Context: Randomized controlled trials and meta-analyses have demonstrated that male circumcision reduces men's risk of contracting human immunodeficiency virus (HIV) infection during heterosexual intercourse. Less is known about whether male circumcision provides protection against HIV infection among men who have sex with men (MSM).
Objectives: To quantitatively summarize the strength of the association between male circumcision and HIV infection and other sexually transmitted infections (STIs) across observational studies of MSM.
Data sources: Comprehensive search of databases, including MEDLINE, EMBASE, ERIC, Sociofile, PsycINFO, Web of Science, and Google Scholar, and correspondence with researchers, to find published articles, conference proceedings, and unpublished reports through February 2008.
Study selection: Of 18 studies that quantitatively examined the association between male circumcision and HIV/STI among MSM, 15 (83%) met the selection criteria for the meta-analysis.
Data extraction: Independent abstraction was conducted by pairs of reviewers using a standardized abstraction form. Study quality was assessed using the Newcastle-Ottawa Scale.
Data synthesis: A total of 53,567 MSM participants (52% circumcised) were included in the meta-analysis. The odds of being HIV-positive were not significantly lower among MSM who were circumcised than uncircumcised (odds ratio, 0.95; 95% confidence interval, 0.81-1.11; number of independent effect sizes [k]=15) [corrected].). Higher study quality was associated with a reduced odds of HIV infection among circumcised MSM (beta, -0.415; P = .01). Among MSM who primarily engaged in insertive anal sex, the association between male circumcision and HIV was protective but not statistically significant (odds ratio, 0.71; 95% confidence interval, 0.22-2.28; k=4) [corrected].Male circumcision had a protective association with HIV in studies of MSM conducted before the introduction of highly active antiretroviral therapy (odds ratio, 0.47; 95% confidence interval, 0.32-0.69; k = 3).Neither the association between male circumcision and other STIs (odds ratio, 1.06; 95% confidence interval, 0.97-1.15; k=8) nor its relationship with study quality was statistically significant (beta, 0.265; P=.47) [corrected].
Conclusions: Pooled analyses of available observational studies of MSM revealed insufficient evidence that male circumcision protects against HIV infection or other STIs. However, the comparable protective effect of male circumcision in MSM studies conducted before the era of highly active antiretroviral therapy, as in the recent male circumcision trials of heterosexual African men, supports further investigation of male circumcision for HIV prevention among MSM.