Sunday, April 10, 2011

HPV Uncut: Get Vaccinated and Wear a Coat

As you probably know by now if you read my blog with any consistency, I was a professional scientist first, before becoming a science teacher, and that I like to stay up to date on the latest scientific news and discoveries, not only for professional growth and development, but also for my own amusement and. And, like my students, I am particularly drawn to science that is creepy, disgusting, prurient and weird. So it should be no surprise that the following article by Michelle Clement (Scientific American online blogs) caught my attention: What's the deal with male circumcision and female cervical cancer?
Circumcision Tools at the Jewish Museum, NY (Image by istolethetv)

As one would hope, the article was written with a great deal of humor: “Recently, while I was getting drinks at a pub with about a dozen or so other biologists, I was involved in a very animated discussion about circumcision -- because that's what biologists argue about when they're drinking, apparently. ‘They do it to increase stamina. It desensitizes the penis,’ said a microbiologist. (There's some evidence to the contrary on the bit about stamina, actually.)”

This reminded me of the two things I miss most about being a scientist (in contrast to being a science teacher): having the time and energy to go pubs in the first place and having the time, energy, interest and knowledge to casually talk science with peers. The one or two times I have found myself in a pub with colleagues, the conversation was dominated by complaining about work, which is not surprising since our spouses and partners are sick of hearing about it, while the public in general thinks we have it way too easy. When we do discuss science at work, it is almost always in the context of how to best teach it and never just a casual discussion of the merits of a particular new study or discovery. Fortunately for me my wife is a scientist. So when she gets tired of hearing me complain about my job (and vice versa) we can geek out together and talk about circumcision, autism, anti-vaccine hysteria, coprophagia and other important topics.

Let us return to the merits of male circumcision. Clement, in a fit of drunken lucidity, decided it was best to not rely on the unsubstantiated claims of her male peers, and decided to research the subject more thoroughly. She reviewed a 2002 paper in the New England Journal of Medicine (NEJM) that found that circumcision correlated with a decreased risk of penile HPV infection. Similar results were found by a 2009 study in African men. HPV, of course, can cause cervical cancer. The curious thing is that there was no significant correlation between circumcision and cervical cancer except if the uncircumcised partners were also likely to engage in risky sexual behavior.

This research tells us several important things. First, parents should relax and not immediately go have junior’s dingus snipped just to protect his future sexual partners. Rather, it would be safer, cheaper and less cruel to simply encourage safer sexual activity and get him vaccinated against HPV. It also reminds us that correlation is not the same as causation. HPV can cause cervical cancer, whereas circumcision correlates with a decreased risk of HPV. However, increasing the risk of HPV is not the same as causing HPV. In other words, an uncircumcised man may have an increased risk of HPV, especially if he engages in risky sexual behavior, but that doesn’t mean he has or will have HPV.

That being said, Clement also found a more recent paper published this year in The Lancet which looked at African men and their partners. This research found that after controlling for lifestyle variables, monogamous women partnered with circumcised men had significantly lower rates of HPV infection. The authors of this study concluded that circumcision should not be ruled out as a method of reducing HPV infection. However, because they only looked at monogamous women, these results cannot be extrapolated to women with multiple sexual partners. Also, if the men were non-monogamous, they would have a higher risk of contracting HPV regardless of the status of their foreskins. Lastly, this study showed an increase risk in HPV transmission, not cervical cancer.

Even if circumcision does reduce the risk of contracting and spreading HPV, it is certainly not as effective as condoms and vaccines, and therefore should only be considered as a supplement to the promotion of safer sex practices (and not a solution on its own) and only in populations where vaccines and condoms are routinely rejected. Considering that there is now an effective HPV vaccine, (and that there are so many other STDs that can be reduced through safer sex practices) it seems absurd to even consider circumcision as a prophylactic.

Of course, all this talk about circumcision reminds me of the old one about the moyel who, after a long and productive career of circumcising young Jewish boys, had acquired quite a collection of old foreskins. So he took his collection to the village leather worker and asked if he could make him something nice.

"Sure," said the leather worker. "Come back in a week."

So a week later the moyel returns and the leather worker hands him a wallet. Needless to say, the moyel is crestfallen. "This is it, this tiny little wallet? After 40 years of toil and saving, and all I get is this little thing?"

"Ah, but if you rub it," said the leather worker, "it will become a suitcase."

1 comment:

  1. Funny joke, I heard it several years ago, but it is still funny....