Association of Mild Cognitive Impairment With Exposure to General Anesthesia for Surgical and Nonsurgical Procedures

Abstract

Objective To examine whether exposure to general anesthesia for surgeries and procedures after the age of 40 is associated with incident mild cognitive impairment (MCI) in the elderly. Patients and Methods A population-based prospective cohort of Olmsted County, MN, residents ages 70-89 years on October 1, 2004, underwent baseline and 15-month interval evaluations that included the Clinical Dementia Rating scale, a neurologic evaluation, and neuropsychological testing. Anesthesia records after age 40 until last evaluation for MCI were abstracted. Proportional hazards regression, adjusting for other known MCI risk factors, was used to assess whether exposure to surgical general anesthesia after the age of 40 is associated with the incidence of MCI. Results Of 1,731 participants (mean age 79), 536 (31%) developed MCI during median 4.8 years follow-up. Anesthesia exposure was not associated with MCI when analyzed as a dichotomous variable (any vs. none, adjusted HR 1.07 [95% CI 0.83-1.37]; P=.61), the number of exposures (adjusted HR = 1.05 [0.78-1.42], 1.12 [0.86-1.47], and 1.02 [0.76-1.34] for 1, 2-3, and ≥4 exposures compared to no exposure as the reference; P=.73), or as the total cumulative duration of exposure (adjusted HR =1.00 [0.98-1.01] per 60 min increase, P=.83). In secondary sensitivity analyses anesthesia after age 60 was associated with incident MCI (adjusted HR =1.25 [1.02-1.55], P=.04), as was exposure in the previous 20 and 10 years. Conclusion We found no significant association between cumulative exposure to surgical anesthesia after age 40 and MCI. However, these data do not exclude the possibility that anesthetic exposures occurring later in life may be associated an increase in the rate of incident MCI.

Cognitive decline in the elderly after surgery and anaesthesia: results from the Oxford Project to Investigate Memory and Ageing (OPTIMA) cohort

“…But neither we nor Sprung et al 18 found any such effect. Further, a meta‐analysis of 1063 APOEε4 carriers and 2983 non‐carriers 32 found no association of APOEε4 with increased cognitive decline at 1 year after surgery (OR 1.15, 95% CI 0.71–1.86).…”

“…A few longitudinal studies have examined cognitive 15, 16, 17, 18 or functional decline 16, 30 after surgery. An early study 15, with a wide age‐range (24–86 years), found no association of cognitive performance with a history of general anaesthesia, nor any interaction with age.…”

“…An early study 15, with a wide age‐range (24–86 years), found no association of cognitive performance with a history of general anaesthesia, nor any interaction with age. However, two recent studies 16, 18 have found effects of surgery on cognitive decline in the elderly. One of those studies 18, of 1731 cognitively normal participants, with a mean age of 79 years at recruitment, found no association of surgery after the age of 40 years with incident mild cognitive impairment during a median follow‐up of 4.8 years, but did find a risk of mild cognitive impairment associated with surgery after the age of 60 years or during the 10 years or 20 years before diagnosis of mild cognitive impairment.…”

“…However, two recent studies 16, 18 have found effects of surgery on cognitive decline in the elderly. One of those studies 18, of 1731 cognitively normal participants, with a mean age of 79 years at recruitment, found no association of surgery after the age of 40 years with incident mild cognitive impairment during a median follow‐up of 4.8 years, but did find a risk of mild cognitive impairment associated with surgery after the age of 60 years or during the 10 years or 20 years before diagnosis of mild cognitive impairment. They did not find any increased risk associated with multiple (≥ 4) episodes of surgery, however.…”

“…Short‐term postoperative cognitive dysfunction is well known. But there have been rather few longitudinal studies of longer term (> 3 months) cognitive decline 15, 16, 17, 18. There have been more studies of the risk of dementia, or specifically of Alzheimer's disease, following surgery with general anaesthesia.…”