How long does it take to scale-up obesity prevention interventions?

OBJECTIVE: The scale-up of evidence-based interventions is necessary to reverse high rates of obesity. However, scale-up doesn't occur frequently nor in a timely manner. While it has been estimated that takes 14-17 years for research translation to occur, the time taken to scale-up prevention interventions is largely unknown. This study examined the time taken to scale-up obesity prevention interventions across four scale-up pathways. METHODS: A sample of obesity prevention interventions that had been scaled-up or implemented at scale were found using a structured search strategy. Included interventions were mapped against four scale-up pathways and timeframes associated with each stage of the scale-up pathway were identified to determine the time taken to scale-up. RESULTS: Of the 90 interventions found that were scaled-up to at least a city-wide level, less than half reported a comprehensive research pathway to scale-up and a third did not report any evidence of efficacy or effectiveness prior to scale-up. The time taken to scale-up ranged from 0 to 5 years depending on the pathway taken. Those following a comprehensive pathway took approximately 5 years to scale-up, while interventions that had only one evidence generating step took between 1 and 1.5 years to scale-up. For the remaining interventions, scale-up occurred immediately post-development without evidence generation. CONCLUSIONS: Our findings indicate that the scale-up of obesity prevention interventions can occur more quickly than previous estimates of 14-17 years. Our findings support previous research that scale-up of interventions occurs through a variety of pathways and often scale-up occurs in absence of prior evidence of effectiveness.

Sustaining health obesity prevention programs: Lessons from real-world population settings.

Current understanding of what sustains public health programs is derived primarily from evaluations of programs delivered for only a few years. To improve program planning and knowledge on program sustainment, we examined real-world population programs that have been delivered for >2 years. Our focus was physical activity and nutrition programs for obesity prevention. We identified programs through published literature and searched through publicly available information on the theoretical factors determining sustainment. We reviewed 90 programs and explored intervention characteristics, provider, delivery and process level factors, and the outer environment influences. Programs were sustained on average 15 years and more frequently characterised as behavioural change skills programs targeting children, funded by non-government organisations and delivered by community organisations. Most programs had undergone some modification (n = 55). Differences between programs were observed across key factors: Programs sustained 15+ years were mainly behaviour skills programs (n = 21); and characterised by interactive designs (i.e., face-to-face or digital) over static innovations (i.e., print material) compared with those sustained <15 years (p = 0.024). While government funding supported many of the programs (n = 45;), those sustained 15+ years were more likely to have been commercially funded (p = 0.044); and were less likely to have current community involvement (p = 0.013). Differences in ownership and funding were also observed across countries. While multiple factors may influence program sustainment, longer delivered programs where distinguished by their program characteristics and outer contextual factors, suggesting such factors may have an important role in sustaining programs in the longer-term.

COVID-19 and working from home-related changes in physical activity in Sydney, Australia.

ISSUES ADDRESSED: Evidence on how COVID-19 lockdowns impacted physical activity (PA) is mixed. This study explores changes in PA following initial mobility restrictions, and their subsequent relaxation, in a sample of Sydney (Australia) residents using a natural experiment methodology. METHODS: Participants' health and travel behaviours were collected pre-pandemic in late 2019 (n = 1937), with follow-up waves during the pandemic in 2020 (n = 1706) and 2021 (n = 1514). Linear mixed-effects models were used to analyse changes in weekly duration of PA between the three waves. RESULTS: Compared with pre-pandemic, average weekly PA increased in 2021 by 42.6 min total PA (p = .001), 16 min walking PA (p = .02), and 26.4 min moderate-vigorous PA (MVPA) (p = .003). However, average weekly sessions of PA decreased in 2020 and remained lower in 2021. For participants who were sufficiently active in 2019, weekly total PA (-66.3 min) MVPA (-43.8 min) decreased in 2020 compared to pre-pandemic. Conversely, among participants who were insufficiently active in 2019, average weekly PA increased in both 2020 (total PA, +99.1 min; walking PA, +46.4 min; MVPA +52.8 min) and 2021 (total PA, +117.8 min; walking PA, +58.4 min; MVPA +59.2 min), compared to 2019. Participants who did more work from home increased their average weekly total PA in 2021 compared to pre-pandemic (+45.3 min). CONCLUSION: These findings reveal the complex variability in PA behaviour brought about by the pandemic. SO WHAT?: Strategies to support the population in achieving sufficient PA must focus on maintaining an appetite for PA as we move out of the pandemic and on promoting more frequent PA sessions.

Development and Application of the Scale-Up Reflection Guide (SRG).

Scaling up effective interventions in public health is complex and comprehensive, and published accounts of the scale-up process are scarce. Key aspects of the scale-up experience need to be more comprehensively captured. This study describes the development of a guide for reflecting on and documenting the scale-up of public health interventions, to increase the depth of practice-based information of scaling up. Reviews of relevant scale-up frameworks along with expert input informed the development of the guide. We evaluated its acceptability with potential end-users and applied it to two real-world case studies. The Scale-up Reflection Guide (SRG) provides a structure and process for reflecting on and documenting key aspects of the scale-up process of public health interventions. The SRG is comprised of eight sections: context of completion; intervention delivery, history/background; intervention components; costs/funding strategies and partnership arrangements; the scale-up setting and delivery; scale-up process; and evidence of effectiveness and long-term outcomes. Utilization of the SRG may improve the consistency and reporting for the scale-up of public health interventions and facilitate knowledge sharing. The SRG can be used by a variety of stakeholders including researchers, policymakers or practitioners to more comprehensively reflect on and document scale-up experiences and inform future practice.

School-level factors associated with the sustainment of weekly physical activity scheduled in Australian elementary schools: an observational study.

BACKGROUND: We aimed to: (1) identify school-level factors associated with the sustainment of weekly physical activity (PA) scheduled in elementary schools following withdrawal of effective implementation support; and (2) determine teacher's perceived usefulness of suggested strategies for sustaining the scheduling of weekly PA. METHODS: A secondary exploratory analysis was employed of data from the intervention arm (n = 31 schools) of a randomised controlled trial. Self-report survey data from 134 classroom teachers in New South Wales, Australia, collected following withdrawal of initial implementation support (follow-up T1) and six-months following completion of support (follow-up T2) were used. The outcomes of sustainment of weekly overall PA and energisers (short classroom PA breaks) scheduled were measured via teachers' completion of a daily activity logbook, with results presented as the difference in mean minutes of PA and energisers scheduled at T1 and T2. An adapted version of the Program Sustainability Assessment Tool (PSAT) was used to measure capacity for program sustainability across seven key domains at follow-up T2. Linear mixed regressions were conducted to evaluate associations between school-level sociodemographic characteristics (e.g., school size, remoteness, and type), teacher-reported school factors (i.e., seven adapted PSAT domains) and the sustainment of PA and energisers scheduled across the school week. Perceived usefulness of 14 proposed sustainability strategies was measured via the teacher survey at follow-up T2 and reported descriptively. RESULTS: No school-level factor was statistically associated with the sustainment of overall weekly PA or energisers scheduled. Teacher-reported factors in two PSAT domains - 'strategic planning' and 'program evaluation' were statistically negatively associated with the sustainment of weekly energisers scheduled (- 6.74, 95% CI: - 13.02; - 0.47, p = 0.036 and - 6.65, 95% CI: - 12.17; - 1.12, p = 0.019 respectively). The proposed support sustainability strategy - 'provision of PA equipment packs that enable energisers or integrated lessons' was perceived useful by the most teachers (85%). CONCLUSIONS: Further research is required to explore additional contextual-specific, and end-user appropriate factors associated with schools' sustainment of weekly PA scheduled. This will help accurately inform the development of strategies to address these determinants and support the sustainment and long-term benefits of school-based health interventions more broadly.

Perceptions of air quality and concern for health in relation to long-term air pollution exposure, bushfires, and COVID-19 lockdown: A before-and-after study.

Background: Air pollution is a major health burden and the leading environmental risk factor for non-communicable diseases worldwide. People's perceptions and concerns about air pollution are important as they may predict protective behaviour or support for climate change mitigation policies. Methods: This repeat cross-sectional study uses survey data collected from participants in Sydney, Australia in September-November 2019 (n = 1,647) and October-December 2020 (n = 1,458), before and after the devastating 2019/2020 bushfires and first COVID-19 lockdown restrictions in Sydney in 2020. Participants' perceptions of air quality and concerns for health in relation to air quality were modeled against estimates of annual average NO2 and PM2.5 concentrations in their neighbourhood. Results: Participants in suburbs with higher estimated air pollution concentrations generally perceived poorer air quality and were more concerned for health in relation to air quality. A 5 µg/m3 increase in NO2 was associated with perceived poorer air quality (OR 1.32, 95%CI 1.18-1.47). A 1 µg/m3 increase in estimated PM2.5 was associated with perceived poorer air quality (OR 1.37, 95%CI 1.24-1.52) and greater concern for health (OR 1.18, 95%CI 1.05-1.32). Air quality was perceived as better in 2020 than in 2019 in both NO2 and PM2.5 models (p<0.001). Air quality concern increased in 2020 in both models. Discussion: This study provides the first Australian data on the association between estimated air quality exposure and air quality perceptions and concerns, contributing new evidence to inform public health approaches that increase awareness for air pollution and reduce the health burden.

Understanding the sustainment of population health programmes from a whole-of-system approach.

BACKGROUND: Population health prevention programmes are needed to reduce the prevalence of chronic diseases. Nevertheless, sustaining programmes at a population level is challenging. Population health is highly influenced by social, economic and political environments and is vulnerable to these system-level changes. The aim of this research was to examine the factors and mechanisms contributing to the sustainment of population prevention programmes taking a systems thinking approach. METHODS: We conducted a qualitative study through interviews with population health experts working within Australian government and non-government agencies experienced in sustaining public health programs at the local, state or national level (n = 13). We used a deductive thematic approach, grounded in systems thinking to analyse data. RESULTS: We identified four key barriers affecting program sustainment: 1) short term political and funding cycles; 2) competing interests; 3) silo thinking within health service delivery; and 4) the fit of a program to population needs. To overcome these barriers various approaches have centred on the importance of long-range planning and resourcing, flexible program design and management, leadership and partnerships, evidence generation, and system support structures. CONCLUSION: This study provides key insights for overcoming challenges to the sustainment of population health programmes amidst complex system-wide changes.

Interventions Designed to Support Physical Activity and Disease Prevention for Working from Home: A Scoping Review.

Working from home (WfH) has public health implications including changes to physical activity (PA) and sedentary behavior (SB). We reviewed published and grey literature for interventions designed to support PA or reduce SB in WfH contexts. From 1355 published and grey literature documents since 2010, we screened 136 eligible documents and extracted ten intervention studies. Interventions designed specifically for WfH were limited and included structured exercise programs, infrastructure (e.g., sit-stand workstations), online behavioral and educational programs, health professional advice and peer support, activity trackers and reminder prompts. Evidence of interventions to improve PA and reduce SB in WfH contexts is emergent but lacking in variety and in utilization of local environments to promote good health. Evidence is needed on the adaptation of existing workplace interventions for home environments and exploration of opportunities to support PA through alternative interventions, such as urban planning and recreational strategies.

Evidence-informed urban health and sustainability governance in two Chinese cities.

Sustainable development is best supported by intersectoral policies informed by a range of evidence and knowledge types (e.g. scientific and lay). Given China's rapid urbanisation, scale and global importance in climate mitigation, this study investigates how evidence is perceived and used to inform urban health and sustainability policies at central and local levels. Well-informed senior professionals in government/scientific agencies (12 in Beijing and 11 in Ningbo) were interviewed. A thematic analysis is presented using deductive and inductive coding. Government agency participants described formal remits and processes determining the scope and use of evidence by different tiers of government. Academic evidence was influential when commissioned by government departments. Public opinion and economic priorities were two factors that also influenced the use or weight of evidence in policymaking. This study shows that scientific evidence produced or commissioned by government was routinely used to inform urban health and sustainability policy. Extensive and routine data collection is regularly used to inform cyclical policy processes, which improves adaptive capacity. This study contributes to knowledge on the 'cultures of evidence use'. Environmental governance can be further improved through increased data-sharing and use of diverse knowledge types.

A multi-scalar perspective on health and urban housing: an umbrella review.

With more than half the world's population living in cities, understanding how the built environment impacts human health at different urban scales is crucial. To be able to shape cities for health, an understanding is needed of planetary health impacts, which encompass the human health impacts of human-caused disruptions on the Earth's natural ecosystems. This umbrella review maps health evidence across the spatial scales of the built environment (building; neighbourhood; and wider system, including city, regional and planetary levels), with a specific focus on urban housing. Systematic reviews published in English between January 2011 and December 2020 were searched across 20 databases, with 1176 articles identified and 124 articles screened for inclusion. Findings suggests that most evidence reports on health determinants at the neighbourhood level, such as greenspace, physical and socio-economic conditions, transport infrastructure and access to local services. Physical health outcomes are also primarily reported, with an emerging interest in mental health outcomes. There is little evidence on planetary health outcomes and significant gaps in the research literature are identified. Based on these findings, three potential directions are identified for future research.

How equitable are the distributions of the physical activity and accessibility benefits of bicycle infrastructure?

BACKGROUND: Cycling for transport provides many health and social benefits - including physical activity and independent access to jobs, education, social opportunities, health care and other services (accessibility). However, some population groups have less opportunity to reach everyday destinations, and public transport stops, by bicycle - owing in part to their greater aversion to riding amongst motor vehicle traffic. Health equity can therefore be improved by providing separated cycleway networks that give more people the opportunity to access places by bicycle using traffic-free routes. The aim of this study was to assess the health equity benefits of two bicycle infrastructure development scenarios - a single cycleway, and a complete network of cycleways - by examining the distributions of physical activity and accessibility benefits across gender, age and income groups. METHODS: Travel survey data collected from residents in Sydney (Australia) were used to train a predictive transport mode choice model, which was then used to forecast the impact of the two intervention scenarios on transport mode choice, physical activity and accessibility. The latter was measured using a utility-based measure derived from the mode choice model. The distributions of the forecast physical activity and accessibility benefits were then calculated across gender, age and income groups. RESULTS: The modelled physical activity and accessibility measures improve in both intervention scenarios. However, in the single cycleway scenario, the benefits are greatest for the male, high-income and older age groups. In the complete network scenario, the benefits are more equally distributed. Forecast increases in cycling time are largely offset by decreases in walking time - though the latter is typically low-intensity physical activity, which confers a lesser health benefit than moderate-intensity cycling. CONCLUSIONS: Separated cycleway infrastructure can be used to improve health equity by providing greater opportunities for transport cycling in population groups more averse to riding amongst motor vehicle traffic. Disparities in the opportunity to access services and economic/social activities by bicycle - and incorporate more physical activity into everyday travel - could be addressed with connected, traffic-free cycleway networks that cater to people of all genders, ages and incomes.

Service provider perspectives on implementing the NSW Get Healthy at Work program.

Purpose: One approach increasingly used by governments to deliver on public initiatives is to partner with private enterprise through public-private partnerships. This study is a qualitative process evaluation of an Australian state-wide workplace health programme "Get Healthy at Work" from the currently under-researched perspective of the private service providers. Methods: Semi-structured interviews were conducted with nine service providers. Interviews were transcribed and analysed inductively. Results: Service providers reported an alignment of motives and skills between the programme and their organizations as a benefit of the partnership. However, they also described misalignments: between the potential and realized value of the programme to businesses and service providers; the programme cycle and business operational processes; and the capacity building approach and businesses' expectations of the service.Conclusions: Although several hallmarks of a well-functioning private-public partnership were evident, misalignments of process and expectations challenged sustained partnership involvement by providers. Careful consideration must be given to the ongoing management functioning of cross-sector engagement and partnering in health promotion practice in order to ensure public health goals are being met, but also that the model is mutually sustainable.

Developing a programme theory for a transdisciplinary research collaboration: Complex Urban Systems for Sustainability and Health.

Background: Environmental improvement is a priority for urban sustainability and health and achieving it requires transformative change in cities. An approach to achieving such change is to bring together researchers, decision-makers, and public groups in the creation of research and use of scientific evidence. Methods: This article describes the development of a programme theory for Complex Urban Systems for Sustainability and Health (CUSSH), a four-year Wellcome-funded research collaboration which aims to improve capacity to guide transformational health and environmental changes in cities. Results: Drawing on ideas about complex systems, programme evaluation, and transdisciplinary learning, we describe how the programme is understood to "work" in terms of its anticipated processes and resulting changes. The programme theory describes a chain of outputs that ultimately leads to improvement in city sustainability and health (described in an 'action model'), and the kinds of changes that we expect CUSSH should lead to in people, processes, policies, practices, and research (described in a 'change model'). Conclusions: Our paper adds to a growing body of research on the process of developing a comprehensive understanding of a transdisciplinary, multiagency, multi-context programme. The programme theory was developed collaboratively over two years. It involved a participatory process to ensure that a broad range of perspectives were included, to contribute to shared understanding across a multidisciplinary team. Examining our approach allowed an appreciation of the benefits and challenges of developing a programme theory for a complex, transdisciplinary research collaboration. Benefits included the development of teamworking and shared understanding and the use of programme theory in guiding evaluation. Challenges included changing membership within a large group, reaching agreement on what the theory would be 'about', and the inherent unpredictability of complex initiatives.

Climate action for health and wellbeing in cities: a protocol for the systematic development of a database of peer-reviewed studies using machine learning methods.

Cities produce more than 70% of global greenhouse gas emissions. Action by cities is therefore crucial for climate change mitigation as well as for safeguarding the health and wellbeing of their populations under climate change. Many city governments have made ambitious commitments to climate change mitigation and adaptation and implemented a range of actions to address them. However, a systematic record and synthesis of the findings of evaluations of the effect of such actions on human health and wellbeing is currently lacking. This, in turn, impedes the development of robust knowledge on what constitutes high-impact climate actions of benefit to human health and wellbeing, which can inform future action plans, their implementation and scale-up. The development of a systematic record of studies reporting climate and health actions in cities is made challenging by the broad landscape of relevant literature scattered across many disciplines and sectors, which is challenging to effectively consolidate using traditional literature review methods. This protocol reports an innovative approach for the systematic development of a database of studies of climate change mitigation and adaptation actions implemented in cities, and their benefits (or disbenefits) for human health and wellbeing, derived from peer-reviewed academic literature. Our approach draws on extensive tailored search strategies and machine learning methods for article classification and tagging to generate a database for subsequent systematic reviews addressing questions of importance to urban decision-makers on climate actions in cities for human health and wellbeing.

Reporting physical activity in minutes not bouts: findings from a survey in Australia.

OBJECTIVE: Physical activity has been commonly measured as time spent in bouts of at least 10 minutes, however, each minute of physical activity achieved in a day is now regarded as beneficial. This study aims to compare differences in total time spent walking in a week to time spent walking in 10-minute bouts over the same seven-day period. METHODS: Two self-reported measures of time spent walking were compared: one using time-constrained bouts and the other using total minutes. The first measure comes from the validated Active Australia Survey and reports walking in bouts of 10min or more, the second measure reports total estimated time spent walking. RESULTS: Data from 4,582 university participants in a census-styled survey were analysed. When comparing the reported minutes of walking in either 10-minute bouts or total minutes, more walking occurs in short bursts with a difference of 117min/week (p<0.001). CONCLUSIONS: This result shows more walking is reported across a week in short bursts of less than 10 minutes. Implications for public health: To monitor trends and evaluate physical activity interventions, reliable and valid measures of physical activity are necessary. Our result questions the usefulness of reporting bouted-walking as a measure which accurately captures population behaviour.

Transforming cities for sustainability: A health perspective.

Transformational change is urgently needed to address planetary health challenges in cities. Through an interdisciplinary overview of the literature, we consider how to frame and unpack city-level transformation towards synergistic benefits for urban health and environmental sustainability. By describing the characteristics of a 'healthy sustainable city' and by bringing together the ideas underlying frameworks for health and sustainability, we develop a conceptual understanding of how cities may progress towards achieving significant improvements in health and the environment. We investigate how urban change works, and build a theoretical understanding of how urban change may be directed to integrate health and sustainability. We conclude that urban transformation needs to be a multi-scalar process across city sectors to meet the scale, speed and form of change required. We propose that this can best be achieved in practice through a composition of mechanisms, including strengthening city governance, enabling technological and social innovations, applying sustainable urban planning and infrastructure development, and impelling social behaviour change; supported by systems-driven policy and practice-focused scientific evidence.

The CUSSH programme: supporting cities' transformational change towards health and sustainability.

This paper describes a global research programme on the complex systemic connections between urban development and health. Through transdisciplinary methods the Complex Urban Systems for Sustainability and Health (CUSSH) project will develop critical evidence on how to achieve the far-reaching transformation of cities needed to address vital environmental imperatives for planetary health in the 21st Century. CUSSH's core components include: (i) a review of evidence on the effects of climate actions (both mitigation and adaptation) and factors influencing their implementation in urban settings; (ii) the development and application of methods for tracking the progress of cities towards sustainability and health goals; (iii) the development and application of models to assess the impact on population health, health inequalities, socio-economic development and environmental parameters of urban development strategies, in order to support policy decisions; (iv) iterative in-depth engagements with stakeholders in partner cities in low-, middle- and high-income settings, using systems-based participatory methods, to test and support the implementation of the transformative changes needed to meet local and global health and sustainability objectives; (v) a programme of public engagement and capacity building. Through these steps, the programme will provide transferable evidence on how to accelerate actions essential to achieving population-level health and global climate goals through, amongst others, changing cities' energy provision, transport infrastructure, green infrastructure, air quality, waste management and housing.

Using natural experiments to improve public health evidence: a review of context and utility for obesity prevention.

BACKGROUND: Natural experiments are increasingly valued as a way to assess the health impact of health and non-health interventions when planned controlled experimental research designs may be infeasible or inappropriate to implement. This study sought to investigate the value of natural experiments by exploring how they have been used in practice. The study focused on obesity prevention research as one complex programme area for applying natural experiment studies. METHODS: A literature search sought obesity prevention research from January 1997 to December 2017 and identified 46 population health studies that self-described as a natural experiment. RESULTS: The majority of studies identified were published in the last 5 years, illustrating a more recent adoption of such opportunities. The majority of studies were evaluations of the impact of policies (n = 19), such as assessing changes to food labelling, food advertising or taxation on diet and obesity outcomes, or were built environment interventions (n = 17), such as the impact of built infrastructure on physical activity or access to healthy food. Research designs included quasi-experimental, pre-experimental and non-experimental methods. Few studies applied rigorous research designs to establish stronger causal inference, such as multiple pre/post measures, time series designs or comparison of change against an unexposed group. In general, researchers employed techniques to enhance the study utility but often were limited in the use of more rigorous study designs by ethical considerations and/or the particular context of the intervention. CONCLUSION: Greater recognition of the utility and versatility of natural experiments in generating evidence for complex health issues like obesity prevention is needed. This review suggests that natural experiments may be underutilised as an approach for providing evidence of the effects of interventions, particularly for evaluating health outcomes of interventions when unexpected opportunities to gather evidence arise.

Closing the loop: short term impacts on physical activity of the completion of a loop trail in Sydney, Australia.

BACKGROUND: In Australia, an estimated 57% of the population do not meet physical activity recommendations for health. The built environment is important for active living, and recreational trails provide safe and pleasant settings for this purpose. However, evidence for positive impacts on physical activity from real world natural experiments is sparse. We describe the impact of transforming a recreational trail into a loop on usage by cyclists and pedestrians and users' physical activity levels. METHOD: We conducted time series analyses of pre and post-completion (November 2013-July 2015) counts taken from infrared electronic counters of pedestrians and cyclists on two established sections of the trail adjusted for underlying trend, trend change, weather, holidays and trail closures. Chi-square analyses of pre and post-completion visual counts examined change in the distribution of pedestrian/cyclist, adult/child, and male/female users. Descriptive and bivariate analyses of post-completion intercept survey data of 249 trail users were conducted to examine user characteristics and impact on physical activity. RESULTS: Pedestrian and cyclist counts on established trail sections increased by between 200 and 340% from pre to post-completion. Visual count data showed a significant 7% increase in children (vs adults) using the trail at one site pre to post (p = 0.008). Of previous users, 48% reported doing more physical activity at the trail and this was additional to (not replacing) physical activity done elsewhere. Those users not meeting physical activity recommendations were more likely to report increased total physical activity since the loop was created (55.5% vs 39.2%, p = 0.031). The connected loop nature of the trail and its length was perceived to encourage more and different forms of physical activity. CONCLUSION: Creating an accessible loop trail away from motorised traffic can lead to increased trail use and potentially total physical activity. The modification to the trail encouraged proportionate and real increases in usage among vulnerable populations such as children and perhaps greater total physical activity especially for people not meeting physical activity recommendations. The findings suggest that the benefits of environmental changes such as these can accrue to those most in need of support for being physically active.

Participant profile and impacts of an Aboriginal healthy lifestyle and weight loss challenge over four years 2012-2015.

OBJECTIVE: To explore participation, consistency of demographic and health profiles, and short-term impacts across six Aboriginal Knockout Health Challenge (KHC) team-based weight loss competitions, 2012 to 2015. METHODS: Data comprised one competition each from 2012 and 2013 and two per year in 2014 and 2015. We compared baseline and change (pre- to post-competition) in weight, fruit and vegetable consumption, physical activity and waist circumference (baseline only) across competitions using mixed models. RESULTS: Numbers of teams and participants increased from 2012 to 2015 from 13 and 324 to 33 and 830, respectively. A total of 3,625 participants registered, representing 2,645 unique people (25.4% repeat participation). Participants were mainly female and >90% were classified obese at baseline. Baseline weight and weight lost (between 1.9% and 2.5%) were significantly lower in subsequent competitions compared with the first. Improvements in fruit and vegetable consumption and physical activity were comparable across competitions. CONCLUSION: The KHC has increasing and sustained appeal among Aboriginal communities, attracting those at risk from lifestyle-associated chronic disease and effectively reducing weight and promoting healthy lifestyles in the short term. Implications for public health: Community-led programs generated by, and responsive to, Aboriginal Australians' needs can demonstrate consistent community reach and sustained program-level lifestyle improvements.