediatricians across Canada who completed an online survey in February 2013. Frequencies were calculated for each question.

RESULTS

Few paediatricians reported being very familiar with the physical activity (6% for the early years, and 9% for children and youth) or sedentary behaviour guidelines (5% for the early years, children and youth). When made aware of the guidelines, a large percentage strongly agreed or agreed with the physical activity (99% for the early years, and 96% for children and youth) and sedentary behaviour recommendations (96% for the early years, and 94% for children and youth). Of paediatricians who performed well-child visits, 16% and 27% reported almost always making physical activity and sedentary behaviour recommendations, respectively, to parents or caregivers of children in the early years, compared with 37% for both behaviours among children and youth. Thirty-nine per cent (for the early years) and 46% (for children and youth) of paediatricians reported it would be highly feasible to briefly explain the guidelines at a well-child visit. The most common barriers reported for recommending the guidelines were insufficient motivation or support from parents, caregivers or youth, and lack of time.

CONCLUSION

To increase the use of these new evidence-informed guidelines, strategies are needed to increase paediatricians' awareness and reduce perceived barriers.

Children's sedentary behaviour: descriptive epidemiology and associations with objectively-measured sedentary time

BACKGROUND

Little is known regarding the patterning and socio-demographic distribution of multiple sedentary behaviours in children. The aims of this study were to: 1) describe the leisure-time sedentary behaviour of 9-10 year old British children, and 2) establish associations with objectively-measured sedentary time.

METHODS

Cross-sectional analysis in the SPEEDY study (Sport, Physical activity and Eating behaviour: Environmental Determinants in Young people) (N=1513, 44.3% boys). Twelve leisure-time sedentary behaviours were assessed by questionnaire. Objectively-measured leisure-time sedentary time (Actigraph GT1M, <100 counts/minute) was assessed over 7 days. Differences by sex and socioeconomic status (SES) in self-reported sedentary behaviours were tested using Kruskal-Wallis tests. The association between objectively-measured sedentary time and the separate sedentary behaviours (continuous (minutes) and categorised into 'none' 'low' or 'high' participation) was assessed using multi-level linear regression.

RESULTS

Sex differences were observed for time spent in most sedentary behaviours (all p ≤ 0.02), except computer use. Girls spent more time in combined non-screen sedentary behaviour (median, interquartile range: girls: 770.0 minutes, 390.0-1230.0; boys: 725.0, 365.0 - 1182.5; p = 0.003), whereas boys spent more time in screen-based behaviours (girls: 540.0, 273.0 - 1050.0; boys: 885.0, 502.5 - 1665.0; p < 0.001). Time spent in five non-screen behaviours differed by SES, with higher values in those of higher SES (all p ≤ 0.001). Regression analyses with continuous exposures indicated that reading (β = 0.1, p < 0.001) and watching television (β = 0.04, p < 0.01) were positively associated with objectively-measured sedentary time, whilst playing board games (β = -0.12, p < 0.05) was negatively associated. Analysed in categorical form, sitting and talking (vs. none: 'low' β = 26.1,ns; 'high' 30.9, p < 0.05), playing video games (vs. none: 'low' β = 49.1, p < 0.01; 'high' 60.2, p < 0.01) and watching television (vs. lowest tertile: middle β = 22.2,ns; highest β = 31.9, p < 0.05) were positively associated with objectively-measured sedentary time whereas talking on the phone (vs. none: 'low' β = -38.5, p < 0.01; 'high' -60.2, p < 0.01) and using a computer/internet (vs. none: 'low' β = -30.7, p < 0.05; 'high' -4.2,ns) were negatively associated.

CONCLUSIONS

Boys and girls and children of different socioeconomic backgrounds engage in different leisure-time sedentary behaviours. Whilst a number of behaviours may be predictive of total sedentary time, collectively they explain little overall variance. Future studies should consider a wide range of sedentary behaviours and incorporate objective measures to quantify sedentary time where possible.

Associations of sedentary behavior, sedentary bouts and breaks in sedentary time with cardiometabolic risk in children with a family history of obesity

BACKGROUND

Although reports in adults suggest that breaks in sedentary time are associated with reduced cardiometabolic risk, these findings have yet to be replicated in children.

PURPOSE

To investigate whether objectively measured sedentary behavior, sedentary bouts or breaks in sedentary time are independently associated with cardiometabolic risk in a cohort of Canadian children aged 8-11 years with a family history of obesity.

METHODS

Data from 286 boys and 236 girls living in Quebec, Canada, with at least one biological parent with obesity (QUALITY cohort) were collected from 2005-2008, and analyzed in 2013. Sedentary behavior, light and moderate-to-vigorous physical activity were measured over 7 days using accelerometry. Leisure time computer/video game use and TV viewing over the past 7 days were self-reported. Outcomes included waist circumference, body mass index Z-score, fasting insulin, fasting glucose, triglycerides, HDL-cholesterol, C-reactive protein and a continuous cardiometabolic risk score.

RESULTS

After adjustment for confounders, breaks in sedentary time and the number of sedentary bouts lasting 1-4 minutes were associated with reduced cardiometabolic risk score and lower BMI Z-score in both sexes (all p<0.05). The number of sedentary bouts lasting 5-9 minutes was negatively associated with waist circumference in girls only, while the number of bouts lasting 10-14 minutes was positively associated with fasting glucose in girls, and with BMI Z-score in boys (all p<0.05). Leisure time computer/video game use was associated with increased cardiometabolic risk score and waist circumference in boys, while TV viewing was associated with increased cardiometabolic risk, waist circumference, and BMI Z-score in girls (all p<0.05).

CONCLUSIONS

These results suggest that frequent interruptions in sedentary time are associated with a favourable cardiometabolic risk profile and highlight the deleterious relationship between screen time and cardiometabolic risk among children with a family history of obesity.

What practices do parents perceive as effective or ineffective in promoting a healthy diet, physical activity, and less sitting in children: parent focus groups

Background

To support parents in improving the health of their young children, examples of effective parenting practices for a healthy diet, physical activity (PA) and sedentary behavior (SB) are needed. This study explores perceived effective and ineffective parenting practices in difficult situations concerning raising healthy children and investigates their relationship with Self-Determination Theory (SDT) and Social Cognitive Theory (SCT). The current study is formative work to inform the content of a randomized controlled trial.

Methods

Four focus groups were conducted between June and October 2012 at worksites during lunch break. A total of 21 unrelated parents of primary schoolchildren (6 fathers, 15 mothers) participated. A short written questionnaire introduced typical difficult situations derived from parental anecdotal reports, concerning healthy diet, PA and SB. These situations formed the backbone for the subsequent focus group discussion. In October 2012, discussions were audio-recorded and analyzed in Nvivo to identify key response items using thematic analysis.

Results

Parents experienced explaining why the child should behave healthily, monitoring, being consistent, offering alternatives, reacting empathetically, modeling, motivating, increasing intrinsic value and availability, and using time-out as effective practices, whereas anger was considered ineffective. Opinions were mixed about the effectiveness of giving as much freedom as possible, obliging, rewarding and punishing, and setting rules and agreements. Parenting practices were consistent with principles from both SDT and SCT.

Conclusions

Parents identified numerous perceived effective practices to respond to their child’s health-related behavior. Since many of them coincide with the evidence base and the success of a parenting program depends upon the degree to which parents’ concerns and motivations are integrated into the program design, important opportunities are created for future intervention programs.

Economic Differences in Risk Factors for Obesity Among Overweight and Obese Children

The purpose of the study was to identify the economic differences in familial, physiological, psychological, and lifestyle characteristics associated with overweight and obese children in South Korea. A total of 407 overweight and obese children participated in the study. The obesity rate was 69.0% and the prevalence of metabolic syndrome (MS) was 33.3% in the low-income bracket, and the prevalence of MS was 27.2% for the population. The children in the low-income group were more prone to have poor eating behavior and more likely to spend more than 2 hr viewing television. They also were more likely to have lower self-esteem and more depressive symptoms. School nurses should understand that risk factors for childhood obesity are more prevalent in low-income groups, which will eventually aggravate health disparities between socioeconomic status groups. Therefore, prevention programs for childhood obesity, which target high-risk groups of such children need to be developed and prioritized.

Fine and gross motor skills differ between healthy-weight and obese children

Within the obesity literature, focus is put on the link between weight status and gross motor skills. However, research on fine motor skills in the obese (OB) childhood population is limited. Therefore, the present study focused on possible weight related differences in gross as well as fine motor skill tasks. Thirty-four OB children (12 ♀ and 22 ♂, aged 7-13 years) were recruited prior to participating in a multidisciplinary treatment program at the Zeepreventorium (De Haan, Belgium). Additionally, a control group of 34 age and gender-matched healthy-weight (HW) children was included in the study. Anthropometric measures were recorded and gross and fine motor skills were assessed using the Bruininks-Oseretsky Test of Motor Proficiency, second edition (BOT-2). Results were analyzed by independent samples t-tests, multivariate analysis of variance, and a chi-squared test. Being OB was detrimental for all subtests evaluating gross motor skill performance (i.e., upper-limb coordination, bilateral coordination, balance, running speed and agility, and strength). Furthermore, OB children performed worse in fine motor precision and a manual dexterity task, when compared to their HW peers. No group differences existed for the fine motor integration task. Our study provides evidence that lower motor competence in OB children is not limited to gross motor skills alone; OB children are also affected by fine motor skill problems. Further investigation is warranted to provide possible explanations for these differences. It is tentatively suggested that OB children experience difficulties with the integration and processing of sensory information. Future research is needed to explore whether this assumption is correct and what the underlying mechanism(s) could be.

Development and evaluation of the Motivation to Limit Screen-time Questionnaire (MLSQ) for adolescents

OBJECTIVE

The aim of this study was to design and evaluate a brief scale to assess adolescents' motivation to limit their screen-time using a self-determination theory (SDT) framework.

METHODS

The development and evaluation of the Motivation to Limit Screen-time Questionnaire (MLSQ) involved three phases. In Phase 1, experts in SDT were asked to review the content validity of the MLSQ items. In Phase 2, adolescent boys (N=342, mean age=12.7 ±.5 years) completed the MLSQ and the factorial validity of the model was explored. In Phase 3, adolescent boys (N=48, mean age=14.3 ± 1.3 years) completed the MLSQ on two occasions separated by 1-week. Phases 2 and 3 were conducted in New South Wales, Australia in 2012.

RESULTS

Twenty four SDT experts reviewed the original scale items. Validity coefficients associated with six of the original eight items exceeded the threshold value (V>.68, p<.01). In Phase 2, the revised three-factor (9-items) model provided a good fit to the data (SRMR=.07, CFI=.96). The intraclass correlation (ICC) values were .67 for amotivation and .70 and .82 for controlled and autonomous motivation, respectively.

CONCLUSION

This study has provided preliminary evidence for the validity and reliability of the MLSQ in adolescent boys.

A cross-sectional examination of school characteristics associated with overweight and obesity among grade 1 to 4 students

BACKGROUND

Excessive weight gain among youth is an ongoing public health concern. Despite evidence linking both policies and the built environment to adolescent and adult overweight, the association between health policies or the built environment and overweight are often overlooked in research with children. The purpose of this study was to examine if school-based physical activity policies and the built environment surrounding a school are associated with weight status among children.

METHODS

Objectively measured height and weight data were available for 2,331 grade 1 to 4 students (aged 6 to 9 years) attending 30 elementary schools in Ontario, Canada. Student-level data were collected using parent reports and the PLAY-On questionnaire administered to students by study nurses. School-level policy data were collected from school administrators using the Physical Activity Module of the Healthy School Planner tool, and built environment data were provided by the Enhanced Points of Interest data resource. Multi-level logistic regression models were used to examine the school- and student-level characteristics associated with the odds of a student being overweight or obese.

RESULTS

There was significant between-school random variation in the odds of a student being overweight [σ²(μ0) = 0.274(0.106), p < 0.001], but not for being obese [σ²(μ0) = 0.115(0.089)]. If a student attended a school that provided student access to a variety of facilities on and off school grounds during school hours or supported active transportation to and from school, he/she was less likely to overweight than a similar student attending a school without these policies. Characteristics of the built environment were not associated with overweight or obesity among this large cross-sectional sample of children.

CONCLUSIONS

This new evidence suggests that it may be wise to target obesity prevention efforts to schools that do not provide student access to recreation facilities during school hours or schools that do not support active transportation for students. Future research should evaluate if school-based overweight and obesity prevention programming might be improved if interventions selectively targeted the school characteristics that are putting students at the greatest risk.

Prolonged sitting and markers of cardiometabolic disease risk in children and youth: a randomized crossover study

OBJECTIVE

Recent evidence suggests that short bouts of uninterrupted sedentary behavior reduce insulin sensitivity and glucose tolerance while increasing triglyceride levels in both healthy and overweight/obese adults. To date no study has examined the acute impact of uninterrupted sitting in children and youth. The objective of the present study was to determine whether 8 h of uninterrupted sitting increases markers of cardiometabolic disease risk in healthy children and youth, in comparison to 8 h of sitting interrupted by light intensity walk breaks or structured physical activity.

MATERIALS/METHODS

11 healthy males and 8 healthy females between the ages of 10 and 14 years experienced 3 conditions in random order: (1) 8 h of uninterrupted sitting (Sedentary); (2) 8 h of sitting interrupted with a 2-min light-intensity walk break every 20 min (Breaks); and (3) 8 h of sitting interrupted with a 2-min light-intensity walk break every 20 min as well as 2×20 min of moderate-intensity physical activity (Breaks+Physical Activity). Insulin, glucose, triglyceride, HDL and LDL cholesterol area under the curve were calculated for each condition.

RESULTS

We observed no significant differences in the area under the curve for any marker of cardiometabolic disease risk across the 3 study conditions (all p>0.09).

CONCLUSIONS

These results suggest that in comparison to interrupted sitting or structured physical activity, a single bout of 8 h of uninterrupted sitting does not result in measurable changes in circulating levels of insulin, glucose, or lipids in healthy children and youth.

Children and youth do not compensate for an imposed bout of prolonged sitting by reducing subsequent food intake or increasing physical activity levels: a randomised cross-over study

The behavioural impact of an imposed bout of prolonged sitting is yet to be investigated in the paediatric population. The objective of the present study was to determine the acute effect of prolonged sitting onad libitumfood intake and spontaneous physical activity (PA) levels in healthy children and youth. A total of twenty healthy youth (twelve males and eight females) aged 10–14 years, with a mean BMI of 18·6 (sd4·3) kg/m2, were exposed to three experimental conditions in a random order: (1) a day of uninterrupted sitting (Sedentary); (2) a day of sitting interrupted with a 2 min light-intensity walk break every 20 min (Breaks); (3) a day of sitting interrupted with a 2 min light-intensity walk break every 20 min as well as 2 × 20 min of moderate-intensity PA (Breaks+PA). Food intake (ad libitumbuffet meal) and PA (accelerometry for 24 h) were assessed following exposure to each experimental condition. Despite significant differences in sedentary behaviour and activity levels during the three in-laboratory sessions (allP< 0·01), we did not observe any differences inad libitumfood intake immediately following exposure to each experimental condition or any changes in the levels of sedentary behaviour or PA in the 24 h following exposure to each experimental condition (allP>0·25). These findings suggest that children and youth may not compensate for an imposed bout of sedentary behaviour by reducing subsequent food intake or increasing PA levels.

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.

Weekday and weekend patterns of physical activity and sedentary time among Liverpool and Madrid youth

Levels of physical inactivity and sedentary behaviour among English and Spanish youth are high and vary within different regions of each country. Little though is known about these during specific periods of the day. The purpose of this study was to describe physical activity (PA) and sedentary time during segments of the day and week, and compare these critical contexts between youth in the Liverpool and Madrid areas of England and Spain, respectively. PA was objectively assessed in 235 Liverpool- and 241 Madrid youth (aged 10-14 years) who wore accelerometers for seven consecutive days. Minutes of sedentary time, moderate PA, vigorous PA and moderate-to-vigorous physical activity (MVPA) were calculated for weekdays, weekend days, school time, non-school time and after-school. Between-country differences were analysed using analysis of covariance (ANCOVA). Madrid youth spent significantly more time in sedentary activities than their Liverpool counterparts. Madrid youth engaged in more minutes of moderate intensity physical activity (MPA) than Liverpool youth during weekdays, school time and non-school time (P<0.01). Liverpool children recorded more time in vigorous physical activity (VPA) than Madrid peers during week days and weekend days (P<0.01) and during school time and after-school periods (P<0.01). The MVPA was significantly higher among Madrid youth during non-school time (P<0.01). Around 25% of all youth achieved recommended levels of MVPA. Low levels of MVPA and systematic differences in sedentary time, MPA and VPA exist between Liverpool and Madrid youth. Interventions targeted at the least-active children during weekends, after-school and non-school periods within the cultural contexts common to each city are required.

Position of the Academy of Nutrition and Dietetics: the role of nutrition in health promotion and chronic disease prevention

It is the position of the Academy of Nutrition and Dietetics that primary prevention is the most effective and affordable method to prevent chronic disease, and that dietary intervention positively impacts health outcomes across the life span. Registered dietitians and dietetic technicians, registered are critical members of health care teams and are essential to delivering nutrition-focused preventive services in clinical and community settings, advocating for policy and programmatic initiatives, and leading research in disease prevention and health promotion. Health-promotion and disease-prevention strategies are effective at reducing morbidity and mortality and improving quality of life, and have a significant impact on the leading causes of disease. By applying these principles within a social ecological theoretical framework, positive influence can be applied across the spectrum of engagement: at intrapersonal, interpersonal, institutional, community, and public policy levels. Through the application of efficacious and cost-effective interventions, registered dietitians and dietetic technicians, registered, can positively impact public health as well as health outcomes for the individuals that they counsel. This position paper supports the "Practice Paper of the Academy of Nutrition and Dietetics: The Role of Nutrition in Health Promotion and Chronic Disease Prevention" published on the Academy's website at: www.eatright.org/positions.

A place for play? The influence of the home physical environment on children's physical activity and sedentary behaviour

The home environment is an important influence on the sedentary behaviour and physical activity of children, who have limited independent mobility and spend much of their time at home. This article reviews the current evidence regarding the influence of the home physical environment on the sedentary behaviour and physical activity of children aged 8–14 years. A literature search of peer reviewed articles published between 2005 and 2011 resulted in 38 observational studies (21 with activity outcomes, 23 with sedentary outcomes) and 11 experimental studies included in the review. The most commonly investigated behavioural outcomes were television watching and moderate to vigorous physical activity. Media equipment in the home and to a lesser extent the bedroom were positively associated with children’s sedentary behaviour. Physical activity equipment and the house and yard were not associated with physical activity, although environmental measures were exclusively self-reported. On the other hand, physical activity equipment was inversely associated with sedentary behaviours in half of studies. Observational studies that investigated the influence of the physical and social environment within the home space, found that the social environment, particularly the role of parents, was important. Experimental studies that changed the home physical environment by introducing a television limiting device successfully decreased television viewing, whereas the influence of introducing an active video game on activity outcomes was inconsistent. Results highlight that the home environment is an important influence on children’s sedentary behaviour and physical activity, about which much is still unknown. While changing or controlling the home physical environment shows promise for reducing screen based sedentary behaviour, further interventions are needed to understand the broader impact of these changes. Future studies should prioritise investigating the influence of the home physical environment, and its interaction with the social environment, on objectively measured sedentary time and home context specific behaviours, ideally including technologies that allow objective measures of the home space.

A systematic review of the psychological and social benefits of participation in sport for children and adolescents: informing development of a conceptual model of health through sport

BACKGROUND

There are specific guidelines regarding the level of physical activity (PA) required to provide health benefits. However, the research underpinning these PA guidelines does not address the element of social health. Furthermore, there is insufficient evidence about the levels or types of PA associated specifically with psychological health. This paper first presents the results of a systematic review of the psychological and social health benefits of participation in sport by children and adolescents. Secondly, the information arising from the systematic review has been used to develop a conceptual model.

METHODS

A systematic review of 14 electronic databases was conducted in June 2012, and studies published since 1990 were considered for inclusion. Studies that addressed mental and/or social health benefits from participation in sport were included.

RESULTS

A total of 3668 publications were initially identified, of which 30 met the selection criteria. There were many different psychological and social health benefits reported, with the most commonly being improved self-esteem, social interaction followed by fewer depressive symptoms. Sport may be associated with improved psychosocial health above and beyond improvements attributable to participation in PA. Specifically, team sport seems to be associated with improved health outcomes compared to individual activities, due to the social nature of the participation. A conceptual model, Health through Sport, is proposed. The model depicts the relationship between psychological, psychosocial and social health domains, and their positive associations with sport participation, as reported in the literature. However, it is acknowledged that the capacity to determine the existence and direction of causal links between participation and health is limited by the fact that the majority of studies identified (n=21) were cross-sectional.

CONCLUSION

It is recommended that community sport participation is advocated as a form of leisure time PA for children and adolescents, in an effort to not only improve physical health in relation to such matters as the obesity crisis, but also to enhance psychological and social health outcomes. It is also recommended that the causal link between participation in sport and psychosocial health be further investigated and the conceptual model of Health through Sport tested.

Sedentary Behavior and Health Outcomes in Children and Adolescents

The purpose of this review was to summarize findings from epidemiological studies that determined if sedentary behavior was associated with obesity, metabolic risk factors, and cardiorespiratory fitness in children and adolescents. We noted if studies adjusted for moderate-to-vigorous physical activity (MVPA), dietary intakes, and/or sleep duration. Articles were identified through PubMed using the search terms: (sedentary OR sitting OR television) AND (adiposity OR blood pressure OR body mass index OR cardiometabolic OR metabolic risk OR waist circumference). The search was limited to ages 6 to 18 years, humans, and published between January 1, 2008 and September 26, 2012. Cross-sectional and longitudinal studies observed associations between more sedentary behavior, especially screen-based sedentary behavior, and measures of obesity; and most associations were independent of MVPA and dietary intake. Cross-sectional and longitudinal studies reported associations between screen-based sedentary behavior and lower cardiorespiratory fitness, and most associations were independent of MVPA and obesity. Cross-sectional studies observed associations between more screen-based and objectively measured sedentary behavior and lower insulin sensitivity; and most associations were independent of MVPA and obesity. There was little-to-no evidence that sedentary behavior was associated with increased blood pressure and increased blood lipids.

The association of screen time, television in the bedroom, and obesity among school-aged youth: 2007 National Survey of Children's Health

BACKGROUND

Among school-aged youth, we sought to identify characteristics associated with (1) exceeding screen time recommendations (ie, television/videos/video games more than 2 hours/weekday), and (2) exceeding screen time recommendations, the presence of a television in the bedroom, and obesity.

METHODS

Using 2007 National Survey of Children's Health data, we used multivariable logistic regression to identify sociodemographic and behavioral characteristics associated with excessive screen time among 6 to 11- and 12 to 17-year-olds on a typical weekday. For 12 to 17-year-olds only, we used logistic regression to examine the odds of obesity using the same variables as above, with the addition of screen time.

RESULTS

Overall, 20.8% of 6 to 11-year-olds and 26.1% of 12 to 17-year-olds had excessive screen time. For both age groups, having a bedroom TV was significantly associated with excessive screen time. For the older age group, the dual scenario of excessive screen time with a bedroom TV had the strongest association with obesity (OR = 2.5, 95% CI 1.9, 3.2).

CONCLUSIONS

Given the similar risk factors for excess screen time and having a TV in the bedroom, a public health challenge exists to design interventions to reduce screen time among school-aged youth.

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

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

Adolescents' prospective screen time by gender and parental education, the mediation of parental influences

Background

The present study investigated associations in gender dyads of parents’ and adolescents’ time spent on television and video viewing (TV/DVD), and computer and electronic game use (PC/games) at the ages of 11 and 13 years. Possible mediating effects of parental modelling and parental regulation in the relationship between parental education and adolescents’ prospective TV/DVD and PC/game time were further examined.

Methods

A total of 908 adolescents, participating at both ages 11 and 13 years in the Norwegian HEalth In Adolescents (HEIA) cohort study (2007–2009), were included in the analyses. Data on adolescents’, mothers’ and fathers’ self reported time spent on TV/DVD and PC/games were measured at both time points by questionnaires. Correlation coefficients were used to examine gender dyads of parents’ and adolescents’ reports. Mediation analyses using linear regression investigated possible mediation effects of parental modelling and parental regulation in the prospective relationship between parental education and adolescents’ time spent on TV/DVD and PC/games between the ages of 11 and 13 years.

Results

Correlations of screen time behaviours in gender dyads of parents and adolescents showed significant associations in time spent on TV/DVD at the age of 11 and 13 years. Associations between mothers and sons and between fathers and daughters were also observed in time spent on PC/games at the age of 11 years. Maternal and paternal modelling was further found to mediate the relationship between parental education and adolescents’ prospective TV/DVD time between the ages of 11 and 13 years. No mediation effect was observed for parental regulation, however a decrease in both maternal and paternal regulation at the age of 11 years significantly predicted more TV/DVD time among adolescents at the age of 13 years.

Conclusion

Cross-sectional and longitudinal relationships were observed in gender dyads of parents’ and adolescents’ screen time behaviours at the ages of 11 and 13 years, and further studies including both parents and their children should be emphasized. Moreover, maternal and paternal modelling were found to be important target variables in interventions aiming to reduce social differences by parental education in adolescents’ prospective time spent on TV/DVD.

Cardiorespiratory fitness and nutritional status of schoolchildren: 30-year evolution

OBJECTIVE

To compare the changes in cardiorespiratory fitness in evaluations performed every ten years since 1978/1980, according to the nutritional status and gender of students in the city of Ilhabela, Brazil.

METHODS

The study is part of the Mixed Longitudinal Project on Growth, Development and Physical Fitness of Ilhabela. The study included 1,291 students of both genders, aged 10 to 11 years old. The study periods were: 1978/1980, 1988/1990, 1998/2000, and 2008/2010. The variables analyzed were: body weight, height, and cardiorespiratory fitness (VO2max - L.min-1 and mL.kg-1.min-1) performed using a submaximal progressive protocol on a cycle ergometer. Individuals were classified as normal weight and overweight according to curves proposed by the World Health Organization of body mass index for age and gender. Analysis of variance (ANOVA) with three factors followed by the Bonferroni method were used to compare the periods.

RESULTS

The number of normal weight individuals (61%) was higher than that of overweight. There was a significant decrease in cardiorespiratory fitness in both genders. Among the schoolchildren with normal weight, there was a decrease of 22% in males and 26% in females. In overweight schoolchildren, males showed a decrease of 12.7% and females, of 18%.

CONCLUSION

During a 30-year analysis with reviews every ten years from 1978/1980, there was a significant decrease in cardiorespiratory fitness in schoolchildren of both genders, which cannot be explained by the nutritional status. The decline in cardiorespiratory fitness was greater in individuals with normal weight than in overweight individuals.