Collaborating with planners and environmental sustainability specialists on health prevention initiatives could allow the pooling of funding and human resources, thus enabling shared objectives to be achieved more cost effectively.

Such collaboration is fundamental to making progress in addressing the ?causes of the causes? of health outcomes (i.e. addressing the ?upstream? social/wider determinants of health, rather than simply addressing ?downstream? lifestyle choices). Research indicates such a whole system approach is necessary to achieve a significant impact on health outcomes and health inequalities (Phelan et al, 2004; Marmot 2004; UCL Institute of Health Equity, 2013). This will be especially the case in light of cuts to local authority budgets which has increased the pressure to find new solutions such as a greater focus on prevention.

The evidence base for the links between the wider determinants of health, health promotion interventions targeting these, and health outcomes is continuing to improve (see evidence of impact of environment on health section; and joint working section). A recent position paper from the Landscape Institute highlights research results from Canada indicating that it is 27 times cheaper to achieve a given reduction in cardiovascular mortality through implementing local preventative public health interventions than by using clinical care interventions.

The health outcomes of increased levels of activity can in principle be quantified (on an appropriate average basis) and linked to health outcomes and economic values. Tools to do this for walking and cycling have been developed by the World Health Organisation (see The challenges lies in quantifying at a local level the relationship between the new or improved environmental features and any change in activity levels, particularly given the need to take into account substitution effects (people changing exercise locations, but not the total amount of activity undertaken).

In prioritising local interventions, public health professionals may want to consider not just the estimated financial savings to health care and social services from preventative interventions, but also wider social and environmental benefits that specific interventions may bring alongside improved health outcomes (e.g. see section on overlaps between health and climate change resilience).