Learning Your Risk for Alzheimer’s Disease...

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July 5, 2011

Scientists continue to make advances in new tests that may predict for Alzheimer’s disease, in some cases years before memory loss and thinking problems become apparent. They can test for genes that increase your risk for the disease, MRI or PET scans that look for telltale changes in the memory centers of the brain, and blood tests and spinal taps to look for substances in the blood or spinal fluid that may indicate you may be on the road to Alzheimer’s, though these tests are still in an experimental phase.

But experts and medical ethicists, as well as the millions of people concerned about developing the disease, also continue to debate whether knowing you may be at heightened risk for Alzheimer’s is a good thing or not. Since there are no effective treatments to stave off the disease’s effects on the brain, does it help to know that you are likely to get it?

A new study from the journal Health Economics found that consumers place a high value on information to help them predict their future health – and are even willing to pay out-of-pocket for the information. In a large national survey conducted via the Internet by researchers at Tufts Medical Center, 72 percent of people said that they would take a hypothetical predictive test to find out if they will later develop Alzheimer's disease, even if the tests were not perfectly accurate. Even more wanted tests to predict breast or prostate cancer or arthritis.

"This study brings us a step closer to understanding people's preferences and motivations for wanting a diagnostic test, even if it has no bearing on subsequent medical treatment," said lead author Peter J. Neumann, ScD, director of the Center for the Evaluation of Value and Risk in Health at the Institute for Clinical Research and Health Policy Studies at Tufts Medical Center. "While we have to proceed cautiously in this area, given that tests have costs and risks as well as benefits, our study suggests that many people value information—both for its own sake and because they will adjust lifestyle and behavior choices accordingly."

Gender, age, and education appeared to influence test participation. Generally, older respondents, women, those with a bachelor's or higher degree, and those with healthier behaviors were less inclined to undergo testing, even if it were free. Among those not wanting the test, major concerns expressed included the cost of the test, living with the knowledge of one's disease risk, and the lack of preventive measures.

Test results may alter future behavior. When faced with positive test results, individuals indicated they would change certain aspects of their lives. More than half said they would spend more time with loved ones, and almost as many said they would concentrate on putting their finances in order. Almost a third said they would travel more.

Other research has shown that those who learn they may be at increased risk for Alzheimer’s are more likely to buy long-term care insurance. They are also more likely to start exercising more, and to turn to nutritional supplements and vitamins, even though these measures have not been proven to protect against Alzheimer’s.

One study from 2009 called the Risk Evaluation and Education for Alzheimer’s Disease, or REVEAL, looked at people who had learned that they carry the APOE-E4 gene, which confers an increased risk but no guarantee that you will develop Alzheimer’s in old age. The researchers found that any depression or anxiety that ensued from learning the test results was not long lasting. They found that at six weeks, those who had learned they carried the APOE-E4 gene showed some signs of distress. But anxiety, depression and stress levels were not heightened after six months or a year.

Those who inherit one copy of the APOE-E4 gene from a parent are at three- to five-fold increased risk of developing Alzheimer’s compared to those who don’t carry the gene. And those who carry two copies of the gene are at 15-fold risk of developing Alzheimer’s. Still, many people who have the gene never develop Alzheimer’s.

Some experts argue it is better not to test for this Alzheimer’s gene, as the test is not definitive and only tells you that you may be at increased risk for developing the disease. Furthermore, there are currently no effective treatments for halting the downward progression of disease, and getting the test, they argue, will only lead to heightened stress and anxiety for some people.

By ALZinfo.org. Reviewed by William J. Netzer, Ph.D., Fisher Center for Alzheimer's Research Foundation at The Rockefeller University.

Source: Joshua T. Cohen, James K. Hammitt, Thomas W. Concannon, Hannah R. Auerbach, ChiHui Fang, and David M. Kent : "Willingness to Pay for Predictive Diagnostic Information with No Immediate Treatment: A Survey of U.S. Residents," Health Economics, published online before print, 28 December 2010: doi: 10.1002/hec.1704; Institute for Health Technology Studies (InHealth).

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