of the medical benefits of circumcision
Evidence, mainly but not exclusively amassed since the mid-1990s, overwhelmingly indicates that circumcision provides significant health benefits in respect of a number of otherwise unrelated diseases and conditions. The following text identifies some of the key findings and provides a précis of their content. It is by no means a complete bibliography; that would run into thousands of documents. At the foot of the page you will find links to more extensive lists of peer-reviewed academic papers.
Always remember that one act of circumcision confers all the benefits listed, not just one benefit achieved to the subsequent exclusion of all the others. Critics of circumcision frequently make the mistake of basing their conclusions on a single-issue analysis of the benefits. Circumcision is a multi-benefit procedure and any analysis of its merit must include all the benefits - every time.
Urinary tract infections (UTIs)
The absolute risk of UTI in uncircumcised boys is approximately 1 in 25 (0.04) and in circumcised boys is 1 in 500 (0.002). [Roberts, 1986.]
It follows that 20 baby boys need to be circumcised to prevent one case of UTI. That may not sound like a worthwhile payback, but the potential seriousness and pain of UTI should weigh heavily on the minds of parents. The complications of UTI can include kidney failure, meningitis and/or infection of bone marrow, all of which can have lifelong consequences and all of which are potentially fatal.
It is also necessary to remember that the risk of UTI extends beyond the diaper-wearing stage of babyhood and into the age group where a boy will be caring for himself. Albeit at a lower threat level, the risk of UTI persists into adulthood, as does the effect of circumcision in reducing that risk. Glib promises by parents to pay particular attention to their baby boy’s hygiene are not an adequate substitute for neonatal circumcision.
Roberts JA. Does circumcision prevent urinary tract infections? J Urol 1986; 135: 991-992.
Wiswell TE, Smith FR, Bass JW. Decreased incidence of urinary tract infections in circumcised male infants. Pediatrics 1985; 75: 901-903.
Wiswell TE, Hachey WE. Urinary tract infections and the circumcision state: An update. Clin Pediat 1993; 32: 130-134.
The subject of infant UTIs provides us with a good example of a study that fails to take into account all the benefits of circumcision, in CIRCLIST’s view resulting in a false conclusion irrespective of the accuracy of the rest of the work.
Chessare JB. Circumcision: Is the risk of urinary tract infection really the pivotal issue?. Clin Pediatr 1992;31(2):100-4.
The author’s own summary of the paper reads “A decision model was built that addressed the question of whether or not to circumcise a newborn male considering the probability of a non-circumcised boy having a UTI in the first year of life, the probability of a circumcised boy having a UTI in the first year of life and the likelihood of renal scarring from a UTI.”
No mention in the summary of all the other benefits of circumcision and no attempt to allow for them in the detailed analysis of his data, yet the author somehow deems it appropriate to conclude that “the choice of no circumcision yielded the highest expected utility”.
This example is by no means unique; it is not our intention to single out John Chessare for special criticism but merely to illustrate that peer-reviewed scientific papers are not always perfect!
Cervical Cancer in female partners
Observational studies have long recognised that rates of cervical cancer (cancer of the neck of the womb) are significantly lower in Jewish and Islamic societies, where male circumcision is routinely done as a matter of religious observance. Hochman et al. (1955) document a number of studies going back to 1902, all of which mention low rates amongst Jewesses.
The theoretical possibility of variations in rates of cervical cancer being due to genetic factors has now been largely discarded, consequent upon the discovery that a virus (a member of the family of viruses called Human Papillomavirus or "HPV") is the causal agent and the realisation that circumcision disrupts the way in which the virus is transmitted.
It is a matter of amazement to proponents of male circumcision that sexually active females are not insisting on their male partners being circumcised. Whilst there is a vaccine now available to immunise a female against HPV, it is only effective in respect of the most common strains of the virus. In contrast, circumcision appears to have approximately the same efficacy as the vaccine but is effective against all 20 or so sexually transmitted strains of HPV. Furthermore, the vaccine appears to need boosting every so often (meaning that it does not confer life-long immunity), whereas circumcision only needs to be done once.
Boon ME, Susanti I, Tasche MJ, Kok LP. Human papillomavirus (HPV) associated male and female genital carcinomas in a Hindu population. The male as a vector and victim. Cancer 1989; 64: 550-565.
Castellsague X, Bosch FX, et al. Male circumcision, penile human papillomavirus infection, and cervical cancer in female partners. N Engl J Med 2002; 346: 1105-1112.
Dunne EF, Unger ER, et al. Prevalence of HPV infection among females in the United States. JAMA 2007; 297: 813-819.
Gray RH. Infectious disease: Male circumcision for preventing HPV infection. Nat Rev Urol 2009a; 6: 298-299.
Hochman A, Ratzkowski E, Schreiber H. Incidence of carcinoma of the cervix in Israel. Br J Cancer 1955;9:358–64.
On a technical note, be aware that HPV is not
a retrovirus. No valid comparison can be made with HIV when it comes to the precise mechanisms involved either in the transmission of HPV or in the way that males can harbour it.
Males can themselves suffer in consequence of HPV infection. This is most definitely a scenario where one action, circumcision, potentially benefits more than one person - the male himself and all his female sexual partners.
Cancer of the Penis
Why risk this? Such tumours are normally
untreatable other than by penectomy.
Image © 2012 europeanurology.com
The incidence of penile cancer in the USA is 1 per 100,000 men per year (nationwide that’s 750 to 1000 cases annually) and mortality rate is 25 to 33% . It represents approximately 1% of all malignancies in men in the USA, but the rate is not constant as between the various ethnic groups. Incidence is highest in Hispanic men, then Black men, then White. This sequence is inversely proportional to rates of neonatal circumcision in the same population. In 5 major series in the USA, starting in 1932, not one man with invasive penile cancer had been circumcised neonatally. This disease is almost completely confined to uncircumcised men.
At the Peter McCallum Cancer Institute (Melbourne, Australia) 102 cases of penile cancer were seen between 1954 and 1984, with twice as many in the final decade of the study compared with the first. Several authors have linked the rising incidence of penile cancer to a decrease in the number of neonatal circumcisions. It would thus seem that prevention by circumcision in infancy is the best policy.
In under-developed countries the incidence is higher, typically 3 to 6 cases per 100,000 men per year.
The so-called high-risk papillomavirus types 16 and 18 (HPV 16/18) are found in a large proportion of cases of cancer of the penis and there is good reason to suspect that they are involved in its causation. HPV 16 and 18 are, moreover, more common in uncircumcised males. Other factors, such as poor hygiene and other STDs have been suspected of contributing to penile cancer as well.
Goodman MT, Hernandez BY, Shvetsov Y. Demographic and pathologic differences in the incidence of invasive penile cancer in the United States, 1995-2003. Cancer Epidemiol Biomarkers Prev 2007; 16: 1833-1839.
Maden C, Sherman KJ et al. History of circumcision, medical conditions, and sexual activity and risk of penile cancer. J Nat Canc Inst 1993; 85: 19-24.
Sandeman TF. Carcinoma of the penis. Australasian Radiol 1990; 34: 12-16.
HIV and AIDS
As with cervical cancer, the realisation that male circumcision influenced the spread of AIDS (Acquired Immunity Deficiency Syndrome) started with an empirical observation. With the exception of North America, societies that routinely practiced circumcision were observed to have lower rates of AIDS than societies that did not circumcise. Coincidence, or a clue to a means of prevention?
During the 1980s and 1990s the following key discoveries were made:
- AIDS is caused by a virus that is a member of the family of pathogens called "Retroviruses".
- The virus is spread by exchange of body fluids. Thus there is more than one possible transmission route.
- One significant transmission route is heterosexual intercourse.
- When female-to-male sexual transmission occurs, the virus enters the male body via Langerhans cells.
- The vast majority of Langerhans cells in male genitalia are to be found in the inner foreskin and frenulum.
Taken together, these findings suggest (but do not themselves conclusively prove) that male circumcision curbs the spread of HIV. The next stage of the investigation involved what is called a Randomised Controlled Trial ("RCT"), an investigative technique regarded as the gold standard of epidemiological research.
In general terms, the mechanism of a RCT is this:
Participants in the trial are selected from a population that is homogeneous. Same background, same culture, same economic status and so on. This is done to minimise the possibility of results being confounded by variations other than the one put forward in the hypothesis as being the variable worthy of investigation. In this case, the starting point also required that the participants tested HIV-negative and were uncircumcised.
Members of the homogeneous group are then allocated at random to different categories of treatment. In this case there were only two groups, one of which underwent circumcision whilst the other did not.
The two groups were then 'let loose' to live their normal, nominally similar lives involving, it is assumed, identical exposure to the risk (in this case the risk of encountering a female partner who is HIV-positive). After a given time interval, all the trial participants are re-tested; any significant difference between the two groups is taken as evidence that the hypothesis is validated.
The first such RCT took place in a township of South Africa called Orange Farm. The results, published in 2005, gave a clear indication of a cause-&-effect relationship between male circumcision and transmission rates of HIV. Wary of the possibility of a rogue result, two further RCTs were set up, one in Kenya and one in Uganda. Part-way through the planned time span of these RCTs, interim results showed such a clear difference between the circumcised and uncircumcised groups that the Ethics Committee overseeing the trials stopped the experiments and offered circumcision to the uncircumcised groups. Many accepted the offer. This in effect terminated the RCT, any subsequent data collection having only the status of an Observational Study. The truly random nature of the experiments had been destroyed. Contrary to what opponents of circumcision would have you believe, the early conclusion does not totally invalidate the Kenyan and Ugandan studies. Consider, as a simple example, the status of the results had the originally stipulated time span been that much shorter to start with.
Taken together, research since the early 1980s has now conclusively proved that AIDS is caused by HIV, that one of the significant transmission routes of HIV is sexual intercourse and that male circumcision reduces - but does not wholly eliminate - the risk of a man acquiring HIV in this way.
Cynics have suggested that a certain callousness was involved in selecting impoverished neighbourhoods in sub-Saharan Africa, maybe even as a deliberate attempt to attach a label of racism to the RCTs. Not so. What was needed for the trials was a population with a high existing incidence of HIV infection in females, along with low rates of other possible transmission mechanisms - particularly injecting drug abuse involving the sharing of needles but also insertive anal intercourse amongst homosexual men. In the longer term, these impoverished African societies have benefitted from their selection as the location for the RCTs. It is now realised that campaigns of mass circumcision will have the greatest effect in precisely such situations. The World Health Organisation currently recommends that male circumcision should be promoted most strongly in exactly these places, because that is where the epidemiological, social and economic benefits are maximised at whole-population level. That’s not to say that circumcision does not have its place elsewhere. What WHO is doing is building a picture of global priorities in the context of Public Health; their recommendations do not change the efficacy of circumcision as a form of HIV prophylaxis at a personal level.
And why is North America different?
At the very beginnings of the AIDS epidemic, HIV infection in North America was primarily found amongst male homosexuals and needle-sharing drug addicts. This produces a different pattern of spread of the disease. Thus the fact that circumcision rates in North America are well above the world average was at first of no relevance when it comes to containing HIV, because circumcision did not interrupt the predominant US transmission route. The following diagrams, adapted from originals published in 1998, highlight that difference:
|Comparative Risk Scenarios - HIV
||USA - 20th century
|Adapted from: Kelly. Sexuality Today : The Human Perspective © 1998, McGraw-Hill
Slowly, the situation in the USA has been moving into line with that found in the rest of the world, as illustrated here:
Note that the two presentations above do not record exactly the same thing; one observing HIV Risk Scenarios and the other AIDS cases diagnosed. These statistics need to be treated with caution.
In 2010 the Centers for Disease Control and Prevention (Atlanta, Georgia) published a paper “Male Circumcision in the United States for the Prevention of HIV Infection and Other Adverse Health Outcomes : Report from a CDC Consultation”. Readers with a special interest in transmission mechanisms and transmission rates within the USA can read a copy here
The efficacy of circumcision as a form of prophylaxis against HIV
Auvert B, Taljaard D, Lagarde E, et al. Randomized, controlled intervention trial of male Circumcision for reduction of HIV infection risk: The ANRS 1265 Trial. PLoS Med 2005:2;(e298):1112-1122.
Bailey RC, Moses S, Parker CB, et al. Male circumcision for HIV prevention in young men in Kisumu, Kenya: a randomised controlled trial. Lancet 2007:369:643-656.
Gray RH, Kigozi G, Serwadda D, et al. Male circumcision for HIV prevention in men in Rakai, Uganda: a randomised trial. Lancet 2007:369:657-666.
These three RCTs are by no means the only investigations to have been conducted, but together they form the baseline for almost all subsequent research.
The mechanism of HIV infection
The precise way in which HIV enters the male is the subject of ongoing research. As at mid-2012, the current thinking was as follows. The text below is the published abstract of a paper "Biological basis for the protective effect conferred by male circumcision against HIV infection" published in the International Journal of STD & AIDS 2012; 23: 153-159.
Here we provide an up-to-date review of research that explains why uncircumcised men are at higher risk of HIV infection. The inner foreskin is a mucosal epithelium deficient in protective keratin, yet rich in HIV target cells. Soon after sexual exposure to infected mucosal secretions of a HIV-positive partner, infected T-cells from the latter form viral synapses with keratinocytes and transfer HIV to Langerhans cells via dendrites that extend to just under the surface of the inner foreskin. The Langerhans cells with internalized HIV migrate to the basal epidermis and then pass HIV on to T-cells, thus leading to the systemic infection that ensues. Infection is exacerbated in inflammatory states associated with balanoposthitis, the presence of smegma and ulceration - including that caused by infection with herpes simplex virus type 2 and some other sexually transmitted infections (STIs). A high foreskin surface area and tearing of the foreskin or associated frenulum during sexual intercourse also facilitate HIV entry. Thus, by various means, the foreskin is the primary biological weak point that permits HIV infection during heterosexual intercourse. The biological findings could explain why male circumcision protects against HIV infection.
Link to Full Text
Herpes and other STIs
Circumcision reduces the risk of acquiring Herpes, according to a study reported to the Conference on Retroviruses and Opportunistic Infections, 2008.
Tobian A, et al "Trial of male circumcision: prevention of HSV-2 in men and vaginal infections in female partners, Rakai, Uganda" CROI 2008; Abstract 28LB.
In a randomized clinical trial in Africa, male circumcision reduced the risk of acquiring herpes simplex-2 (HSV-2) by 24%. The procedure also reduced a range of genitorurinary complications in female partners of men circumcised for the study. The starting point of this study, conducted in Rakai, Uganda, began with the dual observations that HSV-2 infection more than doubles the risk for a man to get HIV and that circumcision reduces the risk of HIV transmission.
The study enrolled 3516 men who were not infected with either virus and randomized them to immediate circumcision or circumcision two years later. At the end of two years, those in the circumcision arm had a relative risk of HSV-2 of 0.76, with a 95% confidence interval from 0.60 to 0.96, which was significant at P=0.019 compared with controls.
In higher risk categories -- those with two or more sex partners, those aged 20 to 24 and those with inconsistent condom use -- the risk of HSV-2 acquisition increased in the control arm and remained low in the circumcision arm. For instance, for men who were inconsistent in the use of condoms, the relative risk of HSV-2 for those who were circumcised compared with those in the control arm was 0.53, which was statistically significant at P=0.001.
The researchers also enrolled 1608 female partners of the men in the trial, 825 linked to men who were circumcised and 783 to those in the control arm. They were followed for a year and tested for genitourinary disease, bacterial vaginosis and trichomonas. The study found, among other things, that:
- The relative risk of symptomatic genitourinary disease in intervention wives compared with control arm wives was 0.76 (with a 95% confidence interval from 0.60 to 0.97, which was significant at P=0.03).
- There were no differences in vaginal discharge or dysuria by study arm.
- The relative risk of trichomonas in intervention wives compared with control arm wives was 0.53 with a 95% confidence interval from 0.33 to 0.85.
- The relative risk of bacterial vaginosis in intervention wives compared with control arm wives was 0.80 with a 95% confidence interval from 0.71 to 0.89.
The study was supported by the NIH, the NAIAD, the Fogarty International Center and the Gates Foundation.
See also: http://www.medpagetoday.com/MeetingCoverage/CROIMeeting/tb/8230
Research published in March 2012 confirms a statistically significant reduction in the occurrence of prostate cancer in circumcised males compared with uncircumcised males. This is despite the supposed reduction in masturbation brought about by circumcision, masturbation in teenage years and early adulthood itself having in the past been associated with a reduction in prostate cancer. Further research appears to be needed here, given that masturbation habits were not controlled in the following research:
Cancer. 2012 Mar 12. doi: 10.1002/cncr.26653. [Abstract, Epub ahead of print]
Circumcision and the risk of prostate cancer. Wright JL, Lin DW, Stanford JL.
Department of Urology, University of Washington School of Medicine, Seattle, Washington; Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington.
Several lines of evidence support a role for infectious agents in the development of prostate cancer (PCa). In particular, sexually transmitted
infections (STIs) have been implicated in PCa etiology, and studies have found that the risk of acquiring a STI can be reduced with circumcision. Therefore, circumcision may reduce PCa risk.
Participant data collected as part of 2 population-based case-control studies of PCa were analyzed. Self-reported circumcision status, age at circumcision, and age at first sexual intercourse were recorded along with a history of STIs or prostatitis. Multivariate logistic regression was used to estimate the relative risk of PCa by circumcision status.
Data from 1754 cases and 1645 controls were available. Circumcision before first sexual intercourse was associated with a 15% reduction in risk of PCa compared to that of uncircumcised men (95% confidence interval [CI], 0.73-0.99). This risk reduction was observed for cases with both less aggressive (odds ratio, 0.88; 95% CI, 0.74-1.04) and more aggressive (odds ratio, 0.82; 95% CI, 0.66-1.00) PCa features.
Circumcision before first sexual intercourse is associated with a reduction in the relative risk of PCa in this study population. These findings are consistent with research supporting the infectious/inflammation pathway in prostate carcinogenesis.
Source: Cancer 2012;. © 2012 American Cancer Society.
Overviews (all written before the latest findings about prostate cancer)
A paper published October 2011 in JAMA (Journal of the American Medical Association) provides a convenient 2-page overview of the state of knowledge at that date. JAMA. 2011 Oct 5;306(13):1479-80
. The medical benefits of male circumcision
. Tobian AA and Gray RH. [PMID: 21972310]
Favourable independent commentary can be found in Science Daily
October 2011 also saw the publication of a book chapter entitled The role of circumcision in preventing STIs
by Brian J. Morris and Xavier Castellsague, in Gross GE, Tyring S, eds. Sexually Transmitted Infections and Sexually Transmitted Diseases
, (ISBN 978-3-642-14662-6), chapter 54, Springer, Heidelberg, 2011, pp. 715-739. The key points of the chapter are:
Male circumcision affords substantial protection against genital ulcer disease (GUD), human immunodeficiency virus (HIV), high-risk types of human papilloma virus (HPV), herpes simplex virus type 2 (HSV-2), Treponema pallidum (syphilis), Haemophilus ducreyi (chancroid), Trichomonas vaginalis and Candida albicans (Thrush).
It offers little or no protection against Neisseria gonorrhea, Chlamydia trachomatis and non-specific urethritis.
In the female sexual partner, circumcision of the male partner is associated with greatly reduced HPV, chlamydia, HSV-2, Trichomonas and bacterial vaginosis.
At the population level, increased rate of male circumcision should reduce heterosexually acquired HIV/AIDS, as well as genital HPV, penile and cervical cancer, prostate cancer, genital herpes, infertility in each sex, pelvic inflammatory disease and ectopic pregnancy.
Male circumcision is an important component of strategies to reduce the global burden of many STIs.
The full text is available here
For a comprehensive list of published academic papers relating to male circumcision:
, the website of Professor Brian Morris.
To conduct your own search of the literature on this or any other academic subject, we recommend
Google Scholar’s specialist search engine
. This should return predominantly peer-reviewed academic references. See the associated Help Page
if you have not used this facility previously and familiarised with it.
For a discussion forum applicable to all the above (Over 18s only - a restriction imposed by Yahoo):
The Inter-Circ Yahoo Group
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