Washington A subtle change in a memory-making brain region seems to predict who will get Alzheimer's disease nine years before symptoms appear, scientists reported Sunday.
The finding is part of a wave of research aimed at early detection of the deadly dementia - and one day perhaps even preventing it.
Researchers scanned the brains of middle-aged and older people while they were still healthy. They discovered that lower energy usage in a part of the brain called the hippocampus correctly signaled who would get Alzheimer's or a related memory impairment 85 percent of the time.
"We found the earliest predictor," said the lead researcher, Lisa Mosconi of New York University School of Medicine. "The hippocampus seems to be the very first region to be affected."
But it is too soon to offer Alzheimer's-predicting PET scans. The discovery must be confirmed. Also, there are serious ethical questions about how soon people should know that Alzheimer's is approaching when nothing yet can be done to forestall the disease.
Still, the discovery may provide leads to scientists searching for therapies to at least delay the onset of the degenerative brain disease. It already affects 4.5 million people in the U.S. and is predicted to strike 14 million by 2050 as the population ages.
Moreover, researchers are honing in on lifestyle choices that may help protect the brain in the first place.
"It's exciting that we can even talk about prevention," said William Thies, scientific director of the Alzheimer's Assn. He noted that just 10 years ago there was hardly any research into that possibility.
A brain-healthy lifestyle aside, a big quest is to develop ways to identify Alzheimer's disease before symptoms emerge - finding biomarkers that could be targets for preventive therapies.
The National Institute on Aging, with financial help from the pharmaceutical industry and Alzheimer's Assn., is beginning a $60 million study to scan the brains of 800 older Americans and pin down Alzheimer's earliest biological changes.
That Alzheimer's begins developing so early means even young people should adopt a brain-healthy lifestyle, said Dr. Mark Sager of the Wisconsin Registry for Alzheimer's Prevention.
"What we're hoping is that 55 is not too late," he said.
Among the findings presented Sunday at the Alzheimer's association's first prevention conference:
¢ People who drink fruit or vegetable juice at least three times a week seem four times less likely to develop Alzheimer's than nonjuice drinkers, according to a study of 1,800 elderly Japanese-Americans. The theory is that juice contains high levels of polyphenols, compounds that may play a brain-protective role.
¢ Less education, gum disease early in life or a stroke were more important than genes in determining who got dementia, concluded a study of 100 dementia patients with healthy identical twins. Education stimulates neuronal growth; gum disease is a marker of brain-harming inflammation.
¢ Decreasing social activity in old age is a risk factor, a National Institute on Aging study suggests. It is not clear if the men in the study became less social because Alzheimer's already was at work, but social activity is mentally stimulating.