Age and Dementia Don't Have to Go Hand in Hand
July 14, 2000 -- "You're not getting older, you're getting better." Nice slogan, but can it really happen? Not exactly, say Alzheimer's disease researchers, but you can get older without getting worse mentally. In fact, there is evidence that some people are still hitting on all mental cylinders well after age 90, according to studies presented at the World Alzheimer Congress 2000.
But avoiding the confusion and memory loss seen in Alzheimer's disease probably depends on a combination of genetics, lifestyle, education, and just plain luck.
Perhaps most encouraging is the news from Mary N. Haan, MPH, DrPH, who studied about 6,000 volunteers aged 65 or older and followed them over seven years. During that time she says that 70% of the volunteers had no change in a test that measures mental acuity during the course of the study. Haan says that persons who did score lower over time were likely to have the genetic marker for Alzheimer's disease and risk factors for heart disease such as high blood pressure, high cholesterol, and diabetes. "It's a case of two plus two adding up to eight," she tells WebMD. Haan is now an associate professor of epidemiology in the school of public health at University of Michigan in Ann Arbor.
Haan, who was at the University of California-Davis until last month, says education also influences cognition. When she checked the educational level of the volunteers, she found that being at least a high school graduate lower the risk of cognitive decline. She says, "those with nine to 11 years of education had some change, but the most rapid decline in cognition was associated with those who had less than nine years of education."
John C. Morris, MD, "healthy brain aging can occur after 90. Alzheimer's disease is not inevitable." Morris, who is co-director of the Alzheimer's Disease Research Center at Washington University in St. Louis, presented findings of brain studies from a study started in 1979. This ongoing study attempts to quantify changes associated with aging.
He reported on the results of brain tests of 69 volunteers who lived to be 90 or older. Twenty-five of the volunteers had no evidence of Alzheimer's disease when the study began, but at the time of death, only seven still had no clinical evidence of Alzheimer's disease. At autopsy, however, one of the seven actually did have evidence indicating early state Alzheimer's disease, Morris tells WebMD. On the other hand, the majority of these older adults did develop Alzheimer's disease.
But the other six had no evidence of mental decline, says Morris. He says, however, that "we have no idea why these six survived intact. ... They had a wide range of occupations and they came from diverse ethnic backgrounds." He says that when they died, not only was there no evidence of Alzheimer's disease in their brains but also no evidence of stroke, a finding that ties into Haan's data on heart disease risk factors and risk for mental decline.