Early and Midlife Exposure to Anesthesia and Age of Onset of Alzheimer's Disease

Patients with Alzheimer's disease (AD) who have a late onset of dementia may represent a subgroup of AD that has a unique multifactorial/genetic profile. It was hypothesized in the present study that if external factors interact with a biological or genetic susceptibility in at least some subsets of patients with AD, these factors may accelerate the manifestation of the disease. The cumulative exposure to different types of general and major regional anesthetics prior to the onset of dementia was calculated in a population-based study of incident cases of AD residing in Rochester, MN, for more than 40 years preceding the onset of dementia (N = 252). Correlational analysis revealed that age of onset was inversely related to cumulative exposure to general and spinal anesthesia before the age of 50, whereas there was no, or an expected positive, correlation for anesthetic exposure after 50 years. These findings may suggest that the manifestation of dementia in AD patients may be related to exposure to external factors at an earlier age.