The risk of sexual dysfunction in men increases as the number of medications they take rises, a new study says.

Researchers found that men who took 10 or more medications were almost twice as likely to have erectile dysfunction (ED) as men who took less than two.

Study results remained stable despite the type of medication being taken and even after controlling for other ED risk factors: age, body mass index, diabetes and smoking history.

“The findings from this study suggest that a crucial step in the evaluation of ED would be to review the current medications the patient is taking and their potential side effects,” said study researcher Dr. Diana C. Londoño, a urologist at Kaiser Permanente Los Angeles Medical Center.

For the study, about 38,000 men from Southern California, ages 46 to 69, were surveyed about their medication use and how often they had an erection rigid enough for sexual activity. More than half of the men surveyed were taking more than three medications.

Based on their responses, 29 percent of the men were determined to have moderate to severe ED; of these, 31 percent were taking 10 or more meds, and just 16 percent taking two or fewer meds.

Researchers found the severity of ED increased as the number of medications increased. They theorize that interactions between medications may play a role in ED – i.e., possible side effects of any one medication may not lead to ED, but taken together they may. The study findings were published in the British Journal of Urology this week.

Medications commonly associated with ED include those treating high blood pressure, depression and those that interfere with testosterone levels.