Alzheimer's disease and cumulative exposure to anesthesia: a case-control study.
OBJECTIVE
To evaluate prior exposure to general anesthesia as a potential risk factor for Alzheimer's disease (AD).


METHODS
A retrospective, population-based, case-control study.


METHODS
The Rochester Epidemiology Resource.


METHODS
Cases were all incident cases of AD from 1975 to 1984 who resided for 40 years or more in Olmsted County prior to the onset of their dementia (n = 252). One age- and gender-matched control for each case was selected from all registrations for care at Mayo Clinic during the year of onset in the incident case. The case and control groups each had 252 individuals. Of these, 208 cases and 199 controls had at least one exposure to general anesthesia prior to the year of onset of dementia in the matched AD patient.


METHODS
The cumulative duration of anesthesia and the total number of general anesthetic exposures prior to the age of onset of dementia and the corresponding year in each matched control were ascertained.


RESULTS
There was no significant difference in mean cumulative exposure (in minutes) to general anesthesia (patients vs controls: 188.4 vs 170.5 minutes, ns). Neither exposure to six or more episodes of general anesthesia (OR = 1.44; 95% CI: 0.77-2.71) nor cumulative exposure to 600 minutes or more of general anesthesia (OR = 1.63; 95% CI: 0.53-5.04) were associated with a significantly increased risk of AD.


CONCLUSIONS
It is unlikely that multiple exposures to general anesthesia increase the risk of AD.
Bohnen
N I
NI
Department of Health Sciences Research, Mayo Clinic and Foundation, Rochester, Minnesota 55905.
Warner
M A
MA
Kokmen
E
E
Beard
C M
CM
Kurland
L T
LT
D000368:Aged; D000544:Alzheimer Disease / Q000139:chemically induced*; D000758:Anesthesia / Q000009:adverse effects*; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D008297:Male; D016017:Odds Ratio; D012189:Retrospective Studies; D012307:Risk Factors