Recent research has revealed a significant impact of residence location on the risk of dementia-related death. It turns out that the risk is highest in areas with a moderate level of urbanization, rather than in the heart of big cities or remote rural areas. This study was conducted by researchers at the University of Cambridge and analyzed data from 2011 to 2023.

Dementia Mortality Risk and Population Density

The researchers analyzed data by linking census information from 32,844 areas in England with individual mortality data. The study included 40,948,445 residents aged 16 and over registered with general practitioners in the UK's National Health Service (NHS), who were followed up for a median of 8.68 years.

The analysis found an 'inverse U-shaped' relationship between dementia mortality risk and local population density. As population density increased, dementia mortality risk rose, peaking in moderately dense areas with about 20-40 people per hectare, or 2,000-4,000 people per square kilometer. Conversely, the risk was relatively lower in densely populated urban centers and sparsely populated rural areas.

The Challenges of Moderately Dense Areas

The researchers explained that these differences are likely not just a matter of 'urban versus rural,' but stem from access to healthcare and living services in the area of residence and the outdoor living environment. Densely populated urban areas may face environmental burdens like air pollution, but they offer easy access to essential services such as hospitals, pharmacies, and public transportation. Rural areas, on the other hand, might have limited access to healthcare services but offer more opportunities for physical activity in a relatively clean environment with natural surroundings.

The Importance of Healthcare Access and Living Environment

However, moderately dense areas often possess the environmental drawbacks of urban settings while having less convenient access to hospitals and services. In such environments, older adults might miss appointments or face delayed diagnoses, making ongoing management difficult. Furthermore, a lack of walkable environments or outdoor recreational spaces can lead to reduced physical activity and increased social isolation. All these factors are known risk factors associated with cognitive decline.

The Need for Improving Local Environments

The researchers reported that after statistically adjusting for local characteristics such as income, employment, education, crime, housing, living environment, and service accessibility, over 71% of the gap in dementia mortality risk based on population density was reduced. Specifically, service accessibility and the living environment contributed most significantly to explaining the differences between regions. It was analyzed that improving these local environments could substantially reduce dementia mortality.

In conclusion, this study suggests that regional disparities in dementia mortality risk may be more influenced by healthcare service accessibility and the living environment than by population density alone. Therefore, policy interventions aimed at improving these factors could help alleviate the burden of dementia mortality.