Electrophysiological Examination of Executive Functioning in Lean and Obese Younger Adults

Abstract

AbstractBackgroundObesity rates of adults in the United States have increased from 30.5% in 1999‐2000 to 42.4% in 2017‐2018, with a further projected prevalence to nearly 50% by 2030. Greater adiposity has been consistently associated with exacerbated brain atrophy and central glucose hypometabolism in prefrontal cortices that govern executive functions, including inhibitory control, working memory, emotion regulation, and cognitive flexibility. However, there is a paucity of research elucidating how neural physiology that governs these executive functions is impacted by obesity. Thus, our primary aim of this study was to investigate whether such electrophysiological changes due to obesity could be detected in healthy young adults.MethodIn this cross‐sectional study, we recruited 60 participants (18‐40 years, 55% female) and examined real‐time neural electrophysiology using electroencephalography (EEG) on 34 lean participants (mean body mass index (BMI)=22.1±2) and 26 overweight/obese participants (mean BMI=34.9±6.1) while they completed four cognitive tasks which separately focused on inhibitory control, working memory, emotion regulation, and cognitive flexibility. Serum proteomics were collected, and glycemic control was quantified from glycated hemoglobin (HbA1c) serum measures. We directly assessed body composition via dual energy X‐ray absorptiometry (DXA). Structural equation modeling was utilized in to probe direct/indirect associations between body composition, cardiometabolic biomarkers, and EEG waveforms.ResultAfter controlling for age, sex, HbA1c, and DXA android/gynoid ratio, we found that higher body fat percentage was associated with a significantly slower response in order to reach trough amplitudes on the FC1 electrode (196.3±134.4 milliseconds (ms) versus 204.4±311.1ms; β=0.94, p<0.001), as well as a significantly slower response in order to reach peak amplitudes on the FT7 electrode (215.9±129.9ms versus 334.1±327.2ms; β=‐0.537, p=0.019) during a Stroop task. Furthermore, we found that higher body fat associated with significantly slower responses in order to reach trough and peak amplitudes on the FT7 electrode (202.9±95.4ms versus 567.2±434.5ms, β=‐0.87, p=0.032; and 543.4±205.2ms versus 613±333.9ms, β=‐0.79, p=0.049, respectively) during an Operation Span task. No differences were observed between obese and lean subjects for emotion regulation or cognitive flexibility tasks.ConclusionYoung adults with greater adiposity may have impaired cognitive inhibition and decreased working memory capacity compared to lean counterparts.