Men over 40 who use erectile dysfunction drugs have higher rates of sexually transmitted diseases, according to a recent Harvard Medical School study.

A tangible impact of the study, according to lead researcher Anupam B. Jena, is that the request for ED medication can serve as a screening tool for STDs. When a patient requests a prescription for an ED drug, physicians should consider the possibility that the individual may have an STD.

Though the findings suggest a strong association between rates of ED medication use and of STDs, the study could not determine whether ED medication actually causes STDs, said Jena, who is a resident physician at Massachusetts General Hospital.

A possible explanation of the correlation is that men who take ED drugs may have sex more often, and are thus prone to increased risk of STDs, according to Jena.

The study, which used information from an insurance database covering employees from 44 large companies in the United States, is the first to analyze a wide group of men of varying sexual orientations, unlike previous studies about STDs that typically use a sample of homosexual men.

Jena noted that certain types of individuals were excluded from the research, including men who use ED drugs but do not have insurance plans, and men who have insurance but receive ED medication outside of their drug plan by paying out of pocket or from illegal internet pharmacies.

Finally, because the individuals classified as having STDs only appear as such in the database because they have billed their insurance company for treatment, the study excluded men who visit free STD clinics or do not consult a doctor for their disease.

The next step after the recent study, Jena said, is to explore the cause-and-effect relationship between the use of ED medication and the rates of STDs among middle-aged men.

The study was published in the Annals of Internal Medicine on Tuesday.