Insulin resistance (IR) is associated with poorer cognitive performance and greater cognitive decline in heart disease patients with or without diabetes, a new study says.
Insulin resistance is frequently associated with chronic liver disease and occurs when cells no longer respond normally to the hormone insulin. This prevents cells (such as muscle, fat, and liver cells) from absorbing glucose, an important nutrient for cell function and survival.
As a result, more insulin is produced to compensate for this lack of response. An insufficient amount of insulin leads to the accumulation of glucose in the blood, which may lead to blood vessel damage, prediabetes, diabetes, and other serious health conditions.
To investigate the association between IR and cognitive function changes over a period of years in patients with or without diabetes who have cardiovascular disease, researchers followed 489 patients (with an average age of 57.7) with coronary heart disease for over two decades who took part in the Bezafibrate Infarction Prevention (BIP) trial (1990–97).
Biochemical parameters (such as IR) and cognitive functions were assessed at the start of the study to be used as a baseline. Follow-up assessments were performed 15 years later, then again five years after that. To assess cognitive function, various tests were done to examine memory, executive function, visual-spatial processing, and attention.
For all patients, the results showed that IR was associated with an overall decline in cognitive performance. Nondiabetic patients showed particularly poor memory and executive function. The results were similar after adjusting for stroke and dementia factors.
“These are exciting findings because they may help to identify a group of individuals at increased risk of cognitive decline and dementia in older age,” David Tanne, professor at the Tel Aviv University Sackler Faculty of Medicine, and the study’s senior author, said in a news release.
“We know that insulin resistance can be prevented and treated by lifestyle changes and certain insulin-sensitizing drugs. Exercising, maintaining a balanced and healthy diet, and watching your weight will help you prevent insulin resistance and, as a result, protect your brain as you get older,” he added.
Researchers concluded that insulin resistance is related to cognitive decline in cardiovascular disease patients with or without diabetes.
“This study lends support for more research to test the cognitive benefits of interventions such as exercise, diet, and medications that improve insulin resistance in order to prevent dementia,” the researchers wrote. “The team is currently studying the vascular and non-vascular mechanisms by which insulin resistance may affect cognition.”