ACE Inhibitors and Alzheimer's Disease

Alvin B. Lin, MD, FAAFP

Dr. Lin is an associate professor of family and community medicine at University of Nevada School of Medicine and an adjunct professor of family medicine and geriatrics at Touro University Nevada College of Medicine. He also serves as an advisory medical director for Infinity Hospice Care and as medical director of Lions HealthFirst Foundation. Dr. Lin maintains a small private practice in Las Vegas, NV. The posts represent the views of Dr. Lin, and in no way are to be construed as representative of the above listed organizations. Dr. Lin blogs about current medical literature and news at http://alvinblin.blogspot.com/.

Just 3 days ago, I pointed out a study published in Neurology in which the authors concluded that beta blockers lowered one's risk for loss of cognitive function but that angiotensin converting enzyme (ACE) inhibitors, calcium channel blockers, diuretics, and vasodilators did not. Ironically, in that very same issue, a secondary longitudinal data analysis of the Ginkgo Evaluation of Memory Study was published in which the authors concluded that ACE inhibitors, angiotensin II receptor blockers (ARBs) & diuretics reduced risk for Alzheimer's disease.

To arrive at their conclusion, the authors reviewed over 6 years worth of data for 1,928 adults w/normal cognitive function, who were older than 75yo at study entry. Some benefit was noted w/calcium channel blockers and even beta blockers, too, but w/o statistical significance. Ironic, isn't it then, that last week's study suggested benefit from beta blockers but not ACE inhibitors.

So what are we to make of this quandary & contradictory evidence. First, let's recall that science is never that clear cut and transparent. Second, in the big scheme of things, 5-6 year studies of 800-1900 participants is neither long nor large enough. Third, observational studies such as these are useful for developing hypotheses but not for proving cause and effect. But with all that said, I can't think of a single reason (aside from anaphylactic allergy) not to lower one's blood pressure and pray for secondary benefit, even as we wait for more definitive proof.