Alzheimer's Disease May Affect More People.

• Position: Brief Article - Statistical Data Included

Decline in memory in older persons is frequently due to Alzheimer's disease (AD) pathology. Current estimates put the number of people with AD in the U.S. at 4,000, 000, but a study by David Bennett, director of the Rush Alzheimer's Research Center at Rush-Presbyterian-St. Luke's Medical Center, Chicago, Ill., suggests that the actual number may be much larger. He examined the rate of change in memory function over six years in nearly 750 older nuns, priests, and brothers participating in the Religious Orders Study, a longitudinal clinical-pathologic study of aging and AD. In addition, Bennett measured the amount of Alzheimer's disease pathology in the first 100 participants who had a brain autopsy.

The research studied the extent to which people with mild cognitive impairment are really expressing the earliest manifestations of the pathology of Alzheimer's disease--as opposed to having mild cognitive impairment from some other cause. Persons with mild cognitive impairment declined faster on memory tests than those with no cognitive impairment. Furthermore, Alzheimer's disease pathology was already present to a large degree in persons who died with mild cognitive impairment.

Because there is no consensus on how to diagnose mild...