Calculating a national Anomie Density Ratio: Measuring the patterns of loneliness and social isolation across the UK's residential density gradient using results from the UK Biobank study

Abstract

Urban life has long been pilloried in history for its negative effects on the human condition and mind. From Thomas Jefferson to Emile Durkheim, high density urban living as an aberration to be rectified has been part of the modern discourse on cities. While empirical studies into the psychiatric effects of unwanted social contact began in earnest after WW2 and we now know much about environmental causes of stress, the evidence of the impacts of increasing urban densification upon loneliness and social isolation in humans still remains inconclusive. We employed high-resolution geospatial built environment exposure data to examine associations between residential density and loneliness and social isolation among 405,925 UK Biobank cohort participants. Residential unit density was measured within a 1- and 2-Km residential street network catchment of participant's geocoded dwelling. Other health-specific built environment (i.e., street-level physical walkability, density of public transport, traffic intensity of the nearest road, mean street distance to destinations), and physical environment exposures (terrain variability and greenspace exposure modelled from remotely-sensed data) were also measured at individual-level, within pre-specified catchments of each participant's geocoded dwelling. We found for the UK, that every 1,000 units/km2 increment in residential density within a 1-Km network catchment was independently associated with a 2.8% (odds ratio: 1.028, p = 0.0058) and 11.4% (OR: 1.114, p < 0.0001) higher odds of loneliness and social isolation respectively. This can be interpreted as the density elasticity of loneliness (social isolation), which we coin as the Anomie Density Ratio (ADR). In addition, with reference to the lowest density quartile, the fourth-quartile was associated with 14.4% and 30.4% higher odds of loneliness and social isolation respectively. The associations were slightly more pronounced at spatial scale of 2-Km, indicating the possibility of a scale effect in this emblematic urban-ill. Higher density of detached housing was negatively associated with both loneliness and social isolation, while density of flats was positively associated with both outcomes. More pronounced effects of residential density on loneliness were identified among males and those retired, while for social isolation, similar effect was observed among the retired. As far as we know, this is the first study to measure the density-loneliness effect using individual (non-ecological) data on a large national sample, controlling for personal confounders and mitigating environmental factors such as green space. Density was associated with loneliness and social isolation independently of other factors, which means that urban design and density planning strategies matter; especially in an age of accelerating suburban densification.