Those are two of several theories being tested by researchers, an expert on the disease said Thursday.
But most research still centers on identifying genes that cause Alzheimer's, which Rudolph Tanzi said is like "finding a needle in a haystack."
Tanzi spoke to more than 300 people, mostly students and faculty, Thursday morning at Kansas University's Budig Hall. He also spoke Thursday evening at the Kansas Union. His appearance was part of the Takeru Higuchi Memorial Lecture series.
Tanzi, professor of neurology at Harvard Medical School and director of the Genetics and Aging Unit at Massachusetts General Hospital, said that after age, family history is the most common risk factor for Alzheimer's.
That's why researchers are attempting to identify the genes that cause the disease. About 100 genes have been identified so far, but Tanzi said 80 or 90 percent remain unknown.
Alzheimer's affects 4 million people in the United States, but is expected to reach 14 million in the next 40 years, as the population continues to age.
Other research has shown high cholesterol encourage Alzheimer's, and that education -- which builds synapses, or connections between brain cells -- could help slow the onset.
"So you save up synapses like money in the bank," he explained.
The key to future Alzheimer's treatment will be identifying the at-risk genes early, before the disease's onset.
That could lead to a new legal battle over "genetic discrimination," Tanzi said, because insurance companies could use the genetic information to drop coverage for those at risk. He suggested adding "DNA sequence" to lists of nondiscrimination that usually include race and religion.
"With all this great hope for genetic treatment, we're going to be stopped at genetic testing if people cannot protect their own genome," he said.
-- Staff writer Terry Rombeck can be reached at 832-7145.