If you are not kind to yourself in your 20s, a series of cognitive troubles could affect you in your 40s. Researchers from UC San Francisco found that higher inflammation in young adulthood may lead to reduced cognitive function in midlife. High levels of inflammation are associated with obesity, physical inactivity, stress and smoking. While the link between higher inflammation in adults and dementia is already well-established, this is the first time a connection has been made between inflammation in early adulthood and lower cognitive abilities in one's 40s.
Study author Amber Bahorik, from the UCSF department of psychiatry and behavioural sciences and the Weill Institute for Neurosciences, explained, “Long-term studies indicate that brain changes linked to Alzheimer’s disease and other dementias can evolve over decades. Our aim was to investigate whether health and lifestyle habits during early adulthood could impact cognitive abilities in midlife, potentially affecting the risk of dementia later in life.”
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The study tracked 2,364 adults enrolled in the CARDIA study, which investigates factors in young adulthood that contribute to cardiovascular disease decades later. Participants, aged 18 to 30 upon entry, underwent testing four times over an 18-year span to measure the inflammatory marker C-reactive protein (CRP). Cognitive tests were administered five years after the final CRP measurement, when most participants were in their forties and fifties.
About half the participants were female. Among the participants, some 45 per cent had lower stable inflammation, while 16 per cent had moderate or increasing inflammation; 39 per cent had higher levels.
Researchers discovered that among participants, only 10 per cent with low inflammation performed poorly on tests of processing speed and memory, whereas 21 per cent and 19 per cent of those with moderate or higher inflammation levels, respectively, struggled on these tests.
Even after adjusting for factors such as age, physical activity, and total cholesterol, disparities persisted in processing speed. The researchers also observed differences in executive functioning, encompassing working memory, problem-solving, and impulse control.
The researchers discovered both direct and indirect effects of inflammation on cognition. They emphasised that increasing physical activity and quitting smoking are effective ways to reduce inflammation. However, while these steps may sound straightforward, many find them hard to implement.