Recent research suggests that medications commonly used to treat erectile dysfunction (ED) may also help reduce one’s risk of developing Alzheimer’s disease. This revelation comes from a large study conducted at University College London in the United Kingdom, which tracked the health records of about 270,000 men over several years.
The primary focus of this study was on phosphodiesterase type 5 (PDE5) inhibitors, a class of drugs that includes sildenafil (Viagra), tadalafil (Cialis), vardenafil (Levitra), and avanafil (Stendra). These medications are well-known for their ability to treat ED by enhancing blood flow, but they also have potential benefits for cardiovascular and cognitive health.
The present study included 269,725 men with a new diagnosis of erectile dysfunction between 2000 and 2017. Those with a prior history of cognitive impairment or dementia were excluded to ensure a more accurate assessment of Alzheimer’s risk. The average age of participants at the start of the study was 58.5 years, and the median follow-up period was 5.1 years. During this time, 1,119 men were newly diagnosed with Alzheimer’s disease.
A total of 749 men who used PDE5 inhibitors developed Alzheimer’s, translating to an incident rate of 8.1 per 10,000 person-years at risk. In contrast, 370 men who did not use these drugs were diagnosed with Alzheimer’s, with an incident rate of 9.7 per 10,000 person-years.
Over the median follow-up period, men who began using PDE5 inhibitors showed a significant reduction in their likelihood of receiving an Alzheimer’s diagnosis compared to those who did not use these drugs. Specifically, the researchers found that men on PDE5 inhibitors had a 18% lower risk of Alzheimer’s disease, indicating a hazard ratio of 0.82.
In medical research, a “hazard ratio” (HR) is a measure used to compare the risk of a certain event happening at any given point in time between two groups. Therefore, in the context of this study, an HR of 0.82 means that the group taking PDE5 inhibitors had an 18% lower risk of developing Alzheimer’s compared to the group not taking the drugs. An HR less than 1 shows a reduced risk, while an HR greater than 1 indicates an increased risk.
Interestingly, the protective effect of PDE5 inhibitors appeared to be dose-dependent. Men who had more than 20 prescriptions for these medications exhibited even greater reductions in Alzheimer’s risk. The individuals with 21 to 50 prescriptions of these medications had a hazard ratio of 0.56, and those with more than 50 prescriptions had a hazard ratio of 0.65.
The potential cognitive benefits of PDE5 inhibitors are also supported by animal studies, where sildenafil has been shown to improve memory and cognitive function, enhance synaptic plasticity (i.e., the adaptability of the connections between neurons in the brain), and reduce amyloid plaques, which are associated with Alzheimer’s. Tadalafil has also demonstrated similar effects in animal trials. However, translating these findings to humans is still a challenge, and more research is needed to confirm these benefits in clinical settings.
One of the limitations noted in the study is the reliance on electronic health records and insurance claims data, which may reflect an underdiagnosis or misdiagnosis of dementia. While the findings are promising, the data must be interpreted with caution due to potential biases in diagnosis and classification.
Given these limitations, there is a need for additional studies to explore the underlying mechanisms of PDE5 inhibitors in reducing Alzheimer’s risk. The authors of this study emphasized that a well-designed randomized controlled trial is necessary to establish a causal relationship and consider PDE5 inhibitors as a potential preventive measure for Alzheimer’s disease.
References:
Adesuyan, M., Jani, Y. H., Alsugeir, D., Howard, R., Ju, C., Wei, L., & Brauer, R. (2024). Phosphodiesterase type 5 inhibitors in men with erectile dysfunction and the risk of Alzheimer disease: A cohort study. Neurology, 102(4). https://doi.org/10.1212/WNL.0000000000209131
Brauer, R., et al. (2024). Erectile dysfunction drugs tied to less Alzheimer’s risk. Neurology. Retrieved from MedPage Today. https://www.medpagetoday.com/neurology/dementia/108626