Memory Loss Not Inevitable With Age

Many in 90s Are Free of Alzheimer's, Able To Live Independently

From the WebMD Archives

Feb. 11, 2003 -- It seems that 90-plus birthday candles aren't the only things being blown concerning those who manage to reach that elusive 10th decade of life. So are opportunities for nonagenarians to live independently, typically by well-meaning but misguided loved ones who believe Alzheimer's disease and other forms of dementia will inevitably occur.

In reality, many people reach their 90s with no signs of memory loss or symptoms so minor that they are able to continue routine chores and activities without assistance, Mayo Clinic researchers report in the Feb. 11 issue of Neurology. In their study, fully one-half of the 111 nonagenarians -- people 90-99 years old -- had no signs of clinically measurable memory loss, while another 12% had only mild cognitive impairment. Only about one in three had dementia.

"There are a lot perceptions out there that once you reach your 90s, the odds are great that you will be functionally impaired and unable to take care of yourself," says Ronald Petersen, MD, director of the Mayo Alzheimer's Disease Research Center. "In fact, that need not be the case.

"While dementia is a major problem for people that age, it is not inevitable," he tells WebMD. "Unfortunately, many times adult children think it may be, and take over for their aging parents because they feel they should. But it's not necessarily because they have to."

The nonagenarians' average age was 94 when the study was conducted -- approaching two decades beyond the typical U.S. average -- and all were residents of Rochester, Minnesota, where the Mayo Clinic is located. On a state-by-state basis, Minnesotans statistically enjoy some of the longest life expectancies, and having access to quality medical care is a well-documented contributor to an extended lifespan.

However, the researchers did make some personal observations.

"One of the things that struck me is that most of the people we studied who lived into their 90s -- whether or not they had dementia -- had at least one parent who lived into their 80s or 90s," says lead investigator Bradley Boeve, MD, who personally examined each participant. "And while some were obese, the vast majority of the study participants and those who had no signs of memory loss were thin. And there is compelling research on both humans and animals that a calorie-restrictive diet is associated with a longer lifespan."

However, they were not without health problems. "Many were cancer survivors and some had surgery or chemotherapy for two or three different types of cancer," Boeve tells WebMD. "A fair number had heart attacks and some even had heart surgery when they were in their 80s, and this treatment allowed them to live longer. I think that this suggests that we need to look beyond age as the major factor -- whether it's in treating medical problems or how we perceive their cognitive abilities."

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SOURCES: Neurology, Feb. 11, 2003 • Neurology, Sept. 24, 2002 • Neurology, Jan. 24, 2002 • Alzheimer's Foundation • Ronald Petersen, MD, PhD, director of the Mayo Alzheimer's Disease Research Center; professor of neurology, Mayo Medical School • Bradley Boeve, MD, behavioral neurologist and assistant professor of neurology, Mayo Medical School.
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