If you only read the headlines this week, you might think that taking Viagra could keep the spark alive in your brain, as well as in other parts of your anatomy. It’s being reported that Viagra — along with similar drugs, such as Cialis — may lower the risk of developing Alzheimer’s in men. This is based on a new study conducted by researchers at University College, London, and published in the latest edition of the journal Neurology.
“Once researchers adjusted for other factors that could affect the rate of Alzheimer’s disease, such as age, smoking status and alcohol consumption, they found that people who took erectile dysfunction drugs were 18% less likely to develop Alzheimer’s than people who did not take the drugs,” the American Academy of Neurology reported. Those who were issued more prescriptions for the erectile-dysfunction drugs were least likely to develop the disease.
Cue the irresistible headlines.
But there are several problems with this.
The first is that another study, conducted by the U.S. National Institutes of Health, found the opposite — that taking Viagra or Cialis does not reduce the risk of Alzheimer’s and related dementias.
There was also a third study, which like the most recent one did find an association between Viagra and lower dementia risk. So now we’re left guessing. Each study has its constraints and caveats. Which one should we be guided by?
Meanwhile, the latest study raises more questions than it answers.
It was based just over 1,100 newly diagnosed Alzheimer’s cases in a group of nearly 270,000 men age 40 and over. That’s a very small percentage. And the median follow-up period was just five years.
What percentage of the people in the study who go on to develop dementia will have done so within those five years? We really want to know how many will develop dementia over 20 years or longer.
And we don’t even know which way the causation flows, if it’s there at all. Did the Viagra protect some of these people from developing dementia? Or was it the case that people who were already in the early, undiagnosed stages of Alzheimer’s were simply much less likely to go to their doctor and ask for a prescription for Viagra? Or maybe it was the sex, not the Viagra, that lowered the risk of Alzheimer’s.
“The study does not prove that erectile dysfunction drugs reduce the risk of Alzheimer’s disease,” the AAN said. “It only shows an association.”
I reached out to the authors of the new study. I haven’t heard back yet.
