There is a lack of understanding of how patterns of population health are
shaped by complex systems of external influence often at the global level,
which are themselves subject to change by human interventions and natural
phenomena. Different diseases, nutritional status, water supplies, macro and
micro environments, transport and infrastructure, social and political
perturbations, and access to quality health care all interact to influence
each other with health consequences.

These interactions are particularly concentrated in urban areas, which are
rapidly expanding. The prevailing approach to studying urban environmental
influences on human health is predominantly piecemeal and reductionist. This
has served us well in linking individual causal factors to specific disease
outcomes but has severe limitations when extrapolated to the realities and
complexity of urban living.

There is increasing recognition of the need to develop a systems approach
that takes account of complex, non-linear interactions between various
different processes and factors. From the policy maker perspective, there is
an urgent need for good scientific and engineering evidence that addresses
the complex matrix of issues that influence human health and well being in
our cities.

The International Council for Science (ICSU) is in the process of planning a
major interdisciplinary program, involving science, technology and
engineering disciplines whose goal is to develop an overall systems approach
that can be used to advise policy makers and urban planners. My presentation
will focus on some of the factors that are being considered as input to the
analysis and the contributions that engineering, and in particular
biomedical engineering, can make to implementation of this program.