Coronary artery bypass grafting is not a risk factor for dementia or Alzheimer disease

Objective: To study coronary artery bypass grafting (CABG) as a risk factor for dementia and Alzheimer disease ( AD) using a case-control design. Methods: The authors used the records-linkage system of the Rochester Epidemiology Project to ascertain incident cases of dementia in Rochester, MN, for the 5-year period 1990 to 1994. The authors defined dementia and AD using the criteria of the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV). Each case was individually matched by age (+/- 1 year) and sex to a person drawn randomly from the same population, and free of dementia in the index year ( year of onset of dementia in the matched case). Results: Among 557 dementia cases, 24 (4.3%) had undergone a CABG prior to the onset of dementia with a median lag time of 5.5 years (range = 0.1 to 15.9). Among 557 controls, 28 subjects (5.0%) had undergone a CABG prior to the index year with a median lag time 3.9 years (range = 0.1 to 12.3); OR = 0.85 (95% CI = 0.49 to 1.49; p = 0.57) for dementia and OR = 0.78 ( 95% CI = 0.39 to 1.56; p = 0.48) for AD. The findings did not change after adjustment for education. The perioperative courses of cases and controls were comparable. Analyses including only the 481 cases of dementia with presumed neurodegenerative or cerebrovascular etiology were also negative. Conclusions: This population-based case-control study suggests that coronary artery bypass grafting is not a major risk factor for dementia overall, or for Alzheimer disease.