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Poor insulin sensitivity can slow information processing, reaction time
Cognitive performance in adults with obesity and overweight was negatively affected by poor glucose tolerance and increased visceral fat, according to findings published in Obesity.
“In addition to its metabolic consequences, excess adiposity has been linked to decrements in cognition, along with a higher risk for cognitive decline,” Naiman Khan, PhD, assistant professor, department of Kinesiology and Community Health at the University of Illinois at UrbanaChampaign, and colleagues wrote. “Although the mechanisms by which excess adiposity leads to cognitive decrements are unclear, dysregulation in glucose and insulin homeostasis is a likely marker or direct contributor to adiposity-related cognitive dysfunction.”
Kahn and colleagues analyzed data from 39 adults (23 women) aged 25 to 45 years (mean age, 36 years) with BMI at least 25 kg/m2 (mean BMI, 33.9 kg/m2) to determine effects of glucose level and insulin sensitivity on information processing and reaction time. Researchers recorded EEG activity while participants performed a two-stimulus oddball task that involved reacting to white circles on a black screen. Reaction time was recorded, and an oral glucose tolerance test was administered to measure insulin resistance as homeostatic model assessment of insulin resistance (HOMA-IR) and insulin sensitivity as Matsuda index and Stumvoll metabolic clearance rate. Adiposity was assessed using dual-energy absorptiometry.
Almost all participants had normal fasting glucose below 100 mg/dL (98%). Researchers found that worse insulin sensitivity was associated with longer periods of latency and, thus, slower information processing in the group (P = .01), and task accuracy was worse for those with more visceral fat tissue. Conversely, participants with greater insulin sensitivity displayed a stronger ability to process information, according to researchers.
“Given that our findings indicate that insulin resistance influences cognitive control, after adjusting for [visceral adipose tissue], it is possible that the detrimental effects of insulin resistance on cognitive control may precede those of VAT or obesity,” the researchers wrote.
Researchers also found that basing measures on oral glucose tolerance tests was more informative than those from a homeostatic model assessment of insulin resistance (HOMA-IR).
“This was surprising given that previous work has often shown that HOMA-IR is related to poorer cognitive function,” the researchers wrote. “However, much of the evidence linking HOMA-IR to cognitive function has been predominantly based on findings among older populations and among adults with dysregulation in either glycemic control and/or cognitive impairment. Given that our sample was composed of younger adults without diagnosed [type 2 diabetes] or cognitive deficits, it is possible that HOMA-IR may not explain significant variability in attentional control among such populations.” – by Phil Neuffer
Disclosures: The authors report no relevant financial disclosures.