Neighbourhood Effects

Cities have been associated with many things – more pollution, crime, inequality and traffic congestion. When they are poorly designed,with high population density, they can also increase social isolation and a sense of loneliness.

This insight has been well-embedded in urban planning and design for years. But a study led by HKU was the first to support it with robust evidence, using a dataset of more than 400,000 subjects from the UK Biobank.

Professor Chinmoy Sarkar, Associate Professor at the Department of Urban Planning and Design, was part of the team that showed, paradoxically, that being physically close to many people can leave us feeling lonely.

“When there are higher densities, there will be more unwanted social contacts. If the quality of social contacts is not good, and there is a lack of privacy and social overload, then people tend to withdraw or confine themselves,” he said. “Unwanted social contacts have been found to cause a loss of social networks and social support and eventually lead to loneliness and social isolation.”

Professor Sarkar and his colleagues drew on the UK Biobank, which contains information on people’s self-reported sense of loneliness and their social isolation in terms of engagement with other people, and compared this with their environment, such as residential unit density, walkability and greenness. They looked at one- and two-kilometre buffers around the places where individuals lived.

For every increase of 1,000 units in the one-kilometre buffer, the odds of feeling lonely rose by 2.8 per cent while social isolation rose by 11 per cent. When that was broken down further, and the people in the top quartile of density were compared with the lower quartile, the odds increased by 14.4 per cent for loneliness in the upper quartile and 30.4 per cent for social isolation.

Perception of safety

The researchers also looked at housing types. People living in self-contained flats in high-density areas had the worst outcomes – those in the highest-density of flats had increased odds of 9.6 per cent for loneliness and 28.9 per cent for social isolation versus those living in the lowest flat density.

Conversely, living in detached housing actually had a higher protective or beneficial effect with increasing density – those in the highest density of detached housing had reduced odds of 13.2 per cent for loneliness and 20.2 per cent for social isolation versus the lowest density. There were also protective effects from such attributes as greenness, the density of public transport and walkability, or centrality, of a place.

“If you are living in a detached house in the leafy suburbs with a garden or other defensible space, you have the perception of safety. You can sit in your garden and talk to your neighbours, which contributes to a sense of community and cohesion that may reduce your perception of loneliness or isolation. Whereas in apartment blocks, at least from my experience in Hong Kong and other high-density cities, you may not even know who your next-door neighbour is; hence the importance of designing functionally interactive public spaces in neighbourhoods,” he said.

In all cases, the effects were more pronounced at the two-kilometre buffer, which Professor Sarkar said was due to the urban scaling effect, and among males and older people.

Need to optimise density

Loneliness and social isolation are both associated with poor mental and physical health, and he said the findings imply that government loneliness strategies need to take into account urban planning and policies, such as densification.

“Optimising housing density and the mix of housing should be the cornerstone of any government’s population-wide policy that aims to enhance the social well-being and mental capacity of our population. This should happen alongside the design of neighbourhoods that allow people to interact in ways that help reduce the burden of social isolation and perceived or actual psychosocial stress,” he said.

“After all, these policies affect millions of city residents. With demographic shifts to ageing societies, the way we design and pack our cities will be the key to creating multifunctional and interactive neighbourhoods that promote social well-being and longevity.”

Professor Sarkar is also looking at the relationship between the living environment in Hong Kong and depression by measuring the build-up of the stress hormone, cortisol, in hair samples. And he is participating in a study looking at the effects of urban design and density on longevity in Hong Kong and the UK.