A new study conducted by researchers at the Université de Montréal suggest that gay men with a large amount of sexual partners are at higher risks of developing prostate cancer.
The Montreal study PROTEUS (Prostate Cancer & Environment Study) questioned 3,208 men on various lifestyle factors, work and their sex lives.
1,590 of these men were found to have prostate cancer between September 2005 and August 2009, while the rest served as the control group.
According to the Montreal Gazette:
They were also 19 per cent less likely to develop an aggressive form of the disease.
But that protection did not hold true for men who slept with men. Parent’s team found that having more than 20 male partners doubled the risk of prostate cancer compared to those who have never slept with a man. And their risk of getting a non-aggressive cancer was five times more likely. Sleeping with one man did not affect the risk.
On the other hand, virgins who had never experienced sex were almost twice as likely to have prostate cancer as those who did.
Researchers suggest that this is the first study to show that having many female sex partners, over a lifetime, provided significant protection against the disease, perhaps because frequent ejaculations reduce the concentration of cancer-causing substances in prostatic fluid and other structures associated with cancer.
But Parent could not explain why that does not apply to gay encounters. Perhaps because men who sleep with men engage in more risky sexual behaviour, or that anal intercourse may result in trauma to the prostate, but that’s only speculation, Parent said. More studies are needed.
The age of the first sexual encounter or the number of sexually transmitted infections had no bearing on the results.