Effect of socioeconomic status on objectively measured physical activity

The impact of sociodemographic status on the association of classical cardiovascular risk factors with coronary artery disease: a stratified Mendelian randomization study

OBJECTIVES

Low socioeconomic status (SES) is associated with cardiovascular risk factors and increased coronary artery disease (CAD) risk. We tested whether SES is an effect modifier of the association between classical cardiovascular risk factors and CAD using SES-stratified Mendelian Randomization in European-ancestry participants from UK Biobank.

STUDY DESIGN AND SETTING

We calculated weighted genetic risk scores (GRS) for the risk factors body mass index (BMI), systolic blood pressure, low-density lipoprotein cholesterol, and triglycerides. Participants were stratified by Townsend deprivation index score. Logistic regression models were used to investigate associations between GRSs and CAD occurrence. Additionally, stratification based on GRS-adjusted Townsend deprivation index residuals was conducted to correct for possible collider-stratification bias.

RESULTS

In a total sample size of N = 446,485, with 52,946 cases, the risk for CAD per standard deviation increase in genetically influenced BMI was highest in the group with the lowest 25% SES (odds ratio: 1.126, 95% confidence interval: 1.106-1.145; odds ratio: 1.081, 95% confidence interval: 1.059-1.103 in high SES), remaining similar after controlling for possible collider-stratification bias. The effects of genetically influenced systolic blood pressure, low-density lipoprotein cholesterol, and triglyceride on CAD were similar between SES groups.

CONCLUSION

CAD risk attributable to increased BMI is not homogenous and could be modified by SES. This emphasizes the need of tailor-made approaches for BMI-associated CAD risk reduction.

Early Years Physical Activity and Motor Skills Intervention-A Feasibility Study to Evaluate an Existing Training Programme for Early Years Educators

A lack of fundamental motor skills (FMS) in the early years can lead to lower engagement with physical activity (PA), and track into adulthood. This study aimed to test the feasibility of an existing intervention for Early Years Educators ("Educators") designed to increase knowledge, confidence and the ability to increase PA and FMS of children in a deprived area of England. Non-randomised design with wait-list control. Sixty-seven settings in Middlesbrough, North East England were invited. Recruitment target: 10 settings, 2 Educators per setting, four children per Educator.

INTERVENTION

one-day training course "Physical Literacy in the Early Years", an age-appropriate theoretical and practical training course to support the development of physical literacy.

PRIMARY OUTCOMES

recruitment, retention, acceptability of intervention and outcome measures.

SECONDARY OUTCOMES

change in Educators' knowledge, intentions and behaviour, and change in children's BMI z-score, PA and FMS. Eight settings were recruited; all Intervention Educators completed the training. Six settings participated at follow-up (four Intervention, two Control). The target for Educator recruitment was met (two per setting, total n = 16). Questionnaires were completed by 80% of Intervention Educators at baseline, 20% at follow-up. Control Educators completed zero questionnaires. No Educators took part in a process evaluation interview. Forty-eight children participated at baseline, 28 at follow-up. The intervention was deemed acceptable. The recruitment, retention and acceptability of measurements were insufficient to recommend proceeding. Additional qualitative work is needed to understand and surmount the challenges posed by the implementation of the trial.

Physical fitness and somatic structure in adolescent taekwondo athletes and untrained peers

Study aim: The purpose of the study was to assess the level of physical fitness (PF) and somatic structure in children training a Korean martial art (ITF taekwondo) and untrained peers and to determine the associations of children’s BMI with that of their parents.

Material and methods: The research material consisted of data from 135 individuals, representing 45 child-mother-father triplets, including 22 triplets with children practicing taekwondo and 23 triplets with untrained children. The children had an average chronological age of 10.08 ± 1.35 years, whereas the age of mothers and fathers was 38.09 ± 4.56 years and 40.57 ± 4.70 years, respectively. Traits analyzed included those evaluated by selected physical fitness tests from the Eurofit Physical Fitness Test battery, body mass index (BMI), and waist-to-height ratio (WHtR) in children, and BMI in parents. Statistical analyses included the chi-square test, Mann-Whitney U test, and Spearman’s correlations, with a significance level set at α = 0.05.

Results: The results showed no significant differences in the somatic structure, physical fitness, BMI, and WHtR in the children studied. However, a tendency was observed for children attending ITF taekwondo classes to be characterized by higher levels of physical fitness. Higher BMI was found in the parents of the trained children and positive correlations were found between the BMI of the trained children and their parents.

Conclusions: Identifying and studying the effect size of PA determinants in adolescents, with a particular focus on the influence of parents, may be the key to improving the health of future generations.

The Associations Between Daily Activities and Affect: a Compositional Isotemporal Substitution Analysis

BACKGROUND

Daily activities are associated with affective experiences. A 24-h day can be separated into five mutually exclusive activity types: sleep, awake in bed, moderate-to-vigorous physical activity (MVPA), light-intensity physical activity (LIPA), and sedentary behavior (SB). Most research has examined these activities independently and not collectively, yet increased time in one activity must be offset by decreasing other activities. Using compositional isotemporal substitution analyses, this study examined the associations between time spent in daily activities and affect, including both high and low arousal positive and negative affect.

METHOD

Across three separate studies, daily activities and affect were measured throughout 7-15 days (M_days = 10) in 361 healthy community adults (72.5% females, M_age = 22.79 years). Activities were objectively assessed using accelerometry and self-reported affect was assessed using repeated ecological momentary assessments. Minutes spent in each activity and affect values across the three studies were averaged for each participant.

RESULTS

Longer sleep duration at the expense of time awake in bed was associated with lower high arousal negative affect (e.g., nervousness, b =  - 0.24, p = .007). More MVPA at the expense of LIPA or SB was associated with higher high arousal positive affect (e.g., happiness, b = 0.35, p = .027). Activity composition was not associated with low arousal positive or negative affect (all p ≥ .06).

CONCLUSION

Associations between 24-h activity composition and affect differed based on types of activities, types of affect, and the interrelationships between activities within the composition. Findings can aid interventions to develop integrated guidance on the optimal activity patterns for mental health.

Association of Lifestyle Factors and Neuropsychological Development of 4-Year-Old Children

BACKGROUND

We aimed to assess how lifestyle factors such as diet, sleep, screen viewing, and physical activity, individually, as well as in a combined score, were associated with neuropsychological development in pre-school age children.

METHODS

We conducted a cross-sectional study in 1650 children of 4 years of age, from the Environment and Childhood Project (INMA) population-based birth cohorts in four regions of Spain. Children were classified per a childhood healthy lifestyle score (CHLS) with a range of 0 to 4 that included eating in concordance with the Mediterranean diet (1 point); reaching recommended sleep time (1 point); watching a maximum recommended screen time (1 point); and being physically active (1 point). The McCarthy Scales of Children's Abilities (MSCA) were used to test neuropsychological development. Multi-adjusted linear regression models were created to assess the association with the lifestyle factors individually and as a combined score.

RESULTS

CHLS was not associated with MSCA general cognitive score (1-point increment = -0.5, 95% CI: -1.2, 0.2). Analyzed by separate lifestyle factors, physical activity had a significant negative association with MSCA score and less TV/screen time had a negative association with MSCA score.

CONCLUSION

In this cross-sectional study, a combined score of lifestyle factors is not related to neuropsychological development at pre-school age.

Correlates of sedentary time in young children: A systematic review

Background: Young children appear to spend large portions of their waking time being sedentary. Understanding the correlates of sedentary time would assist in developing effective interventions among young children. The purpose of this systematic review was to summarize the current literature on the correlates of objectively measured sedentary time in young children aged 1-5.99y. Methods: This review was registered with PROSPERO (registration no. CRD42017081374) and aligned with the PRISMA Statement for systematic reviews. Five electronic databases (MEDline, CINAHL Complete, PsycINFO, SportDiscus, Scopus) were searched up to October 26, 2017 for studies investigating correlates of sedentary time measured using objective devices. A semiquantitative approach was used to synthesize data. Results: Forty-five studies were retrieved comprising 13,430 participants, and 84 correlates of sedentary time in young children were evaluated. The associations between sex, sleep habits, daily patterns (childcare vs. non-childcare hours), childcare type and sedentary time were indeterminate. Thirty-nine correlates were consistently unrelated. Forty-one potential correlates were examined in too few studies (<4) to make confident conclusions. Parental sedentary behaviour was reported 3 times and maternal sedentary behaviour was reported once. Out of these four studies, three were positively associated with child sedentary time. Conclusions: Despite reviewing 45 studies that evaluated associations for 84 correlates, this review was unable to identify any consistent correlates of sedentary time in young children. Additional research is needed in this area to provide robust evidence of the correlates of sedentary time in young children, particularly for those examined in only a small number of studies.

[Association between physical activity level, body mass index and body fat mass in young people of school age in the Wilaya of Marrakesh (Morocco)]

INTRODUCTION

Physical activity is a good indicator of health state and well-being. The purpose of this study is to assess physical activity level and to study its association with body mass index and body fat mass in young people of school age in the Wilaya of Marrakech.

METHODS

A sample of 1173 young people of school age (aged 15- 20 years) was recruited in the city of Marrakech (urban area) and in the Al Haouz Province (rural area). Physical activity level was determined by measuring the energy expenditure compared to the recommended levels of physical activity. Logistic regression was used in the statistical study of these associations.

RESULTS

Forty-one point one percent (41.1%) of respondents were physically active for three hours and more per week, 31.1% practiced less than three hours per week, while 27.3% (41.1% of girls against 14.2% of boys; p < 0.001) do not practice any sport activity in their free time outside the school. Boys were more active than girls (OR = 3.16; p < 0.001). Rural students were more active than urban dwellers (OR = 1.9; p < 0.001). Among girls, passing from the level of "sedentary" lifestyle to the level "very active" lifestyle, the means of body-mass index (BMI) and body fat mass decreased by 1.9 kg/m2 (F = 8.03; p < 0.001) and 6.28% (F = 15.80; p < 0.001) respectively. Among boys, the decrease in BMI was 0.85 kg/m2 (F = 1.17; p = 0.17) and 2.77% (F = 5.15; p = 0.006) in body fat.

CONCLUSION

Physical activity is significantly associated with body fat mass and BMI. Physical activity promotion in young people into their daily activities as well as during their leisure time, is a basic need to cope with the downstream effects of sedentary lifestyle on their health.

Unravelling the association between accelerometer-derived physical activity and adiposity among preschool children: A systematic review and meta-analyses

Evidence on the association between physical activity (PA) and adiposity in young children is inconclusive. A systematic review and meta-analyses were conducted to examine associations between accelerometer-derived PA and varying adiposity outcomes in preschool children. Searches were conducted in Embase, MEDLINE and Web of Science to identify studies on the association between total PA, sedentary behaviour or different PA intensities and adiposity in children aged 2 to 7 years. Separate random effects meta-analyses were performed for varying PA intensities and adiposity outcomes. Fifty-six articles were included in the review and 48 in the meta-analyses. There was substantial evidence of an inverse association between moderate-to-vigorous- or vigorous PA and body fat percentage (stdβ [SE] = -0.162[0.041]; 5 studies), weight status (r = -0.120, P<.001; 11 studies), fat mass (stdβ [SE] = -0.103[0.051]; 5 studies), fat mass index (stdβ [SE] = -0.121[0.036]; 2 studies) and skinfold thickness (stdβ [SE] = -0.145[0.036]; 4 studies). However, total PA, sedentary behaviour, and different PA intensities were not associated with body mass index (BMI) or waist circumference. Adiposity levels were lower among preschool children engaged in more (moderate-to-) vigorous PA compared with their peers, but no associations between PA and BMI or waist circumference were found.

How socio-demographic and familiar circumstances are associated with total and domain-specific sedentary behaviour in youth? The UP&DOWN study

Objective: The aims of the present study were to analyze the associations between the socio-demographic and familiar circumstances with: (i) the total leisure-time sedentary behavior (SB) assessed by accelerometry, and (ii) the domain-specific leisure-time SB (i.e., screen-based, educational-based, social-based, and other-based SB), in a sample of Spanish youth. Method: The sample consisted of 1,543 youth (12.02 ± 2.51 years) included in the UP&DOWN study. SB was evaluated by accelerometry and questionnaire. Nationality, location of school, type of school, socio-economic status, parental educational level, parental occupation status, family structure, number of siblings and position among siblings were self-reported by participants or their parents. Linear mixed models, including school and city as random effects, were performed. Results: Several associations were found; however, socio-demographic and family circumstances differently associated with SB according to the domain-specific SB, the sex and the type of day. For example, participants with a father holding a high-skilled occupation spent lower time in screen-based SB during weekdays; and mother occupation status of high qualification was related to higher educational-based SB in boys. Having three or more sibling was associated with lower total SB in boys, while having an obese mother was related to higher screen-based SB on weekends both in boys and girls. Conclusions: Socio-demographic and familiar circumstances are associated with SB in young people, so future interventions should consider multiple and sex-specific factors for reduce SB of young people, focusing especially on youth with a low number of siblings and with parents holding low-skilled employments.

Association of physical activity with adiposity in preschoolers using different clinical adiposity measures: a cross-sectional study

BACKGROUND

More research is needed about the association between physical activity (PA), sedentary behaviour (SB), and adiposity in preschoolers, particularly using more direct clinical measures of adiposity. Therefore, the main objective of this study was to investigate the association between objectively measured PA and different clinical adiposity measures in a large sample of preschoolers.

METHODS

Four hundred sixty-three predominantly normal-weight (77%) 2-6-year-old preschool children participated in the Swiss Preschoolers' Health Study (SPLASHY). Physical activity was measured using accelerometers and was analyzed using 15-s (uni-axial) epoch length using validated cut-offs. Adiposity measures included body mass index (BMI), the sum of four skinfolds, and waist circumference (WC). Multilevel linear regression modeling, adjusted for age, sex and wear time, was used to assess the association between PA and SB with BMI, WC, and skinfold thickness.

RESULTS

Total PA and different PA intensities were positively and SB was inversely associated with BMI in the total sample and in the normal-weight children (p < 0.05). Total PA was inversely associated with skinfold thickness in overweight and obese children (p < 0.05), while there was only a weak association for vigorous PA (p > 0.05). Moderate and moderate-to-vigorous PA were positively, and SB was negatively associated with WC in the total sample and in the normal-weight children (p < 0.05). Additional adjustment for potential sociocultural and biological confounding variables attenuated some of the results.

CONCLUSIONS

In this very young and predominantly normal-weight population, PA is positively related to BMI and WC, but this relationship is not observed in overweight and obese children. In this latter population, PA is inversely, and SB is positively related to skinfold thickness. Skinfold thickness could represent a useful and simple clinical measure of body fat in preschoolers. The role of vigorous PA in the prevention of early childhood obesity should be further investigated in future studies.

TRIAL REGISTRATION

ISRCTN ISRCTN41045021 . Retrospectively registered 06 May 2014.

Neighborhood Recreation Facilities and Facility Membership Are Jointly Associated with Objectively Measured Physical Activity

Efforts to increase physical activity have traditionally included either individual-level interventions (e.g., educational campaigns) or neighborhood-level interventions (e.g., additional recreational facilities). Little work has addressed the interaction between spatial proximity and individual characteristics related to facility use. We aimed to better understand the synergistic impact of both physical activity environments and recreational facility membership on objectively measured physical activity. Using the New York City Physical Activity and Transit (PAT) survey (n = 644), we evaluated associations between counts of commercial physical activity facilities within 1 km of participants' home addresses with both facility membership and accelerometry-measured physical activity. Individuals living near more facilities were more likely to report membership (adjusted odds ratio for top versus bottom quartile of facility count: 3.77 (95% CI 1.54-9.20). Additionally, while amount of facilities within a neighborhood was associated with more physical activity, this association was stronger for individuals reporting gym membership. Interventions aiming to increase physical activity should consider both neighborhood amenities and potential barriers, including the financial and social barriers of membership. Evaluation of neighborhood opportunities must expand beyond physical presence to consider multiple dimensions of accessibility.

What if all children achieved WHO recommendations on physical activity? Estimating the impact on socioeconomic inequalities in childhood overweight in the UK Millennium Cohort Study

BACKGROUND

The World Health organization (WHO) recommends that children engage in 60 min daily moderate-to-vigorous physical activity (dMVPA). Just half of children in the UK achieve these levels (with similarly low levels in other high-income countries). Thus, the dMVPA target is a focus of national obesity strategies. However, the potential impact of increased physical activity on prevalence and inequalities in childhood overweight is unknown. Using objective data from the Millennium Cohort Study (∼18 000 children born 2000-02) we simulated a series of hypothetical physical activity intervention scenarios: achievement of the target, and more realistic increases demonstrated in trials.

METHODS

Predicted probabilities of overweight and obesity (using measured heights and weights at age 11) were estimated in multinomial marginal structural models, adjusting for dMVPA (measured with accelerometers at age 7) and confounding. Inequalities were assessed according to household income quintiles [risk ratios (RRs) and risk differences (RDs)]. Intervention scenarios were simulated by re-estimating predicted probabilities of overweight/obesity after manipulating (increasing) dMVPA by varying amounts, for different eligibility criteria and with varying uptake. Analyses included 6493 children with accelerometer data. Survey weights and multiple imputation addressed sampling design, attrition and item missingness.

RESULTS

In all, 27% children were overweight/obese, with relative and absolute inequalities in the expected direction; 51% children were achieving 60 min dMVPA, with those from the lowest income quintile achieving, on average, 3 min more dMVPA than those from the highest income quintile. A simulation of universal achievement of the dMVPA target reduced the prevalence of overweight/obesity to 22%, but increased relative inequalities (absolute inequalities were unchanged). Smaller increases in dMVPA (informed by intervention evidence) did little to reduce prevalence or inequalities, even when targeting high-risk groups.

CONCLUSIONS

Universal achievement of the WHO dMVPA target, if attainable, would reduce prevalence of childhood overweight and obesity but not inequalities. Scale-up of more realistic interventions would have limited impact.

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

OBJECTIVE

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

STUDY DESIGN

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

RESULTS

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

CONCLUSIONS

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

A review of early influences on physical activity and sedentary behaviors of preschool-age children in high-income countries

PURPOSE

Promoting physical activity (PA) is a key component of preventing and controlling childhood obesity. Despite well-documented benefits of PA, globally, rates of PA among young children have declined over the past decades, and most children are not accruing sufficient PA daily. Helping children develop the foundation for PA habits early in life is critical for the promotion of health in childhood and prevention of chronic diseases later in life, and will ultimately promote longer and healthier lives for individuals and the general population. The purpose of this review is to provide a synthesis of current evidence on influences on PA and sedentary behaviors of preschool-age children in high-income countries.

DESIGN AND METHODS

A systematic review of three databases was performed. Studies conducted in high-income countries and published from 2000 onward that addressed influences on PA and sedentary behaviors of preschool-age children were identified and reviewed. Additionally, reference lists of identified articles and relevant published reviews were reviewed. Studies that met the following inclusion criteria were considered: (a) sample included preschoolers (age ≤5 years); (b) PA and/or sedentary behaviors or factors associated with PA and/or sedentary behaviors was assessed; (c) published in English; (d) used either quantitative or qualitative methods; and (e) conducted in a high-income country. Data were extracted from selected studies to identify influences on PA and sedentary behaviors of preschool-age children and organized using the social-ecological model according to multiple levels of influence.

RESULTS

Results from included studies identify multiple factors that influence PA and sedentary behaviors of young children in high-income countries at the various levels of the social-ecological model including intrapersonal, interpersonal, environmental, organizational, and policy.

PRACTICE IMPLICATIONS

Given pediatric nurses' role as primary care providers, and their frequent and continued contact with parents and their children throughout childhood through well-child visits, immunization, and minor acute illnesses, they are well positioned to promote and support the development of early healthful PA habits of children starting in early childhood.

Fathers' perspectives on the diets and physical activity behaviours of their young children

Background

Children’s learning about food and physical activity is considerable during their formative years, with parental influence pivotal. Research has focused predominantly on maternal influences with little known about the relationships between fathers’ and young children’s dietary and physical activity behaviours. A greater understanding of paternal beliefs regarding young children’s dietary and physical activity behaviours is important to inform the design and delivery of child-focussed health promotion interventions. This study aimed to describe fathers’ perceived roles in their children’s eating and physical activity behaviours. It also sought to document fathers’ views regarding how they could be best supported to promote healthy eating and physical activity behaviours in their young children.

Methods

In depth, semi-structured interviews were conducted with twenty fathers living in socio-economically diverse areas of metropolitan Melbourne, Australia who had at least one child aged five years or less. All interviews were audio recorded, transcribed verbatim and thematically analysed.

Results

Thematic analysis of the transcripts revealed eight broad themes about fathers’ beliefs, perceptions and attitudes towards the dietary and physical activity behaviours of their young children: (i) shared responsibility and consultation; (ii) family meal environment; (iii) parental role modelling; (iv) parental concerns around food; (v) food rewards; (vi) health education; (vii) limiting screen time; and (viii) parental knowledge. Analysis of themes according to paternal education/employment revealed no substantial differences in the views of fathers.

Conclusions

This exploratory study presents the views of a socio-economically diverse group of fathers regarding the dietary and physical activity behaviours of their young children and the insights into the underlying perceptions informing these views. The findings suggest that fathers believe healthy eating behaviours and being physically active are important for their young children. Fathers believe these behaviours can be promoted and supported in different ways including through the provision of appropriate meal and physical activity environments and parental role modelling of desired dietary and physical activity behaviours.

Physical Activity During the Early Years: A Systematic Review of Correlates and Determinants

CONTEXT

Being physically active during the early years (age 0-6 years) is vital for healthy development. Identifying correlates and determinants of physical activity (PA) is crucial to guide effective interventions. This systematic review synthesized studies investigating potential correlates and determinants of PA during the early years, accounting for different types of PA assessment.

EVIDENCE ACQUISITION

Nine electronic databases were searched from inception year (1900) until September 2014; data were analyzed/interpreted in April 2015. The following inclusion criteria were used: written in English, published in peer-reviewed journals, participants not in statutory/school education, and an observational design investigating associations between an exposure/variable, and a quantitative measure of PA. Correlates/determinants of total, moderate to vigorous, and light PA were reported using an ecologic model.

EVIDENCE SYNTHESIS

Of 22,045 identified studies, 130 were included. All took place in high-income countries and few (6%) were of high quality. Correlates of total PA were sex (male, ++); parental PA (+); parental support (+); and time outdoors (+). Determinants of total PA were sex (+) and time spent playing with parents (+). The only correlate of moderate to vigorous PA was sex (male, ++). No determinants of moderate to vigorous or light PA were found. PA correlates/determinants were relatively consistent between objective and subjective PA measures.

CONCLUSIONS

Numerous studies investigated potential correlates and determinants of PA, but overall quality was low. A small number of demographic/biological and social/cultural factors were associated with PA. There is a need for high-quality studies exploring correlates/determinants across all domains of the ecologic model.

Does home equipment contribute to socioeconomic gradients in Australian children's physical activity, sedentary time and screen time?

BACKGROUND

Activity behaviours (physical activity, sedentary time and screen time) have been linked to health outcomes in childhood. Furthermore, socioeconomic disparities have been observed in both children's activity behaviours and health outcomes. Children's physical home environments may play a role in these relationships. This study aimed to examine the associations and interactions between children's physical home environment, socioeconomic status and moderate-to-vigorous physical activity, sedentary time and screen time.

METHODS

Australian children (n = 528) aged 9-11 years from randomly selected schools participated in the cross-sectional International Study of Childhood Obesity, Lifestyle and the Environment. Children's physical home environment (access to equipment), socioeconomic status (household income and parental education) and demographic variables (gender and family structure) were determined by parental questionnaire. Moderate-to-vigorous physical activity and sedentary time were measured objectively by 7-day 24-h accelerometry. Screen time was obtained from child survey. The associations between the physical home environment, socioeconomic status and moderate-to-vigorous physical activity, sedentary time and screen time were examined for 427 children, using analysis of covariance, and linear and logistic regression, with adjustment for gender and family structure.

RESULTS

The presence of TVs (p < 0.01) and video game consoles (p < 0.01) in children's bedrooms, and child possession of handheld video games (p = 0.04), cell phones (p < 0.01) and music devices (p = 0.04) was significantly and positively associated with screen time. Ownership of these devices (with the exception of music devices) was inversely related to socioeconomic status (parental education). Children's moderate-to-vigorous intensity physical activity (p = 0.04) and possession of active play equipment (p = 0.04) were both positively associated with socioeconomic status (household income), but were not related to each other (with the exception of bicycle ownership).

CONCLUSIONS

Children with less electronic devices, particularly in their bedrooms, participated in less screen time, regardless of socioeconomic status. Socioeconomic disparities were identified in children's moderate-to-vigorous physical activity, however socioeconomic status was inconsistently related to possession of active play equipment. Home active play equipment was therefore not a clear contributor to the socioeconomic gradients in Australian children's moderate-to-vigorous physical activity.

Determinants of moderate to vigorous physical activity and obesity in children: a structural equation modeling analysis

BACKGROUND

The determinants of physical activity (PA) and body fatness in Chinese adolescents are rarely examined. This study aimed to investigate the effect of attitude toward PA, screen time, parents' socioeconomic status (SES), and exercise habit on PA and body fatness among Chinese children by using structural equation modeling (SEM) analysis.

METHODS

Data obtained from the second Community Fitness Survey in Hong Kong were utilized, in which students from one secondary school of each of the 18 districts of Hong Kong were recruited. A total of 2517 questionnaires with physical fitness items were successfully distributed to students aged 13-19 years in these districts. Families' SES, parents' exercise habit, children's intention to participate in PA, amount of moderate to vigorous PA (MVPA), screen time, children's attitude toward PA, and children's body fat percentage were measured and analyzed with SEM. The structural equation model was composed of a measurement model and a structural model. The model was tested with Mplus 6. The Chi-square test, root mean square error of approximation, comparative fit index, and Tucker-Lewis index were calculated to evaluate model fit. The model was then modified based on the model fit indices.

RESULTS

Children's intention to participate in PA was a strong predictor of their engagement in MVPA. Parents' exercise habit had both direct and indirect (via attitude) effects on their children's intention to participate in PA. Screen time was not a predictor of body composition. Children's intention to participate in PA directly affected their body composition. Children's attitude toward PA, parents' exercise habit, and SES had significant effects on the children's intention to participate in PA. Furthermore, obesity had a negative effect on the children's attitude toward PA.

CONCLUSION

To promote MVPA and prevent obesity in Chinese children of Hong Kong, it is important to design intervention that enhances children's intention and attitude in PA, as well as parent's exercise habits. Tailormade programs that take SES into consideration are also essential. Further studies are necessary to extend the results and test the model in other metropolitan areas in China.

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

Background

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

Objective

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

Methods

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

Results

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

Conclusions

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

Objectively measured physical activity in two-year-old children - levels, patterns and correlates

Background

The aim was to describe levels, patterns and correlates of physical activity and sedentary behavior in a sample of Swedish children, two years of age, with normal weight, overweight and obese parents.

Methods

Data from 123 children, 37 with normal-weight parents and 86 with overweight/obese parents, enrolled in the Early Stockholm Obesity Prevention Project study was used. Children wore an Actigraph GT3X+ accelerometer for seven days. Average activity (counts per minute), number of steps and time spent in low and high-intensity physical activity and in sedentary was assessed. Differences between weekdays and weekend days were examined as were correlations with sex, body mass index (BMI), motor skills and family-related factors.

Results

Children were active at high intensity 11% of the day. On average 55% of the day was spent being sedentary. Number of steps and time in low-intensity physical activity differed between weekdays and weekend days: on weekdays, 363 more steps (p = 0.01) and six more minutes in low physical activity (p = 0.04). No differences were found for any physical activity or sedentary behavior variable by sex, BMI, motor skills or any family-related variable (p = 0.07 – 0.95).

Conclusions

Two-year-old children have an intermittent activity pattern, that is almost similar on weekdays and they spend about half of the daytime active. The absence of any association with sex, BMI, motor skills or parental factors indicates that the individual variation in this age group is primarily due to endogenous factors.

Trial registration

Clinicaltrials.gov: NCT01198847.

An investigation into the minimum accelerometry wear time for reliable estimates of habitual physical activity and definition of a standard measurement day in pre-school children

The purpose of this study was to determine the number of hours and days of accelerometry data necessary to provide a reliable estimate of habitual physical activity in pre-school children. The impact of a weekend day on reliability estimates was also determined and standard measurement days were defined for weekend and weekdays.Accelerometry data were collected from 112 children (60 males, 52 females, mean (SD) 3.7 (0.7)yr) over 7 d. The Spearman-Brown Prophecy formula (S-B prophecy formula) was used to predict the number of days and hours of data required to achieve an intraclass correlation coefficient (ICC) of 0.7. The impact of including a weekend day was evaluated by comparing the reliability coefficient (r) for any 4 d of data with data for 4 d including one weekend day.Our observations indicate that 3 d of accelerometry monitoring, regardless of whether it includes a weekend day, for at least 7 h  d(-1) offers sufficient reliability to characterise total physical activity and sedentary behaviour of pre-school children. These findings offer an approach that addresses the underlying tension in epidemiologic surveillance studies between the need to maintain acceptable measurement rigour and retention of a representatively meaningful sample size.

A review of preschool children's physical activity and sedentary time using objective measures

CONTEXT

Identifying current physical activity levels and sedentary time of preschool children is important for informing government policy and community initiatives. This paper reviewed studies reporting on physical activity and time spent sedentary among preschool-aged children (2-5 years) using objective measures.

EVIDENCE ACQUISITION

Databases were searched for studies published up to and including April 2013 that reported on, or enabled the calculation of, the proportion of time preschool children spent sedentary and in light- and moderate to vigorous-intensity physical activity. A total of 40 publications met the inclusion criteria for physical activity and 31 met the inclusion criteria for sedentary time. Objective measures included ActiGraph, Actiwatch, Actical, Actiheart, and RT3 accelerometers, direct observation, and Quantum XL telemetry heart rate monitoring. Data were analyzed in May 2013.

EVIDENCE SYNTHESIS

Considerable variation in prevalence estimates existed. The proportion of time children spent sedentary ranged from 34% to 94%. The time spent in light-intensity physical activity and moderate to vigorous-intensity physical activity ranged from 4% to 33% and 2% to 41%, respectively.

CONCLUSIONS

The considerable variation of prevalence estimates makes it difficult to determine the "true" prevalence of physical activity and sedentary time in preschool children. Future research should aim to reduce inconsistencies in the employed methodologies to better understand preschoolers' physical activity levels and sedentary behavior.

Psychosocial perspectives and the issue of prevention in childhood obesity

A dramatic increase in childhood overweight/obesity has been recognized globally over the past 50 years. This observed increase may reflect genetic, as well as psychological, environmental, and socio-cultural influences. In the first part of this review, we present an updated summary of the psychosocial factors associated with this change and discuss possible ways in which they operate. Among these factors, lower socio economic status (in both industrialized and non-industrialized countries), being female, belonging to a minority group, and being exposed to adverse life events may all be associated with a greater risk of childhood overweight/obesity. These influences may be mediated via a variety of mechanisms, in particular above-average food intake of low nutritional quality and reduction in physical activity. Other important psychosocial mediators include the influence of the family and peer environment, and exposure to the media. In the second part of the review, we discuss the potential of psychosocial prevention programs to intervene in the processes involved in the rise of childhood overweight/obesity. Two points are emphasized. First, prevention programs should be multidisciplinary, combining the knowledge of experts from different professions, and taking into consideration the important role of the family environment and relevant influential social organizations, particularly school. Second, effective change is unlikely to occur without large-scale programs carried out on a public policy level.

Parental education and physical activity in pre-school children

BACKGROUND

The purpose of this study was to objectively assess pre-school children's total physical activity (TPA) patterns and compliance with guidelines and to examine differences relative to parental education.

METHODS

The sample consisted on 509 healthy pre-school children, aged 3-6 years recruited from kindergartens located in the metropolitan area of Porto, Portugal. The PA was assessed for 7 consecutive days by accelerometry. For TPA, we followed the guidelines of the National Association for Sport and Physical Education (NASPE) (children who spent at least >120  min per day in active play). For TPA, we calculated the proportion of children who spent at least >120  min per day in active play and moderate-to-vigorous physical activity (MVPA), we calculated the proportion of children who spent at least >60  min per day in active play. Parental education was analysed according to the Portuguese education system.

RESULTS

Children with parents in the highest education level were less active than children from low and middle education level (P ≤ 0.001) in all patterns of PA (week and weekend). Regarding TPA during the week we found that the majority of children from low and middle parental education meet the NASPE guidelines. On the other hand, more than half the children from high parental education did not meet these recommendations (P ≤ 0.001) and MVPA recommendations (P ≤ 0.05). In both recommendations, children from low parental education were twice more likely to meet the recommendations compared with children belonging to high parental education.

CONCLUSION

Parent education was negatively associated with children's daily physical activity patterns and compliance with guidelines.

Socioeconomic status. The relationship with health and autoimmune diseases

Socioeconomic status (SES) is a hierarchical social classification associated with different outcomes in health and disease. The most important factors influencing SES are income, educational level, occupational class, social class, and ancestry. These factors are closely related to each other as they present certain dependent interactions. Since there is a need to improve the understanding of the concept of SES and the ways it affects health and disease, we review herein the tools currently available to evaluate SES and its relationship with health and autoimmune diseases.

Validity of actigraphs uniaxial and triaxial accelerometers for assessment of physical activity in adults in laboratory conditions

Background

Few studies to date have directly compared the Actigraphs GT1M and the GT3X, it would be of tremendous value to know if these accelerometers give similar information about intensities of PA. Knowing if output is similar would have implications for cross-examination of studies. The purpose of the study was to assess the validity of the GT1M and the GT3X Actigraph accelerometers for the assessment of physical activity against oxygen consumption in laboratory conditions.

Methods

Forty-two college-aged participants aged 18-25 years wore the GT1M and the GT3X on their right hip during treadmill exercise at three different speeds, slow walking 4.8 km^.h^-1, fast walking 6.4 km^.h^-1, and running 9.7 km^.h^-1). Oxygen consumption was measured minute-by minute using a metabolic system. Bland-Altman plots were used to assess agreement between activity counts from the GT3X and GT1M, and correlations were assessed the ability of the accelerometers to assess physical activity.

Results

Bias for 4.8 km^.h^-1 was 2814.4 cpm (limits 1211.3 to 4417.4), for 6.4 km^.h^-1 was 3713.6 cpm (limits 1573.2 to 5854.0), and for 9.7 km^.h^-1 was−3811.2 cpm (limits 842.1 to 6780.3). Correlations between counts per minute for the GT1M and the GT3X were significantly correlated with VO₂ (r = 0.881, p < 0.001; r = 0.810, p < 0.001 respectively).

Conclusion

The present study showed that both the GT1M and the GT3X accurately measure physical activity when compared to oxygen consumption.

Physical activity in 3-6 year old children measured by SenseWear Pro®: direct accelerometry in the course of the week and relation to weight status, media consumption, and socioeconomic factors

BACKGROUND

Data on objectively measured physical activity (PA) in preschoolers are controversial. Direct accelerometry was performed in children aged 3-6 years, and differences in PA patterns over the course of the week were evaluated. Data were analyzed with gender, BMI, lifestyle, and socioeconomic parameters as covariates.

METHODS

PA was measured in 119 children by the SensewearPro® accelerometer and analyzed in the 92 (40 girls) that wore it for at least 4 days including one day of the weekend. Median measuring time in this group was 7 consecutive days (median/mean daily measuring time: 23.5 h/d and 21.8 h/d, respectively), corresponding to 834,000 analyzed minutes. PA questionnaires were completed by 103 parents and 87 preschool teachers to collect anthropometric, lifestyle, and socioeconomic data.

RESULTS

Median daily PA (MET>3) was 4.3 hours (mean: 4.4 hours). Boys spent an estimated 52 min/week more being very active (MET>6) than girls (95% CI [6, 96] min/week, p = 0.02). PA was lower during the weekend (3.7 h/d) compared to weekdays (4.5 h/d), p = 3 × 10(-6)), where a 95% CI for the difference is [0.5, 1.0] h/d. PA levels did not differ between overweight/obese children (median 4.7 h/d) and normal-weight peers (median 4.2 h/d). Daily media consumption increased with decreasing social class on weekdays (p = 0.05) and during the weekend (p = 0.01), but was not related to the amount of daily PA. A multivariate regression with BMI-SDS as independent variable and gender, age, amount of PA>6 MET, parental BMI, media time and socioeconomic status as explanatory variables revealed that only SES had a significant contribution.

CONCLUSION

The negative impact of obesity-promoting factors in older children is rather low for preschoolers, but there is evidently a gradient in PA between weekdays and weekends already in this age group. Weight status of preschoolers is already considerably influenced by SES, but not physical activity levels.

Association between objectively measured sedentary behavior and body mass index in preschool children

OBJECTIVE

To determine the association between accelerometry-derived sedentary behavior and body mass index (BMI) z-score in preschool children, and to determine whether the association changed when applying three different accelerometry cutpoints for sedentary behavior.

DESIGN AND SUBJECTS

Cross-sectional design. Data came from two completed studies: Children's Activity and Movement in Preschool Study (CHAMPS) and the Environmental Determinants of Physical Activity in Preschool Children (EDPAPC) study. Children of ages 3-5 years with complete data on sedentary behavior, BMI z-score, physical activity and other covariates were included in the analyses (N=263 in CHAMPS and N=155 in EDPAPC). Accelerometry data were summarized as time spent in sedentary behavior (min h(-1)) using three different cutpoints developed specifically for preschool children (<37.5, <200 and <373 counts per 15 s). Linear mixed regression models were used to determine the association between time spent in sedentary behavior and BMI z-score; age, gender, race, parental education, preschools and moderate-to-vigorous physical activity (MVPA) were included as covariates.

RESULTS

In both CHAMPS and EDPAPC studies, no independent association between time spent in sedentary behavior and BMI z-score was observed after adjusting for MVPA. The observed null association between sedentary behavior and BMI z-score was maintained even with different sedentary behavior cutpoints.

CONCLUSIONS

Regardless of cutpoints used, accelerometry-derived sedentary behavior was not independently associated with BMI z-score in two independent samples of preschool children. Longitudinal studies addressing this research question are needed.

Physical activity in the prevention of childhood obesity

The current high prevalence of childhood obesity and its co-morbidities is concomitant with a low level of physical activity and an abundance of sedentary pastimes for Westernised children. To increase the participation of a majority of children in a sustained physical activity, interventions require a fair understanding and consideration of the influences of this behaviour, especially as children are overweight or obese. Basically, the physical activity behaviour of children depends on biological, sociocultural and psychosocial factors and their interplay. The recent literature lends support to the fact that some psychosocial factors such as self-efficacy and physical competence may be solid anchor points upon which to improve the participation of overweight and obese children in free-living physical activity. Thus, interventionists should first concentrate on improving these personal dimensions around which physiological and environmental factors might revolve. The development of motor skills may be a good means for enhancing the self-image of obese children.

Relationship of objective measurement of physical activity during school hours and BMI in preschool children

The measurement of the physical activity (PA) since early ages is a key factor in lifestyle evaluation. The aims of this study were to describe objective levels of PA and to determine the association of body mass index status (BMI) with PA patterns in preschool children. Weight and height were measured in 59 healthy pre-school children. The children used the accelerometer for 4 consecutive days during school hours. The prevalence of OW+OB was 30.5%. The 82.31% of the time spent at kindergarten was allocated to sedentary tasks. The 5 years-old boys were significantly more engaged in TPA and MVPA and less in SB than girls. No statistically significant associations were found between OW/OB and PA patterns. Most of the time spent at school is related to SB, which is central to childhood obesity risk. Early interventions to increase PA in preschool children are needed.

Accelerometer-derived physical activity levels of preschoolers: a meta-analysis

OBJECTIVES

This study synthesized the published estimates of daily moderate-to-vigorous physical activity (MVPAd(-1)) of preschooler-age children (3-5 years).

DESIGN

Meta-analysis of previously published studies reporting accelerometer-derived estimates of daily MVPA of preschoolers.

METHODS

A comprehensive literature review was conducted to identify studies published by March 2010 that reported daily minutes of accelerometer-derived MVPA in preschool-age children (3-5 years). Random effects point estimates and 95% confidence intervals (95% CIs) were calculated based on study weighted means and standard deviations of raw accelerometer counts per minute (cpm) and reported minutes of MVPA and/or percentage of time spent in MVPAd(-1).

RESULTS

29 articles representing 6309 preschoolers were included. Overall, preschoolers engaged in 42.8 min (95% CI 28.9-56.8) of MVPAd(-1), and 54.4 min (95% CI 29.9-78.9) and 45.4 min (95% CI 25.2-65.6) for boys and girls separately. This translated into approximately 5.5% (95% CI 3.7-7.2%) of time spent in MVPAd(-1), and 7.1% (95% CI 3.9-10.3%) for boys and 6.3% (95% CI 3.9-8.7%) for girls. Studies (76%) using ActiGraph accelerometers reported an average of 714 cpm (95% CI 678-751), with boys and girls having 783 cpm (95% CI 753-813) and 696 cpm (95% CI 665-727), respectively.

CONCLUSIONS

Interpretation of accelerometer-derived MVPA is confounded by differences in cutpoints applied within a study. Great care, therefore, should be taken when interpreting the activity levels of preschoolers to inform policy decisions, such as the development of physical activity guidelines. Hence, considerable attention is required to unify accelerometer-derived MVPA so that unbiased comparisons across studies can be made.

Correlates of energy balance-related behaviours in preschool children: a systematic review

Childhood overweight is a multifactorial health problem influenced by several factors. The interaction of behaviours such as physical activity, sedentary behaviour and eating behaviour determines whether or not a positive energy balance or weight gain is experienced. Knowing the correlates of these behaviours in 4- to 6-year-old children is of major interest for intervention development. According to the systematic literature search, attending a rural preschool was positively associated with physical activity. Gender, age and socioeconomic status were not associated with physical activity, while an indeterminate result was found for ethnicity. Gender and ethnicity were not associated with sedentary behaviour and indeterminate results were found for age and socioeconomic status. Preschoolers were more physically active as well as sedentary on weekdays. Watching television was associated with a higher consumption of snacks and sweet beverages. Strategies aiming to influence energy balance-related behaviours in preschoolers should target both boys and girls and all ethnic groups from low as well as high social status. During the week, there should be a focus on decreasing sedentary behaviour and in the weekend on increasing physical activity. Focusing on television viewing and the consumption of snacks and sweet beverages could/should also be a strategy.

Physical activity and cardiovascular disease risk factors among young and middle-aged men in urban Mwanza, Tanzania

BACKGROUND

Cardiovascular diseases (CVD) risk factors are increasing at an unprecedented rate in developing countries. However, fewer studies have evaluated the role of physical activity in preventing CVD in these countries. We assessed level physical activity and its relationship with CVD risk factors among young and middle aged men in a fast growing city of Mwanza in Tanzania.

METHODS

Physical activity was assessed among 97 healthy men aged 20-50 years using Sub-Saharan Africa Activity Questionnaire. An updated compendium of physical activity was used to code the metabolic equivalent. Energy expenditure was calculated using Harris Benedict equation. Anthropometric measurements, blood pressure, fasting blood glucose and serum lipids were also measured.

RESULTS

The mean energy expenditure in this population was 6,466 ± 252 kcal/week. More than half (53.6%) of the participants had energy expenditure of ≥ 4,000 kcal/week. Only three (3.1%) had energy expenditure below the recommended 1,000 kcal/week. Except for hypertension, prevalence of CVD risk factors was low in this population; hypertension 23.7%, low HDL-cholesterol 10.3%, high LDL-cholesterol 9.3% and obesity 4.1%. Physical activity energy expenditure had an inversely relationship with waist to hip ratio, systolic blood pressure, heart rate, total cholesterol, HDL-cholesterol, LDL-cholesterol, triglycerides and fasting blood glucose.

CONCLUSION

Physical activity energy expenditure was high in this population and was inversely correlated with CVD risk factors. Physical activity may play an important role in the prevention of CVD in this urban population of young and middle aged men.

An observational study on socio-economic and ethnic differences in indicators of sedentary behavior and physical activity in preschool children

OBJECTIVE

We studied associations between social disadvantage and indicators of sedentary behavior and physical activity at preschool age.

METHODS

Data from 4688 children enrolled in a birth cohort in Rotterdam, the Netherlands, between 2002 and 2006 were analyzed. Indicators of sedentary behavior (watching television ≥ 2 h/day and sitting in a buggy ≥ 0.5 h/day) and physical inactivity (playing outside < 3 h/day) were measured by a parent-reported questionnaire at age 3. Adjustments were made for social circumstances and indicators of health behaviors. Logistic regression was used to obtain odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

Children with low-educated mothers (OR: 3.27, 95% CI 2.12-5.05) and non-Dutch children (OR(nonWestern): 2.67, 95% CI 2.04-3.49, OR(Western): 2.09, 95% CI 1.42-3.0) were more likely to watch television for at least 2 h/day. Similar results were seen for sitting in a buggy for at least 0.5h/day. Non western children were more likely to play outside for less than 3 h/day (OR: 1.95, 95% CI: 1.39-2.73) than native Dutch children, while no differences were seen for other western children or children from mothers with a low educational level.

CONCLUSIONS

Socio-economic status and ethnicity are already associated with indicators of sedentary lifestyles at preschool age.

Correlates of sedentary time and physical activity among preschool-aged children

INTRODUCTION

Few studies have examined the correlates of objectively measured amounts of sedentary time and physical activity in young children. We evaluated the demographic, biological, behavioral, social, and environmental correlates of the amount of sedentary time and moderate-to-vigorous physical activity (MVPA) as measured by accelerometry in preschool-aged children.

METHODS

We obtained baseline measurements of physical activity by using an Actical accelerometer among 337 preschool-aged children (aged 2-5) of overweight or obese mothers. For children, we defined sedentary time as less than 12 counts per 15 seconds and MVPA as 715 or more counts per 15 seconds. Body mass index of the mother and child (calculated from measured height and weight) and maternal physical activity as measured by accelerometer were included as potential correlates. Mothers self-reported all other potential correlates. We used multivariable linear regression analyses to examine correlates of the amount of sedentary time and MVPA.

RESULTS

Children had an average of 6.1 hours per day of sedentary time and 14.9 minutes per day of MVPA. In multivariable analysis, boys (P <.001) had fewer minutes per day of sedentary time, whereas older children (P <.001), boys (P <.001), children in high-income households (>$60,000/y [P = .005]), and children who spent more time outdoors (P = .001) had more MVPA.

CONCLUSION

Both modifiable and nonmodifiable factors were correlated with preschool children's amount of MVPA, which can be helpful when designing interventions for this age group. The lack of correlates for sedentary time indicates the need for further investigation into this behavior.

Is directly measured physical activity related to adiposity in preschool children?

This review summarizes the association between directly assessed physical activity and adiposity in preschool children (age 1.5-6 years). It includes 17 cross-sectional and longitudinal studies that were published between January 1999 and February 2010. The association between physical activity and obesity seems to depend on the outcome measure of adiposity. In 60% (3/5) of the studies using percentage body fat, an inverse significant relationship with physical activity was found against 18% (2/11) of the studies that used body mass index as method to assess adiposity. Physical activity is inversely related to percentage body fat in preschool children. The associations between physical activity and body mass index as a measure of adiposity in preschool children remain elusive. Further studies using directly measured physical activity and percentage body fat to define adiposity are needed to draw more firm conclusions.

Objectively measured physical activity and sedentary time in European adolescents: the HELENA study

The authors' aim in this cross-sectional study was to characterize levels of objectively measured physical activity and sedentary time in adolescents from 9 European countries. The study comprised 2,200 European adolescents (1,184 girls) participating in the HELENA cross-sectional study (2006-2008). Physical activity was measured by accelerometry and was expressed as average intensity (counts/minute) and amount of time (minutes/day) spent engaging in moderate- to vigorous-intensity physical activity (MVPA). Time spent in sedentary behaviors was also objectively measured. Cardiorespiratory fitness was measured by means of the 20-m shuttle run test. Level of maternal education was reported by the adolescents. A higher proportion of boys (56.8% of boys vs. 27.5% of girls) met the physical activity recommendations of at least 60 minutes/day of MVPA. Adolescents spent most of the registered time in sedentary behaviors (9 hours/day, or 71% of the registered time). Both average intensity and MVPA were higher in adolescents with high cardiorespiratory fitness, and sedentary time was lower in the high-fitness group. There were no physical activity or sedentary time differences between maternal education categories. These data provide an objective measure of physical activity and amount of time spent in sedentary behaviors in a relatively large number of European adolescents.

Influences on preschool children's physical activity: exploration through focus groups

This study explored mothers' perceptions of influences on preschoolers' physical activity. Six semistructured focus groups with 23 mothers were conducted across a range of socioeconomic position locations. Mothers identified 4 key areas of influence: child fundamentals (eg, sex, personality), parent power (eg, rules, support), people to share with (eg, peers, adults), and places and things (eg, physical environments, toys). No substantial differences in themes were identified among socioeconomic position groups. Influences on preschoolers' physical activity are multidimensional, multifactorial, and support the use of ecological models to conceptualize and understand the influencing factors. Associations among factors influencing preschoolers' physical activity should be further investigated through quantitative research.

Parental influences on child physical activity and screen viewing time: a population based study

Background

Parents can influence their children's physical activity participation and screen time.This study examined the relative significance of perceived parental barriers and self-efficacy in relation to children's physical activity participation and screen time viewing. The associations between these factors and the behaviours were analysed.

Methods

Cross-sectional population survey in New South Wales, Australia of parents of pre-school (N = 764), younger (Kindergarten, Grades 2 and 4; N = 1557) and older children (Grades 6, 8 and 10; N = 1665). Parents reported barriers and self-efficacy to influence their child's physical activity and screen time behaviours in a range of circumstances. Differences were examined by child's sex and age group, household income, maternal education and location of residence. The duration of physical activity and screen viewing was measured by parental report for pre-school and younger children and self-report for older children. Associations between parental factors and children's organised, non-organised and total activity and screen time were analysed.

Results

Cost, lack of opportunities for participation and transport problems were the barriers most often reported, particularly by low income parents and those in rural areas. The number of barriers was inversely related to children's time spent in organised activity, but not their non-organised activity. Higher parental self-efficacy was positively associated with organised physical activity in the younger and older children's groups and the non-organised activity of older children. School-age children (younger and older groups) were less likely to meet physical activity guidelines when parents reported ≥4 barriers (OR 3.76, 95% CI 1.25-11.34 and OR 3.72, 95% CI 1.71-8.11 respectively). Low parental self-efficacy was also associated with the likelihood of children exceeding screen time guidelines for each age group (pre-school OR 0.62, 95% CI 0.43-0.87; young children OR 0.56, 95% CI 0.39-0.80; and older children OR 0.57, 95% CI 0.43-0.74).

Conclusion

Parental barriers are associated with the time that children spend in both active and sedentary pursuits. These findings highlight family, economic and environmental factors that should be addressed in programs to promote child physical activity and tackle sedentary behaviour.

[Determining factors of physical activity level in school children and adolescents: the OPACA study]

INTRODUCTION

Physical activity is a key factor for human health. This study attempts to measure the level of physical activity in children and to find out what are the factors that determine it.

METHOD

In a sample of the 11 and 14 year-old population of the centre-south area of Palencia, physical activity was measured using a three day diary, and anthropometric and socioeconomic variables were collected. Three variables were analysed: fat-free mass adjusted activity energy expenditure (AEE/FFM), physical activity level (PAL), and categorical physical activity (active/inactive).

RESULTS

A total of 179 children were included, of whom 71.5% were active or very active. Males were more active than females, and activity was also higher in summer. Physical activity declined between 11 and 14 years, and was lower during the weekends than in working days. There were no differences related to obesity, overweight or percent body fat. More active children had lower blood pressure. Physical activity was directly related to weekly hours spent in sport activities, and inversely related to time spent on sedentary activities. Multivariate analysis showed that children from families with low educational levels had a higher activity level not related to sport activities.

CONCLUSIONS

The level of physical activity in this population is acceptable, although there are sex differences and there is a declining trend through the adolescence.

Correlates of sedentary behaviours in preschool children: a review

BACKGROUND

Sedentary behaviour has been linked with a number of health outcomes. Preschool-aged children spend significant proportions of their day engaged in sedentary behaviours. Research into the correlates of sedentary behaviours in the preschool population is an emerging field, with most research being published since 2002. Reviews on correlates of sedentary behaviours which include preschool children have previously been published; however, none have reported results specific to the preschool population. This paper reviews articles reporting on correlates of sedentary behaviour in preschool children published between 1993 and 2009.

METHODS

A literature search was undertaken to identify articles which examined correlates of sedentary behaviours in preschool children. Articles were retrieved and evaluated in 2008 and 2009.

RESULTS

Twenty-nine studies were identified which met the inclusion criteria. From those studies, 63 potential correlates were identified. Television viewing was the most commonly examined sedentary behaviour. Findings from the review suggest that child's sex was not associated with television viewing and had an indeterminate association with sedentary behaviour as measured by accelerometry. Age, body mass index, parental education and race had an indeterminate association with television viewing, and outdoor playtime had no association with television viewing. The remaining 57 potential correlates had been investigated too infrequently to be able to draw robust conclusions about associations.

CONCLUSIONS

The correlates of preschool children's sedentary behaviours are multi-dimensional and not well established. Further research is required to provide a more comprehensive understanding of the influences on preschool children's sedentary behaviours to better inform the development of interventions.

[Social disparities in the prevalence of overweight and obesity in adolescents]

INTRODUCTION

Many social factors have a role in determining the risk of overweight/obesity in children and adolescents, and are the main barriers in their management. This study tries to define the effect that some familial and social factors have on the risk of overweight/obesity in children and adolescents.

METHOD

Population sample of 11- and 14-years old children recruited in three Primary Care Centres in Palencia. Their weight, height and skin folds were measured, and information gathered about sport activities, TV watching, and parental data (weight, height, educational status and occupation). Multivariate models were used to analyse the effect of these variables on the weight status and on the body fat.

RESULTS

Three hundred and twenty-two children were included. Prevalence of obesity was 5.6% and that of any degree of overweight was 28.9%. Overweight was not related to educational status or occupation, but it was more often found in males (OR 2.07; 95% CI; 1.12-3.83), in children whose father (OR 2.18; 95% CI; 1.14-4.15) or mother (OR 2.17; 95% CI; 1.18-3.98) were overweight, and in those who spent ≥2 h daily watching TV (OR 2.72; 95% CI; 1.43-5.19), and it was less frequent in 14 than in 11-year old children (OR 0.42; 95% CI; 0.23-0.78). Obesity was only related to a low educational level (OR 19.45; 95% CI; 1.95-193.82).

CONCLUSIONS

Overweight is related with genetic-environmental factors and the modern society way of life, and occurs across the whole social spectrum. But obesity is strongly related to a low educational status of the family, and it still is a marker for health disparities.

Influence of socio-economic status on habitual physical activity and sedentary behavior in 8- to 11-year old children

BACKGROUND

While socio-economic status has been shown to be an important determinant of health and physical activity in adults, results for children and adolescents are less consistent. The purpose of this study, therefore, is to examine whether physical activity and sedentary behavior differs in children by socio-economic status (SES) independent of body mass index.

METHODS

Data were from two cohorts including 271 children (117 males; 154 females) in study 1 and 131 children in study 2 (63 males; 68 females). The average age was 9.6 and 8.8 years respectively. Height and body mass were assessed according to standard procedures and body mass index (BMI, kg/m2) was calculated. Parent-reported household income was used to determine SES. Habitual, free-living physical activity (PA) was assessed by a pedometer (steps/day) in study 1 and accelerometer (time spent in moderate-to-vigorous PA) in study 2. Self-reported time spent watching TV and on the computer was used as measure of sedentary behavior. Differences in PA and sedentary behavior by SES were initially tested using ANOVA. Further analyses used ANCOVA controlling for BMI, as well as leg length in the pedometer cohort.

RESULTS

In study 1, mean daily steps differed significantly among SES groups with lower SES groups approximating 10,500 steps/day compared to about 12,000 steps/day in the higher SES groups. These differences remained significant (p < 0.05) when controlling for leg length. Lower SES children, however, had higher body mass and BMI compared to higher SES groups (p < 0.05) and PA no longer remained significant when further controlling for BMI. In study 2 results depended on the methodology used to determine time spent in moderate-to-vigorous physical activity (MVPA). Only one equation resulted in significant group differences (p = 0.015), and these differences remained after controlling for BMI. Significant differences between SES groups were shown for sedentary behavior in both cohorts (P < 0.05) with higher SES groups spending less time watching TV than low SES groups.

CONCLUSIONS

Children from a low SES show a trend of lower PA levels and spend more time in sedentary behavior than high SES children; however, differences in PA were influenced by BMI. The higher BMI in these children might be another factor contributing to increased health risks among low SES children compared to children from with a higher SES.

Socioeconomic position and the tracking of physical activity and cardiorespiratory fitness from childhood to adulthood

This study examined the influence of childhood socioeconomic position (SEP) and social mobility on activity and fitness tracking from childhood into adulthood. In a prospective cohort of 2,185 Australian adults (aged 26-36 years), first examined in 1985 (at ages 7-15 years), self-reported physical activity and cardiorespiratory fitness (subsample only) were measured. SEP measures included retrospectively reported parental education (baseline) and own education (follow-up). There was little evidence of a relation between childhood SEP and activity tracking, but high childhood SEP (maternal education) was associated with a 59% increased likelihood of persistent fitness, and medium childhood SEP (paternal and parental education) was associated with a 33%-36% decreased likelihood of persistent fitness. Upward social mobility was associated with a greater likelihood of increasing activity (38%-49%) and fitness (90%), and persistently high SEP was associated with a greater likelihood of increasing activity (males: 58%) and fitness (males and females combined: 89%). In conclusion, persistently high SEP and upward social mobility were associated with increases in activity and fitness from childhood to adulthood. Findings highlight socioeconomic differentials in activity and fitness patterns and suggest that improvements in education may represent a pathway through which physical activity levels can be increased and health benefits achieved.

Socioeconomic effects on meeting physical activity guidelines: comparisons among 32 countries

PURPOSE

This study examined the relationship between age and gender with physical activity (PA) and how meeting of PA guidelines (PAGL) is related to socioeconomic status (SES) and sedentary behaviors (SB).

METHODS

Data were collected from 11-, 13-, and 15-yr-old students in 32 countries participating in the Health Behaviour in School-aged Children (HBSC) survey 2001/2002. A self-completed questionnaire assessed weekly moderate-to-vigorous physical activity (MVPA) and SB for the past 7 d and MVPA for a typical week. SES was assessed using the Family Affluence Scale (FAS).

RESULTS

None of the countries averaged enough MVPA to meet PAGL. The pattern of MVPA across age and gender was consistent among all countries. In all countries, older children were less active when compared with the youngest children; girls were significantly less active than boys were (mean hours per week of MVPA 3.52 +/- 1.88 vs 4.13 +/- 1.95) and were more likely to not meet the PAGL. SES was significantly associated with the amount of reported MVPA. SES and PAGL were not significantly related in seven countries, and a significant decrease in the influence of age was observed in these countries compared with other countries.

CONCLUSIONS

Levels of MVPA during adolescence showed consistent patterns across countries in relation to age, gender, and social class. The limited effect of age on PA in countries where the influence of social class was less strong suggests the possibility of a moderating effect of context in the development of habits acquired during childhood.