The Association Between Reduced Inflammation and Cognitive Gains After Bariatric Surgery

Bariatric surgery is associated with improved cognitive function, although the mechanisms are unclear. Elevated inflammation is common in obesity and associated with impaired cognition. Inflammation decreases after bariatric surgery, implicating it as a possible mechanism for cognitive improvement. The objective of this study was to examine whether reduced inflammation is a possible mechanism for postoperative cognitive improvement in bariatric surgery patients.

Participants were 77 bariatric surgery patients who completed cognitive testing before surgery and 1 year postsurgery. Cognitive domains assessed were attention/executive function, language, and memory. High-sensitivity C-reactive protein (CRP) was assessed at both time points.

Patients exhibited preoperative cognitive impairment, although improvements 1 year postsurgery were seen in both attention/executive function (mean [M; standard deviation {SD}]baseline = 53.57 [8.68] versus M (SD)follow-up= 60.32 [8.19]) and memory (M [SD]baseline= 44.96 [7.98] versus M [SD]follow-up= 51.55 [8.25]). CRP was elevated at baseline and fell into the normative range postsurgery (M [SD]baseline= 0.9 [0.7] versus M [SD]follow-up= 0.2 [0.3] mg/dl). Preoperative CRP was not associated with baseline cognitive function (β values = -0.10 to 0.02) and changes in CRP also did not correspond to changes in cognition postsurgery (β values = 0.02-0.11; p values > .05 for all domains). A trend was detected for smaller improvements in memory among participants with elevated baseline CRP (>0.30 mg/dl) versus those with normal levels (group × time: p = .083).

Improvements in high-sensitivity CRP were not associated with postoperative cognitive benefits. Future studies are needed to explore other inflammatory markers and potential mechanisms of cognitive improvement after bariatric surgery, including improved glycemic control and neurohormone changes.