Disinhibited eating in obese adolescents is associated with orbitofrontal volume reductions and executive dysfunction

Abstract

In adults, obesity has been associated with disinhibited eating, decreased cortical gray matter (GM) volume, and lower performance on cognitive assessments. Much less is known about these relationships in adolescence and there are no studies assessing behavioral, cognitive, and neurostructural measures in the same group of study participants. This study examined the relationship between obesity, executive function, disinhibition, and brain volumes in relatively healthy youth. Participants included 54 obese and 37 lean adolescents. Participants received a cognitive battery, questionnaires of eating behaviors, and magnetic resonance imaging (MRI). Neuropsychological assessments included tasks targeting frontal lobe function. Eating behaviors were determined using the Three Factor Eating Questionnaire (TFEQ), and structural MRIs were performed on a 1.5 T Siemens Avanto MRI System (Siemens, Erlangen, Germany) to determine brain GM volumes. Lean and obese adolescents were matched on age, years of education, gender, and socioeconomic status. Relative to lean adolescents, obese participants had significantly higher ratings of disinhibition on the TFEQ, lower performance on the cognitive tests, and lower orbitofrontal cortex (OFC) volume. Disinhibition significantly correlated with BMI, Stroop color-word score, and OFC volume. This is the first report of these associations in adolescents and point to the importance of better understanding the associations between neurostructural deficits and obesity.

Figures

Figure 1. Association between Body Mass Index and Disinhibition

Shows the association between Body Mass Index (in kg/m2) and Three Factor Eating Questionnaire Disinhibition factor score. Obese individuals are noted by filled pyramids and lean individuals by filled circles.

Figure 2. Association between OFC Gray Matter Volume and Disinhibition in Adolescents (Lean and Obese)

Shows the association between Body Mass Index and ICV-residualized orbitofrontal cortex volume. Panel A shows all study participants, Panel B shows the significant association for lean youth, and Panel C, shows the lack of association for obese adolescents.