Chronic inflammation in middle age may be associated with an increased risk for brain shrinkage and Alzheimer’s disease later in life.

A new study, published in Neurology, looked at 1,633 people whose average age was 53 in 1987-89, measuring white blood cell count and various blood proteins that indicate inflammation.

They followed the participants for 24 years. In 2011-13, when the subjects’ average age was 77, the scientists measured their brain volume using M.R.I. and tested their mental agility with a word-memorization task.

They found that the greater the number of elevated inflammatory markers earlier in life, the smaller the volume of several parts of the brain, including those associated with Alzheimer’s disease. Higher levels of inflammation were also associated with poorer performance on the memory test.

The authors acknowledge that they had blood tests for only one point in time, and that they are assuming that brain loss occurred in the years after the inflammatory markers were assessed.

“It’s important early in life that we prevent diseases like diabetes, heart disease or hypertension that cause systemic inflammation,” said the lead author, Keenan A. Walker, a postdoctoral fellow at Johns Hopkins. “This study shows a temporal relationship between early inflammation and later brain volume loss.”