A cluster-randomized controlled trial to reduce sedentary behavior and promote physical activity and health of 8-9 year olds : the transform-us! study

Background: Physical activity (PA) is associated with positive cardio-metabolic health and emerging evidence suggests sedentary behavior (SB) may be detrimental to children’s health independent of PA. The primary aim of the Transform-Us! study is to determine whether an 18-month, behavioral and environmental intervention in the school and family settings results in higher levels of PA and lower rates of SB among 8-9 year old children compared with usual practice (post-intervention and 12-months follow-up). The secondary aims are to determine the independent and combined effects of PA and SB on children’s cardio-metabolic health risk factors; identify the factors that mediate the success of the intervention; and determine whether the intervention is cost-effective.
Methods/design: A four-arm cluster-randomized controlled trial (RCT) with a 2 × 2 factorial design, with schools as the unit of randomization. Twenty schools will be allocated to one of four intervention groups, sedentary behavior (SB-I), physical activity (PA-I), combined SB and PA (SB+PA-I) or current practice control (C), which will be evaluated among approximately 600 children aged 8-9 years in school year 3 living in Melbourne, Australia. All children in year 3 at intervention schools in 2010 (8-9 years) will receive the intervention over an 18-month period with a maintenance ‘booster’ delivered in 2012 and children at all schools will be invited to participate in the evaluation assessments. To maximize the sample and to capture new students arriving at intervention and control schools, recruitment will be on-going up to the post-intervention time point. Primary outcomes are time spent sitting and in PA assessed via accelerometers and inclinometers and survey.
Discussion: To our knowledge, Transform-Us! is the first RCT to examine the effectiveness of intervention strategies for reducing children’s overall sedentary time, promoting PA and optimizing health outcomes. The integration of consistent strategies and messages to children from teachers and parents in both school and family settings is a critical component of this study, and if shown to be effective, may have a significant impact on educational policies as well as on pedagogical and parenting practices.

Promoting physical activity and reducing sedentary behavior in disadvantaged neighborhoods : a qualitative study of what women want

Since women living in socioeconomically disadvantaged neighborhoods are more likely to be physically inactive and engage in higher levels of sedentary behavior than women living in more advantaged neighborhoods, it is important to develop and test the feasibility of strategies aimed to promote physical activity and reduce sedentary behavior amongst this high-risk target group. Thirty-seven women (aged 19–85) living in a disadvantaged neighborhood, and five key stakeholders, received a suite of potential intervention materials and completed a qualitative questionnaire assessing the perceived feasibility of strategies aimed to increase physical activity and reduce sedentary behavior. Thematic analyses were performed. Women perceived the use of a locally-relevant information booklet as a feasible strategy to increase physical activity and reduce sedentary behavior. Including weight-loss information was suggested to motivate women to be active. Half the women felt the best delivery method was mailed leaflets. Other suggestions included reference books and websites. Many women mentioned that an online activity calendar was motivational but too time-consuming to commit to. Most women preferred the information booklet as a strategy to increase physical activity/reduce sedentary behavior, yet several suggested that using the booklet together with the online calendar may be more effective. These findings make an important contribution to research informing the development of intervention strategies to increase physical activity and reduce sedentary behavior amongst women living in disadvantaged neighborhoods.

Physical activity, sedentary behavior, and postnatal depressive symptoms: a review

Context:
Postnatal depression is highly prevalent in mothers. Although physical activity has been found to reduce the risk of depression in the general population, little is known regarding its link with postnatal depression. This review examined original research investigating the relationship between physical activity and sedentary behavior dose (frequency, intensity, and duration) and domain, and postnatal depressive symptoms. 

Evidence acquisition:
A systematic search for original research investigating the relationship between physical activity and sedentary behavior dose and domain, and postnatal depressive symptoms, was performed using several electronic databases in early 2012. A total of ten observational and seven intervention studies were included. 

Evidence synthesis:
Most studies (one cross-sectional, two longitudinal, and six intervention studies) found an inverse association between postpartum leisure-time physical activity (LTPA) and postnatal depressive symptoms. One longitudinal study found that occupational physical activity was positively associated with postnatal depressive symptoms. There was inconclusive evidence to suggest an optimal dose of postpartum physical activity for reducing postnatal depressive symptoms. Two longitudinal studies found an inverse association between antenatal LTPA and presence of postnatal depressive symptoms. One of two studies that investigated sedentary behavior found a positive cross-sectional association between sedentary behavior and presence of postnatal depressive symptoms.

Conclusions:
Although studies are limited, on balance, LTPA prior to, during, and after pregnancy may be important for reducing the risk of postnatal depression. Further research is required to determine the optimal dose and domain of physical activity for reducing postnatal depressive symptoms as well as to examine the link between  sedentary behavior and postnatal depressive symptoms.

Driving down daily step counts: the impact of being driven to school on physical activity and sedentary behavior

This study investigated whether being driven to school was associated with lower weekday and weekend step counts, less active out-of-school leisure pursuits, and more sedentary behavior. Boys aged 10–13 years (n = 384) and girls aged 9–13 years (n = 500) attending 25 Australian primary schools wore a pedometer and completed a travel diary for one week. Parents and children completed surveys capturing leisure activity, screen time, and sociodemographics. Commute distance was objectively measured. Car travel was the most frequent mode of school transportation (boys: 51%, girls: 58%). After adjustment (sociodemographics, commute distance, and school clustering) children who were driven recorded fewer weekday steps than those who walked (girls: –1,393 steps p < .001, boys: –1,569 steps, p = .009) and participated in fewer active leisure activities (girls only: p = .043). There were no differences in weekend steps or screen time. Being driven to and from school is associated with less weekday pedometer-determined physical activity in 9- to 13-year-old elementary-school children. Encouraging children, especially girls, to walk to and from school (even for part of the way for those living further distances) could protect the health and well-being of those children who are insufficiently active.

Mediators of the relationship between sedentary behavior and depressive symptoms amongst disadvantaged women

Statement of problem
Associations between sedentary behavior (e.g. time spent sitting watching TV/using the computer) and physical health have been well documented, however, studies are increasingly reporting a positive relationship between certain sedentary behaviors and poor mental health (e.g. depression). Little is known about the underlying factors that may explain the link between sedentary behavior and likelihood of depression. The purpose of this study was to investigate the contribution of selected intra-personal and social factors as potential mediators of the relationship between sedentary behavior and depressive symptoms among women from disadvantaged neighborhoods.
Method
Cross-sectional survey data were provided by 4065 women (aged 18–45) living in disadvantaged neighborhoods. Women self-reported their sedentary behavior (total sitting time and screen time), depressive symptoms (CES-D 10), as well as a number of intra-personal (leisure-time physical activity, diet quality, weight status) and social (social cohesion, interpersonal trust, club membership) factors.
Results
Mediating analyses, controlling for confounders, showed that women's leisure-time physical activity partly mediated the relationship between total sitting time and increased likelihood of depressive symptoms. Women's diet quality, and social cohesion partly mediated the relationship between screen time and increased likelihood of depressive symptoms.
Conclusions
Acknowledging the cross-sectional study design, findings suggest that there may be several factors that explain the increased likelihood of depressive symptoms associated with greater sedentary time. Although future studies should test the mediating relationships longitudinally, these findings may help inform interventions aimed at reducing the likelihood of depression in disadvantaged women with high sitting time.

Maternal efficacy and sedentary behavior rules predict child obesity resilience

Abstract
Background:
To identify longitudinal individual, social and environmental predictors of adiposity (BMI z-score),
and of resilience to unhealthy weight gain, in healthy weight children and adolescents.
Methods:
Two hundred healthy weight children aged 5–12 years at baseline and their parents living in socio-economically disadvantaged neighborhoods were surveyed at baseline and three years later. Children’s height and weight were objectively measured, parents completed a detailed questionnaire that examined the home, social and neighborhood environments, and objective measures of the neighborhood environment were assessed using geographic information system data. Ch
ildren classified as healthy weight at baseline who had
small or medium increases in their BMI z-score between baseline and three year follow up (those in the bottom
and middle tertiles) were categorized as‘ resilient to unhealthy weight gain’. Where applicable, fully adjusted
multivariable regression models were employed to determine baseline intrapersonal, social and environmental predictors of child BMI z-scores at follow-up, and resilience to unhealthy weight gain at
follow-up.
Results:
Maternal efficacy for preventing their child from engaging in sedentary behaviors (B = − 0.03, 95 % CI: 0.06, 0.00) was associated with lower child BMI z-score at follow up. Rules to limit sedentary behaviors (OR = 1.14, 95 % CI: 1.03, 1.25) was a predictor of being resilient to unhealthy weight gain.
Conclusion:
The findings suggest that strategies to support parents to limit their children ’s sedentary behavior may be important in preventing unhealthy weight gain in socioeconomically disadvantaged communities.

Prevalence of sedentary behavior in children under 2 years: a systematic review

Sedentary behavior has negative health outcomes, evident even in young children. Identifying the prevalence of sedentary behavior in children <2years is important for determining the necessity for intervention strategies. The aim of this systematic review was to determine the prevalence of sedentary behavior in children <2years. Medline, PsycINFO, SPORTDiscus, and Education Research Complete electronic databases were searched, as were reference lists of included articles and the authors' own collections. Inclusion criteria were: published in a peer-reviewed English language journal; mean age of children <2years; and a reported measure of the prevalence of sedentary behavior. Twenty-four studies met the inclusion criteria. Most studies used parent-reported screen time as the sedentary behavior measure; only one study reported time spent restrained (i.e., kept inactive) and no studies reported objectively assessed sedentary time. Estimates of young children's screen time ranged from 36.6 to 330.9min/day. The proportion of children meeting the zero screen time recommendation ranged from 2.3% to 83.0%. In conclusion, very little is known about sedentary behaviors other than screen time in this age group. Although highly variable, findings suggest that children are already engaging in high levels of screen time by age 2 and the majority exceed current recommendations.

Friendship network characteristics are associated with physical activity and sedentary behavior in early adolescence

INTRODUCTION: There is limited understanding of the association between peer social networks and physical activity (PA), sedentary and screen-related behaviors. This study reports on associations between personal network characteristics and these important health behaviors for early adolescents. METHODS: Participants were 310 students, aged 11-13 years, from fifteen randomly selected Victorian primary schools (43% response rate). PA and sedentary behaviors were collected via accelerometer and self-report questionnaire, and anthropometric measures via trained researchers. Participants nominated up to fifteen friends, and described the frequency of interaction and perceived activity intensity of these friends. Personal network predictors were examined using regression modelling for PA and sedentary/screen behavior. RESULTS: Perceived activity levels of friends, and friendships with very frequent interaction were associated with outside-of-school PA and/or sedentary/screen time. Differences according to sex were also observed in the association between network characteristics and PA and sedentary time. A higher number of friends and greater proportion of same sex friends were associated with boys engaging in more moderate-to-vigorous PA outside of school hours. PA intensity during school-day breaks was positively associated with having a greater proportion of friends who played sports for girls, and a greater proportion of male friends for boys. CONCLUSION: Friendship network characteristics are associated with PA and sedentary/screen time in late childhood/early adolescence, and these associations differ by sex. The positive influence of very active peers may be a promising avenue to strengthen traditional interventions for the promotion of PA and reduction in screen time.

Independent and Combined Effects of Physical Activity and Sedentary Behavior on Blood Pressure in Adolescents: Gender Differences in Two Cross-Sectional Studies

Objectives: To examine the independent and combined association of physical activity (PA) and sedentary behavior (SB) on both systolic (SBP) and diastolic blood pressure (DBP) in adolescents from two observational studies. Methods: Participants from two cross-sectional studies, one conducted in Europe (n = 3,308; HELENA study) and the other in Brazil (n = 991; BRACAH study), were selected by complex sampling. Systolic and diastolic blood pressure (outcomes), PA and SB, both independently and combined, and potential confounders were analyzed. Associations were examined by multilevel linear regression. Results: Performing the recommended amount of PA (≥60 min/d) attenuated the effect of SB on DBP in BRACAH study girls and in boys from both studies. In contrast, PA did not attenuate the effects of SB on the SBP of girls in the HELENA study. The combination of less than recommended levels of PA with 2-4 h/d of sedentary behavior was found to be associated with increased SBP in boys from both studies. Conclusions: Meeting current PA recommendations could mediate the association between SB and DBP in both sexes. In boys, the joint effect of low levels of PA and excessive sedentary activity increases SBP levels. Longitudinal studies are required to confirm these findings. © 2013 de Moraes et al.