Neuropsychological functioning in mid-life treatment-seeking adults with obesity: a cross-sectional study

Objective: To compare cognitive functioning between treatment-seeking individuals with obesity and healthy-weight adults. Design and Methods: Sixty-nine bariatric surgery candidates (BMI>30kg/m2) and 65 healthy-weight control participants (BMI 18.5-25kg/m2) completed a neuropsychological battery and a self-report psychosocial questionnaire battery. Results: Hierarchical regression analyses indicated that obesity was predictive of poorer performance in the domains of psychomotor speed (p=.043), verbal learning (p<.001), verbal memory (p=.002), complex attention (p=.002), semantic verbal fluency (p=.009), working memory (p=.002), and concept formation and set-shifting (p=.003), independent of education. Obesity remained a significant predictor of performance in each of these domains, except verbal memory, following control for obesity-related comorbidities. Obesity was not predictive of visual construction, visual memory, phonemic verbal fluency or inhibition performance. Individuals with obesity also had significantly poorer decision making compared to healthy-weight controls. Conclusions: Findings support the contribution of obesity to selective aspects of mid-life cognition after controlling for obesity-related comorbidities, while addressing limitations of previous research including employment of an adequate sample, a healthy-weight control group, and stringent exclusion criteria. Further investigation into the functional impact of such deficits, the mechanisms underlying these poorer cognitive outcomes, and the impact of weight-loss on cognition is required