January 29th, 2009
Over the past few days the press has been full of the story that ‘masturbation causes cancer’.
As a result I’ve had a number of anxious emails from men saying they either masturbate frequently now or did in the past, and are extremely worried they’re going to get cancer. Some of them expressed confusion over media messages on masturbation as they’d previously thought masturbation stopped you getting prostate cancer.
So what’s the answer? Is masturbation really that dangerous?
Well, before we get to that, here’s the background to the latest research.
What was the study that’s caused the fuss?
The study behind all the scary headlines is called ‘Sexual activity and prostate cancer risk in men diagnosed at a younger age’ by Polyxeni Dimitropoulou and colleagues, just published in the BJUI (British Journal of Urology International). You can read an abstract of the research here.
What did the study involve?
This was a case control study involving 431 men with prostate cancer matched with 409 similar men who did not have cancer. All men were aged below 60 at time of study. Participants completed a postal questionnaire that included items on their life and sexual behaviours and included questions about frequency and type of sexual activity participants engaged in during their 20s through to their 50s. Information about their sexual partners over that time period, STIs, and age when they had intercourse for the first time was also included. High rates of sexual activity were defined as intercourse on average of 4-7 times per week (or more) and masturbation 2-7 times per week (or more).
What did the study find?
The study indicated that men who have a lot of sexual activity in their 20s and high rates of sexual activity and/or masturbation in their 30s are at an increased risk of prostate cancer. While men in their 50s who have higher levels of masturbation and sexual activity appear to have a reduced risk of prostate cancer.
In plain English that means if you have a lot more activity in your younger years but less as you age then you may have an increased risk of prostate cancer, whereas if you didn’t have as much sexual activity/masturbation when younger but you do in your middle years (40s and particularly 50s) then this may offer a protective effect.
How does this fit with other data in this area?
Existing research on the impact of masturbation/sexual activity on prostate cancer risk are very mixed. Most theories agree prostate cancer is linked to hormones, but not on how this may affect men. So some studies suggest men with higher levels of androgens are more at risk. Associated with this is the idea that since male hormones influence sexual activity, then those with higher levels of hormones will engage in more frequent sexual activity. The sexual activity itself may not be the cause of increased prostate cancer risk, but an indicator of higher hormone levels that could contribute to an increased risk in later life.
Other studies looking at masturbation, frequency of ejaculation and frequency of intercourse have generated mixed results. Some show no apparent link between sexual activity/ejaculation on prostate cancer risk. Some suggest sexual activity/ejaculation increases a man’s risk of developing prostate cancer, and some indicate sexual activity/ejaculation reduces a man’s risk of prostate cancer.
Recently (and probably most famously) a study by Graham Giles and colleagues argued men who masturbate frequently have a reduced risk of prostate cancer since masturbation would prevent hormones building up in the prostate. That study was explained by many journalists incorrectly as ‘masturbation cures cancer’ and has been cited by plenty of sex educators to recommend regular masturbation as a prevention of all male cancers (another incorrect and unhelpful interpretation of the study).
The conflicting findings don’t mean this area isn’t worthy of investigation, but it does mean we don’t fully know exactly how hormones and sexual activity may impact upon prostate cancer risk.
What are the limitations of the current study?
The authors acknowledge they were studying a group of men with prostate cancer who had the disease at a younger age than most. This isn’t necessarily a limitation but does make them different to the average prostate cancer patient and needs to be borne in mind when you consider the findings.
The use of a self reported, retrospective, postal questionnaire could be problematic since postal surveys are among the most unreliable way of getting questionnaire data from people (due to a low response rate to this method). Asking people to remember what they were doing in their 20s or 30s or even last year can increase recall bias, so we’ve only got someone’s estimate about their activity to go on and the reliability of this information varies depending on individuals and the sensitivity of information required.
To give you an idea of how difficult this may be, can you recall accurately how often you masturbated in your twenties? (presuming you’re older now!). You may be able to say it’s more or less than now, but can you be specific about sexual activity then – or in any other subsequent decade? You may have had more activity in your 20s and generalised that you masturbated or had sex very frequently during that time, whereas you may have had particular peaks within those years where you did have a lot of sexual activity, but that may not have been consistently high throughout that time.
How ‘intercourse’ and ‘masturbation’ was defined on the survey isn’t made clear in the paper, and particularly the idea of masturbation is quite vague – so it’s not transparent whether the researchers were asking someone to talk about masturbation alone or with a partner, and masturbation to orgasm or not. Those factors may help interpret the results and it would have been useful to know more about that aspect of the survey.
I wasn’t sure if it was just an aspect of reporting style but the study didn’t appear to include gay participants, or if it did sexuality wasn’t clearly disclosed in the results. For example we’re told participants marital status and the number of women partners they had, but nothing about anyone who was gay, bi (or men who had sex with men but didn’t consider themselves gay or bi). That may also have had a bearing on the data. If participants were all heterosexual, then this isn’t necessarily a problem, but it does need to be explained and justified.
So should we ignore the study?
No! The media have been very strange in their approach to this research – either using it in an I-told-you-so kind of way to set out masturbation is bad, or by encouraging all ‘red blooded males’ to ignore the results entirely.
This study is useful as it suggests there’s more to the original research in this area that indicated masturbation either had no impact on or may help reduce the risk of prostate cancer. It suggests that while sex/masturbation when older could do this, higher levels of activity when younger might be linked to an increase – with the suggestion that higher levels of male hormones are the cause of both increased activity when younger and risk of prostate cancer when older.
The study doesn’t offer any definitive guidance on prostate cancer risks and sexual activity, in fact it raises more questions than it answers, and some cancer self help have been somewhat dismissive of the findings as a result. It’s fair to say the study could confuse or worry men, but that doesn’t mean we should dismiss it as it makes a number of important observations about male sexual activity and later prostate cancer risk which should be explored in future studies.
Evidently more research is needed in this area to identify exactly what the risks and possible contributory factors are for men in relation to prostate cancer. A retrospective survey allows us to hypothesise the direction in which we think risk factors may arise, but it doesn’t confirm this. To be more certain we’d need studies that follow up men over time, study men in different age groups, and include a far wider range of monitoring – so added to surveys you’d need to measure changing hormone levels and other physical changes, plus monitoring lifestyle factors (diet, exercise, smoking etc).
If you are a counsellor, sex educator or working in sexual/reproductive healthcare your message to anyone asking about risks between developing prostate cancer and sexual activity should be as follows. At this time the evidence is not completely clear about the association between sexual behaviour/male sex hormones and prostate cancer, and future research will investigate this further. You should not be telling clients they will be cured of cancer or have no risk of prostate cancer if they masturbate, nor should you advise that masturbation/sexual intercourse causes prostate cancer.
So should I stop masturbating?
No! This study isn’t saying that all men who masturbate or have sex will automatically get cancer. It’s saying that some men who have a lot of sexual activity could be at greater risk when older. But that’s not completely proven as different studies have had different outcomes.
You can definitely do a lot to protect yourself by ensuring you cut back on smoking, eat a balanced diet, get exercise, use condoms when you have sex with new/different partners, and if you spot any symptoms that might suggest prostate cancer to speak to a doctor straight away. It’s worth pointing out that most men aren’t diagnosed with prostate cancer until their in middle or old age, so younger men could be being led to worry unnecessarily by media coverage of this study which has wrongly suggested masturbation and sex are causing cancer in very young men (aged 20 or 30) which isn’t what the original paper says at all.
It’s a shame the study hasn’t been given a clear account in the media, although I suspect this may be because it’s used a method journalists aren’t familiar with. It is a complex paper to follow (in both design and description) which may make it difficult for some to know exactly what to say about it. That said, I suspect the paper hasn’t been read by most journalists who’ve covered the story, they’ve just gone from the press release, misunderstood the findings, and misled us that masturbation = cancer. Unfortunately I suspect some anti sex groups (particularly some faith based ones) will use this to confirm their agenda that masturbation is harmful.
Your take home message is this. Masturbation doesn’t cure cancer (as some press reports have wrongly stated in the past), nor will any man who masturbates automatically get cancer (as some misleading reports have claimed of this study). Future research is needed, and while that’s under way you should not feel anxious about masturbation or sex, but if you are concerned then speak to your doctor.
Postscript – Cory Silverberg also has a great take down of this study, and makes the important point that the existing studies on masturbation/sex and prostate cancer all use different definitions and measurements of sex and masturbation. Meaning it’s very difficult to compare studies. Perhaps while we’re looking to expand our knowledge in this area it might be a good idea to go back to the basics of good social science and think about terms like validity and reliability so we can be sure when we’re trying to measure something, that we’re actually managing to do that.Tweet