What is Male Circumcision?
Male circumcision is the surgical removal of some or all of the foreskin (or prepuce) from the penis.
Male Circumcision and Risk for HIV Acquisition by Heterosexual Men
Several types of research have documented that male circumcision significantly reduces the risk of men contracting HIV through penile-vaginal sex.
Compared with the dry external skin surface of the glans penis and penile shaft, the inner mucosa of the foreskin has less keratinization (deposition of fibrous protein) and a higher density of target cells for HIV infection. Some laboratory studies have shown the foreskin is more susceptible to HIV infection than other penile tissue, although others have failed to show any difference in the ability of HIV to penetrate inner compared with outer foreskin surface. The foreskin may also have greater susceptibility to traumatic epithelial disruptions (tears) during intercourse, providing a portal of entry for pathogens, including HIV. In addition, the microenvironment in the preputial sac between the unretracted foreskin and the glands penis may be conducive to viral survival. Finally, the presence of other sexually transmitted diseases (STDs), which independently may be more common in uncircumcised men, increase the risk for HIV acquisition.
International Observational Studies for Prevention of HIV Acquisition by Heterosexual Men
A systematic review and meta-analysis that focused on male circumcision and heterosexual transmission of HIV in
Africa was published in 2000. It included 19
cross-sectional studies, 5 case-control studies, 3 cohort studies, and 1
partner study. A substantial protective effect of male circumcision on risk for
HIV infection was noted, along with a reduced risk for genital ulcer disease.
After adjustment for confounding factors in the population-based studies, the
relative risk for HIV infection was 44% lower in circumcised men. The strongest
association was seen in men at high risk, such as patients at STD clinics, for
whom the adjusted relative risk was 71% lower for circumcised men.
Another review that included stringent assessment of 10 potential confounding factors and that was stratified by study type or study population was published in 2003. Most of the studies were from
Africa. Of the 35 observational studies in the review,
the 16 in the general population had inconsistent results. The one large
prospective cohort study in this group showed a significant protective effect:
The odds of infection were 42% lower for circumcised men. The remaining 19
studies were conducted in populations at high risk. These studies found a
consistent, substantial protective effect, which increased with adjustment for
confounding. Each of the four cohort studies included in the review
demonstrated a protective effect, and two were statistically significant.
Ecologic studies also indicate a strong association between lack of male circumcision and HIV infection at the population level. Although links among circumcision, culture, religion, and risk behaviour may account for some of the differences in HIV infection prevalence, the countries in Africa and
with prevalence of male circumcision of less than 20% have HIV infection
prevalences several times higher than those in countries in these regions where
more than 80% of men are circumcised.
International Clinical Trials for Prevention of HIV Acquisition by Heterosexual Men
Three randomized controlled clinical trials (RCTs) were conducted in
Africa to determine
whether circumcision of adult males reduces their risk for HIV infection. The
controlled follow-up period in all three studies was stopped early, and the
control group offered circumcision when interim analyses found that medical
circumcision significantly reduced male participants' HIV infection risk. The
controlled follow-up period in the study in South
Africa was stopped in 2005, and the controlled follow-up
periods for the studies in Kenya
were stopped in 2006. Uganda
In these studies, men who had been randomly assigned to the circumcision group had a 60% (
Africa), 53% ( Kenya),
and 51% ( )
lower incidence of HIV infection compared with men assigned to the wait-list
group to be circumcised at the end of the study. In all three studies, a small
number of men who had been assigned to be circumcised did not undergo the
procedure; likewise, a small number of men assigned to the control groups did
undergo circumcision. When the data were reanalysed to account for these
occurrences, men who had been circumcised had a 76% ( Uganda South
Africa), 60% ( Kenya),
and 55% ( )
reduction in risk for HIV infection compared with those who were not
A 2008 meta-analysis, which examined data from the three RCTs, as well as from cohort and case-control studies, found that HIV risk was reduced 58% in circumcised men (overall risk ratio [RR], 0.42; 95% confidence interval .The authors concluded that the studies provided enough evidence to conclude that circumcision causes a reduction in transmission of HIV-1 infection.
Male Circumcision and Other Health Conditions
Carcinogenic subtypes of human papillomavirus (HPV)—which are believed to cause 100% of cervical cancers, 90% of anal cancers, and 40% of cancers of the penis, vulva, and vagina —have also been associated with lack of circumcision in men. A Ugandan RCT found a lower prevalence of high-risk HPV subtypes among men in the circumcised group. In a South African trial, circumcision was also associated with a lower prevalence of high-risk HPV subtypes. These prevalence associations may result from an effect of circumcision on HPV acquisition by men, its persistence, or both. The Ugandan RCT also found incidence of high-risk HPV infection among women to be lower among those with circumcised male partners.
The lifetime risk for a
male of ever being diagnosed
with penile cancer is 1 in 1,437. In a retrospective analysis of 89 cases of
invasive penile cancer diagnosed from 1954 through 1997, 98% were in
uncircumcised men; of 118 cases of carcinoma in situ, 84% were in uncircumcised
men. Schoen published a retrospective review of 5 studies with 592 cases of
invasive penile cancer in the U.S. ; none of the cases were in men who
had been circumcised in infancy. United
In a meta-analysis of male circumcision status and cervical cancer in female partners, data from 7 case-control studies were pooled. Circumcision was associated with significantly less HPV infection in men. In an analysis restricted to monogamous women, there was a nonsignificant reduction in the odds of having cervical cancer among women with circumcised partners. When the couples with men with 5 or fewer lifetime partners (40% of the study population) were excluded, there was a significantly reduced odds of cervical cancer in female partners of circumcised men compared with the female partners of uncircumcised men.
Studies have consistently demonstrated decreased incidence of urinary tract infections (UTIs) among circumcised compared with uncircumcised boys. A meta-analysis including 18 studies found a pooled UTI prevalence of 20.1% among febrile uncircumcised boys <3 months of age and a prevalence of 2.4% among febrile circumcised boys <3 months of age. Another systematic review included 12 studies and over 400,000 children and concluded that male circumcision was associated with a significantly reduced risk of UTI.
Overall, UTIs are not common among male infants, with estimates of the annual rate of UTI in uncircumcised infants being 0.70% versus 0.18% for circumcised infants.
Data from clinical trials also provides evidence that circumcision is significantly associated with decreased incidence of herpes simplex virus type 2 (HSV-2). The Ugandan trial also found that male circumcision may reduce self-reported genital ulcer disease in men. In female partners of circumcised men, evidence from the trials showed a significant reduction of female genital ulceration, bacterial vaginosis, and trichomoniasis.
Results from observational studies have been mixed but have found lower risk for some STDs in circumcised men. A 2006 meta-analysis included 26 studies that assessed the association between male circumcision and risk for male genital ulcer disease. The analysis concluded that, overall, there was a significantly lower risk for syphilis (however, an RCT showed that syphilis was not reduced) and chancroid among circumcised men, whereas the reduced risk of herpes simplex virus type 2 infection had a borderline statistical significance .
Risks Associated with Male Circumcision
Reported complication rates depend on the type of study (e.g., chart review vs. prospective study), setting (medical vs. nonmedical facility), person operating (traditional vs. medical practitioner), patient age (infant vs. adult), and surgical technique or instrument used.
In large studies of infant circumcision in the
reported inpatient complication rates are approximately 0.2%. The most common
complications are bleeding and infection, which are usually minor and easily
managed. United States
A recent meta-analysis of 16 prospective studies from diverse settings worldwide that evaluated complications following neonatal, infant, and child male circumcision found that median frequency of severe adverse events was 0% (range, 0%-2%). The median frequency of any complication was 1.5% (range, 0%-16%). Male circumcision by medical providers on children tended to be associated with more complications (median frequency, 6%; range, 2%-14%) than for neonates and infants.
In the three African trials of adult circumcision, complication rates for adult male circumcision ranged from 2% to 8%. The most commonly reported complications were pain, bleeding, infection, and unsatisfactory appearance. There were no reported deaths or long-term effects documented.
Minimizing pain is an important consideration for male circumcision. Appropriate use of analgesia is considered standard of care for the procedure at all ages and can substantially control pain. One study found that 93.5% of neonates circumcised in the first week of life using analgesia gave no indication of pain on an objective, standardized neonatal pain rating system.
Effects of Male Circumcision on Penile Sensation and Sexual Function
Well-designed studies of sexual sensation and function in relation to male circumcision are few, and the results present a mixed picture. Taken as a whole, the studies suggest that some decrease in sensitivity of the glans to fine touch can occur following circumcision. However, several studies conducted among men after adult circumcision suggest that few men report their sexual functioning is worse after circumcision; most report either improvement or no change. The three African trials found high levels of satisfaction among the men after circumcision.
HIV Infection and Male Circumcision in the
States has a much lower population prevalence of HIV
infection (0.4%) than sub-Saharan Africa ,
and an epidemic that is concentrated among men who have sex with men, rather
than men who have sex with women. In 2006, it is estimated that approximately
56,300 new HIV infections occurred, of which 73% were in males. Of all new
infections, 53% were in MSM, 31% in heterosexuals with reported high risk of
exposure, 12% in injection drug users (IDUs), and 4% in MSM-IDUs. Among men,
72% of estimated new infections occurred in the male-to-male sexual contact
transmission category, while heterosexual transmission accounted for 13%.
In one prospective study of heterosexual men attending an urban STD clinic, when other risk factors were controlled, uncircumcised men had a 3.5-fold higher risk for HIV infection than men who were circumcised. However, this association was not statistically significant due to small sample size. And in an analysis of clinic records for African American men attending an STD clinic, circumcision was not associated with HIV status overall, but among heterosexual men with known HIV exposure, circumcision was associated with a statistically significant 58% reduction in risk for HIV infection.
Male circumcision reduces the risk that a man will acquire HIV from an infected female partner, and also lowers the risk of other STDs, penile cancer, and infant urinary tract infection. Although male circumcision has risks including pain, bleeding, and infection, more serious complications are rare.
Of late health ministers in Zimbabwe, South Africa, and Botswana where HIV/AIDS is most prevalent have been encouraging adult men to go for circumcision because there is evidence it reduces the risk of the disease. The same could not be said of FGM.