When Where We Live Becomes a Risk Factor for Dementia

Living in impoverished neighborhoods can affect the brain and increase the risk of dementia. A study with middle-aged adults showed that socioeconomic deprivation is linked to worse results on memory and attention tests, as well as more cerebrovascular damage. These effects appear to occur because inequality increases risk factors such as hypertension and obesity, which damage the brain's blood vessels. Combating dementia, therefore, also means combating social inequalities.

Dementia is a complex and devastating neurological condition that affects millions of people worldwide, but it does not affect all populations equally. Recent studies show that individuals living in socioeconomically disadvantaged neighborhoods have a higher risk of cognitive decline and dementia, regardless of their individual income or education.

This means that where a person lives, and not just their personal habits, can literally shape their brain health.

Researchers from several international centers analyzed data from 585 healthy middle-aged adults (40 to 59 years old) to understand how socioeconomic deprivation in the neighborhood relates to modifiable risk factors, small vessel disease (SVD), and cognitive performance.

Deprivation was measured using neighborhood indicators (such as average income, access to services and infrastructure), and all participants underwent detailed cognitive tests (COGNITO), clinical examinations, and 3 Tesla magnetic resonance imaging, which allows for precise observation of vascular changes in the brain.

The results were clear: People living in poorer neighborhoods had worse cognitive performance. They also had more risk factors for cardiovascular disease (such as hypertension, obesity, and smoking). And a greater presence of microscopic damage to cerebral vessels, detected by imaging.

These small lesions, called small vessel disease (SVD), are considered one of the main mechanisms of brain damage that precede dementia. They include white matter hyperintensities, microhemorrhages, cerebral lacunae, and alterations in perivascular spaces, which affect communication between different areas of the brain.

Scientists discovered that the impact of deprivation does not act directly on cognition, but is mediated by two main mechanisms:

- Modifiable risk factors, such as lifestyle and cardiovascular health.

- Cerebrovascular damage, especially that associated with hypertension.

This figure visually illustrates how socioeconomic deprivation in a neighborhood (i.e., living in a place with fewer resources, more poverty, and less access to services) is linked to worse cognitive outcomes, difficulties with memory, attention, and reasoning. In the left panel, the pie chart (heliogram) shows which neighborhood factors are most associated with poorer cognition. The blue bars pointing outward indicate that the greater the deprivation in areas such as housing, safety, environment, and access to healthcare, the greater the negative impact on the brain tends to be. Conversely, the red bars pointing inward indicate the opposite: less deprivation and therefore less cognitive impairment. On the right, the scatter plot shows this relationship in general: each point represents a person, and the sloping line indicates that the greater the neighborhood deprivation, the greater the cognitive impairment. In other words, living in a more disadvantaged environment is associated with lower mental performance, even in apparently healthy middle-aged adults.

Together, these factors explained up to 20% of the total effect of deprivation on cognition, and CVD alone accounted for 28%. In other words, social inequality literally accelerates brain aging, and this can begin decades before the onset of dementia symptoms.

Understanding this relationship is essential for developing fairer and more effective prevention strategies. While 45% of dementia cases worldwide are potentially preventable by controlling risk factors, the greatest possible impact is in the poorest communities, where these risks are more common and less addressed.

These findings suggest that combating dementia depends not only on medication or genetics, but also on public policies that guarantee access to healthy food, safety, leisure, and quality medical care. Improving the social environment is, therefore, a concrete way to protect the brain, especially during middle age, when prevention is still possible.

READ MORE:

Neighborhood deprivation and midlife cognition: Evidence of a modifiable vascular pathway involving health behaviors and cerebral small vessel disease

Audrey Low, Kamen A. Tsvetanov, Georgios Ntailianis, Maria A. Prats-Sedano, Elizabeth McKiernan, Stephen F. Carter, James D. Stefaniak, Stefania Nannoni, Li Su, Anna McKeever, Maria-Eleni Dounavi, Graciela Muniz-Terrera, Katie Bridgeman, Sarah Gregory, Karen Ritchie, Brian Lawlor, Lorina Naci, Charlotte Connolly, Paresh Malhotra, Ivan Koychev, Craig W. Ritchie, John T. O'Brien, the PREVENT Dementia Investigators 

Alzheimer and dementia. Volume21, Issue11, November 2025, e70756

https://doi.org/10.1002/alz.70756

Abstract:

Neighborhood deprivation increases dementia risk, although mechanisms remain unclear. We tested a framework in which modifiable risk factors and cerebral small vessel disease (SVD) mediate the link between neighborhood deprivation and cognition. In 585 cognitively healthy midlife adults (ages 40–59), neighborhood deprivation was derived from postcodes, cognition was assessed using the COGNITO, lifestyle risk factors were measured using clinical assessments, and SVD (white matter hyperintensities, lacunes, microbleeds, perivascular spaces) was assessed on 3T magnetic resonance imaging. Multivariate analyses examined association pathways among these variables. Neighborhood deprivation was associated with poorer cognition (r = 0.36, p < 0.001), greater prevalence of modifiable risk factors (r = 0.36, p < 0.001), and greater SVD burden (β = 0.18, p = 0.008). Serial mediation showed that the effects of deprivation on cognition were indirect, possibly operating via lifestyle risk and SVD, explaining 20% of the total effect, whereas SVD alone explained 28%. Neighborhood disadvantage relates to poorer cognition, possibly mediated through vascular risk factors and cerebrovascular disease.