Fu­ture-proof­ing health in China’s cities

China Daily European Weekly - - Cover Story - The au­thor is as­sis­tant pro­fes­sor of ur­ban health and en­vi­ron­ment at Hong Kong Univer­sity. The views do not nec­es­sar­ily re­flect those of China Daily.

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.

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