 I'd like to continue this theme and talk about how we address, how we collect the evidence. What would I do? Oh, right. Just to recap, why are we interested in studying this question? There are increasing number of people moving from urban areas to cities. And the demographic change really necessitates that we focus on the elderly population because they're more frail. And so this brings with the question, what is the relationship between urban design and health? Focusing on the issue of age-friendly and health-promoting environments. Now, the previous speaker referred to an integrated framework. This is my version of the integrated framework. You want to look at outcomes at population, individual, and perhaps cellular levels to get your research grants. We don't want to just focus on mortality because you could argue that this is, if you have increased life expectancy, is because the obstetricians and pediatricians are doing a good job. We want to focus on frailty. So this is accumulation of deficits. And there are factors impacting aging well outcomes. The group of personal factors which we tend to focus on, which is physical activity, socioeconomic factors, and psychological factors. But not so much on environmental factors. So this is neighborhood environment, open spaces, air pollution, and climate. Now, just to show you in Hong Kong, although we topped the table for global health indicators, you can see if you look at these maps, they're temporal and spatial changes. If red is bad and green is good, this is looking at hip fracture case fatality. This is looking at hip fracture incidents. We're improving, but certainly wide district variations. This is stroke case fatality, and this is stroke incidence. And you can immediately appreciate the difference in patterns between hemorrhagic and ischemic stroke. Hemorrhagic stroke doesn't seem to be going anywhere with time, but ischemic stroke seems to be improving. So why is that? These are research questions that we need to ask. And in order to do that, you need money. It's very difficult to establish a direct causal relationship that previous speakers referred to. So we can only draw inferences from associations, and you want to collect data on as many confounding factors, the impact on health, environment being one of them, in order to go deeper into addressing the research question. And the relevant factors, why do we need to do that? Just to emphasize, we need to design a living environment to promote healthy lifestyle. We need city planning for easy access to transport care shops and so on, and planning buildings and roads with awareness of the impact of climate, heat, cold, noise, pollution, open spaces. And because of the aging population, there's a whole issue around special design for elder housing and residential care homes for the elderly and then neighborhoods. Now, as an example, how we can delve further into analyzing spatial variations in health outcomes. We opportunistically look at a data set of people aged 65 years and over, and we look at various outcome indicators other than mortality. We look at frailty, and we collect data about lifestyle, socioeconomic, and also the district. And we look at the associations and make some conclusions about direct and indirect relationships. And using this pathway, I think all you need to look at is this. This is the outcome measure we use, the frailty of your population. And these boxes are all the personal factors, dietary quality, alcohol smoking, physical activity, socioeconomic, where you live, we don't, at this stage, we don't analyze what that means. And you can see that, of course, where you live impact on all these things, right? But this particular line shows that it has a direct impact on frailty. So this is independent of your diet, your alcohol smoking and physical activity level, and independent of socioeconomic. So it doesn't help to just focus on raising people's income. You've got to look at your living environment. So this is really a summary of what I said just now. Then the next question is, what are the district factors that impact the outcome? And to do that, you need to go down into the district to look at the neighborhoods. You can look at social support, you can look at facilities, safety, pollution, etc. Many things you can look at. Incidentally, we talked about density, is there a limit to it? With this data set, we looked at telomere length. The longer it is, the longer your life expectancy, the more disease you have, the shorter it is. And basically, this is to show that in Shatin, if you use that as a reference district, all these crowded areas that Professor Yeat referred to, you have shorter telomeres. Shatin is a new planned district built on reclaimed land with rivers and harbour views and so on. Lots of open spaces. So maybe there's something, maybe we should pursue that. Now if we go down to the neighborhood, I chose two contrasting areas, Saikong and Shamshoipo. This is a poorer, denser area, this is more open. And this is Shamshoipo, and this is Saikong. There are high-rise village houses, a lot of open spaces. These are some of the characteristics. We looked at accessibility, safety, pollution, amenities, medical, social facilities, and so on. And we particularly focus on one, walkability. And then we relate that to health-related quality of life. And we show that there is a relationship. And walkability in Hong Kong may be different to how it's defined in other countries. Basically, we look at obstruction to walkways and safety to walk around neighbourhood at night. So this is a narrow definition to the international one. And you're supposed to be able to tell which is more walkable, which is not. But maybe many of you can't. This is the only slide that is good, and here is obstruction and steep stairs and so on. And there is age-related difference in what people would like to see. The older people, walkability is most important whereas leisure and social facilities are not too important. So to conclude, neighbourhood design impacts on health of aging populations. The magnitude of impact could be equivalent to that from lifestyle and socioeconomic factors. There's a dearth of research in this area which requires cross-disciplinary research. And the research questions we need to focus on, we need to collect evidence on the interaction between health and environment using quantitative and qualitative studies because these facts influence policy. And we, perhaps we can utilise existing networks of contrasting cities and atrocity differences to address these questions. And examine subgroup differences, age, culture, ethnicity and so on. Thank you for your attention.