Combination of larger, smaller brain infarctions in middle age associated with later-life cognitive decline
Over a 20-year period, cognitive decline was steeper in participants with a combination of larger and smaller infarctions versus no infarctions on MRI, meaning that the presence of both types was equivalent to 13.6 years of aging, researchers noted.
Patients with a combination of smaller and larger brain infarctions on MRI in middle age may be at higher risk for cognitive decline later in life, a new study found.
Researchers used data from two sites participating in the Atherosclerosis Risk in Communities (ARIC) Study to examine the relationship between cognitive decline over 20 years and the presence of smaller, larger, and both smaller and larger infarctions on MRI in middle age. Stroke-free participants who were 50 years of age or older were included. MRI data were from 1993 to 1995, and up to five cognitive assessments were performed over the next 20 years. Infarctions on MRI were categorized as none, smaller only, larger only (3 to 20 mm), or both smaller and larger, and three cognitive tests administered up to five times were used to develop global cognitive Z scores.
The current study's primary outcome was 20-year decline in global cognition, with adjusted associations between infarctions and cognitive decline estimated using mixed-effects models. The study results were published Aug. 27 by Annals of Internal Medicine.
A total of 1,884 participants were included in the study. Mean age at the index examination for the ARIC study was 62 years, 60% of participants were women, and 50% were black. Overall, 1,611 participants (86%) had no infarctions in middle age, 50 (3%) had only smaller infarctions, 185 (10%) had only larger infarctions, and 35 (2%) had both types.
Over a 20-year period, cognitive decline was steeper in participants with both types of infarctions versus those with no infarctions (difference, −0.57 SD; 95% CI, −0.89 to −0.26 SD), meaning that the presence of both larger and smaller infarctions was equivalent to 13.6 years of aging, the researchers noted. Participants with only smaller infarctions (difference, 0.04 SD; 95% CI, −0.52 to 0.44 SD) and those with only larger infarctions (difference, −0.09 SD; 95% CI, −0.31 to 0.13 SD) had similar cognitive decline and did not differ significantly from participants with no infarctions.
The researchers noted that the numbers of participants with only smaller infarctions or both types of infarctions were small and that detailed measurements of smaller infarctions and white-matter hyperintensities were lacking, among other limitations. However, they concluded that while only larger or only smaller infarctions in middle age do not appear to be associated with 20-year cognitive decline from middle age to later life, both types of infarction in middle age may represent more severe disease.
“This possibility is especially important because smaller infarctions, whether isolated or in combination with larger infarctions, are typically ignored,” the authors wrote. “Preventing subtle changes in the brain structure and vasculature earlier in life may reduce late-life cognitive impairment.”