MON-LB103 Hyperactivation of Reward and Cognitive Control Brain Regions in Response to Food Images in Women Compared to Men With Obesity

Abstract

Background: Obesity is a major public health concern with an estimated two thirds of the population being overweight or obese. Women have a higher rate of obesity than men (40% vs. 35%), twice the rate of class 3 obesity (10% vs. 5% with BMI>40), and greater increases in obesity prevalence from 2005-2014. While emerging evidence highlights the role of food motivation circuitry in eating behavior and obesity risk, sex-specific neurobiological mechanisms have not been well defined in this population but are important to guide individual treatment strategies. Using a well-established food motivation functional magnetic resonance (fMRI) paradigm, we ran a preliminary set of analyses to investigate whether sex modulates the brain response to visual presentations of food items. We hypothesized that in a fasted state, women would demonstrate greater blood-oxygen-level-dependent (BOLD) activation in response to food images in reward-related brain regions compared to men.Methods: Twenty-nine adults with obesity (16 female, age (mean±SD): 31.2±4.9 years, and BMI=36.5±4.1 kg/m2) completed fMRI imaging in a 3T scanner while viewing images of food (high-calorie vs. low-calorie), non-food items, and fixation stimuli following a 10-hour overnight fast. Functional MRI data were analyzed using SPM12. Regions of interest included the nucleus accumbens (NAcc), amygdala, caudate, anterior insula (aINS), hypothalamus, putamen, orbitofrontal cortex (OFC), dorsolateral prefrontal cortex (DLPFC), dorsal anterior cingulate cortex (dACC), and supplementary motor area (SMA). Statistical significance of p<0.05 is reported at the whole brain level given the small sample size.Results: Women with obesity exhibited greater activation than men in response to food (vs. non-food) stimuli in NAcc (t=2.44, p[uncorrected]=0.011), caudate (t=2.9, p[uncorrected]=0.004), DLPFC (t=3.32, p[uncorrected]=0.001), and dACC (t=3.17, p[uncorrected]=0.002) in a fasted state. There were no regions in which men exhibited greater activation than women.Conclusion: Our preliminary results show that during a fasting state, women with obesity (vs. men) show greater activation in brain regions processing reward (NAcc) and control over behavior (DLPFC, dACC) in response to food (vs. non-food) stimuli. Future studies with larger sample sizes are needed to investigate the link between the highlighted sex differences in neural responses to food in the context of obesity and eating behavior and weight to further inform whether men and women would benefit from different approaches in the treatment of obesity.