Neurologist: Retrospective Studies Deserve Attention in Determining Ways to Prevent Alzheimer's

Dorian Martin Health Guide
  • I always worry when someone uses the line, “In retrospect….” Often, it seems like that line is used by a politician who is trying to put some distance from an unpopular vote. Or you hear it from a celebrity who made some poor decisions in their personal life.


    But what if you took the attitude that “hindsight is 20/20” in considering how to prevent Alzheimer’s? That’s what Dr. David Perlmutter, a board certified neurologist who co-authored “Power Up Your Brain: The Neuroscience of Enlightenment” does brilliantly in the Huffington Post article, “Alzheimer’s Prevention:  Reducing Your Risk.” His suggestion – consider retrospective studies when coming up with health-related recommendations, instead of only looking at double-blind placebo-controlled studies with control groups. 

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    His logic behind this recommendation makes a lot of sense. “Take for instance the recommendation that people should wear seat belts in the car,” Perlmutter noted. “This well-founded recommendation is based on the studies that looked back and revealed that a person's risk of serious injury in a car accident was much reduced if that person had been wearing a seat belt. Obviously, we wouldn't need to do a double-blinded study to prove this point, or ever even consider doing so. The point is, retrospective studies are powerful and meaningful.”


    Perlmutter pointed out that several peer-reviewed studies have identified which individuals are at the most risk of being diagnosed with Alzheimer’s. For example, one study that followed participants for 27 years found that having a high amount of body fat increased risk of Alzheimer’s by 293 percent. The neurologist also described a study of 1200 people which determined that individuals who exercised regularly were 40 percent less likely to develop Alzheimer’s.  Other studies that Perlmutter mentioned suggested brain benefits from nonprescription B vitamins, high levels of omega-3 fatty acids, higher education, and engagement in leisure activities.


    Another study involved looking at the effect of aerobic exercise on the brain. Scientific American reported that a research team found that adults aged 44-80 who walked for 40 minutes three days a week for a year saw growth in their hippocampus (which is a critical for memory and spatial reasoning). In comparison, older adults who did a stretching routine did not have hippocampal growth. Reporter Katherine Harmon stated, “The growth of the hippocampus was modest, increasing 2.12 percent in the left hippocampus and 1.97 percent in the right hippocampus, which effectively turns back the clock one to two years in terms of volume. The stretching group, on the other hand, experienced continued reduction in pace with expected age-related losses, losing on average 1.40 percent and 1.43 percent in the volume of their left and right hippocampus, respectively.” The researchers concluded that older adults who start an exercise regimen could enhance cognition and add brain volume.


  • So what should we do? Perhaps we should take the reins of our own care. Perlmutter agrees. “For now, we are being told to pretty much live our lives, come what may and hope for a pharmaceutical magic bullet,” he said. “But the science tells us otherwise, and gives us hope that we can indeed take action today to reduce our risk for Alzheimer's disease.”

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Published On: February 28, 2011