Chronic inflammation in middle age may lead to memory and thinking problems later in life.
Unlike acute inflammation, which arises in response to injury, chronic inflammation persists over months or years. Autoimmune disease, lingering infection, exposure to polluted air, psychological stress and other conditions can all promote chronic inflammation.
Researchers did blood tests on 12,336 men and women, average age 57, assigning them an “inflammation composite score” based on white blood cell count, clotting factors and other tests. They also assessed their cognition with standardized tests of memory, processing speed and verbal fluency. The study is in Neurology.
After controlling for age, education, blood pressure, cholesterol, heart disease and many other factors, they found that the greater the number of inflammatory factors, the steeper the cognitive decline over 20 years of follow-up. Inflammation was most strongly associated with declines in memory.
“We know that dementia starts earlier than the appearance of symptoms,” said the lead author, Keenan A. Walker, a postdoctoral researcher at Johns Hopkins, “and we’ve shown that levels of inflammation matter for dementia risk. Reducing chronic inflammation involves the same health behaviors that we already know are important for other reasons — regular exercise, healthy diet, avoiding excessive weight gain and so on.”