(HealthDay)—The combination of smaller and larger infarctions detected in stroke-free individuals in middle age is associated with substantial cognitive decline later in life, according to a study published online Aug. 27 in the Annals of Internal Medicine.

B. Gwen Windham, M.D., from the University of Mississippi Medical Center in Jackson, and colleagues characterized the relationships of smaller, larger, and both smaller and larger infarctions in middle age with subsequent cognitive decline in a longitudinal study. Magnetic resonance imaging data and cognitive assessments were included for 1,884 stroke-free participants aged 50 years and older.

The researchers found that 86 percent of the participants had no infarctions and 3, 10, and 2 percent had small infarctions only, larger infarctions only, and both, respectively. Steeper cognitive decline by more than half a (SD) was seen for participants with both smaller and larger infarctions compared with those with no infarctions (difference, −0.57 SD). Similar amounts of cognitive decline were seen in association with only smaller or only larger infarctions; these findings were not statistically different compared with no infarctions.

"The combination in of larger with smaller subclinical infarctions may represent more severe disease that amplifies the effects of infarctions of either size on and thus on cognitive function in late life," the authors write. "This possibility is especially important because smaller infarctions, whether isolated or in combination with larger infarctions, are typically ignored."