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Monday, July 28, 2008

Rates of Mild Cognitive Impairment Higher Than Anticipated (Alzheimers)


More from the Alzheimer's Association International Conference on Alzheimer's Disease 2008

"These results underscore the urgency of developing new and better strategies to create disease modifying therapies for Alzheimer's. In addition, for public health purposes, we need to know how many people are cognitively impaired and potentially on the road to Alzheimer's," Petersen added.



Rates of Cognitive Impairment Higher Than Anticipated

As the field of Alzheimer's research moves toward earlier treatment and ultimately prevention, it becomes necessary to identify patients at the earliest point in the disease. Mild Cognitive Impairment (MCI) is the term used to describe the intermediate state between normal aging and the very earliest features of Alzheimer's, but its frequency in the population is not known.

Ronald C. Petersen, MD, PhD, and colleagues at Mayo Clinic, Rochester, MN, are conducting the Mayo Clinic Study of Aging, which is a longitudinal study of people ages 70 to 89 from Olmsted County, Minnesota. One of the goals of the Study is to follow healthy subjects over time to detect the earliest point of cognitive impairment. In 2004, the researchers recruited 1,786 people who were found to be cognitively normal, and reevaluated them a year later. All subjects underwent a baseline evaluation including an interview of the subject and their study partner by a nurse, a cognitive assessment, and a neurological exam by a physician.

Individuals in the study developed MCI at a rate of about 5.3 percent per year, and this rate was higher with advanced age – about 3.5 percent per year for 70-79 year olds and about 7.2 percent per year for 80-89 year olds. Men were nearly twice as likely to develop MCI as women.

"The rate of new MCI cases in this group was considerably higher than anticipated," Petersen said. "If we extrapolate Alzheimer's incidence rates to MCI, we would expect perhaps 1 to 2 percent per year, but our findings were substantially higher than that."

"These results underscore the urgency of developing new and better strategies to create disease modifying therapies for Alzheimer's. In addition, for public health purposes, we need to know how many people are cognitively impaired and potentially on the road to Alzheimer's," Petersen added.