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    Lose It: Fat Might Raise Dementia Risk

    Obesity Could Increase Risk of Alzheimer's Disease

    What's Going On?

    "Body fat has a profound effect on blood vessels -- it causes stiffening of blood vessels throughout the body, including heart and brain," says Gustafson. However, obesity could also trigger an as-yet-unknown metabolic syndrome that leads to Alzheimer's, she says.

    Gustafson's study is "consistent with emerging evidence," says Lindsay Farrer, PhD, chief of genetics and professor of medical neurology, genetics, and genomics, and epidemiology at Boston University School of Medicine.

    Indeed, evidence suggests that risk factors for cardiovascular disease and Alzheimer's are similar, but no one is sure why. "The smoking gun has yet to come out of the closet," he tells WebMD.

    Should people take weight-reducing drugs to prevent Alzheimer's? "There are lots of reasons to lose weight -- it prevents diabetes, heart disease, high blood pressure, cancer. But taking one of those drugs to prevent Alzheimer's should not be the main reason," Farrer says.

    "Being leaner puts you at lower risk for those other diseases," says Farrer. "But what's protecting you -- is it the fact that you're leaner, or that you don't have diabetes? Diabetes, after all, is a risk factor for Alzheimer's. There are a lot of unmeasured variables."

    Genetics Research Ongoing

    Since 1991, Farrer has led a large, multi-center, multi-ethnic study tracking 1,000 pairs of siblings -- all between ages 60 and 85. The siblings were chosen for the study if one has Alzheimer's, but the other does not.

    As in Gustafson's study, each person has a battery of tests every few years, including brain scans and genetic testing. "We're looking at 100-plus genes that are suspected or known to have a role in [blood vessel changes]," says Farrer.

    "Gene therapy is not necessarily tinkering with the genetic makeup," he tells WebMD. "Here, gene therapy means using genetics to understand more rational approaches -- lifestyle changes -- that accentuate or lessen the effects of these genes."

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