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.
Biologic Plausibility
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 Asia
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
and Uganda
In these studies, men who had been randomly
assigned to the circumcision group had a 60% (South
Africa ), 53% (Kenya ),
and 51% (Uganda South
Africa ), 60% (Kenya ),
and 55% (Uganda
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 U.S. United
States
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 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 United States
The United
States has a much lower population prevalence of HIV
infection (0.4%) than sub-Saharan Africa [53],
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.
Summary
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.