Drugs used to treat erectile dysfunction may also be associated with a reduced risk of Alzheimer’s disease, according to a study published online in the American Academy of Neurology’s medical journal Neurology.

The study involved nearly 270,000 men with an average age of 59 who had recently been diagnosed with erectile dysfunction. The participants had no memory or thinking problems at the start of the study. They were then followed for an average of five years. The study compared 55% of participants who had prescriptions for erectile dysfunction drugs to 45% who did not.

During the study, 1,119 people developed Alzheimer’s disease. The researchers found that men who took erectile dysfunction drugs were 18 percent less likely to develop Alzheimer’s than people who did not take the drugs. The association was strongest in those who were issued the most prescriptions during the study period.

Erectile dysfunction drugs, which dilate blood vessels to allow more blood to flow, were originally developed to treat high blood pressure.

The researchers point out that the study does not prove that the drugs reduce Alzheimer’s risk, but it does show an association. “More research is needed to confirm these findings, to learn more about the potential benefits and mechanisms of these drugs, and to consider optimal dosing,” says University College London lecturer and study author Ruth Brower. She adds that “a randomized, controlled trial with male and female participants is warranted to determine whether these findings would hold for women.”