Population Heath Interventions Programme

Physical activity reduces the risk of diseases such as diabetes and heart disease, and the health of most people in the UK and many other countries would be improved if the population were to become more physically active. However, efforts to bring this about have met with little success to date. One reason may be that the environments we have created for people to live in — our cities, transport systems and workplaces, for example — are not sufficiently conducive to an active lifestyle. Changing the economic, physical and social factors that influence our behaviour is possible, but more scientific evidence about the effects of doing so is needed to guide policy and practice. The aim of this research programme is to investigate the effects of environmental or policy changes on population physical activity patterns. We use a combination of epidemiological and social science research methods to study what happens when people’s circumstances change — for example, when new public transport, cycling or walking routes are provided or when people move into a new neighbourhood. This research is important because it enables us to understand which approaches to changing the environment are more or less beneficial to health, who is likely to benefit most from them and which offer the best value for money. Our findings can therefore make an important contribution to shaping policy to improve the health of the population.

Rationale: The UK and many other countries have developed policies aimed at creating and fostering an environment that is more conducive to a sustained increase in population physical activity. However, the evidence base to guide policy in this area is limited. Aetiological epidemiology has quantified many of the health benefits of physical activity, behavioural epidemiology has explored its individual, social and environmental correlates and determinants, and some interventions have been found to be effective in increasing physical activity at the individual level, at least in the short to medium term. Nevertheless, major scientific uncertainty surrounds the effects of interventions to change population patterns of physical activity and the mechanisms by which that might be achieved. Aim: To elucidate the potential of population-level approaches to the promotion of active living by evaluating the effects of environmental and policy interventions and understanding related patterns and mechanisms of behaviour change. Approach: Drawing on a broad social-ecological conceptual framework and collaborations within the MRC, the UKCRC Centre for Diet and Activity Research (CEDAR) and other networks, the programme focuses on investigating approaches to changing physical activity behaviour that involve modifying the physical environment or influencing wider societal determinants of active living in the social or economic environments. The programme addresses two main concurrent research themes: 1. Quantifying the overall and distributional effects of interventions It is important to reduce the uncertainty surrounding the effects of interventions in order to discriminate between promising and ineffective approaches, identify those most likely to benefit the least active or the least healthy, compare the cost-effectiveness of different approaches, and inform the accurate modelling of their ultimate health impacts. This entails the empirical evaluation of environmental and policy ‘natural experiments’, such as the provision of new transport infrastructure, in a variety of settings. 2. Understanding related patterns and mechanisms of behaviour change It is also necessary to understand why interventions are or are not effective, for whom and in what circumstances so they can be appropriately targeted and tailored. Environmental and policy interventions are often somewhat specific to their contexts, which presents a challenge for deriving generalisable causal inference from evaluative studies. Addressing this challenge entails the empirical analysis and synthesis of quantitative and qualitative data from natural experimental and other observational datasets collected in a variety of settings. Impact: The programme provides a significant test-bed for and methodological development related to MRC guidance on natural experimental studies. It aims to provide empirical quantitative and qualitative inputs into the economic appraisal and evaluation of environmental and policy interventions, the development of models of physical activity behaviours, and the modelling of the ultimate health impacts of current and future interventions. It also aims to produce empirical research outputs with actionable messages for policymakers, particularly through evidence synthesis and by directly serving the needs of NICE guidance and other translational processes.