Age is the single greatest risk factor for getting Alzheimer's disease, which has become a worldwide epidemic. More than 5 million Americans are already afflicted, and every 70 seconds another is diagnosed. As 80 million baby boomers begin reaching age 65, concerns about normal age-related memory slips are escalating. Every misplaced key or forgotten name triggers a lingering question of whether that senior moment heralds the insidious onset of Alzheimer's. Thanks to advances in medical technology, people are living longer, but those added years make us more likely to experience Alzheimer's cognitive losses that devastate the lives of those afflicted.
Such concerns have motivated scientists to search for a cure, or at least a way to delay the onset of the disease for as long as possible. No absolute cure yet exists, but early detection methods have allowed testing of novel treatments, even before symptoms emerge. The goal of many studies, including my own, is to protect healthy brains before they are affected, rather than attempt to repair damaged ones. And as this research continues, people want to know what they can do to lower their risk for developing the disease.
Recent studies show that physical exercise, mental stimulation, healthy diet, and other lifestyle factors lower the risk for Alzheimer's disease and delay the onset of symptoms. All this is within our power to protect our brains. But an NIH consensus panel concluded that the available data are inadequate to prove that Alzheimer's can be prevented, and unfortunately, people read those headlines and conclude that they are powerless. So they sit around, don't bother to exercise, eat an unhealthy diet, and don't stimulate their brains. This is a shame, and those people add to their risk for developing Alzheimer's-type symptoms.
I agree with the NIH conclusion that we don't yet have a definitive, long-term study to prove that prevention techniques work; however, the panel did say that many studies of healthy lifestyle habits -- including diet, physical activity, and cognitive engagement -- are providing new insights into the prevention of cognitive decline and Alzheimer's disease.
Definitively proving the effectiveness of Alzheimer's prevention strategies would require double-blind studies on thousands of individuals who would have to be followed for many years, even decades. But evidence from current epidemiological studies and short-term clinical trials has already detailed what we can do now to delay the onset of Alzheimer's symptoms. The studies suggest that people may be able to stave off cognitive decline that leads to Alzheimer's dementia by as many as four years or more. For many individuals, that would mean preventing the disease for their entire lifetime -- today's only available cure.
Physical exercise and a healthy diet, two of the key strategies of the Alzheimer's prevention program, are already accepted by the medical community as proven ways to prevent diabetes. A recent Japanese study showed that diabetes doubles the risk for Alzheimer's disease. Thus, lifestyle strategies that prevent diabetes also would be expected to prevent Alzheimer's disease. UC San Francisco scientists concluded that up to half of Alzheimer's disease cases are potentially attributable to risk factors that are under our control.
It doesn't make sense to wait years for definitive proof before we start a brain-healthy lifestyle. There's no reason to sit around for decades before beginning to protect our brains. Even though we cannot predict exactly who will get Alzheimer's and when, we do know that people who practice Alzheimer's prevention strategies improve their quality of life and reap immediate benefits in memory and health.
Gary Small, M.D., is director of UCLA's Longevity Center and co-author of "The Alzheimer's Prevention Program: Keep Your Brain Healthy for the Rest of Your Life."
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