Physical activity and sedentary behavior: a review of longitudinal studies of weight and adiposity in youth

Are BMI and Sedentariness Correlated? A Multilevel Study in Children

The purpose of this research was to investigate the relationship between body mass index (BMI) and sedentariness (Sed) in children and to examine the influence of child and school correlates on their variation. The sample comprises 580 children (337 girls, 9-11 years). Sedentariness was assessed with an accelerometer, and BMI was computed. Child- and school-level covariates were analyzed using multilevel models. No significant correlation between Sed and BMI was found. School context explains 5% and 1.5% of the total variance in Sed and BMI, respectively. At the child level, only moderate-to-vigorous physical activity was associated with both Sed (β = -0.02 ± 0.002) and BMI (β = -0.005 ± 0.002). Sleep time is related to Sed (β = -0.42 ± 0.04), while sex (β = 1.97 ± 0.13), biological maturity (β = 1.25 ± 0.07), media in the bedroom (β = 0.26 ± 0.08) and healthy (β = -0.09 ± 0.03) and unhealthy (β = -0.07 ± 0.04) diet scores were associated with BMI. None of the school-level covariates were related to BMI, but access to cafeteria (β = -0.97 ± 0.25), playground equipment (β = -0.67 ± 0.20) and restaurants (β = 0.16 ± 0.08) were related to Sed. In conclusion, Sed and BMI were not correlated. Further, they have different correlates, while children's traits seem to play more relevant roles in their differences in Sed and BMI than the school milieu. This information should be taken into account when strategies to reduce Sed and BMI are implemented.

Weight-related behaviors when children are in school versus on summer breaks: does income matter?

BACKGROUND

Income disparities in US youth in academic achievement appear to widen during the summer because of discontinued learning among children from lower-income households. Little is known about whether behavioral risk factors for childhood obesity, such as diet and physical activity, also demonstrate a widening difference by income when children are out of school.

METHODS

Data from US children in grades 1-12 in the National Health and Nutrition Examination Survey 2003-2008 (N = 6796) were used to estimate screen time, moderate-to-vigorous physical activity (MVPA), and consumption of calories, vegetables, and added sugar. Linear regression was used to compare among children of households ≤185% and >185% poverty, as well as during the school year versus on school breaks.

RESULTS

Children surveyed during summer breaks consumed fewer vegetables (-0.2 cups/day) and more added sugar (+2.1 teaspoons/day), were more active (+4.6 MVPA minutes/day) and watched more television (+18 minutes/day). However, the nonsignificant interaction between school breaks and income indicated that lower-income students were not "less healthy" than higher-income students during the summer breaks.

CONCLUSION

Obesity-related risk factors were more prevalent during the summer and among lower-income youths, but the income disparity in these behaviors was not exacerbated when schools are not in session.

Overview of the Hungarian National Youth Fitness Study

The 2012 Public Act on Education in Hungary made daily physical education (PE) a mandatory part of the school day starting in the 2012-2013 school year. This directive was linked to a significant reorganization of the Hungarian education system including a new National Core Curriculum that regulates the objectives and contents of PE. The Hungarian School Sport Federation (HSSF) recognized the opportunity and created the Strategic Actions for Health-Enhancing Physical Education or Testnevelés az Egészségfejlesztésben Stratégiai Intézkedések (TESI) project. Physical fitness assessments have been a traditional part of the Hungarian PE program; however, the TESI plan called for the use of a new health-related battery and assessment system to usher in a new era of fitness education in the country. The HSSF enlisted the Cooper Institute to assist in building an infrastructure for full deployment of a national student fitness assessment program based on the FITNESSGRAM® in Hungarian schools. The result is a new software-supported test battery, namely the Hungarian National Student Fitness Test (NETFIT), which uses health-related, criterion-referenced youth fitness standards. The NETFIT system now serves as a compulsory fitness assessment for all Hungarian schools. This article details the development process for the test battery and summarizes the aims and methods of the Hungarian National Youth Fitness Study.

The association between sedentary behaviour and risk of anxiety: a systematic review

BACKGROUND

Previous research has linked sedentary behaviour (SB) to adverse physical health outcomes in adults and youth. Although evidence for the relationship between SB and mental health outcomes (e.g., depression) is emerging, little is known regarding risk of anxiety.

METHODS

A systematic search for original research investigating the association between SB and risk of anxiety was performed using numerous electronic databases. A total of nine observational studies (seven cross-sectional and two longitudinal) were identified. Methodological quality of studies was assessed and a best-evidence synthesis was conducted.

RESULTS

One cross-sectional study demonstrated a strong methodological quality, five cross-sectional studies demonstrated a moderate methodological quality and three studies (two cross-sectional one longitudinal) received a weak methodological quality rating. Overall, there was moderate evidence for a positive relationship between total SB and anxiety risk as well as for a positive relationship between sitting time and anxiety risk. There was inconsistent evidence for the relationship between screen time, television viewing time, computer use, and anxiety risk.

CONCLUSION

Limited evidence is available on the association between SB and risk of anxiety. However, our findings suggest a positive association (i.e. anxiety risk increases as SB time increases) may exist (particularly between sitting time and risk of anxiety). Further high-quality longitudinal/interventional research is needed to confirm findings and determine the direction of these relationships.

Associations between objectively assessed and questionnaire-based sedentary behaviour with BMI-defined obesity among general population children and adolescents living in England

OBJECTIVES

Sedentary behaviour (SB) is an emerging candidate risk factor for obesity in young people. Evidence to date is conflicting and it is unclear how different SB types are associated with obesity independently of physical activity. The objective of this study was to examine associations between a range of objectively measured and questionnaire-based SB indicators with obesity and body mass index (BMI) to assess whether these associations were independent of physical activity.

PARTICIPANTS

4469 (705 with accelerometer data) children aged 5-15 years from the 2008 Health Survey for England.

OUTCOMES

The outcome was adiposity, classified using age-specific and sex-specific BMI SD scores (continuous) and obesity cut-offs (binary). Questionnaire-based measures comprised TV time, non-TV sitting time (such as homework, drawing, time at a computer or playing video games), total sitting time (TV time+non-TV sitting time) and average daily MVPA time. Objective SB and moderate to vigorous physical activity (MVPA) time were measured using an Actigraph GT1M accelerometer, with cut-offs of 100 and 200 counts per minute for SB, and 2802 counts per minute for MVPA. Multiple logistic and multiple linear regression models examined associations between each indicator of sedentary time with obesity and BMI SD scores.

RESULTS

TV time (but not non-TV sitting or objectively-measured SB) was consistently associated with higher levels of obesity and BMI SD score, even after adjusting for MVPA and other potential confounders. Weaker associations were observed for total sitting time.

CONCLUSIONS

TV viewing (but not other forms of objectively-measured or questionnaire-based sedentary time) was associated with obesity in children and adolescents. Although a causal relationship cannot be established, TV time may be a reasonable target for obesity prevention in young populations.

Evidence-Based Referral: Effects of the Revised "Youth Fit 4 Life" Protocol on Physical Activity Outputs

The authors contrasted 2 physical activity/nutrition treatments on the basis of social cognitive and self-efficacy theory, and a comparison condition, on time in moderate-to-vigorous physical activity (MVPA) during the 45-min/day physical activity segment of elementary after-school care. The Revised Youth Fit 4 Life protocol that sought to maximize participants' cardiovascular physical activity appeared to improve upon the Original Youth Fit For Life treatment on time in MVPA. Thus, pediatricians might have confidence in referring their patients to such evidence-based approaches.

Factors associated with higher sitting time in general, chronic disease, and psychologically-distressed, adult populations: findings from the 45 & up study

This study examined factors associated with higher sitting time in general, chronic disease, and psychologically-distressed, adult populations (aged ≥45 years). A series of logistic regression models examined potential socio-demographic and health factors associated with higher sitting (≥6hrs/day) in adults from the 45 and Up Study (n = 227,187), including four separate subsamples for analysis comprising those who had ever had heart disease (n = 26,599), cancer (n = 36,381), diabetes (n = 19,550) or psychological distress (n = 48,334). Odds of higher sitting were significantly (p<.01) associated with a number of factors across these groups, with an effect size of ORs≥1.5 observed for the high-income ≥$70,000AUD, employed full-time and severe physical limitations demographics. Identification of key factors associated with higher sitting time in this population-based sample will assist development of broad-based, public health and targeted strategies to reduce sitting-time. In particular, those categorized as being high-income earners, full-time workers, as well as those with severe physical limitations need to be of priority, as higher sitting appears to be substantial across these groups.

Are associations between electronic media use and BMI different across levels of physical activity?

Background

The use of electronic media has been found to be a risk factor for higher BMI and for being overweight. Physical activity has been found to be associated with lower BMI and lower risk for being overweight. Little is known about whether the associations between physical activity and electronic media use are additive or interactive in predicting BMI and risk for overweight among adolescents.

Methods

The data used in this study stem from the 2009/2010 survey of “Health Behaviour in School-aged Children (HBSC) study: A WHO Cross-National Survey. The sample consisted of 107184 13 and 15 year students from 30 different countries. Multilevel regression models were used to produce the presented estimates.

Results

Overall, 18% of boys and 11% of girls were classified as overweight. EM use was found to be associated with increased BMI z-scores and odds for overweight among both boys and girls who did not comply with physical activity guidelines. Among physically active adolescents, EM was found to be significantly associated with BMI or odds for overweight among girls, but not among boys.

Conclusion

While the usage of EM appear to be inconsequential for BMI and the risk of overweight among physically active boys, we find evidence indicating that EM use is associated with BMI and risk for overweight among girls, including those who report complying with MVPA guidelines.

The impact of cell phone use on the intensity and liking of a bout of treadmill exercise

This study used a within-subjects design to assess the effect of three common cellular telephone (cell phone) functions (texting, talking, listening to music) on planned exercise. Forty-four young adults (n = 33 females, 21.8 ± 1.3 years) each participated in four, separate, 30-minute exercise conditions on a treadmill in a random order. During each condition, the treadmill speed display was covered and grade was fixed at zero. However, participants were able to alter treadmill speed as desired. Throughout the texting and talking conditions, research personnel used a pre-determined script to simulate cell phone conversations. During the music condition, participants used their cell phone to listen to music of their choice. Finally, participants completed a control condition with no cell phone access. For each condition, average treadmill speed, heart rate and liking (via visual analog scale) were assessed. Treadmill speed (3.4 ± 1.3 miles∙hour^-1), heart rate (122.3 ± 24.3 beats∙min^-1) and liking (7.5 ± 1.5 cm) in the music condition were significantly (p ≤ 0.014) greater than all other conditions. Treadmill speed in the control condition (3.1 ± 1.2 miles∙hour^-1) was significantly (p = 0.04) greater than both texting and talking (2.8 ± 1.1 miles∙hour^-1 each). Heart rate during the control condition (115.4 ± 22.8 beats∙min^-1) was significantly (p = 0.04) greater than texting (109.9 ± 16.4 beats∙min^-1) but not talking (112.6 ± 16.1 beats∙min^-1). Finally, liking during the talking condition (5.4 ± 2.2 cm) was greater (p = 0.05) than the control (4.3 ± 2.2 cm) but not the texting (5.1 ± 2.2 cm) conditions. In conclusion, using a cell phone for listening to music can increase the intensity (speed and heart rate) and liking of a bout of treadmill exercise. However, other common cell phone uses (texting and talking) can interfere with treadmill exercise and reduce intensity.

Changing from primary to secondary school highlights opportunities for school environment interventions aiming to increase physical activity and reduce sedentary behaviour: a longitudinal cohort study

BACKGROUND

There is little empirical evidence of the impact of transition from primary to secondary school on obesity-related risk behaviour. The purpose of this study was to examine the effect of a change of school system on physical activity (PA) and sedentary behaviour in pre-early adolescents.

METHODS

Fifteen schools in Victoria, Australia were recruited at random from the bottom two strata of a five level socio-economic scale. In nine schools, students in year 6 primary school transitioned to a different school for year 7 secondary school, while in six schools (combined primary-secondary), students remained in the same school environment from year 6 to year 7. Time 1 (T1) measures were collected from students (N=245) in year 6 (age 11-13). Time 2 (T2) data were collected from 243 (99%) of the original student cohort when in year 7. PA and sedentary behaviour data were collected objectively (via ActiGraph accelerometer) and subjectively (via child self-report recall questionnaire). School environment data were collected via school staff survey. Change of behaviour analyses were conducted longitudinally i) for all students and ii) by change/no change of school. Mixed model regression analysis tested for behavioural interaction effects of changing/not changing school.

RESULTS

Sixty-three percent (N=152) changed schools from T1 to T2. Across all students we observed declines in average daily moderate to vigorous physical activity (MVPA) (-4 min) and light PA (-23 min), and increases in average daily sedentary behaviour (16 min), weekday leisure screen time (17 min) and weekday homework screen time (25 min), all P<0.05. Compared to students who remained in the same school environment, students who changed school reported a greater reduction in PA intensity at recess and lunch, less likelihood to cycle to/from school, greater increase in weekday (41 mins) and weekend (45 mins) leisure screen time (P<0.05) and greater encouragement to participate in sport. School staff surveys identified that sport participation encouragement was greater in primary and combined primary-secondary than secondary schools (P<0.05).

CONCLUSION

Transitioning from primary to secondary school negatively impacts on children's PA and sedentary behaviour, and has further compounding effects on behaviour type by changing school environments.

Low physical activity and high screen time can increase the risks of mental health problems and poor sleep quality among Chinese college students

OBJECTIVE

To test the independent and interactive associations of physical activity (PA) and screen time (ST) with self-reported mental health and sleep quality among Chinese college students.

METHOD

Data were collected in October, 2013. The gender, age, residential background, body mass index (BMI), perceived family economy and perceived study burden were obtained from a total of 4747 college students (41.6% males and 58.4% females). The outcomes were self-reported PA status, ST, anxiety, depression, psychopathological symptoms and sleep quality. Analyses were conducted with logistic regression models.

RESULTS

Overall, 16.3%, 15.9% and 17.3% of the students had psychological problems, such as anxiety, depression and psychopathological symptoms, respectively. The prevalence of poor sleep quality was 9.8%. High ST was significantly positively associated with anxiety (OR=1.38, 95%CI: 1.15-1.65), depression (OR=1.76, 95%CI: 1.47-2.09), psychopathological symptoms (OR=1.69, 95%CI: 1.43-2.01) and poor sleep quality (OR=1.32, 95%CI: 1.06-1.65). High PA was insignificantly negatively associated with anxiety, depression, psychopathological symptoms and poor sleep. Low PA and high ST were independently and interactively associated with increased risks of mental health problems and poor sleep quality (p<0.05 for all).

CONCLUSION

Interventions are needed to reduce ST and increase PA in the lifestyles of young people. Future research should develop and measure the impacts of interventions and their potential consequences on sleep, health, and well being.

Determinants of physical activity and sedentary behaviour in university students: a qualitative study using focus group discussions

Background

College or university is a critical period regarding unhealthy changes in energy related behaviours in students. The first objective of this explorative study was to identify determinants of physical activity and sedentary behaviour in Belgian university students. Secondly, we aimed to collect ideas and recommendations to increase physical activity and decrease sedentary behaviours in university students.

Methods

Using a semi-structured question guide, seven focus group discussions were conducted consisting of 17 male and 29 female university students from a variety of study disciplines, with a mean age of 20.7 ± 1.6 yrs. Using Nvivo9, an inductive thematic approach was used for data analysis.

Results

Students reported that both physical and sedentary activities were influenced by individual factors (e.g. perceived enjoyment, self-discipline, time and convenience), their social networks (e.g. (lack of) parental control, modelling, social support), physical environment (e.g. availability and accessibility, travel time/distance, prices), and macro environment (e.g. media and advertising). Furthermore, the relationships between determinants and university students’ physical activity and sedentary behaviour seemed to be moderated by university characteristics, such as residency, university lifestyle, exams and academic pressure. Recommendations for future physical activity interventions include improving information strategies regarding on-campus sports activities, cheaper and/or more flexible sports subscriptions and formulas, including ‘sports time’ into the curricula, and providing university bicycles around campus. Students also believed that increasing students’ physical activity might decrease their sedentary behaviour at the same time.

Conclusions

The recommendations and ideas discussed in this study may facilitate the development of effective and tailored (multilevel) intervention programs aiming to increase physical activity and decrease sedentary behaviours in university students.

Regional differences of physical activity and sedentary behaviour in Swiss children are not explained by socio-demographics or the built environment

OBJECTIVE

We evaluated whether regional differences in physical activity (PA) and sedentary behaviour (SB) existed along language boundaries within Switzerland and whether potential differences would be explained by socio-demographics or environmental characteristics.

METHODS

We combined data of 611 children aged 4 to 7 years from four regional studies. PA and SB were assessed by accelerometers. Information about the socio-demographic background was obtained by questionnaires. Objective neighbourhood attributes could be linked to home addresses. Multivariate regression models were used to test associations between PA and SB and socio-demographic characteristics and neighbourhood attributes.

RESULTS

Children from the German compared to the French-speaking region were more physically active and less sedentary (by 10-15 %, p < 0.01). Although German-speaking children lived in a more favourable environment and a higher socioeconomic neighbourhood (differences p < 0.001), these characteristics did not explain the differences in PA behaviour between French and German speaking.

CONCLUSIONS

Factors related to the language region, which might be culturally rooted were among the strongest correlates of PA and SB among Swiss children, independent of individual, social and environmental factors.

A 9-year, bidirectional prospective analysis of depressive symptoms and adiposity: the African American Health Study

OBJECTIVE

Depression may be a predictor and consequence of obesity. However, available evidence for racial minorities has been inconsistent, and more prospective studies are needed. Thus, this study's objective was to examine whether depressive symptom severity is a predictor and/or consequence of total adiposity over a 9-year period in a representative sample of late middle-aged African-Americans.

METHODS

A total of 410 participants (aged 49-65 years; baseline) in the prospective cohort African American Health study were examined. Depressive symptom severity was assessed with the Center for Epidemiologic Studies-Depression Scale (CES-D). Total body fat percent (BF%) and body mass index (BMI; kg/m(2) ) were assessed. Structural equation models were tested.

RESULTS

All model fit statistics, other than χ(2) , indicated good fit (RMSEA ≤ 0.058, SRMR ≤ 0.052, CFI ≥ 0.95). Baseline CES-D did not predict 9-year changes in BF% (β = -0.01, P = 0.78) or BMI (β = -0.01, P = 0.77). Baseline BF% (β = 0.05, P = 0.39) and BMI (β = 0.08, P = 0.095) did not predict 9-year change in CES-D.

CONCLUSIONS

Depressive symptom severity was not a predictor or consequence of excess total adiposity in late middle-aged African-American adults. Including a depression module in obesity prevention and treatment programs specifically designed for late middle-aged African-Americans may not have a beneficial effect on obesity outcomes.

Typing performance and body discomfort among overweight and obese office workers: A pilot study of keyboard modification

Obesity in the workplace is associated with loss of productivity, high medical care expenses, and increased rates of work-related injuries and illness. Thus, effective, low-cost interventions are needed to accommodate the size of today's obese office worker while alleviating potential physical harm associated with musculoskeletal disorders. Utilizing a sample of 22 overweight and obese office workers, this pilot study assessed the impact of introducing an alternative, more ergonomically-sound keyboard on perceptions about design, acceptability, and usability; self-reported body discomfort; and typing productivity. Data were collected using self-reported questionnaires and objective typing tests administered before and after the intervention. The intervention duration was six weeks. After switching from their standard work keyboard to an alternative keyboard, all participants reported significant decreases in lower back discomfort (t = 2.14, P = 0.044); although obese participants reported significant decreases in both upper (t = 2.46, P = 0.032) and lower (t = 2.39, P = 0.036) back discomfort. No significant changes were observed in overall typing performance scores from baseline to follow-up. Findings suggest that such interventions may be introduced into the workforce with positive gains for workers without reducing short-term worker productivity.

Daily physical activity and screen time, but not other sedentary activities, are associated with measures of obesity during childhood

Childhood obesity is related to low physical activity level and a sedentary lifestyle. The aim of this study was to assess the physical activity level and sedentary behaviour of Malaysian children aged 7 to 12 years and to examine their association with body mass index (BMI), BMI-for-age Z-score (BAZ), body fatness (%BF) and waist circumference (WC). A total of 1736 children, representing all ethnic groups were recruited from six regions of Malaysia. Anthropometric measurements included body weight, height and waist circumference. Body fat percentage (%BF) was assessed using bioelectrical impedance. Physical activity was assessed by a physical activity questionnaire (PAQ) in all children and by pedometers in a subsample (n = 514). PAQ score and pedometer step counts were negatively associated with BMI, BAZ, %BF and WC after adjusting for covariates. Screen time was positively associated with BAZ and WC. However, other sedentary activities were not significantly related with any anthropometric indicators. Strategies to promote active living among children in Malaysia should focus not only on increasing physical activity but also emphasise reduction in sedentary behaviours.

Social inequalities in young children's sports participation and outdoor play

Background

Research on social inequalities in sports participation and unstructured physical activity among young children is scarce. This study aimed to assess the associations of family socioeconomic position (SEP) and ethnic background with children’s sports participation and outdoor play.

Methods

We analyzed data from 4726 ethnically diverse 6-year-old children participating in the Generation R Study. Variables were assessed by parent-reported questionnaires when the child was 6 years old. Low level of outdoor play was defined as outdoor play <1 hour per day. Series of multiple logistic regression analyses were performed to assess associations of family SEP and ethnic background with children’s sports participation and outdoor play.

Results

Socioeconomic inequalities in children’s sports participation were found when using maternal educational level (p < 0.05), paternal educational level (p < 0.05), maternal employment status (p < 0.05), and household income (p < 0.05) as family SEP indicator (less sports participation among low SEP children). Socioeconomic inequalities in children’s outdoor play were found when using household income only (p < 0.05) (more often outdoor play <1 hour per day among children from low income household). All ethnic minority children were significantly more likely to not to participate in sports and play outdoor <1 hour per day compared with native Dutch children. Adjustment for family SEP attenuated associations considerably, especially with respect to sports participation.

Conclusion

Low SEP children and ethnic minority children are more likely not to participate in sports and more likely to display low levels of outdoor play compared with high SEP children and native Dutch children, respectively. In order to design effective interventions, further research, including qualitative studies, is needed to explore more in detail the pathways relating family SEP and ethnic background to children’s sports participation and outdoor play.

Electronic supplementary material

The online version of this article (doi:10.1186/s12966-014-0155-3) contains supplementary material, which is available to authorized users.

The influence of body mass index on survival in breast cancer patients

INTRODUCTION

More than half of breast cancer survivors (BCSs) are obese at diagnosis and experience approximately 50% to 96% of weight gain during treatment that could physically affect their survival. The aim of the study was to evaluate the influence of body mass index (BMI) on physical, anthropometric, and physiological parameters in BCSs.

PATIENTS AND METHODS

A cross-sectional study was conducted with 147 BCSs. Health-related fitness, anthropometric measures, cardiovascular state, and cancer-related fatigue (CRF) were assessed for our analysis and 3 groups were formed.

RESULTS

Tests of force handgrip (affected side: F = 3.44; P < .05; nonaffected side: F = 3.067; P < .05), functional capacity (F = 3.239; P = .043), and endurance of trunk flexors (×2 = 8.264; P = .016) were significantly lower in obese BCSs compared with the normal-weight group, whereas systolic (F = 5.839; P = .004) and diastolic blood pressure (F = 8.794; P < .001), waist circumference (F = 85.81; P < .001), and arm circumference at 10 cm (affected side: F = 23.530; P < .001; nonaffected side: F = 17.095; P < .001) and 5 cm (affected side: F = 21.751; P < .001; nonaffected side: F = 22.490; P < .001) were significantly greater in BCSs with higher BMI compared with other groups. No significant differences were observed between groups regarding lower limb endurance, resting heart rate or CRF.

CONCLUSION

This study demonstrated the influence of obesity on health-related fitness, anthropometric measures, and cardiovascular state.

Four minutes of in-class high-intensity interval activity improves selective attention in 9- to 11-year olds

The amount of time allocated to physical activity in schools is declining. Time-efficient physical activity solutions that demonstrate their impact on academic achievement-related outcomes are needed to prioritize physical activity within the school curricula. "FUNtervals" are 4-min, high-intensity interval activities that use whole-body actions to complement a storyline. The purpose of this study was to (i) explore whether FUNtervals can improve selective attention, an executive function posited to be essential for learning and academic success; and (ii) examine whether this relationship is predicted by students' classroom off-task behaviour. Seven grade 3-5 classes (n = 88) were exposed to a single-group, repeated cross-over design where each student's selective attention was compared between no-activity and FUNtervals days. In week 1, students were familiarized with the d2 test of attention and FUNterval activities, and baseline off-task behaviour was observed. In both weeks 2 and 3 students completed the d2 test of attention following either a FUNterval break or a no-activity break. The order of these breaks was randomized and counterbalanced between weeks. Neither motor nor passive off-task behaviour predicted changes in selective attention following FUNtervals; however, a weak relationship was observed for verbal off-task behaviour and improvements in d2 test performance. More importantly, students made fewer errors during the d2 test following FUNtervals. In supporting the priority of physical activity inclusion within schools, FUNtervals, a time efficient and easily implemented physical activity break, can improve selective attention in 9- to 11-year olds.

Obesity and its relation to depressive symptoms and sedentary lifestyle in middle-aged women

BACKGROUND

The prevalence of obesity increases during female mid-life and although many factors have been identified, data from Latin America is lacking.

OBJECTIVE

To assess factors related to obesity among middle-aged women and determine the association with depressive symptoms, sedentary lifestyle and other factors.

METHODS

A total of 6079 women aged 40-59 years of 11 Latin American countries were asked to fill out the Goldberg Anxiety and Depression Scale, the Menopause Rating Scale, the Athens Insomnia Scale, the Pittsburgh Sleep Quality Index and a general questionnaire containing personal socio-demographic data, anthropometric measures and lifestyle information. Obesity was defined as a body mass index (BMI) ≥30 kg/m(2).

RESULTS

Obesity was observed in 18.5% and sedentary lifestyle in 63.9%. A 55.5% presented vasomotor symptoms, 12.2% had severe menopausal symptoms and 13.2% used hormone therapy for the menopause. Prevalence of depressive symptoms was 46.5% and anxiety 59.7%. Our logistic regression model found that significant factors associated to obesity included: arterial hypertension (OR: 1.87), depressive symptoms (OR: 1.57), sedentary lifestyle (OR: 1.50) diabetes mellitus (OR: 1.34), higher number of individuals living at home (OR: 1.31), sleep problems (OR:1.22), anxiety (OR: 1.21), having a stable partner (OR: 1.20), parity (OR: 1.16) and vasomotor symptoms (OR:1.14). A lower risk for obesity was found among women using hormonal contraceptives (OR: 0.69).

CONCLUSION

Obesity in middle-aged women is the consequence of the interaction of multiple factors. It was associated to hypertension, depressive symptoms, sedentary lifestyle, climacteric symptoms and other factors.

Joint influence of individual choices, parenting practices, and physician advice on adolescent obesity, Nebraska, 2008

Introduction

Reducing childhood obesity remains a public health priority given its high prevalence and its association with increased risk of adult obesity and chronic diseases. The objective of this study was to examine the joint influence of multiple risk factors on adolescent overweight status.

Methods

We conducted a random-digit-dialed telephone survey of adolescents aged 12 to 19 years in fall 2008 in a Midwestern city in Nebraska. On the basis of survey data for 791 youths aged 12 to 18 years, we conducted latent class analysis to group youths by the joint occurrence of dietary behavior, physical activity, parenting practices, and physician advice. We then examined the association between the groups and overweight status by using logistic regression, controlling for age, sex, race/ethnicity, and parent and family information.

Results

Youths were clustered into 3 groups. Group I (52%) were youths with healthy dietary behavior and physical activity, less permissive parenting practices, and physician advice; Group II (30%) were youths with moderately healthy dietary behavior and physical activity, less permissive parenting practices, and no physician advice; and Group III (18%) were youths with unhealthy dietary behavior and physical activity, permissive parenting practices, and physician advice. Youths in Groups I and II were less likely to be overweight than youths in Group III.

Conclusions

Youths with healthier behavior and less permissive parenting practices were less likely to be overweight. Study findings highlight the need to address obesity risk factors among youths with unhealthy dietary behavior, inadequate exercise, permissive parenting practices, and some physician advice. Tailored interventions should be used to target youths with different obesity risk factors.

The development and effectiveness of a health information website designed to improve parents' self-efficacy in managing risk for obesity in preschoolers

PURPOSE

To evaluate the effects of web-based information on parental self-efficacy in managing obesity risk in preschoolers.

DESIGN AND METHODS

The project included a literature review and the development and field testing of an information website that presented information on how to manage nine obesity risk factors for childhood obesity.

RESULTS

Parents stated that they had no problems using the website, and 69% reported improved self-efficacy on at least two risk factors.

PRACTICE IMPLICATIONS

Many parents access the Internet to obtain health information. A website that offers practical information on managing childhood obesity risk factors is a valuable resource for obesity prevention efforts.

Relationship between physical activity and the development of body mass index in children

PURPOSE

Studies estimating the contribution of physical activity (PA) to the development of body mass index (BMI) in critical periods of childhood are warranted. Therefore, we have prospectively investigated this relationship in boys and girls of the KOALA Birth Cohort study, the Netherlands, in the period around adiposity rebound (i.e., 4-9 yr old).

METHODS

PA was assessed in 470 children (231 boys, 239 girls) using accelerometers at the ages of 5 and 7 yr, and height and weight were measured at 5, 7, and 9 yr. BMI z-scores were calculated to standardize for age and sex. Leaner and heavier children were classified according to the 25th and 75th percentile of our study sample. To examine longitudinal relationships between PA and BMI z-scores, generalized estimating equation analyses were performed and stratified for sex and baseline weight status (leaner, normal weight, and heavier children).

RESULTS

In heavier children, an increment of 6.5 min of moderate to vigorous PA (MVPA) was related to a subsequent decrease of 0.03 BMI z-scores both in boys (95% confidence interval = -0.07 to -0.001) and girls (95% confidence interval = -0.05 to -0.002). Light PA was also associated with a decrease of BMI in heavier boys but not girls. In normal weight children, MVPA was associated with decrease of BMI in boys but not girls.

CONCLUSION

Increments of MVPA were associated with decreases in BMI z-score in heavier children, both boys and girls. Promoting MVPA should remain a major prevention vehicle for improving body composition in 4- to 9-yr-old children.

Risk factors for childhood overweight: a 30-month longitudinal study of 3- to 6-year-old children

OBJECTIVE

The increasing prevalence of childhood overweight is an important health issue. There is a need for longitudinal research among children in order to identify risk factors for childhood overweight. The objective of the present research was to identify potential sociodemographic and behavioural risk factors for development of childhood overweight among 3- to 6-year-old children.

DESIGN

Longitudinal study.

SETTING

Sixteen pre-primary and primary schools.

SUBJECTS

BMI Z-scores at baseline and two follow-up measurements were calculated for 568 children. Sociodemographic, parental adiposity, familial composition, child's diet, physical activity and sedentary behavioural data were collected through questionnaires.

RESULTS

Several risk factors for the development of childhood overweight were found. Being an only child, lower maternal educational level, maternal and paternal overweight, more than 1 h screen time on weekdays and high soft drinks consumption were shown to be positively associated with the development of childhood overweight.

CONCLUSIONS

Although behavioural factors are important, our findings support the thesis that interventions on the prevention of childhood overweight should focus on high-risk groups, i.e. children from low socio-economic background or with high parental BMI. Interventions should address the whole family and take into account their lifestyle and structure.

Associations of social and environmental supports with sedentary behavior, light and moderate-to-vigorous physical activity in obese underserved adolescents

Background

Evidence to support differential health impacts of sedentary behavior (SB), light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA) is building. However, few studies have examined individual, social, and environmental supports across the full range of sedentary and physical activities, including key influences such as self-efficacy, parenting factors, and home and neighborhood resources. This may be particularly important in underserved (low-income, minority), overweight/obese adolescents due to the social and environmental challenges (lack of resources, etc.) associated with increasing MVPA. This study evaluated a range of bioecological factors including individual (self-efficacy), parental (parental support, monitoring, limit-setting, and nurturance), and environmental (perceived home resources for PA and neighborhood support for PA) predictors of SB, LPA and MVPA in overweight/obese adolescents.

Methods

Overweight/obese and predominantly minority adolescents and caregivers (n = 181) completed measures in 2010 in the US including surveys assessing self-efficacy for PA, parenting variables related to PA and home and neighborhood supports for PA. Outcomes included 7-day accelerometer estimates of SB, LPA, and MVPA.

Results

Regression analyses showed parental social support and neighborhood support were significantly associated with LPA. No significant associations were found for SB or MVPA.

Conclusions

Results emphasized the importance of examining a range of sedentary and PA intensities and highlighted the role of parental and neighborhood social supports for LPA. These results have important implications that suggest that health promotion efforts should target social and environmental supports for increasing LPA in youth who are overweight/obese.

How Effective Are Active Videogames Among the Young and the Old? Adding Meta-analyses to Two Recent Systematic Reviews

OBJECTIVE

Two recent systematic reviews have surveyed the existing evidence for the effectiveness of active videogames in children/adolescents and in elderly people. In the present study, effect sizes were added to these systematic reviews, and meta-analyses were performed.

MATERIALS AND METHODS

All reviewed studies were considered for inclusion in the meta-analyses, but only studies were included that investigated the effectiveness of active videogames, used an experimental design, and used actual health outcomes as the outcome measures (body mass index for children/adolescents [k=5] and functional balance for the elderly [k=6]).

RESULTS

The average effect of active videogames in children and adolescents was small and nonsignificant: Hedges' g=0.20 (95 percent confidence interval, -0.08 to 0.48). Limited heterogeneity was observed, and no moderator analyses were performed. For the effect of active videogames on functional balance in the elderly, the analyses revealed a medium-sized and significant effect of g=0.68 (95 percent confidence interval, 0.13-1.24). For the elderly studies, substantial heterogeneity was observed. Moderator analyses showed that there were no significant effects of using a no-treatment control group versus an alternative treatment control group or of using games that were especially created for health-promotion purposes versus off-the-shelf games. Also, intervention duration and frequency, sample size, study quality, and dropout did not significantly moderate the effect of active videogames.

CONCLUSIONS

The results of these meta-analyses provide preliminary evidence that active videogames can have positive effects on relevant outcome measures in children/adolescents and elderly individuals.

Sedentary behaviors, physical activity behaviors, and body fat in 6-year-old children: the generation R study

Background

Childhood overweight and obesity is a major public health concern. Knowledge on modifiable risk factors is needed to design effective intervention programs. This study aimed to assess associations of children’s sedentary behaviors (television viewing and computer game use) and physical activity behaviors (sports participation, outdoor play, and active transport to/from school) with three indicators of body fat, i.e., percent fat mass, body mass index (BMI) standard deviation scores, and weight status (normal weight, overweight).

Methods

Cross-sectional data from 5913 6-year-old ethnically diverse children were analyzed. Children’s weight and height were objectively measured and converted to BMI. Weight status was defined according to age- and sex-specific cut-off points of the International Obesity Task Force. BMI standard deviation scores were created, based on Dutch reference growth curves. Fat mass was measured my dual-energy X-ray absorptiometry (DXA). Sedentary and physical activity behaviors were assessed by parent-reported questionnaires. Series of logistic and linear regression analyses were performed, controlling for confounders (i.e., socio-demographic factors, family lifestyle factors, and other sedentary behaviors and physical activity behaviors).

Results

Sports participation was inversely associated with fat mass (p < 0.001), even after adjustment for socio-demographic factors, family lifestyle factors, and other sedentary behaviors and physical activity behaviors. No other independent associations were observed.

Conclusions

The results of this study indicate that sports participation is inversely associated with percent body fat among ethnically diverse 6-year-old children. More research in varied populations including objective measurements and longitudinal designs are needed to confirm these current results.

Sedentary behaviors, physical activity behaviors, and body fat in 6-year-old children: the generation R study

BACKGROUND

Childhood overweight and obesity is a major public health concern. Knowledge on modifiable risk factors is needed to design effective intervention programs. This study aimed to assess associations of children's sedentary behaviors (television viewing and computer game use) and physical activity behaviors (sports participation, outdoor play, and active transport to/from school) with three indicators of body fat, i.e., percent fat mass, body mass index (BMI) standard deviation scores, and weight status (normal weight, overweight).

METHODS

Cross-sectional data from 5913 6-year-old ethnically diverse children were analyzed. Children's weight and height were objectively measured and converted to BMI. Weight status was defined according to age- and sex-specific cut-off points of the International Obesity Task Force. BMI standard deviation scores were created, based on Dutch reference growth curves. Fat mass was measured my dual-energy X-ray absorptiometry (DXA). Sedentary and physical activity behaviors were assessed by parent-reported questionnaires. Series of logistic and linear regression analyses were performed, controlling for confounders (i.e., socio-demographic factors, family lifestyle factors, and other sedentary behaviors and physical activity behaviors).

RESULTS

Sports participation was inversely associated with fat mass (p < 0.001), even after adjustment for socio-demographic factors, family lifestyle factors, and other sedentary behaviors and physical activity behaviors. No other independent associations were observed.

CONCLUSIONS

The results of this study indicate that sports participation is inversely associated with percent body fat among ethnically diverse 6-year-old children. More research in varied populations including objective measurements and longitudinal designs are needed to confirm these current results.

Screen time and sleep among school-aged children and adolescents: a systematic literature review

We systematically examined and updated the scientific literature on the association between screen time (e.g., television, computers, video games, and mobile devices) and sleep outcomes among school-aged children and adolescents. We reviewed 67 studies published from 1999 to early 2014. We found that screen time is adversely associated with sleep outcomes (primarily shortened duration and delayed timing) in 90% of studies. Some of the results varied by type of screen exposure, age of participant, gender, and day of the week. While the evidence regarding the association between screen time and sleep is consistent, we discuss limitations of the current studies: 1) causal association not confirmed; 2) measurement error (of both screen time exposure and sleep measures); 3) limited data on simultaneous use of multiple screens, characteristics and content of screens used. Youth should be advised to limit or reduce screen time exposure, especially before or during bedtime hours to minimize any harmful effects of screen time on sleep and well-being. Future research should better account for the methodological limitations of the extant studies, and seek to better understand the magnitude and mechanisms of the association. These steps will help the development and implementation of policies or interventions related to screen time among youth.

Classroom-based high-intensity interval activity improves off-task behaviour in primary school students

This study examined the effects of an acute bout of brief, high-intensity interval exercise on off-task classroom behaviour in primary school students. A grade 4 class (n = 24) and a grade 2 class (n = 20) were exposed to either a no-activity break or an active break that consisted of "FUNtervals", a high-intensity interval protocol, on alternating days for 3 weeks. No-activity days consisted of a 10-min inactive break while FUNterval days consisted of a 4-min FUNterval completed within a 10-min break from regular class activities. Off-task behaviour was observed for 50 min after each no-activity/FUNterval break, with the amount of time students spent off-task (motor, passive, and verbal behaviour) being recorded. When comparing no-activity breaks with FUNtervals the grade 4 class demonstrated reductions in both passive (no activity = 29% ± 13% vs. FUNterval = 25% ± 13%, p < 0.05, effect size (ES) = 0.31) and motor (no activity = 31% ± 16% vs. FUNterval = 24% ± 13%, p < 0.01, ES = 0.48) off-task behaviour following FUNtervals. Similarly, in the grade 2 class, passive (no activity = 23% ± 14% vs. FUNterval = 14% ± 10%, p < 0.01, ES = 0.74), verbal (no activity = 8% ± 8% vs. FUNterval = 5% ± 5%, p < 0.05, ES = 0.45), and motor (no activity = 29% ± 17% vs. FUNterval = 14% ± 10%, p < 0.01, ES = 1.076) off-task behaviours were reduced following FUNtervals. In both classrooms the effects of physical activity were greatest in those students demonstrating the highest rates of off-task behaviour on no-activity days. These data demonstrate that very brief high-intensity bouts of exercise can improve off-task behaviour in grade 2 and 4 students, particularly in students with high rates of such behaviour.

Recess physical activity and perceived school environment among elementary school children

Differences in recess physical activity (PA) according to perceived school environment among elementary school children were examined. Participants were 103 children from two schools in Japan. PA was measured using accelerometry for seven consecutive days. Time spent in sedentary or PA (light, moderate, or vigorous) during their morning recess (25 min) and lunch recess (15 min) was determined. The School Physical Activity Environment Scale (three factors: equipment, facility, and safety) was used to investigate perceived school environment. Environmental factor scores were assigned to low or high groups for each factor by median. An analysis of covariance, with grade as the covariate, was conducted separately by gender to examine differences in PA between two groups. During lunch recess, boys in the high-equipment group spent significantly more time in moderate PA (high: 1.5; low: 0.8 min) whereas girls in this group spent less time in light PA (9.3, 11.0). Boys in the high-facility group spent significantly less time in sedentary (2.3, 3.9) and more time in vigorous PA (2.4, 1.4) during lunch recess, and girls spent more time in moderate (2.1, 1.2) and vigorous PA (1.9, 1.3) during morning recess. Differences were observed in recess PA according to school environment perceptions. The present study may be useful for further intervention studies for the promotion of PA during recess.

A latent class analysis of weight-related health behaviors among 2- and 4-year college students and associated risk of obesity

Little is known about the complex patterning of weight-related health behaviors in 2- and 4-year college students. The objective of this study was to identify and describe unique classes of weight-related health behaviors among college students. Latent class analysis was used to identify homogenous, mutually exclusive classes of nine health behaviors that represent multiple theoretically/clinically relevant dimensions of obesity risk among 2- versus 4-year college students using cross-sectional statewide surveillance data (N = 17,584). Additionally, differences in class membership on selected sociodemographic characteristics were examined using a model-based approach. Analysis was conducted separately for both college groups, and five and four classes were identified for 2- and 4-year college students, respectively. Four classes were similar across 2- and 4-year college groups and were characterized as "mostly healthy dietary habits, active"; "moderately high screen time, active"; "moderately healthy dietary habits, inactive"; and "moderately high screen time, inactive." "Moderately healthy dietary habits, high screen time" was the additional class unique to 2-year college students. These classes differed on a number of sociodemographic characteristics, including the proportion in each class who were classified as obese. Implications for prevention scientists and future intervention programs are considered.

Lifestyle practices and obesity in Malaysian adolescents

Aim: To determine the influence of physical activity (PA) and sedentary behavior (SB) on obesity profiles of 454 Malaysian adolescents aged 12 to 19. Methods: Validated PA and SB questionnaires were used and body composition assessed using anthropometry and dual-energy X-ray absorptiometry (DXA). Results: Gender-specific multivariate analyses showed boys with high levels of total PA and moderate-to-vigorous physical activity (MVPA) exhibited significantly lower levels of total body fat, percent body fat and android fat mass compared with low PA and MVPA groups, after adjusting for potential confounders. Girls with high SB levels showed significantly higher BMI, waist circumference and DXA-derived body fat indices than those at lower SB level. Multiple logistic analyses indicated that boys with low levels of total PA and MVPA had significantly greater obesity risk, 3.0 (OR 3.0; 95% CI, 1.1–8.1; p < 0.05) and 3.8-fold (OR 3.8; 95% CI, 1.4–10.1; p < 0.01), respectively, than more active boys. Only in girls with high SB level was there a significantly increased risk of obesity, 2.9 times higher than girls at low SP levels (OR 2.8; 95% CI, 1.0–7.5; p < 0.05). Conclusions: The present findings indicate that higher PA duration and intensity reduced body fat and obesity risk while high screen-based sedentary behaviors significantly adversely influenced body fat mass, particularly amongst girls when the PA level was low.

Effects of a cognitive-behaviorally based physical activity treatment for 4- and 5-year-old children attending US preschools

BACKGROUND

Inadequate volumes of physical activity may be associated with the increases in inappropriately high weight in children of 5 years of age and younger. Preschools have typically lacked sufficient time in daily physical activity.

PURPOSE

A preschool-administered physical activity treatment based on social cognitive and self-efficacy theory (Start For Life) was tested for its association with increased physical activity and reduced body mass index (BMI).

METHODS

Data from accelerometer and BMI assessments over a 9-month preschool year (18 treatment and 8 control classes of 17 to 20 children each; mean age = 4.4 years) were used to contrast the behaviorally based treatment of 30 min per day with a usual care condition of the same duration. The sample was primarily African-American. Preschool teachers administered all processes.

RESULTS

The Start For Life treatment was associated with a significantly greater percentage of the preschool day in moderate-to-vigorous and vigorous physical activity (approximately 30 min per week more), with sedentary time unaffected. The treatment was also associated with a significant reduction in BMI, with effect sizes greatest in overweight and obese children.

CONCLUSIONS

Although results were positive in contrast to usual care and other related interventions, the specific sample requires that the Start For Life treatment undergo sufficient replication to increase confidence in generalizability of the findings to others. Although reduction in sedentary time may require a different strategy, the practical application of the present treatment suggests possibilities for addressing overweight through increasing moderate-to-vigorous physical activity in preschool settings.

Physical activity, sedentary behaviour and fetal macrosomia in uncomplicated pregnancies: a prospective cohort study

OBJECTIVE

to explore maternal energy balance, incorporating free living physical activity and sedentary behaviour, in uncomplicated pregnancies at risk of macrosomia.

METHODS

a parallel-group cross-sectional analysis was conducted in healthy pregnant women predicted to deliver infants weighing ≥ 4000 g (study group) or < 4000 g (control group). Women were recruited in a 1:1 ratio from antenatal clinics in Northern Ireland. Women wore a SenseWear(®) Body Media Pro3 physical activity armband and completed a food diary for four consecutive days in the third trimester. Physical activity was measured in Metabolic Equivalent of Tasks (METs) where 1 MET = 1 kcal per kilogram of body weight per hour. Analysis of covariance (ANCOVA) was employed using the General Linear Model to adjust for potential confounders.

FINDINGS

of the 112 women recruited, 100 complete datasets were available for analysis. There was no significant difference in energy balance between the two groups. Intensity of free living physical activity (average METs) of women predicted to deliver macrosomic infants (n = 50) was significantly lower than that of women in the control group (n = 50) (1.3 (0.2) METs (mean, standard deviation) versus 1.2 (0.2) METs; difference in means -0.1 METs (95% confidence interval: -0.19, -0.01); p = 0.021). Women predicted to deliver macrosomic infants also spent significantly more time in sedentary behaviour (≤ 1 MET) than the control group (16.1 (2.8) hours versus 13.8 (4.3) hours; 2.0 hours (0.3, 3.7), p = 0.020).

KEY CONCLUSIONS AND IMPLICATIONS FOR PRACTICE

although there was no association between predicted fetal macrosomia and energy balance, those women predicted to deliver a macrosomic infant exhibited increased sedentary behaviour and reduced physical activity in the third trimester of pregnancy. Professionals caring for women during pregnancy have an important role in promoting and supporting more active lifestyles amongst women who are predicted to deliver a macrosomic infant given the known associated risks.

Socio-demographic and lifestyle factors for child's physical growth and adiposity rebound of Japanese children: a longitudinal study of the 21st century longitudinal survey in newborns

BACKGROUND

It is unknown whether childhood physical development in Asian populations differs from western populations, since no longitudinal analysis has been performed in Asian countries yet. Utilizing the 21st Century Longitudinal Survey in Newborns, we studied the timing of adiposity rebound (AR) among Japanese children and determined whether AR occurs earlier in obese children compared to nonobese children. Furthermore, we identified important demographic, social, and lifestyle factors that affect their physical development.

METHODS

We used data from the annual surveillance of Japanese children born in 2001, with 45,392 eligible subjects. We applied survival analysis to evaluate the AR and a trajectory method for the BMI transition across 5 ½ years. Time-dependent and time-independent factors affecting BMI changes were investigated using longitudinal analysis. Accounting for the known difference in prevalence between Japanese and Western children, we adopted a 95th percentile of BMI as criterion for obesity.

RESULTS

Mean BMI at birth and at ages 1 ½, 2 ½, 3 ½, 4 ½, and 5 ½ years for all subjects were 12.6, 16.3, 16.1, 15.8, 15.5, and 15.4, respectively, showing a progressive reduction after 1 ½ years. However, among obese children at 5 ½ years, 39.6% had experienced AR as early as at age 4 ½ years. Controlling for sex, Cox's proportional hazards model showed that obese children had a 48.5% higher hazard to experience AR than nonobese children. The difference in BMI transition between obese and non-obese children was also captured by a trajectory method. In longitudinal analysis, BMI was lower for children who had a longer gestational period whereas children who received parental care from non-family members gained higher BMI values.

CONCLUSIONS

With the 95th percentile cutoff for children obesity, obese Japanese children developed AR earlier than nonobese Japanese children, similar to those in Western countries reported in the literature. Primary caretakers and length of gestational period were the most important socio-demographic factors affecting physical development.

Personal, social, and game-related correlates of active and non-active gaming among dutch gaming adolescents: survey-based multivariable, multilevel logistic regression analyses

BACKGROUND

Playing video games contributes substantially to sedentary behavior in youth. A new generation of video games-active games-seems to be a promising alternative to sedentary games to promote physical activity and reduce sedentary behavior. At this time, little is known about correlates of active and non-active gaming among adolescents.

OBJECTIVE

The objective of this study was to examine potential personal, social, and game-related correlates of both active and non-active gaming in adolescents.

METHODS

A survey assessing game behavior and potential personal, social, and game-related correlates was conducted among adolescents (12-16 years, N=353) recruited via schools. Multivariable, multilevel logistic regression analyses, adjusted for demographics (age, sex and educational level of adolescents), were conducted to examine personal, social, and game-related correlates of active gaming ≥1 hour per week (h/wk) and non-active gaming >7 h/wk.

RESULTS

Active gaming ≥1 h/wk was significantly associated with a more positive attitude toward active gaming (OR 5.3, CI 2.4-11.8; P<.001), a less positive attitude toward non-active games (OR 0.30, CI 0.1-0.6; P=.002), a higher score on habit strength regarding gaming (OR 1.9, CI 1.2-3.2; P=.008) and having brothers/sisters (OR 6.7, CI 2.6-17.1; P<.001) and friends (OR 3.4, CI 1.4-8.4; P=.009) who spend more time on active gaming and a little bit lower score on game engagement (OR 0.95, CI 0.91-0.997; P=.04). Non-active gaming >7 h/wk was significantly associated with a more positive attitude toward non-active gaming (OR 2.6, CI 1.1-6.3; P=.035), a stronger habit regarding gaming (OR 3.0, CI 1.7-5.3; P<.001), having friends who spend more time on non-active gaming (OR 3.3, CI 1.46-7.53; P=.004), and a more positive image of a non-active gamer (OR 2, CI 1.07-3.75; P=.03).

CONCLUSIONS

Various factors were significantly associated with active gaming ≥1 h/wk and non-active gaming >7 h/wk. Active gaming is most strongly (negatively) associated with attitude with respect to non-active games, followed by observed active game behavior of brothers and sisters and attitude with respect to active gaming (positive associations). On the other hand, non-active gaming is most strongly associated with observed non-active game behavior of friends, habit strength regarding gaming and attitude toward non-active gaming (positive associations). Habit strength was a correlate of both active and non-active gaming, indicating that both types of gaming are habitual behaviors. Although these results should be interpreted with caution because of the limitations of the study, they do provide preliminary insights into potential correlates of active and non-active gaming that can be used for further research as well as preliminary direction for the development of effective intervention strategies for replacing non-active gaming by active gaming among adolescents.

Mixed reality virtual pets to reduce childhood obesity

Novel approaches are needed to reduce the high rates of childhood obesity in the developed world. While multifactorial in cause, a major factor is an increasingly sedentary lifestyle of children. Our research shows that a mixed reality system that is of interest to children can be a powerful motivator of healthy activity. We designed and constructed a mixed reality system that allowed children to exercise, play with, and train a virtual pet using their own physical activity as input. The health, happiness, and intelligence of each virtual pet grew as its associated child owner exercised more, reached goals, and interacted with their pet. We report results of a research study involving 61 children from a local summer camp that shows a large increase in recorded and observed activity, alongside observational evidence that the virtual pet was responsible for that change. These results, and the ease at which the system integrated into the camp environment, demonstrate the practical potential to impact the exercise behaviors of children with mixed reality.

Semiparametric Estimation of the Impacts of Longitudinal Interventions on Adolescent Obesity using Targeted Maximum-Likelihood: Accessible Estimation with the ltmle Package

While child and adolescent obesity is a serious public health concern, few studies have utilized parameters based on the causal inference literature to examine the potential impacts of early intervention. The purpose of this analysis was to estimate the causal effects of early interventions to improve physical activity and diet during adolescence on body mass index (BMI), a measure of adiposity, using improved techniques. The most widespread statistical method in studies of child and adolescent obesity is multi-variable regression, with the parameter of interest being the coefficient on the variable of interest. This approach does not appropriately adjust for time-dependent confounding, and the modeling assumptions may not always be met. An alternative parameter to estimate is one motivated by the causal inference literature, which can be interpreted as the mean change in the outcome under interventions to set the exposure of interest. The underlying data-generating distribution, upon which the estimator is based, can be estimated via a parametric or semi-parametric approach. Using data from the National Heart, Lung, and Blood Institute Growth and Health Study, a 10-year prospective cohort study of adolescent girls, we estimated the longitudinal impact of physical activity and diet interventions on 10-year BMI z-scores via a parameter motivated by the causal inference literature, using both parametric and semi-parametric estimation approaches. The parameters of interest were estimated with a recently released R package, ltmle, for estimating means based upon general longitudinal treatment regimes. We found that early, sustained intervention on total calories had a greater impact than a physical activity intervention or non-sustained interventions. Multivariable linear regression yielded inflated effect estimates compared to estimates based on targeted maximum-likelihood estimation and data-adaptive super learning. Our analysis demonstrates that sophisticated, optimal semiparametric estimation of longitudinal treatment-specific means via ltmle provides an incredibly powerful, yet easy-to-use tool, removing impediments for putting theory into practice.

Crowdsourcing novel childhood predictors of adult obesity

Effective and simple screening tools are needed to detect behaviors that are established early in life and have a significant influence on weight gain later in life. Crowdsourcing could be a novel and potentially useful tool to assess childhood predictors of adult obesity. This exploratory study examined whether crowdsourcing could generate well-documented predictors in obesity research and, moreover, whether new directions for future research could be uncovered. Participants were recruited through social media to a question-generation website, on which they answered questions and were able to pose new questions that they thought could predict obesity. During the two weeks of data collection, 532 participants (62% female; age  =  26.5±6.7; BMI  =  29.0±7.0) registered on the website and suggested a total of 56 unique questions. Nineteen of these questions correlated with body mass index (BMI) and covered several themes identified by prior research, such as parenting styles and healthy lifestyle. More importantly, participants were able to identify potential determinants that were related to a lower BMI, but have not been the subject of extensive research, such as parents packing their children’s lunch to school or talking to them about nutrition. The findings indicate that crowdsourcing can reproduce already existing hypotheses and also generate ideas that are less well documented. The crowdsourced predictors discovered in this study emphasize the importance of family interventions to fight obesity. The questions generated by participants also suggest new ways to express known predictors.

Consumption patterns of sweetened food and drink products in a Catholic Middle Eastern Canadian community

OBJECTIVE

The present study describes the consumption patterns of sweetened food and drink products in a Catholic Middle Eastern Canadian community and examines its associations with physical activity, sedentary behaviours and BMI.

DESIGN

A two-stage cross-sectional design was used. In Stage 1 (n 42), 24 h recalls enabled the identification of sweetened products. In Stage 2 (n 192), an FFQ was administered to measure the daily consumption of these products and to collect sociodemographic and behavioural data. Sweetened products were defined as processed culinary ingredients and ultra-processed products for which total sugar content exceeded 20% of total energy.

SETTING

Three Catholic Middle Eastern churches located in Montreal, Canada.

SUBJECTS

Normoglycaemic men and women (18-60 years old).

RESULTS

Twenty-six sweetened products represented an average consumption of 75·4 g total sugars/d or 15·1% of daily energy intake (n 190, 56% women). Soft drinks, juices, sweetened coffee, chocolate, cookies, cakes and muffins were the main sources of consumption and mostly consumed between meals. Age (exp (β) = 0·99; P < 0·01), physical activity (exp (β) = 1·08; P < 0·01) and recreational computer use (exp (β) = 1·17; P < 0·01) were independently associated with sweetened product consumption. The association between sweetened product consumption and physical activity was U-shaped. BMI was not significantly associated with sweetened product consumption but all participants regardless of BMI were above the WHO recommendation for free sugars.

CONCLUSIONS

Being physically active and spending less time using a computer may favour a reduced consumption of sweetened products. Very active individuals may, however, overconsume such products.

Relationship of milk intake and physical activity to abdominal obesity among adolescents

What is already known about this subject Diet and physical activity (PA) are recognized as important factors to prevent abdominal obesity (AO). Studies have found an inverse relationship between milk intake or milk products and body weight and/or body fat in children and adolescents. Evidence suggests that low levels of PA are associated with AO in youth. What this study adds Our study explored the combined association of milk intake and PA on AO in adolescents, which are most often studied in isolation. Our findings suggested that adolescents with high milk intakes, regardless of whether they were active or low active, were less likely to have AO. Our findings could have a great epidemiological interest and bring important evidence in the field of AO management among adolescents.

BACKGROUND

Diet and physical activity (PA) are recognized as important factors to prevent abdominal obesity (AO), which is strongly associated with chronic diseases. Some studies have reported an inverse association between milk consumption and AO.

OBJECTIVE

This study examined the association between milk intake, PA and AO in adolescents.

METHODS

A cross-sectional study was conducted with 1209 adolescents, aged 15-18 from the Azorean Archipelago, Portugal in 2008. AO was defined by a waist circumference at or above the 90th percentile. Adolescent food intake was measured using a semi-quantitative food frequency questionnaire, and milk intake was categorized as 'low milk intake' (<2 servings per day) or 'high milk intake' (≥2 servings per day). PA was assessed via a self-report questionnaire, and participants were divided into active (>10 points) and low-active groups (≤10 points) on the basis of their reported PA. They were then divided into four smaller groups, according to milk intake and PA: (i) low milk intake/low active; (ii) low milk intake/active; (iii) high milk intake/low active and (iv) high milk intake/active. The association between milk intake, PA and AO was evaluated using logistic regression analysis, and the results were adjusted for demographic, body mass index, pubertal stage and dietary confounders.

RESULTS

In this study, the majority of adolescents consumed semi-skimmed or skimmed milk (92.3%). The group of adolescents with high level of milk intake and active had a lower proportion of AO than did other groups (low milk intake/low active: 34.2%; low milk intake/active: 26.9%; high milk intake/low active: 25.7%; high milk intake/active: 21.9%, P = 0.008). After adjusting for confounders, low-active and active adolescents with high levels of milk intake were less likely to have AO, compared with low-active adolescents with low milk intake (high milk intake/low active, odds ratio [OR] = 0.412, 95% confidence intervals [CI]: 0.201-0.845; high milk intake/active adolescents, OR = 0.445, 95% CI: 0.235-0.845).

CONCLUSION

High milk intake seems to have a protective effect on AO, regardless of PA level.

Excess screen time in US children: association with family rules and alternative activities

We describe the association of screen time in excess of American Academy of Pediatrics recommendations (≤2 h/d) with family television-use policies and regular nonscreen activities among US school-aged children. Data from the 2007 National Survey of Children's Health were used. The sum of minutes spent on television, videos, video games, and recreational computer use was calculated for children 6 to 17 years old. Bivariate and multivariate logistic regression models were used to calculate relative odds of exceeding American Academy of Pediatrics guidelines and of heavy screen use (>4 h/d) for varying family media-use policies and frequency of alternative activities (physical activity and family meals). In all, 49% of school-aged children had screen time >2 h/d and 16% had screen time >4 h/d. Lower frequency of family meals, presence of TV in the bedroom, absence of rules about TV viewing, and less physical activity were associated with both >2 and >4 hours per day of screen time.

Obesity in children with autism spectrum disorder

Research suggests that the prevalence of obesity in children with autism spectrum disorder (ASD) is at least as high as that seen in typically developing children. Many of the risk factors for children with ASD are likely the same as for typically developing children, especially within the context of today's obesogenic environment. The particular needs and challenges that this population faces, however, may render them more susceptible to the adverse effects of typical risk factors, and they may also be vulnerable to additional risk factors not shared by children in the general population, including psychopharmacological treatment, genetics, disordered sleep, atypical eating patterns, and challenges for engaging in sufficient physical activity. For individuals with ASD, obesity and its sequelae potentially represent a significant threat to independent living, self-care, quality of life, and overall health.

Physical activity growth curves relate to adiposity in adolescents

PURPOSE

Findings from prospective studies on associations between physical activity and adiposity among youth are inconsistent. Our aim was to describe physical activity trajectories during secondary school and examine the association with change in adiposity in youth.

METHODS

Physical activity was measured in 20 survey cycles from 1999 to 2005; anthropometrics were measured in survey cycles 1, 12, and 19. Individual growth curves modeling moderate-to-vigorous physical activity (MVPA) and vigorous physical activity (VPA) were estimated. Estimates of initial level and rate of decline in MVPA and VPA bouts per week were included as potential predictors of body fat% and body mass index using age- and sex-specific linear regression.

RESULTS

Complete data were available for 840 and 760 adolescents aged 12-13 years at baseline, followed from survey cycles 1-12 and 12-19, respectively. Among girls, yearly declines of one MVPA and one VPA bout per week during earlier adolescence were associated with increases of 0.19 (95% confidence interval [CI], 0.02-0.36) and 0.47 (95% CI, 0.015-0.92) units of body fat%, respectively. In boys, a yearly decline of one MVPA bout per week was associated with an increase of 0.38 (95% CI, 0.05-0.70) units of body fat% during later adolescence.

CONCLUSIONS

Obesity prevention programs should include strategies to prevent declines in physical activity.

The effect of age, sex and obesity on fundamental motor skills among 4 to 6 years-old children

Objective: To examine the effect of age, sex and obesity on Fundamental Motor Skills (FMS) in 4 to 6 years-old children.

Methodology: A total of 400 preschool children (200 boys and 200 girls) between the ages of 4 to 6 years old participated in this research. Subjects were selected through multi-stage cluster random sampling. Fundamental motor skills (FMS) were assessed with using the OSU-SIGMA scale. Body mass index (BMI) was directly measured from height(m)²/weight(kg) for each child and based on CDC growth charts, normal weight, overweight and obesity were defined.

Results: The results showed that age and sex variables were a significant effect on walking and running skills, but BMI was not significant (P>0.05). Also, these variables had a significant effect on jumping, skipping, hopping and ladder climbing. In both ages, boys in jumping and ladder climbing skills were better than girls, but the girls were better in skipping and hopping skills (P<0.05). Moreover, the results showed that age and BMI variables have a significant effect on stair climbing skill, but sex was not significant (P>0.05). For object control skills, the results showed that age and sex variables were a significant effect on catching and throwing skills, but BMI was not significant (P>0.05). Finally, the age, sex and BMI variables were a significant effect on kicking and sticking skills.

Conclusion: This research demonstrated that boys performed better than girls, and both overweight and obese children have lower performance than normal children.