Over Half of Alzheimer’s Cases May Be Preventable



Scientists can see the terrible effects of Alzheimer’s disease (AD) when they look at brain tissue under the microscope. AD tissue has many fewer 1) ___ cells and synapses than a healthy brain. Plaques, abnormal clusters of 2) ___ fragments, build up between nerve cells. Dead and dying nerve cells contain tangles, which are made up of twisted strands of another protein.


Plaques form when protein pieces called beta-amyloid  clump together. Beta-amyloid comes from a larger protein found in the fatty membrane surrounding nerve cells. Beta-amyloid is chemically “sticky“ and gradually builds up into plaques. The most damaging form of beta-amyloid may be groups of a few pieces rather than the plaques themselves. The small clumps may block cell-to-cell signaling at 3) ___. They may also activate immune system cells that trigger inflammation and devour disabled cells



Tangles destroy a vital cell transport system made of proteins. This electron microscope picture shows a cell with some healthy areas and other areas where 4) ___ are forming.



Over half of all AD cases could potentially be prevented through lifestyle changes and treatment or prevention of chronic medical conditions, according to a study led by Deborah Barnes, PhD, a mental health researcher at the San Francisco VA Medical Center. Analyzing data from studies around the world involving hundreds of thousands of participants, Barnes concluded that worldwide, the biggest modifiable risk factors for AD are, in descending order of magnitude, low 5) ___, smoking, physical inactivity, depression, mid-life hypertension, diabetes and mid-life obesity. In the United States, Barnes found that the biggest modifiable risk factors are physical 6) ___, depression, smoking, mid-life hypertension, mid-life obesity, low education and diabetes. Together, these risk factors are associated with up to 51%of AD cases worldwide (17.2 million cases) and up to 54% of Alzheimer’s cases in the United States (2.9 million cases), according to Barnes.


“What’s exciting is that this suggests that some very simple lifestyle changes, such as increasing 7) ___ activity and quitting smoking, could have a tremendous impact on preventing AD and other dementias in the US and worldwide,“ said Barnes, who is also an associate professor of psychiatry at the University of California, San Francisco. The study results were presented at the 2011 meeting of the Alzheimer’s Association International Conference on Alzheimer’s Disease in Paris, France, and published online on July 19, 2011 in Lancet Neurology.


Barnes cautioned that her conclusions are based on the assumption that there is a 8) ___ association between each risk factor and AD. “We are assuming that when you change the risk factor, then you change the 9) ___,“ Barnes said. “What we need to do now is figure out whether that assumption is correct.“ Senior investigator Kristine Yaffe, MD, chief of geriatric psychiatry at SFVAMC, noted that the number of people with Alzheimer’s disease is expected to 10) ___ over the next 40 years. “It would be extremely significant if we could find out how to prevent even some of those cases,“ said Yaffe, who is also a professor of psychiatry, neurology and epidemiology at UCSF.


ANSWERS 1) nerve; 2) protein; 3) synapses; 4) tangles; 5) education; 6) inactivity; 7) physical; 8) causal; 9) risk; 10) triple


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