Lifestyle Changes Can Reduce Risk of Alzheimer’s
By OCinSite At-Large on July 19, 2011 8:31 AM | Comments (106)
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By Shirley S. Wang | Wall Street Journal
A new, theoretical analysis finds that about half of the risk factors for Alzheimer’s disease are potentially changeable, and that reducing them could substantially decrease the number of new cases of disease worldwide, according to a study to be presented Tuesday at the Alzheimer’s Association International Conference.
The study is the first known analysis that tries to quantify and compare how risk factors are associated with Alzheimer’s. It will be published Tuesday on the journal Lancet Neurology’s website after the conference presentation.
Factors that increase one’s risk for Alzheimer’s that are considered modifiable include diabetes, high blood pressure, obesity, smoking, sedentary behavior, depression and low educational level, say the authors from the University of California, San Francisco.
In the U.S., physical inactivity is the biggest changeable factor, accounting for 21% of the risk for Alzheimer’s, followed by depression and smoking. Added together, the factors account for about 50% of the risk.
If these risk factors were decreased by just 10%, about 184,000 Alzheimer’s cases in the U.S. and 1.1 million cases world-wide could be prevented, according to the research. A reduction of 25% on all seven risk factors could prevent nearly half a million cases in the U.S. and more than three million world-wide, the analyses showed.
There are some five million people in the U.S. thought to have Alzheimer’s, according to the Alzheimer’s Association, and about 36 million cases globally, according to Alzheimer’s Disease International.
“The estimates suggest that in the population, up to half of Alzheimer’s cases could be modifiable,” said Deborah Barnes, a psychiatry professor at UCSF who will present the results. “If we changed those risk factors…it could have this huge impact” at the population level, she said in an interview.
One caveat to these findings: They are based on mathematical models that predict what might happen if the assumptions on which the model was based are real. In this case, the researchers assumed that the risk factors caused Alzheimer’s disease, which means that if they were modified, the rates of Alzheimer’s would change as well.
In reality, the causes of Alzheimer’s are still unclear, and it hasn’t been proven that stopping smoking, for example, actually lowers one’s risk of getting dementia.
These estimates were calculated based on published data about how frequently the risk factors occur in the population as well as the extent to which each factor increases one’s risk of Alzheimer’s, known as relative risk.
For instance, depression nearly doubles one’s risk of developing Alzheimer’s. Each factor alone increases one’s risk of Alzheimer’s anywhere from about 50% to 100%, according to Dr. Barnes.
The next step in this work is to do prevention trials to try to modify these risks to see if they can actually stave off Alzheimer’s, Dr. Barnes says. She hopes to conduct a trial on physical activity, because it “seems like the biggest bang for your buck,” because it is known to help the brain, the heart and mood, she says.
