During the study, 1,119 men in the cohort were diagnosed with Alzheimer's disease.
Researchers noticed a distinctive pattern. Men who were prescribed Viagra or similar drugs had an 18 percent lower risk of developing Alzheimer's disease compared to men who were not prescribed the drug.
Researchers also found an even greater difference among men who used Viagra more frequently. Among the heaviest users based on total prescriptions, he had a 44% lower risk of being diagnosed with Alzheimer's disease. (Men with erectile dysfunction are instructed to take Viagra only before sex and no more than once a day.)
Ruth Brauer, Lecturer in Pharmacoepidemiology at University College London School of Pharmacy, said: “We are excited about the results of this study, but even more excited that this study shows that there are many diseases that need further research. “This is because I feel it has the potential to lead to high-quality research in this field.” and the principal investigator of this study.
There are limits to what conclusions can be drawn from the research results. The study results show a link between Viagra use and reduced risk of Alzheimer's disease, but do not prove causation. For example, Viagra use may be an indicator of improved overall health, and men who have more sex may also be more physically active. Brauer said physical activity is independently associated with a lower risk of Alzheimer's disease.
Why Viagra may be associated with lower risk of dementia
Sildenafil, the generic name for Viagra, was never intended to be a sex drug. Pfizer was developing the drug as a cardiovascular drug to treat high blood pressure and a type of chest pain called angina. The company was conducting clinical trials using sildenafil as a heart treatment drug when some patients reported an unexpected side effect: erections.
Viagra is part of a class of drugs known as phosphodiesterase type 5 inhibitors, or PDE-5 drugs. This drug works by dilating blood vessels and increasing blood flow throughout the body, including the penis. Since Sildenafil was discovered as a treatment for erectile dysfunction, it has also been used to treat pulmonary arterial hypertension in both men and women.
There is a strong link between heart health and sexual health. Erectile dysfunction may be an early warning sign of coronary artery disease. And an unhealthy vascular system is one of the reasons why men start having problems with erections.
Vascular risk factors have also been linked to certain types of dementia, such as Alzheimer's disease, so researchers were interested in whether treating erectile dysfunction could also affect brain health. ing.
Animal studies of PDE-5 inhibitors have shown that the drugs may help prevent cognitive dysfunction by partially increasing blood flow in the brain, but available research shows that The reviewers said the effectiveness of this class of drugs “remains unclear.” ” And Brauer said the findings in animals are only a “possible mechanism” in humans.
“The idea is that if we can help improve blood flow in the brain, we might also reduce the risk of Alzheimer's disease,” said Sebir Yasar, associate professor of medicine at Johns Hopkins University and co-author of the study. . An editorial accompanying a study in neurology.
Other reasons for effectiveness
Stanton Honig, a professor of urology at Yale University School of Medicine, said the latest research is far from conclusive. “No conclusions can be drawn” from the study because “so many other factors” are involved besides whether men take erectile dysfunction medications.
“People who are more likely to take such drugs at age 70 are probably more active and more likely to be more involved with their partners,” Honig said. “There are too many confounding variables to say for sure whether it's the drug or whether it's the patients who are taking the drug who are less likely to develop neuropathy.”
The average “pack” per prescription is four pills, Brauer said. However, it is unclear whether the men took all the pills prescribed and, if so, how often.
“We don't know whether people are using prescription drugs as intended, and we can't measure sexual activity or physical activity levels,” Brauer said. “Further research is needed to show whether our results apply to a group of men without erectile dysfunction. Even better, it would be better to conduct our study in a group of men and women.” ”
Previous studies on different populations have reached somewhat contradictory conclusions. A Cleveland Clinic study found that people using sildenafil had a significantly reduced risk of Alzheimer's disease, said Fei Xiong, director of Cleveland Clinic's Genome Center and principal investigator on the study.・Mr. Chen said. However, a study by researchers at Harvard Medical School and the National Institute on Aging found “no association” between the use of sildenafil and other PDE-5 inhibitors and the risk of Alzheimer's disease. said Rishi Desai, an associate professor at Harvard Medical School. school.
Rebecca Edelmeyer, senior director of scientific engagement at the Alzheimer's Association, said in an email that it remains unclear whether Viagra and similar drugs affect the risk of Alzheimer's disease. “Further research and specially designed randomized clinical trials are necessary steps,” she said.
For now, the study results do not suggest that men should start taking Viagra if they don't need it. However, we know that Viagra is an effective treatment for erectile dysfunction, and men with this problem should see their doctor to discuss both their sexual and cardiovascular health.
“You shouldn't take Viagra to reduce your risk,” Yasar says. “You should eat healthy. You should exercise. There's a lot of evidence for that.”
Have questions about human behavior or neuroscience? Email BrainMatters@washpost.com I may answer this in a future column.
