Where you live has a huge impact on your health. From the air you breathe to how much you earn, a myriad of factors shape your long-term wellbeing – and now, scientists say they may also influence your risk of developing dementia.
A new study, published in journal Neurology, has found that people living in disadvantaged neighbourhoods are more than twice as likely to develop dementia as those in more affluent areas.
Led by Prof Pankaja Desai of Rush University in Chicago, the research followed nearly 6,800 people over the age of 65 across four neighbouring Chicago communities. Participants were tested regularly on their memory and thinking skills, while data on diagnosis of Alzheimer's disease (the most common form of dementia) was also collected for around 2,500 of the participants.
By the end of the six-year study, dementia had developed in 22 per cent of those living in the most disadvantaged neighbourhoods – compared to just 11 per cent in the least disadvantaged.
Even once the researchers adjusted for other factors, including age, sex and education, the trend held, with the most disadvantaged still more than twice as likely to develop Alzheimer's.
So, what exactly does ‘disadvantage’ mean in this context? The researchers used the Social Vulnerability Index (SVI), a tool that combines 16 variables – including unemployment, income, age, ethnicity, housing types and access to transport – to assess neighbourhood-level risk.
“Our findings show that the community in which you live influences your risk of developing dementia,” Desai said. “Most studies of risk factors for Alzheimer’s disease focus on the individual level, not the community level."
Another striking result: people living in the most disadvantaged neighbourhoods experienced significantly faster cognitive decline with age, regardless of whether they had been diagnosed with Alzheimer’s. On average, memory and thinking skills declined around 25 per cent more quickly in these communities.
The study also offers an insight into racial disparities in dementia. Two-thirds of the participants were Black, and a higher proportion of Black participants lived in disadvantaged areas. But once neighbourhood disadvantage was taken into account, the difference in dementia risk between Black and white participants disappeared.
Desai believes this has big implications for how we plan health services. “Neighbourhood-level social characteristics are important to consider when planning for resources and services to reduce the risk of Alzheimer’s disease,” she told BBC Science Focus. "Taking into account individual and neighbourhood-level factors, may be useful to include as part of dementia care."
In a separate statement, she added: “Of course, intervening at the community level is challenging, but prioritising disadvantaged communities may be an effective way to mobilise resources for older adults and provide avenues for reducing the risk of dementia for the overall community.”
It’s worth noting that the study focused on neighbourhoods in Chicago, so the findings may not apply everywhere. And while the study shows a strong link between neighbourhood disadvantage and dementia, it doesn’t prove that one causes the other.
Still, the message is clear: brain health isn't just about what’s happening in your body – it’s also about what’s happening around you.
About our expert
Dr Pankaja Desai is an assistant professor at the Rush Institute for Healthy Aging and Director of Operations within the Rush Bioinformatics and Biostatistics Core. Her research has been published in the American Journal of Health Behavior and Alzheimer's & Dementia.
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