3. Controls did not have subjective memory complaints or any of 28 diseases and did not have a history suggestive of a decrease in cognitive function (stroke or transient ischemic attack, seizures, Parkinson's disease, multiple sclerosis, cerebral palsy, Huntington's disease, encephalitis, meningitis, brain surgery, vascular surgery of the brain, diabetes requiring insulin control, improperly managed hypertension, cancer diagnosed within the past 3 years excluding skin cancer, shortness of breath while sitting still, use of home oxygen, heart attack with changes in memory, walking, or solving problems lasting at least 24 hours afterwards, kidney dialysis, liver disease, hospitalization for mental or emotional problems in the past 5 years, current use of medications for mental or emotional problems, alcohol consumption greater than 3 drinks each day, drug abuse in the past 5 years, treatment for alcohol abuse in the past 5 years, unconsciousness for more than one hour other than during surgery, overnight hospitalization due to head injury, illness causing a permanent decrease in memory or other mental functions, trouble with vision that prevents reading ordinary print even with glasses, or difficulty understanding conversations because of hearing even with a hearing aid)