Future-proofing health in China’s cities
Well-planned, well-designed communities of today will be the healthy locations of tomorrow
By CHINMOY SARKAR
As China builds new cities and redesigns and retrofits older ones, the necessity for healthy urban planning and design must be embraced. The need to seize public health opportunities can never be emphasized more than at this crucial window in time, when China is vastly increasing its urban population.
Urbanization and the related sedentary lifestyles have been associated with modern urban miasma, characterized by an increasing burden of chronic diseases or disorders — notably obesity, cardiovascular and respiratory diseases, cancers and mental illnesses. The projected doubling of the elderly proportion of the population from 10 percent to 20 percent over the period 2017-37 will mean an increase in the proportion of vulnerable population and constitutes another impending public health challenge.
Cities that are well-planned and well-designed have a significant capacity to promote healthy, active and socially inclusive lifestyles, thereby reducing the health burdens. Healthy urban planning entails optimum allocation of various land uses in a manner that can sustain healthy densities. Optimized urban design implies that the city is configured in a manner that enhances accessibility to health-promoting services such as healthcare facilities, community spaces, green spaces, and walking and biking paths. At the same time, good design segregates risky exposures detrimental to health such as pollution, traffic and unhealthy food environments.
Optimized urban design also enables creation of an underlying configuration that can support compact neighborhoods with a heterogeneous mix of multifunctional land uses. Since these neighborhoods are walkable, the residents don’t need to rely on cars and private vehicles. Well-designed urban spaces promote social interaction and community cohesiveness and minimize social segregation.
For example, well-designed and accessible public spaces both within and outside gated communities have been shown to enhance interactions within, as well as between, communities. Spatial designs and targeted policies are enduring and all-pervasive and can improve the lives of large populations. Hence, creating well-designed cities is likely to accrue long-term public health benefits.
The creation of healthy cities should be based on evidence-based planning and design. Unfortunately, urban planners and designers have thus far relied mostly on inherited knowledge and overall understanding rather than on objective evidence per se. Large-scale, reliable and generalizable evidence on the effect of multiple attributes of the built environment on a range of behavioral and health outcomes is scarce — almost nonexistent.
As has been eloquently emphasized by the recent Tsinghua-Lancet Commission on Healthy Cities in China, the Chinese urbanization process is unique, with cities at multiple stages of evolution. This presents an opportunity to test multiple urban health hypotheses, collect a robust evidence base and then use this evidence to retrofit existing cities as well as design new cities explicitly for health.
The recent advances in big data science, smart technologies for individual health sensing, health record linkage and optimization as well as the evolution of modeling algorithms for environmental exposure assessments and statistical techniques allow a data and evidence base to be generated at a very large scale. There is a need for an interdisciplinary systems-based approach and a collaborative model. Urban planners, designers, environmental scientists, health professionals, epidemiologists and clinicians need to pool their expertise to generate an evidence base for the creation of healthy places and cities.
Large-scale generalizable evidence can emerge from studying the links between the built environment and health in large population cohorts. We also need more targeted evidence about how the urban built environment may affect health and behavior in specific population subgroups, such as older adults, those suffering from specific chronic diseases and the unemployed.
Since the cities of China are dynamic and characterized by massive infrastructure developments, there is a unique opportunity for evidence gathering via natural experiments. In other words, we should carefully measure the effect of each piece of new urban infrastructure on population health.
Drawing from the huge bio-bank of half a million people in 22 cities of the United Kingdom, the Healthy High Density Cities Lab at Hong Kong University has developed the most detailed and largest database on how aspects of the environment affect health. For example, we measure density, street layouts, greenery and amenities such as fast food outlets and sports facilities in relation to where people live.
A similar high-resolution built environment exposure database has been developed for The Family Cohort in Hong Kong. It seeks to understand the health, happiness and harmony at individual, household and neighborhood levels of 46,000 participants. We also plan to examine, in collaboration with Oxford University, detailed associations between the built environment and health in a sample of half a million people from 10 Chinese cities. Such large-scale and detailed urban exposure data platforms and the evidence of built environment health links derived from them are likely to introduce a step change in our understanding of associations between built environment and health.
There is now a consensus that well-planned, well-designed cities of today will be the healthy cities of tomorrow. It is imperative that we act now by investing in the science and practice of healthy city planning and development to future-proof population health risks as well as the economic costs associated with them.