Objective
To examine whether exposure to general anesthesia for procedures at age ≥40 is associated with prevalent mild cognitive impairment (MCI) in the elderly.
Patients and Methods
A case-control study nested within a population-based cohort. Olmsted County, MN, residents ages 70–89 years, underwent baseline evaluations that included the Clinical Dementia Rating scale, a neurologic evaluation, and neuropsychological testing. Individuals identified with MCI (cases) at enrollment were matched 1:2 on age, sex, education and apolipoprotein genotype with participants who were cognitively normal at the time of the index visit. Medical records from age 40 until the index visit were reviewed to determine exposures to general anesthesia. Conditional logistic regression, taking into account the matched set study design and adjusting for MCI risk factors, was used to assess whether exposure to anesthesia after the age of 40 was associated with prevalent MCI.
Results
A total of 387 MCSA participants (219 males, 168 females) were diagnosed with MCI at enrollment with mean age 81±5 years. Exposure to general anesthesia after the age of 40 was not significantly associated with prevalent MCI when analyzed as a dichotomous variable (any vs. none, adjusted OR 0.97 [95% CI 0.68–1.40]) or the number of exposures OR 1.13 [0.74–1.72], 0.81 [0.53–1.22], and 1.03 [0.67–1.58] for 1, 2–3, and ≥4 exposures, respectively, with no exposure as the reference. Similar results were obtained for anesthesia exposure after the age 60, and during 5, 10 and 20 years prior to the first visit.
Conclusion
Exposure to general anesthesia for procedures at ages ≥ 40 years was not associated with prevalent MCI in the elderly.