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Breaking the Diabetes-Alzheimer's Connection

David Mendosa Health Guide January 04, 2009
  • Researchers finally know why people with diabetes are more likely to get Alzheimer's disease. That alone would be big news. The huge news is that we now know what we have to do to break the link.

    Did you miss the growing number of reports in the past few years about how those of us who have diabetes are more likely to get Alzheimer's as we age? I can understand, because until last year I ignored the evidence myself. We have enough on our plate already without worrying about a possible complication many years down the road that until now nobody knew how to prevent anyway.

    Lately many of our diabetes journals are reporting the link. For example, the January 2009 issue of Diabetes Care reported the French Three-City Study of "Metabolic Syndrome and Risk for Incident Alzheimer's Disease or Vascular Dementia." The January 2009 issue of Diabetes reported the results of a study of twins, finding that, "Diabetes increases the risk of Alzheimer disease and vascular dementia."



    Cerebral blood volume in
    a person with diabetes
    (warmer colors = more activity)
    Courtesy: Taub Institute

    But now researchers at the Taub Institute for Research on Alzheimer's Disease and the Aging Brain at Columbia University Medical Center have some great news for all of us. Their study, "The Brain in the Age of Old: The Hippocampal Formation is Targeted Differentially by Diseases of Late Life," just appeared in the December issue of Annals of Neurology. This study was built upon an extensive, ongoing epidemiological imaging study that evaluated 240 healthy elders in Manhattan.

    Only the abstract of the study is free online. But recently a spokesperson for the authors sent me the full-text of the study under embargo.

    The key for everyone to prevent Alzheimer's is to control blood glucose levels, the study concludes. "Maintaining glucose control, even in the absence of disease, should be strongly recommended to preserve cognitive health" is the way that lead author Scott Small, M.D., associate professor of neurology at Columbia University Medical Center, phrases it in the study.

    That's such good news for us because that's exactly what we have to do anyway to control diabetes!

    The study emphasizes physical exercise. "By improving glucose metabolism," it says, "physical exercise also reduces blood glucose." That's the point that The New York Times picked up on in its review of the study. The Times even quoted my friend Sheri Colberg, Ph.D., whose new book, Diabetic Athlete's Handbook, just came out.

    It is, of course, true that physical exercise can help us control our blood glucose levels. But we know that physical activity is hardly the only way to control our blood glucose levels. Dr. Small knows that too, and in fact the very last words of the study talk about the other two legs of the diabetes control tripod -- diet and medication.

    "Whether through physical exercise or other behavioral or pharmacological interventions," the research report states, "our results suggest that improving glucose metabolism is a clinically tractable approach for ameliorating the cognitive slide that occurs in all of us as we age." Blood glucose levels do tend to rise as we grow older, Dr. Small says.


  • But don't let that lead you to a fatalistic acceptance. They don't have to. Just think of Dr. Richard K. Bernstein, who is 74 and has been able to keep his A1C level below 4.5 percent for about 40 years. It's the same mistake as thinking that diabetes is "a progressive disease."

    After reading about how we can break the link between diabetes and Alzheimer's disease, I no longer fear it. I know that by controlling our diabetes -- which means controlling our blood glucose levels -- we can be healthier than we ever were before our diabetes diagnosis.