Typically, Alzheimer s disease is viewed as an affliction over which one has little control; researchers still aren t sure of its etiology and, for the most part, people simply cross their fingers and hope that a few forgetful incidents aren t a sign of worse to come. However, researchers at the University of California, San Francisco, have just pinpointed what they say are seven risk factors for dementia, which, if reduced by even 10 to 25 percent, could prevent nearly 500,000 cases of Alzheimer s each year in the U.S.
In an analysis published online in Lancet Neurology, Dr. Deborah Barnes and Dr. Kristine Yaffe looked at existing literature to calculate the risk factors with the strongest associations to Alzheimer s disease in the U.S. These population attributable risks, which reflect the proportion of disease cases that can be traced to them, are diabetes, midlife hypertension, midlife obesity, depression, physical inactivity, smoking, and low education and mental inactivity. Of the seven, physical inactivity, depression, and smoking are most strongly correlated with Alzheimer s, at rates of 21 percent, 14.7 percent, and 10.8 percent, respectively according to these authors best estimates. (Yet these figures, notes ACSH s Dr. Josh Bloom, should be taken with a grain of salt, as the statistical significance was not strong.)
The researchers conclusions are not without their critics, however. Last year, a National Institutes of Health consensus panel concluded that there was no firm scientific evidence that lifestyle could play a preventive role in Alzheimer s disease. And, while this new analysis provides more data, it s difficult to say to what degree the identified risk factors are causative, as opposed to largely correlative.
While acknowledging that a reduction in the risk factors would benefit public health regardless of its specific benefits for Alzheimer s risk, ACSH s Dr. Gilbert Ross points out that, if medical research can solidify much of the preliminary data on Alzheimer s biomarkers, such as radiological and serum/spinal fluid abnormalities, and pharmaceutical interventions can be found that delay or reverse brain pathology, that would be a truly major advance. Progress toward that goal, he says, may be more practical than hoping for a 25 percent decline in smoking and obesity objectives that are already proving difficult, to say the least.
Still, as ACSH s Dr. Ruth Kava observes, What s important is that these are modifiable factors that people can control themselves. Indeed, the opportunity to lower their risk of developing a devastating disease like Alzheimer s may be the spur that some people need.