How inequality in society affects brain health as we age

Their study was published in the journal Nature Aging and was based on analyses of data from several countries in the Americas, including regions in Latin America and the US.

The main findings are

• Inequality and brain health
  The researchers found that higher levels of social inequality (as measured by the GINI score) are associated with reduced brain volume and deterioration in connections between different areas of the brain. These changes are particularly noticeable in areas important for memory and cognitive function.

• Vulnerable regions
  The most pronounced effects were observed in participants from Latin America, emphasising the vulnerability of this region's population to socioeconomic stressors. Latin Americans with Alzheimer's disease showed the strongest changes in the brain, indicating that unfavourable environments can increase neurodegeneration.

• Genetics vs. environment
  In the case of frontal temporal degeneration the changes in the brain looked weaker, which may indicate a more significant role of heredity for this disease. Nevertheless, the fact remains that living in a highly unequal environment can exacerbate negative processes, even when personal factors (education level, age, gender, cognitive ability) are taken into account.

• Wealth levels of countries
  The authors emphasise that many low- and middle-income regions are increasingly experiencing an increase in the incidence of dementia. These findings confirm that for prevention and treatment, it is important not only to consider lifestyle factors for the individual, but also to pay attention to global factors - social, economic and environmental.

Why it matters

Doctors and policy makers should think about comprehensive measures that can address the negative impact of inequality on brain health. This could be about more democratic governance, reducing air pollution, developing green spaces and supporting the wellbeing of migrants. According to the authors, this is the only way to reduce the risk of 'accelerated brain ageing' and reduce the burden of dementia in low-income communities.

The authors call for a multi-level approach where, in addition to individual factors (such as educational attainment), large "exposome" factors - from social norms to climatic conditions - are taken into account.

Source:
Legaz et al. Structural inequality linked to brain volume and network dynamics in aging and dementia across the Americas, Nature Aging (2024). DOI: 10.1038/s43587-024-00781-2