Alison Carver

Objectively measured sedentary behaviour and health and development in children and adolescents: systematic review and meta‐analysis

Sedentary behaviour has emerged as a unique determinant of health in adults. Studies in children and adolescents have been less consistent. We reviewed the evidence to determine if the total volume and patterns (i.e. breaks and bouts) of objectively measured sedentary behaviour were associated with adverse health outcomes in young people, independent of moderate‐intensity to vigorous‐intensity physical activity. Four electronic databases (EMBASE MEDLINE, Ovid EMBASE, PubMed and Scopus) were searched (up to 12 November 2015) to retrieve studies among 2‐ to 18‐year‐olds, which used cross‐sectional, longitudinal or experimental designs, and examined associations with health outcomes (adiposity, cardio‐metabolic, fitness, respiratory, bone/musculoskeletal, psychosocial, cognition/academic achievement, gross motor development and other outcomes). Based on 88 eligible observational studies, level of evidence grading and quantitative meta‐analyses indicated that there is limited available evidence that the total volume or patterns of sedentary behaviour are associated with health in children and adolescents when accounting for moderate‐intensity to vigorous‐intensity physical activity or focusing on studies with low risk of bias. Quality evidence from studies with robust designs and methods, objective measures of sitting, examining associations for various health outcomes, is needed to better understand if the overall volume or patterns of sedentary behaviour are independent determinants of health in children and adolescents.

Young and free? A study of independent mobility among urban and rural dwelling Australian children.

OBJECTIVES To examine urban/rural differences in childrens independent mobility; associations between mobility licences and childrens independent mobility; and potential correlates of mobility licences. DESIGN Cross-sectional study of 430 primary (48% boys; 72% urban) and 258 secondary schoolchildren (52% boys; 51.6% urban) and their parents. METHODS Parents survey reported the mobility licences they granted to their children (e.g. allowing them to cross main roads on their own), access to outdoor playspaces and mobile phone ownership. Children survey reported their independent mobility on school journeys and on weekends. Differences were examined in mobility licences and independent mobility by sex, urban/rural setting and age-group. Regression analyses examined associations between mobility licences and independent mobility; and how access to playspaces, and mobile phone ownership, were associated with mobility licences. RESULTS Overall, on average, boys were granted more mobility licences, than were girls, but there were no significant differences by urban/rural location. Variations in independent mobility by urban/rural locality were identified on the school journey but not on weekends. Boys attending urban primary schools had highest rates (44%) of walking/cycling independently to school; those attending rural secondary schools had the lowest (14%). Among urban boys and rural primary school-aged girls access to outdoor playspaces was associated with mobility licences. Mobile phone ownership was associated with mobility licences only among boys attending urban primary schools. CONCLUSIONS Many Australian children in urban and rural areas lack independent mobility. Further research should examine social/physical environmental influences on parental restrictions, to inform interventions that aim to promote childrens independent mobility.

A comparison study of children's independent mobility in England and Australia

We compared independent mobility (freedom to move around the neighbourhood – or similar – without adult accompaniment) among English and Australian schoolchildren. Parents reported mobility licences granted to their children (e.g. allowing them to cross main roads alone) and accompaniment on local trips. Children reported travel mode to school. We examined associations between mobility licences and independent school journeys, and accompaniment on local trips. Among 10–12-year-olds, English children had more licences than Australian children. Mobility licences were directly associated with independent school journeys among primary but not among secondary schoolchildren who travelled further; and inversely associated with parental accompaniment to other destinations. Influences on parental restrictions should be examined to promote childrens independent mobility.

A natural experiment to examine the impact of park renewal on park-use and park-based physical activity in a disadvantaged neighbourhood: the REVAMP study methods

BackgroundModifying the built environment by improving parks is potentially a sustainable way to increase population level physical activity. Despite considerable investment in parks and park renovations, few natural experiments on the impact of improving amenities on park use and park-based physical activity have been conducted. REVAMP is a natural experiment that aims to examine whether park improvement increases overall park usage, park-based physical activity and active travel to and from the park in the intervention compared with the control park over a two-year period; and to identify which specific aspects of the park refurbishment attracts park visitors and encourages park users to be more active. This paper describes the methods of the REVAMP study.MethodsThe intervention park is a large regional park (329 hectares) located in a low socio-economic status (SES) area in the north-eastern suburbs of Melbourne, Australia. The control park is a regional park (120 hectares) located in a high SES area in the eastern suburbs of Melbourne. Multiple methodologies to evaluate the impact of the park renovation are being employed including: cross-sectional surveys of local residents living near the two parks, direct observations of park users, intercept surveys with park users, and electronic monitoring of path usage and car traffic within the parks. Baseline measures were conducted in April-May 2013 (T1), and an innovative play space suitable for children of all ages and abilities was installed at the intervention park between September 2013 and February 2014. Follow-up measures will be repeated in April-May 2014 (T2) and April-May 2015 (T3). All methodologies will be completed at both the intervention and control parks at all three time-points, with the exception of the cross-sectional survey of local residents which will only be conducted at T1 and T3.ConclusionThis research will inform future park developments, and will contribute to creating an evidence base of the impact of park refurbishment, and the development of natural experiment methodology.Trial RegistrationCurrent controlled trial ISRCTN50745547, registration date 11.1.2014.

Are independent mobility and territorial range associated with park visitation among youth

BackgroundParks are important for providing opportunities for physical activity among youth. Apart from engaging in physical activity whilst visiting a park, active transportation (e.g. walking or cycling) to parks is potentially an additional source of physical activity. Previous research has shown that a major barrier to young people visiting parks is their inability to visit parks unaccompanied by an adult. It is not known; however, whether young people who have greater independent mobility and territorial range (ability to move around their neighbourhood alone or with friends, unaccompanied by an adult) are more likely to visit parks. This study examined park visitation and travel mode to parks and whether independent mobility and territorial range were associated with park visitation among youth living in disadvantaged areas of Victoria, Australia.MethodsIn 2010–11, 311 youth aged 8–16 years self-reported their park use, active transport, independent mobility to parks, and territorial range. Logistic regression models determined the odds of park visitation (once per week or more) according to independent mobility and territorial range, adjusting for key covariates.ResultsOverall, 75% of participants reported visiting parks, and 37% visited their ‘usual’ park at least once per week. Of those who reported visiting parks, 87% travelled to the park they usually visited using active transport: 57% walked, 22% cycled, and 8% used a scooter/skateboard. Just 15% and 13% of youth regularly walked or cycled alone to parks/playgrounds respectively, and 25% and 19% regularly walked or cycled with friends or siblings (no adults) respectively. For the 84% who reported having parks/playgrounds within walking distance from home, those who regularly walked alone to parks (OR 3.61; CI=1.67, 7.80), and regularly walked (OR 2.27; CI=1.14, 4.55) or cycled (OR 3.38; CI=1.73, 6.62) with friends to parks, were significantly more likely to visit a park at least once per week, compared to others.ConclusionsThis study showed that active transport is frequently used by this sample of young people to travel to parks. Findings also highlight the potential importance of providing opportunities for youth aged 8–16 years to visit local parks independent of an adult.

Safety in numbers: does perceived safety mediate associations between the neighborhood social environment and physical activity among women living in disadvantaged neighborhoods?

OBJECTIVE The aim of this study is to examine associations between the neighborhood social environment and leisure-time physical activity (LTPA)(1) and walking among women, and whether these associations are mediated by perceived personal safety. METHODS Women (n = 3784) living in disadvantaged urban and rural neighborhoods within Victoria, Australia completed a self-administered survey on five social environment variables (neighborhood crime, neighborhood violence, seeing others walking and exercising in the neighborhood, social trust/cohesion), perceived personal safety, and their physical activity in 2007/8. Linear regression analyses examined associations between social environment variables and LTPA and walking. Potential mediating pathways were assessed using the product-of-coefficients test. Moderated mediation by urban/rural residence was examined. RESULTS Each social environment variable was positively associated with engaging in at least 150 min/week of LTPA (OR = 1.16 to 1.56). Only two social environment variables, seeing others walking (OR = 1.45) and exercising (OR = 1.31), were associated with ≥ 150 min/week of walking. Perceived personal safety mediated all associations. Stronger mediation was found in urban areas for crime, violence and social trust/cohesion. CONCLUSION The neighborhood social environment is an important influence on physical activity among women living in disadvantaged areas. Feelings of personal safety should not be included in composite or aggregate scores relating to the social environment.

Australian children's independent mobility levels: Secondary analyses of cross-sectional data between 1991 and 2012

This study investigated changes in Australian childrens independent mobility levels between1991 and 2012. Data from five cross-sectional studies conducted in 1991, 1993, 2010, 2011 and 2012 were analysed. Parent and child surveys were used to assess parental licences for independent mobility and actual independent mobility behaviour in children aged 8–13 years. Findings show declines in the proportion of young children (≤10 years of age) being allowed to travel home from school alone (1991: 68%, 1993: 50%, 2010: 43%, 2011: 45%, 2012: 31%) and travel on buses alone (1991: 31%, 1993: 15%, 2010: 8%, 2011: 6%, 2012: 9%). Furthermore, the proportion of children travelling independently to school decreased (1991: 61%, 1993: 42%, 2010: 31%, 2011: 32%, 2012: 32%). Significantly fewer girls than boys travelled independently to school at each time point (p ≤ .001). Overall, the findings suggest that Australian childrens independent mobility levels declined between 1991 and 2012.

How does perceived risk mediate associations between perceived safety and parental restriction of adolescents’ physical activity in their neighborhood?

BackgroundThere is evidence that adolescence is a critical period of decline in physical activity. However, adolescents may have limited opportunities to be physically active outdoors if their parents are concerned about neighborhood safety and restrict their adolescent’s physical activity within their neighborhood. Pathways that lead to parental restriction of adolescents’ physical activity (constrained behavior) are under-researched. This study aimed to examine perceived risk as a potential mediator of associations between perceived safety/victimization and constrained behavior.MethodsCross-sectional study of adolescents (43% boys) aged 15–17 years (n = 270) in Melbourne, Australia. Parents reported perceived safety (road safety, incivilities and personal safety) and prior victimization in their neighborhood, perceived risk of their children being harmed and whether they constrained their adolescent’s physical activity. Constrained behavior was categorized as ‘avoidance’ or ‘defensive’ behavior depending on a whether physical activity was avoided or modified, respectively, due to perceived risk. MacKinnon’s product-of-coefficients test of mediation was used to assess potential mediating pathways between perceived safety/victimization and constrained behavior.ResultsFor girls only, perceived risk was a significant mediator of associations between perceived road safety and avoidance/defensive behavior, and between perceived incivilities, perceived personal safety, victimization and defensive behavior.ConclusionsAssociations between perceived safety/victimization and constrained behavior are complex. Findings may guide the design of interventions that aim to improve actual and perceived levels of safety and reduce perceptions of risk. This is of particular importance for adolescent girls among whom low and declining levels of physical activity have been observed worldwide.

What predicts children's active transport and independent mobility in disadvantaged neighborhoods?

Abstract This study examined two year changes in childrens active transport and independent mobility and prospective associations between individual, social and physical environmental predictors of interest and these behaviors two years later. Overall, 43.5% of children (12.0±2.1 years) used active transport on the school journey at T1 and at T2 (p=0.77), and 35.3% engaged in independent mobility on the school journey at T1 and 29.6% at T2 (p=0.07). Enjoyment, parental safety concerns, and proximity to walking tracks were associated with independent mobility on the school journey. Road safety and social norms were associated with active transport and independent mobility to local destinations. These factors provide potential targets for interventions. Highlights43% of children habitually used active transport on the school journey.35% engaged in independent mobility (IM) on the school journey.Enjoyment, safety and walking tracks were associated with IM on school journey.Road safety was negatively associated with active transport to local destinations.Social norms were associated with independent mobility to local destinations.

Bicycles gathering dust rather than raising dust - Prevalence and predictors of cycling among Australian schoolchildren

OBJECTIVES To examine social and physical environmental correlates of cycling regularly (i.e. at least once per week) among school-aged children. DESIGN Cross-sectional study of 430 primary (48% boys; 72% urban) and 258 secondary school-aged children (52% boys; 51.6% urban) in Victoria, Australia. METHODS Children survey-reported their frequency of cycling during a typical week. Parents survey-reported on traffic concern, social trust and whether their child was allowed to cycle alone on main roads. Using a Geographic Information System each childs home was mapped along with bike paths, sports/recreational facilities and shops within 800 m and 5000 m (using pedestrian/cyclist network buffers). Logistic regression analyses examined associations between these explanatory variables and the odds of cycling at least once per week. RESULTS Factors associated with reduced odds of cycling at least once per week were: being a girl rather than a boy (odds ratio=0.53, 95% confidence interval 0.38-0.74); and the number of types of sports facilities located with 5000 m of home (odds ratio=0.87; 95% confidence interval 0.78-0.97). Factors associated with increased odds of this were: bike path provision (top tertile) within 5000 m of home (odds ratio=1.70; 95% confidence interval 1.11-2.61) and being allowed to cycle alone on main roads (odds ratio=1.75, 95% confidence interval 1.22-2.52). CONCLUSIONS Further research is required to inform interventions to promote childrens cycling, e.g. by skill-building so that parents feel comfortable allowing their child to cycle without adult accompaniment. Natural experiments are also needed to evaluate the impact of new cycling infrastructure on rates of cycling among children and the broader population.