Glucose regulation and cognitive function after bariatric surgery

Introduction: Obesity is associated with cognitive impairment, and bariatric surgery has been shown to improve cognitive functioning. Rapid improvements in glycemic control are common after bariatric surgery and likely contribute to these cognitive gains. We examined whether improvements in glucose regulation are associated with better cognitive function following bariatric surgery. Method: A total of 85 adult bariatric surgery patients underwent computerized cognitive testing and fasting blood draw for glucose, insulin, and glycated hemoglobin (HbA1c) at baseline and 12 months postoperatively. Results: Significant improvements in both cognitive function and glycemic control were observed among patients. After controlling for baseline factors, 12-month homeostatic model assessment of insulin resistance HOMA-IR predicted 12-month digits backward (beta = -.253, p < .05), switching of attention-A (beta = .156, p < .05), and switching of attention-B (beta = -.181, p < .05). Specifically, as HOMA-IR decreased over time, working memory, psychomotor speed, and cognitive flexibility improved. Decreases in HbA1c were not associated with postoperative cognitive improvements. After controlling for baseline cognitive test performance, changes in body mass index (BMI) were also not associated with 12-month cognitive function. Conclusions: Small effects of improved glycemic control on improved aspects of attention and executive function were observed following bariatric surgery among severely obese individuals. Future research is needed to identify the underlying mechanisms for the neurocognitive benefits of these procedures.