Mechanisms and dose-response
Objectives
To identify feasible and effective approaches to reduce sitting time in children, youth, adults and older adults, with an emphasis on broad population reach and translation into practice via settings-based interventions.
State of the science
The average person spends more than 50 per cent of the day sitting and only 3 per cent in MVPA, yet the majority of research on physical activity and chronic disease prevention has focused on the promotion of MVPA, with relatively little and only recent emphasis on reducing sitting time. Despite more than 50 years of research focus, most of it targeting individual-level behaviour change, evidence of the efficacy of strategies to promote MVPA among very young children through to older adults is equivocal, if not underwhelming.
There are clear research gaps and therefore a public health imperative to determine ways to target those who sit the most across all life stages — and to do so more rapidly and effectively than has been the case with MVPA. Sitting time can be highly contextually-driven and often is dictated by the setting in which it occurs (e.g. most children must sit for much of the day in school, youth are often driven to destinations by car, and most office workers sit for the majority of the day at work).
Accordingly, we have hypothesised, and our research to date has shown, that interventions to reduce sitting are most effective when implemented in settings, such as schools and workplaces, with attention to individual behaviour, environmental and organisational drivers. Importantly, such settings-based approaches have strong potential for rapid, scalable and potentially sustainable behaviour change.
Our trials work to date has demonstrated that while there are challenges in reducing children’s discretionary sitting time at home, it is feasible to reduce home- and school-based sitting time in children by 13 minutes/day (findings under review), workplace sitting time among office-based workers by approximately two hours/day, and total sitting time in older free-living adults by about 30 minutes/day.
Key next steps include building on our mechanistic and dose-response studies (Theme 2) that identify intervention targets for different groups, with our settings-based intervention trials elucidating the patterns of sitting and physically-active time that will be most feasible and beneficial to change.
Proposed research in this theme
From recent research by CRE investigators, we have some evidence of the feasibility and acceptability of reducing sitting time at school (using pedagogical approaches) and rapidly accumulating evidence of efficacy in the workplace (using height-adjustable workstations). The key next research questions for those studies concern translation of the research into ‘real-world’ practice (see below and AC2).
In particular, we plan to examine the:
- Effectiveness of translating research findings from Transform-Us! (which aimed to reduce children’s sitting at home and school — NHMRC #533815) to schools, DEECD, ACHPER etc following dissemination of Transform-Us! Materials.
- Effectiveness of translating the findings from our Stand Up Victoria workplace intervention (NHMRC #1002706) to workplaces; an evaluation of a large-scale dissemination and implementation study in collaboration with our industry partners will be performed.
- Feasibility and effectiveness of placing height-adjustable desks into primary and secondary school classrooms.
In the more nascent areas of youth and older adults’ sitting time and children’s sitting time at home, however, we need to better understand the prevalence and correlates so that potentially effective interventions can be developed.
These studies will address the:
- Feasibility and effectiveness of a previous face-to-face family-based pilot intervention to reduce children’s sitting time at home delivered as an online internet-based intervention.
- Prevalence and correlates of sitting time among older adults living at home and assisted by regular nursing visits (in partnership with BlueCare nursing), in order to inform a subsequent intervention study.
- Feasibility and effectiveness of reducing car dependency among youth, building on findings from an international NIH-funded observational study (IPEN-Adolescent) with AI Sallis.
Central to all the proposed trials will be the use of device-based measurement of sitting time, with the incorporation of markers of adverse health outcomes (e.g. blood lipids, adiposity, blood pressure) and cognitive function measurements where feasible.
Team expertise
Our team of CRE investigators is at the forefront of sitting time intervention research internationally. Theme chairs CI-B Salmon and CI-E Eakin have extensive population intervention experience applying theoretically-framed behaviour change strategies across the age spectrum and among clinical populations.
CI-B Salmon works closely with AI Shilton through her position as Chair of the Heart Foundation’s National Physical Activity Committee. AI Shilton will play a critical role as knowledge broker and will provide important input to all of the interventions from a policy and practice perspective as well as assisting with and advising on dissemination of findings and research translation.
Our enhanced and new collaborations with AIs Chin, A Paw, Hamilton, Daly and Green (already identified in Theme 2) will extend to Theme 3 through their involvement in funded and planned intervention studies such as Transform-Us!. AI Hamilton has consulted a number of CRE investigators with plans to conduct a trial on the effectiveness of height-adjustable desks for reducing sitting time among children in elementary schools in the US and he will collaborate on our related intervention.
AI Green will provide input to non-invasive health assessment techniques (identified in Theme 2) in the child and youth studies. AI Cerin will provide mentorship and guidance in the development of innovative data-analysis methods. AI De Bourdeaudhuij will provide expertise in the application of behavioural science theory and evidence in the development of field-based interventions, as well as access to data from large Europe-wide and Belgian studies.
AI Sallis will provide valuable conceptual input into the development and delivery of the transport-based intervention to reduce sitting in youth, which will be based on findings from IPEN Adolescent (NIH-funded multi-country study, on which Salmon is a CI). AI Biddle will provide guidance and mentorship on the use of intervention trial evidence to inform chronic disease prevention guidelines and policies.
Outcomes
- Evidence on feasible and effective interventions to reduce sitting in schools, workplaces and homes, among children, youth and adults.
- Evidence-based resources, protocols and ‘tool kits’ to support wide-scale intervention roll-out and evaluation.