Inflammation linked to lifestyle factors like obesity, smoking and stress may cause poorer cognitive abilities in midlife, new research has highlighted.
The study is one of the first to link inflammation in early adulthood with lower performance in skills testing 20 years later.
Physical inactivity and chronic illness have also been linked to inflammation in previous research.
Senior author Professor Kristine Yaffe, from the University of California – San Francisco, said: “Inflammation plays a significant role in cognitive aging and may begin in early adulthood. There is likely a direct and indirect effect of inflammation on cognition.
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“Fortunately, there are ways to reduce inflammation – such as by increasing physical activity and quitting smoking – that might be promising paths for prevention.”
Researchers said they know from long-term studies that brain changes leading to Alzheimer’s disease and other dementias may take decades to develop. They set out to see if health and lifestyle habits in early adulthood may play a part in cognitive skills in midlife, which in turn may influence the likelihood of dementia in later life.
Their key finding was that just 10% of those with low inflammation performed poorly on processing speed and memory tests, compared to 21% and 19% of those with moderate or higher inflammation.
The team also found differences in executive functioning, which includes working memory, problem solving and impulse control.
The study involved 2,364 adults in the CARDIA study, which has set out to analyse the factors in young adulthood linked to the development of cardiovascular disease 20 to 30 years later.
The participants were aged from 18 to 30 at the start of the study and over the course of 18 years, they were tested four times for the inflammatory marker C-reactive protein (CRP).
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Around 45% had lower inflammation, 16% had moderate or increasing inflammation, and 39% had higher levels of inflammation.
When they were in their forties and fifties, they took a cognitive test.
Professor Yaffe was part of a group which was the first to identify that 30% of dementia risk is preventable.
More recently, her research has evaluated the link between disturbed sleep and lower cognition in midlife, along with the impact of tailored health and lifestyle adjustments in preventing memory loss in older adults who are at greater risk.
Read the study in full in Neurology.
