Saturday, December 7, 2013

Younger Males Who Jerk off Too Much At Higher Risk of Prostate Cancer: Science Fact or Pseudo-science?


Four years ago the news erupted that those (mainly younger) males with stronger sex drives - inducing them to masturbate more than 1-2x a week are in for trouble later - with prostate cancer. See e.g.

http://www.telegraph.co.uk/health/healthnews/4352270/Sex-drive-linked-to-prostate-cancer-risk.html

Excerpt:

"Those who had regular sexual intercourse and masturbated frequently while they were in their 20s and 30s were most at risk, a new study has found. ........Dr Polyxeni Dimitropoulou, from the University of Cambridge, said: "We were keen to look at the links between sexual activity and younger men as a lot of prostate cancer studies focus on older men as the disease is more prevalent in men over 50.

"Hormones appear to play a key role in prostate cancer and it is very common to treat men with therapy to reduce the hormones thought to stimulate the cancer cells..... a man's sex drive is also regulated by his hormone levels, so this study examined the theory that having a high sex drive affects the risk of prostate cancer."

The researchers also found, get this, that masturbation has a "protective effect" after age 50. They base this on a hypothesis of "reverse causality" so imminent prostate cancer may be inducing the higher frequency then, while it is causing prostate cancer if done in the younger, high 'stud' years.

Can this be believed? First, what was the methodology? According to the paper (and assorted media reports on it) the study looked at the sexual behavior of more than 430 men who had been diagnosed with prostate cancer before age 60 and the behavior of another 409 men who didn't have the disease.  Incredibly,  the researchers concluded that most of the differences in behavior were linked to masturbation and not intercourse.

Why? They don't know and can't say. In basic human biology and sexuality one learns, however, that "an ejaculation is an ejaculation". "Mother Nature" doesn't distinguish between the two, so biologically there's no reason at all the effects should be different. The same hormones, physiological mechanism is the basis for each - which is why Viagra works irrespective of sexual activity. 

The case-controlled study also contradicts an earlier one reported in The Journal of the American Medical Association in 2004 in an article titled “Ejaculation frequency and risk of prostate cancer.” They looked at over 29,000 men who were part of a study of health professional’s health. High ejaculation frequency was reported to be associated with a lower incidence of prostate cancer. Averaged across a lifetime, those men with higher frequency of ejaculation (21 or more per month) had 2/3 the risk of developing prostate cancer as those with a lower frequency of ejaculation (4 to 7 per month).


The earlier study - note- had vastly more subjects included - more than a factor ten beyond the more recent "case study". It also did not distinguish ejaculation, or ages.   Another case-control study from Australia, reported in the British Journal of Urology International in 2003, titled Sexual factors and prostate cancer, found similar risks of prostate cancer incidence-  with those men who reported 5 ejaculations or more per week while in their 20s having 2/3 the risk of those who ejaculated less often.

Meanwhile, according to Dimitropoulou and her Nottingham researchers it’s not masturbation itself that’s increasing prostate cancer risk in young men. More masturbation just means more sex drive — and "more androgens bathing prostate tissues."     Yes, so why doesn't intercourse have the same effect, since androgens will also be released - unless one is impotent?


Dimitropoulou suggests that in older men, masturbation itself may actually be helpful, ridding the prostate gland of fluids that may contain cancer-causing substances. But then she is talking about "frequent masturbation" for older guys being no more than 1-2 times per week. Again, it's all relative.

 

According to her:

 

"In mature age, it may be more important that toxins get flushed out of the system. And because the masturbation frequency was not as high in the men’s 50s as it was in their 20s, even low levels of masturbation in the 50s has a protective effect.”

 
Still, a lot of it comes over as humbug, especially the "reverse causality" claim, e.g. that prostate cancer affected the men’s sexual activity, rather than the other way around.  A cynic or curmudgeon might wonder if her research was funded by the Roman Catholic Church which, of course, frowns on the solo act as "unnatural' like it frowns on artificial contraception - for the same reason.
 
A more objective take on the work appears in The Nursing Times, e.g.

 
The Nursing Times piece has the good sense to lay out the "limitations" of the most recent Nottingham study which are cited as (ibid.):
 
-  Asking men to recall their sexual activity and frequency across different decades of life from their 20s, 30s, 40s and 50s. This is obviously going to involve a lot of estimation inaccuracy.

-  Sexual activity is a highly personal matter. Some men may feel uncomfortable revealing such personal detail and may therefore have either over- or underestimated their activity, depending on their feeling to answering.

-  What constitutes a certain sexual activity to one person may not mean the same thing to another person.


 
The NT article also adds other factors "to take into account" in assessing the work:

-  As with all studies of this type, an association between two factors does not necessarily mean that one causes the other. Other factors (confounders) that have not been adjusted for may be affecting the links found to masturbation.

-  The study involved a lot of statistical comparisons. As more tests and combinations are made, the more likely it is that a result that occurs by chance will appear to be significant.

-  There was a link found between cancer risk and frequency of masturbation, but no link was found to frequency of sexual intercourse. When both masturbation and intercourse were combined to give the variable of overall sexual activity, no link was found for any age group.

-  These are a specific group of people with prostate cancer who were all diagnosed with cancer prior to the age of 60. The men in this study are not typical of the vast majority of people with prostate cancer, who are generally diagnosed over the age of 65. Therefore there may be particular unknown characteristics of these people that makes them more predisposed to prostate cancer at a younger age. The results may also not be representative of what would be seen in men who develop prostate cancer later in life.

-  The study involved predominantly white men. Prostate cancer has been linked to ethnicity, with men of African-American origin believed to be at increased risk. Therefore a wider ethnic representation may have given different results.

 
The omission (of black males)  is especially onerous and problematical and basically, to me, means the study is about as useful as the one of Michel Gauquelin some decades ago which found increasing UFO sightings to be correlated with Martian oppositions (close approaches to Earth).
Those younger males worried they may be overdoing a good thing, I suggest you chill out and get a bit of a laugh. Without a thorough confirmation, and with at least as many males as the earlier 2003-04 research (29,000) the work of Dimitropoulou  looks like one more incidence of "gimmick science"  - by which I mean research done to raise eyebrows, get publicity (and more funding)  and also because most other ground has already been well -covered.

The Nursing Times conclusion then is the one to pay attention to:

"Men should not be overly concerned by this research. Sexual functioning is a normal part of healthy adult life. The causes of prostate cancer are not known for certain. Increasing age is the most established risk factor and more research is needed."
 
 



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