Variables associated with children's physical activity levels during recess : the A-CLASS project

Background
School recess provides a daily opportunity for children to engage in physically active behaviours. However, few studies have investigated what factors may influence children's physical activity levels in this context. Such information may be important in the development and implementation of recess interventions. The aim of this study was to investigate the association between a range of recess variables and children's sedentary, moderate and vigorous physical activity in this context.

Methods
One hundred and twenty-eight children (39% boys) aged 9-10 years old from 8 elementary schools had their physical activity levels observed during school recess using the System for Observing Children's Activity and Relationships during Play (SOCARP). Playground variables data were also collected at this time. Multilevel prediction models identified variables that were significantly associated with children's sedentary, moderate and vigorous physical activity during recess.

Results
Girls engaged in 13.8% more sedentary activity and 8.2% less vigorous activity than boys during recess. Children with no equipment provision during recess engaged in more sedentary activity and less moderate activity than children provided with equipment. In addition, as play space per child increased, sedentary activity decreased and vigorous activity increased. Temperature was a significant negatively associated with vigorous activity.

Conclusions
Modifiable and unmodifiable factors were associated with children's sedentary, moderate and vigorous physical activity during recess. Providing portable equipment and specifying areas for activities that dominate the elementary school playground during recess may be two approaches to increase recess physical activity levels, though further research is needed to evaluate the short and long-term impact of such strategies.

Individual and area-level socioeconomic associations with fast food purchasing

Background It has been suggested that those with lower socioeconomic characteristics would be more likely to seek energy-dense food options such as fast food because of cheaper prices; however, to date the evidence has been inconsistent. This study examines both individual- and area-level socioeconomic characteristics and their independent associations with chain-brand fast food purchasing.

Methods Data from the 2003 Victorian Lifestyle and Neighbourhood Environments Study (VicLANES); a multilevel study of 2547 adults from 49 small-areas in Melbourne, Australia, were used. Multilevel multinomial models adjusted for confounders were used to assess associations between individual socioeconomic position (education, occupation and income) and area socioeconomic characteristics in relation to fast food purchasing from five major fast food chains with outcome categories: never, at least monthly and at least weekly. The study finally assessed whether any potential area-level associations were mediated by fast food access.

Results Increased fast food purchasing was independently associated with lower education, being a blue-collar employee and decreased household income. Results for area-level disadvantage were marginally insignificant after adjustment for individual-level characteristics, although they were suggestive that living in an area with greater levels of disadvantage increased an individual's odds of more frequent fast food purchasing. This effect was further attenuated when measures of fast food restaurant access were included in the models.

Conclusion Independent effects of lower individual-level socioeconomic characteristics and more frequent fast food purchasing for home consumption are demonstrated. Although evidence was suggestive of an independent association with area-level disadvantage this did not reach statistical significance.

Who is eating where? Findings from the SESAW study

Objective: Foods prepared outside of the home have been linked to less-than-ideal nutrient profiles for health. We examine whether the locations where meals are prepared and consumed are associated with socio-economic predictors among women.
Design: A cross-sectional study using self-reported data. We examined multiple locations where meals are prepared and consumed: (i) at home; (ii) fast food eaten at home; (iii) fast food eaten at the restaurant; (iv) total fast food; (v) non-fast-food restaurant meals eaten at home; (vi) non-fast-food restaurant meals eaten at the restaurant; and (vii) all non-fast-food restaurant meals. Multilevel logistic regression was used to determine whether frequent consumption of meals from these sources varied by level of education, occupation, household income and area-level disadvantage.
Setting: Metropolitan Melbourne, Australia.
Subjects: A total of 1328 women from forty-five neighbourhoods randomly sampled for the SocioEconomic Status and Activity in Women study.
Results: Those with higher educational qualifications or who were not in the workforce (compared with those in professional employment) were more likely to report frequent consumption of meals prepared and consumed at home. High individual and area-level socio-economic characteristics were associated with a lower likelihood of frequent consumption of fast food and a higher likelihood of frequent consumption of meals from non-fast-food sources. The strength and significance of relationships varied by place of consumption.
Conclusions: The source of meal preparation and consumption varied by socioeconomic predictors. This has implications for policy makers who need to continue to campaign to make healthy alternatives available in out-of-home food sources.

Love thy neighbour? Associations of social capital and crime with physical activity amongst women

Using a multilevel study design, this study examined the associations between social characteristics of individuals and neighbourhoods and physical activity among women. Women (n = 1405) recruited from 45 Melbourne (Australia) neighbourhoods of varying socioeconomic disadvantage provided data on social factors and leisure-time: physical activity; walking; and walking in one’s own neighbourhood. Individual level social factors were number of neighbours known and social participation. Neighbourhood-level social characteristics (interpersonal trust, norms of reciprocity, social cohesion) were derived by aggregating survey data on these constructs within neighbourhoods. Objective data on crimes within neighbourhoods were obtained from Victoria Police. In bivariable regression models, all social variables at both the individual and neighbourhood level were positively associated with odds of physical activity, walking, and walking in one’s own neighbourhood. Associations with individual social participation (associated with all three physical activity variables) and neighbourhood interpersonal trust (associated with overall physical activity only) remained significant in multivariable models. Neither neighbourhood crime against the person nor incivilities were associated with any form of physical activity. These results demonstrate that women who participated in local groups or events and, less consistently, women living in neighbourhoods where residents trusted one another, were more likely to participate in leisure-time physical activity. While redressing macro-level social and economic policies that contribute to neighbourhood inequalities remains a priority, public health initiatives aimed at promoting physical activity could consider focusing on fostering social interactions targeting both individuals and communities. Further investigation of causal mechanisms underlying these associations is required.

Examining influences on boys' and girls' physical activity patterns: the a-class project

Understanding children’s physical activity (PA) patterns and the factors that may influence PA are important for developing interventions within this population. One hundred and ten children aged 9–0 years from 8 schools had their PA patterns assessed over 7 days. Physiological and self-report data were also collected. Multilevel analyses revealed that cardiorespiratory fitness was a consistent, significant and positive predictor of weekday and weekend PA, while the availability of home sedentary activities was a significant but negative predictor of PA. Since a range of variables were associated with PA levels, intervention developers should be cognizant of variables that may influence children’s activity

Neighbourhood-socioeconomic variation in women's diet : the role of nutrition environments

Background/Objectives: Living in socioeconomically disadvantaged neighbourhoods is associated with increased risk of a poor diet; however, the mechanisms underlying associations are not well understood. This study investigated whether selected healthy and unhealthy dietary behaviours are patterned by neighbourhood-socioeconomic disadvantage, and if so, whether features of the neighbourhood–nutrition environment explain these associations.

Subjects/Methods: A survey was completed by 1399 women from 45 neighbourhoods of varying levels of socioeconomic disadvantage in Melbourne, Australia. Survey data on fruit, vegetable and fast-food consumption were linked with data on food store locations (supermarket, greengrocer and fast-food store density and proximity) and within-store factors (in-store data on price and availability for supermarkets and greengrocers) obtained through objective audits. Multilevel regression analyses were used to examine associations of neighbourhood disadvantage with fruit, vegetable and fast-food consumption, and to test whether nutrition environment factors mediated these associations.

Results: After controlling for individual-level demographic and socioeconomic factors, neighbourhood disadvantage was associated with less vegetable consumption and more fast-food consumption, but not with fruit consumption. Some nutrition environmental factors were associated with both neighbourhood disadvantage and with diet. Nutrition environmental features did not mediate neighbourhood-disadvantage variations in vegetable or fast-food consumption.

Conclusions: Although we found poorer diets among women living in disadvantaged neighbourhoods in Melbourne, the differences were not attributable to less supportive nutrition environments in these neighbourhoods.

Evolution of cooperation in reputation system by group-based scheme

Reputation systems are very useful in large online communities in which users may frequently have the opportunity to interact with users with whom they have no prior experience. Recently, how to enhance the cooperative behaviors in the reputation system has become to one of the key open issues. Emerging schemes focused on developing efficient reward and punishment mechanisms or capturing the social or economic properties of participants. However, whether this kind of method can work widely or not has been hard to prove until now. Research in evolutionary game theory shows that group selection (or multilevel selection) can favor the cooperative behavior in the finite population. Furthermore, some recent works give fundamental conditions for the evolution of cooperation by group selection. In the paper, we extend the original group selection theory and propose a group-based scheme to enhance cooperation for online reputation systems. Related concepts are defined to capture the social structure and ties among participants in reputation system, e.g., group, assortativity, etc. Also, we use a Fermi distribution function to reflect the bounded rationality of participants and the existence of stochastic factors in evolutionary process. Extended simulations show that our scheme can enhance cooperation and improve the average performance of participants (e.g. payoff) in reputation system.

Impact of alcohol harm reduction strategies in community sports clubs : pilot evaluation of the good sports program

Objective: Approximately 4.5 million Australians are involved in community sports clubs. A high level of alcohol consumption tends to be commonplace in this setting. The only program of its type in the world, the Good Sports program was designed to reduce harmful alcohol consumption in these Australian community sports clubs. The program offers a staged accreditation process to encourage the implementation of alcohol harm-reduction strategies.

Method: We conducted a postintervention adoption study to evaluate whether community sports club accreditation through the Good Sports program was associated with lower rates of alcohol consumption. We examined alcohol consumption rates in 113 clubs (N = 1,968 participants) and compared these to consumption rates in the general community. We hypothesized that members of clubs with more advanced implementation of the Good Sports accreditation program (Stage Two) would consume less alcohol than those with less advanced implementation (Stage One).

Results: Multilevel modeling (MLM) indicated that on days when teams competed, Stage Two club members consumed 19% less alcohol than Stage One club members. MLM also indicated that the length of time a club had been in the Good Sports program was associated with reduced rates of weekly drinking that exceeded Australian short-term risky drinking guidelines. However consumption rates for all clubs were still higher than the general community. Higher accreditation stage also predicted reduced long-term risky drinking by club members.

Conclusion: Our findings suggest that community sports clubs show evidence of higher levels of alcohol consumption and higher rates of risky consumption than the general community. Implementation of the Good Sports accreditation strategy was associated with lower alcohol consumption in these settings.

Organizational factors associated with decreased mortality among veterans affairs patients with an ICU stay

In-hospital mortality rates associated with an ICU stay are high and vary widely among units. This variation may be related to organizational factors such as staffing patterns, ICU structure, and care processes. We aimed to identify organizational factors associated with variation in in-hospital mortality for patients with an ICU stay. This was a retrospective observational cross-sectional study using administrative data from 34 093 patients from 171 ICUs in 119 Veterans Health Administration hospitals. Staffing and patient data came from Veterans Health Administration national databases. ICU characteristics came from a survey in 2004 of ICUs within the Veterans Health Administration. We conducted multilevel multivariable estimation with patient-, unit-, and hospital-level data. The primary outcome was in-hospital mortality. Of 34 093 patients, 2141 (6.3%)died in the hospital. At the patient level, risk of complications and having a medical diagnosis were significantly associated with a higher risk of mortality. At the unit level, having an interface with the electronic medical record was significantly associated with a lower risk of mortality. The finding that electronic medical records integrated with ICU information systems are associated with lower in-hospital mortality adds support to existing evidence on organizational characteristics associated with in-hospital mortality among ICU patients.

Association of risky alcohol consumption and accreditation in the 'Good Sports' alcohol management programme

Background Involvement in community sports clubs is often associated with high levels of risky alcohol consumption; however, developing prevention-focused interventions in these settings can be complex. We examined the association of reduced risky alcohol consumption with the implementation of the Good Sports Programme (GSP)—a programme that accredits clubs in three stages, on the basis of their implementation of alcohol-related harm reduction strategies.

Methods Using a cross section of football and cricket clubs, consumption was compared between clubs accredited at level 1, 2 or 3 of the GSP and clubs not accredited (92 clubs; 1924 individuals). Drinking above Australian guidelines for short-term risk (more than four standard drinks) on the last playing day prior to the survey and drinking at the club over the last 12 months at average levels exceeding short- and long-term risk (more than two standard drinks) guidelines were also examined.

Results Multilevel modelling indicated that higher accreditation stage (0, 1, 2, 3) was associated with a 0.79 reduction in the odds of risky consumption on the playing day; a 0.85 reduction in the odds for short-term risky drinking, and a 0.86 reduction in long-term risky drinking.

Conclusions The findings suggest that higher accreditation in the GSP is associated with reduced rates of risky alcohol use at a population level.

Increasing children’s physical activity : individual, social, and environmental factors associated with walking to and from school

Background. Efforts to increase the prevalence of children’s active school transport require evidence to inform the development of comprehensive interventions. This study used a multilevel ecological framework to investigate individual, social, and environmental factors associated with walking to and from school among elementary school-aged children, stratified by gender.
Method. Boys aged 10 to 13 years (n = 617) and girls aged 9 to 13 years (n = 681) attending 25 Australian primary schools located in high or low walkable neighborhoods completed a 1-week travel diary and a parent/child questionnaire on travel habits and attitudes.
Results. Boys were more likely (odds ratio [OR] = 3.37; p < .05) to walk if their school neighborhood had high connectivity and low traffic and less likely to walk if they had to cross a busy road (OR = 0.49; p < .05). For girls, confidence in their ability to walk to or from school without an adult (OR = 2.03), school encouragement (OR = 2.43), scheduling commitments (OR = 0.41), and parent-perceived convenience of driving (OR = 0.24) were significantly associated (p < .05) with walking. Irrespective of gender and proximity to school, child-perceived convenience of walking (boys OR = 2.17 and girls OR = 1.84) and preference to walk to school (child perceived, boys OR = 5.57, girls OR = 1.84 and parent perceived, boys OR = 2.82, girls OR = 1.90) were consistently associated (p < .05) with walking to and from school.
Conclusion. Although there are gender differences in factors influencing children walking to and from school, proximity to school, the safety of the route, and family time constraints are consistent correlates. These need to be addressed if more children are to be encouraged to walk to and from school.

The neighborhood social environment and body mass index among youth : a mediation analysis

Background

This study aimed to examine associations between aspects of the neighborhood social environment and body mass index (BMI) in youth both cross-sectionally and prospectively; and whether this association was mediated by physical activity, screen-time and sedentary time.
Methods

Data were collected in 2004 and 2006 in high and low socio-economic areas of Melbourne, Australia. In 2004, 185 children aged 8-9 years (47% boys) and 359 children aged 13-15 years (45% boys) participated. Parents reported their perceptions of aspects of the social environment (i.e. social networks and social trust/cohesion), and physical activity (i.e. time spent outdoors by their children; and their younger children's walking and cycling trips) and screen-time (i.e. TV viewing, computer use). The older children self-reported their walking and cycling trips and their screen-time. All children wore an accelerometer to objectively assess outside-school hours moderate- to-vigorous physical activity and sedentary time. BMI was calculated from height and weight measured in 2004 and 2006. Multilevel linear regression analyses were conducted to examine associations between the social environment and BMI. Mediation analyses using the products of coefficient method were conducted to determine whether associations between the social environment and BMI were mediated by the time spent in a range of physical activity and sedentary behaviors.
Results

Cross-sectional and prospective regression analyses showed that a more positive social network and higher social trust/cohesion was related to lower BMI among children. There was no evidence that time spent in physical activity or sedentary behaviors mediated this relation, despite significant associations between social networks and screen-time and between screen-time and BMI.
Conclusions

The findings suggest that the neighborhood social environment may be important for preventing overweight and obesity in children. Further research investigating the mechanisms through which the neighborhood social environment exerts its effect on BMI is needed.

Five-year changes in school recess and lunchtime and the contribution to children’s daily physical activity

Objective To investigate the longitudinal changes in children's recess and lunchtime physical activity levels and in the contribution of recess and lunchtime to daily physical activity levels over 5 years among 5–6- and 10–12-year olds.

Methods Data were drawn from two longitudinal studies that were conducted in metropolitan Melbourne, Australia. Boys and girls (n=2782) aged 5–6 years and 10–12 years participated in baseline (T0) measures. Physical activity (n=2490) was measured every 60 s for eight consecutive days using hip-mounted accelerometry. Subsequent measurements were taken at 3-year (T1; n=773) and 5-year (T2; n=634) follow-up. Physical activity intensities were derived using age-adjusted cut-points. Sedentary time was defined as 100 counts/min. Longitudinal data were analysed using three-level (time, child, school) multilevel analyses, stratified by sex and cohort, and adjusted for potential confounding variables.

Results Significant decreases in recess and lunchtime moderate and vigorous physical activity were observed (p<0.001), with larger decreases occurring in the older cohort. Associated increases were observed in sedentary time over time (p<0.01). Although the contribution of recess to daily moderate intensity physical activity increased in the younger cohort over time (p<0.001), significant decreases were observed in the older cohort (p<0.001).

Conclusion Physical activity levels during recess and lunchtime decreased in both cohorts over time. Decreases in the contribution of recess and lunchtime to older children's daily physical activity were also observed. Interventions are needed in both primary and secondary schools to promote physical activity levels during recess and lunchtime, particularly during the early years of secondary school.

Multi-level virtual ring : an architecture for content routing in wireless sensor network

Two main problems prevent the deployment of content delivery in a wireless sensor network: the address, which is widely used in the Internet as the identifier, is meaningless in wireless network, and the routing efficiency is a big concern in wireless sensor network. This paper presents an embedded multi-level ring (MVR) structure to address those two problems. The MVR uses names rather than addresses to identify sensor nodes. The MVR routes packets on the name identifiers without being aware the location. Some sensor nodes are selected as the backbone nodes and are placed on the different levels of the virtual rings. MVR hashes nodes and contents identifiers, and stores them at the backbone nodes. MVR takes the cross-level routing to improve the routing efficiency. Further, MVR is constructed decentralized and runs on the mobile nodes themselves, requiring no central control. Experiments using ns2 simulator for up to 200 nodes show that the storage and bandwidth requirements of MVR grow slowly with the size of the network. Furthermore, MVR has demonstrated as self-administrating, fault-tolerant, and resilient under the different workloads. We also discuss alternative implementation options, and future work.

Does parkland influence walking? The relationship between area of parkland and walking trips in Melbourne, Australia

Background : Using two different measures of park area, at three buffer distances, we sought to investigate the ways in which park area and proximity to parks, are related to the frequency of walking (for all purposes) in Australian adults. Little previous research has been conducted in this area, and results of existing research have been mixed.

Methods : Residents of 50 urban areas in metropolitan Melbourne, Australia completed a physical activity survey (n = 2305). Respondents reported how often they walked for >=10 minutes in the previous month. Walking frequency was dichotomised to 'less than weekly' (less than 1/week) and 'at least weekly' (1/week or more). Using Geographic Information Systems, Euclidean buffers were created around each respondent's home at three distances: 400metres (m), 800 m and 1200 m. Total area of parkland in each person's buffer was calculated for the three buffers. Additionally, total area of 'larger parks', (park space >= park with Australian Rules Football oval (17,862 m2)), was calculated for each set of buffers. Area of park was categorised into tertiles for area of all parks, and area of larger parks (the lowest tertile was used as the reference category). Multilevel logistic regression, with individuals nested within areas, was used to estimate the effect of area of parkland on walking frequency.

Results : No statistically significant associations were found between walking frequency and park area (total and large parks) within 400 m of respondent's homes. For total park area within 800 m, the odds of walking at least weekly were lower for those in the mid (OR 0.65, 95% CI 0.46-0.91) and highest (OR 0.65, 95% CI 0.44-0.95) tertile of park area compared to those living in areas with the least amount of park area. Similar results were observed for total park area in the 1200 m buffers. When only larger parks were investigated, again more frequent walking was less likely when respondents had access to a greater amount of park area.

Conclusions : In this study we found that more park area in residential environments reduced the odds of walking more frequently. Other area characteristics such as street connectivity and destinations may underlay these associations by negatively correlating with park area.