Lower executive function is associated with stroke and CHD risk

Older adults without dementia who had lower executive function had a higher risk of coronary heart disease and stroke, according to an analysis of a prospective, randomized controlled trial.

The researchers from Leiden University Medical Center in the Netherlands found participants in the lowest third of executive function had a 1.85-fold higher risk of coronary heart disease and a 1.51-fold higher risk of stroke compared with those in the highest third. Meanwhile, participants in the lowest third of memory did not have an increased risk of coronary heart disease or stroke.

Results were published online in Neurology on Aug. 5.

“This evidence might suggest that executive function might be a better reflection of brain vascular pathologies compared to memory function,” the researchers wrote. “Impaired cognitive function, in particular executive dysfunction, can serve as an indicator of incipient cardiovascular events. Hence, cognitive assessment might provide a tool for clinicians to identify older participants at extra risk for future cardiovascular events.”

The researchers included 3,926 participants from the PROSPER (Prospective Study of Pravastatin in the Elderly at Risk) trial who were at risk for cardiovascular diseases but did not have a history of MI, stroke or transient ischemic attack. Bristol-Myers Squibb funded the PROSPER study.

At baseline, all participants had complete cognitive measurements. The mean age was 75, and 44 percent of participants were male. The study enrolled men and women from three European sites between December 1997 and May 1999 and randomized them to receive pravastatin or placebo.

Participants completed the Stroop Color-Word Test for selective attention and the Letter Digit Substitution Test to evaluate processing speed. The researchers then converted the results and averaged them to determine a composite executive function score. They also evaluated scores on the Picture Learning Test to calculate a composite memory score.

Strengths of the study included its large population size and the comprehensive data on cognitive domains, comorbidities and socioeconomic status, according to the researchers. They also noted a few limitations, including participants had relatively preserved cognitive function. In addition, the findings may not be generalizable to other populations because the participants were at risk for cardiovascular diseases. Further, they used data at one point in time instead of tracking it over time, which they mentioned would have provided a more comprehensive understanding on the interactions between cognitive function and cardiovascular outcomes.