Research led by the University found a connection between socioeconomic status and changes in the white matter of the brain – a known risk factor of cognitive decline and dementia in older age.
The world-first study analysed data from nearly one million people to determine links between genetics and measures of occupation, income, education and social deprivation.
They found that three quarters of the genetic effects linked to each of these four socioeconomic measures are common across them all.
Genetic signal
This common signal, termed the genetic factor of socioeconomic status, was then analysed in the 947,466 individuals.
Using a research technique called a genome-wide association study – which looks for links with genetic variations and traits in the brain and behaviour – they found 554 regions in the human genome associated with socioeconomic status.
Using these data, they found that differences in socioeconomic status are a likely causal risk factor in the accumulation of white matter hyperintensities, a condition which could affect thinking skills, dementia risk, and brain function in later life.
Researchers say the findings show socioeconomic status may marginally help explain differences in brain health.
However, the majority of differences in cognitive health are explained by other environmental and social factors such as social conditions, specific policies and even luck, the team say.
International study
An international team of researchers from the UK, Netherlands and Italy analysed genetic data from nearly one million people from the age of 30 to older age.
A common genetic variation accounted for nine per cent of the differences in socioeconomic status, researchers said. The majority of the reasons why people differed in social and financial standing was not due to genetic factors, they added.
The team then studied MRI brain scans from a separate group of around 40,000 people to determine if socioeconomic status influences brain structure and whether brain structure, in turn, affects socioeconomic status.
They found evidence that a higher level of socioeconomic status leads to lower levels of white matter hyperintensities in the brain.
Researchers say the results show the value of genetic data in identifying the role of changeable environmental risk factors – such as socioeconomic status – in how our brains age.