I don't know whether a survey has been done in Singapore but apparently Radon gas which is naturally occuring is also a contributing factor to Cancer. A decade back or so there were high incidences of cancer in certain parts of UK or in Scotland and tests were carried out and it was discovered that Radon gas which is natural occuring was most likely cause because of where the cancers were occuring. It can apparently seep into house from under the foundations of buildings ... gas being permeable.
So more buildings and therefore more piling works into the ground would probably release more gas then would be the normal cause of escape.
Life style is also another factor.... the constant stress of 'keeping up appearance' and chasing money, position and status are also factors though maybe not be conciously acknowledge ....
So I would think a laid back lifestyle i.e. not rushing around and worrying too much about 'things' may not be too bad. Mind you I said "laid back" not lazy lay abouts... those need a swift kick on the backside to let them know there are 'NO free lunches' Everyone contributes however they can, even if it's at a slower pace.