Study confirms living in a poor area ups dementia risk

By Stephen Beech

Living in a run-down area really does increase the risk of dementia - even for the well off, according to a new study.

Cambridge University researchers found that living in a disadvantaged neighborhood is associated with damage to brain vessels, which can affect thinking skills.

Previous studies have shown that people living in socio-economically poor areas show greater cognitive decline throughout their lives and higher dementia risk, regardless of their own socio-economic status.

Recent research also found that neighbourhood deprivation is linked to differences in brain structure and greater signs of damage to brain tissue.

To explore the link further, Cambridge scientists examined data from 585 healthy adults aged 40to 59 living in the UK and Ireland.

Among the data collected and examined were neighbourhood deprivation according to postcodes, cognitive performance assessed through a series of tests, and modifiable lifestyle risk factors.

MRI brain scans also looked for signs of damage to the brain’s small blood vessels, which are vital for delivering oxygen and nutrients to brain tissue.

The findings, published in the journal Alzheimer's & Dementia, showed a "strong link" between living in a deprived neighbourhood and poorer management of lifestyle factors known to increase the chances of developing dementia.

In particular, people living in areas of high unemployment, low income and/or poor education and training opportunities were more likely to experience poor sleep, obesity and high blood pressure, and do less physical activity.

But people living in deprived neighbourhoods tended to consume less alcohol - another known risk factor for dementia - than those in less disadvantaged neighbourhoods.

The research team also found a "significant" link between cognition and neighbourhood deprivation – particularly poorer housing and environment and higher levels of crime.

That had the greatest impact on a person’s ability to process information quickly, their spatial awareness and attention, according to the findings.

The researchers say one possible explanation comes from their finding that living in a deprived neighbourhood was associated with damage to the brain’s small blood vessels, which in turn affects thinking skills.

They explained that modifiable lifestyle habits are known to contribute to such damage, suggesting that the effect of deprivation on brain function – and hence performance in cognitive tests – may be down to lifestyle and vascular health.

Study first author Dr. Audrey Low, from Cambridge's department of psychiatry, said: “Where someone lives can affect their brain health as early as midlife.

"It doesn’t do this directly, but by making it more difficult for them to engage in positive lifestyle behaviours.

“This means that people living in these areas may face more challenges in getting quality sleep and exercise, and in managing blood pressure and obesity.

"This can then have a knock-on effect on the health of blood vessels in the brain, leading to poorer cognition."

She added: “These lifestyle factors are no doubt influenced by both individual circumstances and the external environment in which they live.

"But importantly, the links we found were independent of educational attainment.

"So, even a person who has gone on to further or higher education and has a reasonably paid job may be better or worse at managing their lifestyle depending on where they live, perhaps due to better access to affordable, healthy food options and safer recreational spaces.”

The researchers say their findings highlight the fact that dementia risk is influenced by environmental factors rather than just individual behaviour.

Senior author Professor John O’Brien, also from Cambridge's department of psychiatry, said: “Where you live clearly plays an important role in your brain health and risk of dementia, putting people living in deprived neighbourhoods at a serious disadvantage."

He added: "This risk is preventable, but our works shows it’s not enough to assume it’s down to the individual.

"If we’re serious about reducing health inequalities, it will require support from local and national policymakers.”

The researchers said that the study highlights how different areas face their own challenges and so will need different approaches.

For example, in wealthier areas, strategies could focus on reducing alcohol consumption, while lower-income neighbourhoods may benefit from targeted campaigns promoting healthy lifestyles for dementia prevention.