ALZHEIMERS-DISEASE AND CUMULATIVE EXPOSURE TO ANESTHESIA - A CASE-CONTROL STUDY

Objective: To evaluate prior exposure to general anesthesia as a poten tial risk factor for Alzheimer's disease (AD). Design: A retrospective , population-based, case-control study. Setting: The Rochester Epidemi ology Resource. Patients: Cases were all incident cases of AD from 197 5 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 con trol for each case was selected from all registrations for care at May o Clinic during the year of onset in the incident case. The case and c ontrol groups each had 252 individuals. Of these, 208 cases and 199 co ntrols had at least one exposure to general anesthesia prior to the ye ar of onset of dementia in the matched AD patient. Measurements: Tne c umulative duration of anesthesia and the total number of general anest hetic exposures prior to the age of onset of dementia and the correspo nding year in each matched control were ascertained. Results: There wa s no significant difference in mean cumulative exposure (in minutes) t o 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 m ore of general anesthesia (OR = 1.63; 95% CI: 0.53-5.04) were associat ed with a significantly increased risk of AD. Conclusion: It is unlike ly that multiple exposures to general anesthesia increase the risk of AD.