Objective To test the hypothesis that exposure to procedures requiring general anesthesia during adulthood is not significantly associated with incident dementia using a retrospective, population-based, nested case-controlled study design. Patients and Methods Using the Rochester Epidemiology Project and the Mayo Clinic Alzheimer's Disease Patient Registry, residents of Olmsted County, Minnesota, diagnosed with dementia between January 1, 1985, and December 31, 1994, were identified. For each incident case, a sex and age matched control was randomly selected from the general pool of Olmsted County residents who were dementia-free in the index year of dementia diagnosis. Medical records were reviewed to determine exposures to procedures requiring anesthesia after the age of 45 and prior to the index year. Data were analyzed using logistic regression. Results 877 cases of dementia, each with a corresponding control, were analyzed. Among dementia cases, 615 (70%) individuals underwent 1,681 procedures requiring general anesthesia, and 636 controls (73%) underwent 1,638 procedures. When assessed as a dichotomous variable, anesthetic exposure was not significantly associated with dementia (OR 0.89, 95% CI 0.73-1.10; P = 0.27). In addition, no significant association was found (P = 0.51) when exposure was quantified as number of procedures (OR = 0.87, 0.86, and 1.0 for 1, 2-3, and ≥4 exposures compared to none, respectively). Conclusion This study found no significant association between exposure to procedures requiring general anesthesia after the age of 45 years and incident dementia.

Introduction Postoperative acute kidney injury (AKI) following arthroplasty has not been well studied. Our aim was to identify factors associated with increased risk of AKI. Methods The medical records for adult patients who underwent elective total joint arthroplasty during June 1, 2007 to May 31, 2010 at the Mayo Clinic were reviewed to identify patients with normal preoperative kidney function who experienced perioperative AKI, defined as an increase in serum creatinine (sCr) by 26.4 lmolÁL -1 . For each AKI case, two controls were identified and matched for age, sex, and type of operation. Medical records were abstracted for demographics, comorbid conditions, and preoperative, intraoperative, and postoperative variables. Conditional logistic regression analyses were performed to identify risk factors for AKI. Results Of the 9,171 patients who underwent joint replacement operations, 167 with normal preoperative renal function developed AKI with a median [25 th , 75 th ] increase in sCr of 35.4 [26.4, 44.2] lmolÁL -1 . No patient required dialysis. A higher than normal body mass index, diabetes mellitus, the number of baseline antihypertensive medications, cerebral or peripheral vascular disease, use of general anesthesia, and perioperative blood transfusions were independently associated with risk for AKI. Hospital length of stay and intensive care admissions were greater in AKI patients, and in 12.0% of patients, sCr remained at least 26.4 lmolÁL -1 higher than preoperative baseline at least three months after surgery. Conclusion In this case-control investigation, we identified several factors associated with the development of postoperative AKI. Recognition of these risk factors could allow for the adoption of perioperative renal protective strategies in patients undergoing arthroplasty.

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Kidney injury following bariatric surgery is not uncommon and is associated with higher body mass index and diabetes. Further, there should be a high risk of suspicion for kidney injury in postoperative patients developing volume depletion.