Resting-state network functional connectivity before and after bariatric surgery.

BACKGROUND: Bariatric surgery is an increasingly popular treatment for patients with severe obesity and related health issues (e.g., diabetes, cardiovascular disease). Studies have identified alterations in functional connectivity both in obesity and following surgical treatment for severe obesity. OBJECTIVE: This study aimed to assess brain function via resting-state within-network connectivity in bariatric surgery patients with severe obesity. SETTING: University hospital. METHODS: Thirty-four bariatric surgery patients completed functional neuroimaging at baseline and postoperatively (goal, 12 weeks; actual, 16 weeks, on average). They also self-reported health information. Baseline resting-state functional connectivity (RSFC) was predicted by baseline age, body mass index (BMI), continuous positive airway pressure use, and reported history of rheumatoid arthritis and type 2 diabetes. Change in RSFC was assessed using the same predictors. This model was run with and without controlling for baseline RSFC. RESULTS: Higher baseline BMI predicted lower baseline RSFC in 3 networks. Lower baseline RSFC also was related to rheumatoid arthritis and type 2 diabetes. Difference between baseline and follow-up RSFC was strongly negatively associated with baseline RSFC. Controlling for baseline RSFC, type 2 diabetes negatively predicted RSFC difference. CONCLUSIONS: RSFC may reflect brain dysfunction in patients with obesity and related diseases. That less connectivity at baseline predicted greater positive change suggests that RSFC may be a biomarker of neurocognitive improvement following bariatric surgery. Diseases more prevalent in patients with obesity (e.g., rheumatoid arthritis and type 2 diabetes) along with elevated BMI negatively affect RSFC likely through inflammatory pathways.