When Jena and her colleagues studied the insurance claims from 1997 through 2006 from men over 40 years old, they analyzed the billing code data on 33,968 who had at least one prescription for erectile dysfunction drug filled and compared them with 1,376,838 men who did not have a prescription for an ED drug.

They found that the men who had prescribed drugs for erectile dysfunction were two to three times more likely to contract sexually transmitted diseases (STDs), mainly HIV or Chlamydia, than men who were not prescribed.

This record of 1.4 million men showed that there may well be a significant number of people at risk for contracting and spreading sexually transmitted diseases and that this group had to be targeted for safe-sex counseling.

Approximately 40% of the men in the age group of 57 to 85 had some erectile dysfunction. The blockbuster impotence drug Viagra was prescribed as one of the most popular treatments for erectile dysfunction.

Past research had found that people aged 50 and older were one-sixth time less likely to use a condom and one-fifth less likely to be tested for HIV compared with people in their 20s.

About 20% of the U. S. men over 40 had tried a drug to treat erectile dysfunction.

“Anyone who does not practice safe sex, no matter their age, can contract an STD”, says study author Anupam B. Jena, MD, PhD, of the Massachusetts General Hospital Department of Medicine.

While there is no proven cause-and-effect relationship between erectile dysfunction treatments and sexually transmitted diseases, the results do suggest that people who use such treatments could benefit from intervention such as safe-sex practices that reduce risk of infection.