The Association Between Surgery and Mild Cognitive Impairment: Insight from a Case-Control Study.

Background: Surgery may be associated with postoperative cognitive impairment in elder participants, yet the extent of its association with mild cognitive impairment (MCI) remains undetermined. Objective: To determine the relationship between surgery and MCI. Methods: The data of participants from the Alzheimer's Disease Neuroimaging Initiative were analyzed, including individuals with MCI or normal cognition. We focused on surgeries conducted after the age of 45, categorized by the number of surgeries, surgical risk, and the age at which surgeries occurred. Multivariable logistic regression was employed to determine the association between surgery and the development of MCI. Results: The study is comprised of 387 individuals with MCI and 578 cognitively normal individuals. The overall surgery exposure (adjusted OR = 1.14, [95% CI 0.83, 1.56], p = 0.43) and the number of surgeries (adjusted OR = 0.92  [0.62, 1.36], p = 0.67 for single exposure, adjusted OR = 1.12 [0.71, 1.78], p = 0.63 for two exposures, adjusted OR = 1.38 [0.95, 2.01], p = 0.09 for three or more exposures compared to no exposure as the reference) were not associated with the development of MCI. However, high-risk surgeries (adjusted OR = 1.79 [1.00, 3.21], p = 0.049) or surgeries occurring after the age of 75 (adjusted OR = 2.01 [1.03, 3.90], p = 0.041) were associated with a greater risk of developing MCI. Conclusions: High risk surgeries occurring at an older age contribute to the development of MCI, indicating a complex of mechanistic insights for the development of postoperative cognitive impairment.