Larger Plus Smaller Infarctions Linked to Accelerated Cognitive Decline

By Marilynn Larkin

August 29, 2019

NEW YORK (Reuters Health) - The combination of larger and smaller subclinical infarctions in middle age may accelerate the risk for cognitive decline later in life, researchers say.

"Infarctions are generally only reported if they are larger - at least 3mm - and are ignored clinically if they are smaller (less than 3mm)," Dr. B. Gwen Windham of the University of Mississippi Medical Center in Jackson told Reuters Health.

"We examined 20 years of cognitive decline among stroke-free, middle-aged people with and without smaller, and larger infarctions," she said by email. "We found that people who had a combination of smaller infarctions (<3mm and typically ignored) and larger infarctions had the steepest decline in cognitive function over a 20-year period from middle-age."

Dr. Windham and colleagues studied data from two ARIC (Atherosclerosis Risk in Communities) study sites on 1,884 stroke-free patients (mean age, 62; 60% women; 50% black) who had magnetic resonance imaging data from 1993 to 1995 and up to five cognitive assessments over 20 years.

Infarctions were categorized as none, small only, large only (3 to 20 mm), or both small and large.

As reported online August 26 in the Annals of Internal Medicine, 86% of participants had no infarctions; 3% had small infarctions only; 10% had larger infarctions only, and 2% had both.

Participants with no infarctions had better cognition than those with only smaller, only larger, or both smaller and larger infarctions; cognitive decline seemed to be similar between participants with only smaller and only larger infarctions.

Specifically, those with both smaller and larger infarctions had a steeper decline in standardized cognitive scores by more than half a standard deviation on average compared to participants with no infarctions (difference, - 0.57 SD).

Further, each additional year of age was associated with a - 0.04-SD steeper cognitive decline. "Thus, having both smaller and larger infarctions was akin to 13.6 years of aging," the authors state.

However, there were no significant differences in cognitive decline in participants with only smaller or only larger infarctions versus no infarctions.

A limitation of the study, according to the authors, is that "few participants had only smaller infarctions or both smaller and larger infarctions, and the data lacked counts of smaller infarctions and volumes of white matter hyperintensities."

Nonetheless, Dr. Windham said, "We believe our data suggest that people who have both smaller and larger infarctions may have more pervasive cerebrovascular disease processes. This is clinically meaningful because ignoring the smaller infarctions, particularly when they occur along with larger infarctions, may lead to underestimating dementia risk."

Dr. Rebecca Edelmayer, director of scientific engagement at the Alzheimer's Association in Chicago, told Reuters Health, "This newly-published study adds to the growing body of evidence that our heart and brain health in mid-life may impact memory and thinking in late-life."

"We are seeing more conclusive evidence that we may decrease our risk for cognitive decline by better managing our heart health," she said by email. "There are tools that exist today - both healthy lifestyle and medicines - to control these risk factors and protect our brains."

"The Alzheimer's Association recommends that individuals take action now, whatever stage of life they are in," she added. "In addition, the conversation about vascular health - like healthy blood pressure management - is something physicians should be having with their patients."


Ann Intern Med 2019.