A systematic review and meta-analysis published in the Clinical Microbiology and Infection Journal highlights the protective effect of male circumcision on the prevalence, incidence, and clearance of human papillomavirus (HPV) infection in males and their female sexual partners.
Study: Association between male circumcision and human papillomavirus infection in males and females: a systematic review, meta-analysis, and meta-regression. Image Credit: KTStockphotos/Shutterstock.com
Human papillomavirus (HPV) is the most common sexually transmitted infection globally. While low-risk HPV types are associated with genital warts, high-risk HPV types are considered major causative factors for cervical cancer.
Male circumcision is known to have protective effects against many sexually transmitted infections and sexual activity-related conditions.
Many studies have found a link between male circumcision and reduced risk of human immunodeficiency virus (HIV) infection, herpes simplex virus type 2 infection, syphilis, genital ulcer, chancroid, and candidiasis.
In this systematic review, scientists have provided a detailed overview of the association between male circumcision and the risk of HPV infection in males and their female sexual partners. The review also explores whether the protective effects of circumcision vary between different penile sites.
The scientists searched various scientific documentation databases and included observational and experimental studies reporting the effect of male circumcision on the prevalence, incidence, and clearance of HPV infection in males and their female sexual partners.
Regarding study definitions, prevalence refers to the presence of an HPV infection at any timepoints; incidence refers to the presence of an HPV infection absent at a previous time point; and clearance refers to the absence of a previously-present HPV infection.
For the risk of bias assessment, the Newcastle-Ottawa scale and the Cochrane risk-of-bias tool were used for observational studies and randomized trials, respectively.
The initial screening of databases led to the identification of 1,409 studies, of which 32 studies, including 25 unique study populations, were finally included in the systematic review and meta-analysis. These studies were published between 2002 and 2022.
Among selected studies, 17 were cross-sectional, ten compared two groups cross-sectionally, and five were randomized clinical trials.
In these studies, samples for HPV infection detection and genotyping were collected from different sites in males, including the urethra, foreskin, glans and/or corona, shaft, scrotum, and perianal area. In females, the samples were taken from the cervix and vagina.
Prevalence of HPV infection
The prevalence of HPV infection among all participants at baseline ranged from 8.7% to 69.8%. 21 studies reported the association between circumcision and HPV infection prevalence in males.
According to the study estimates, circumcision significantly reduced the risk of HPV infections at both glans and shaft. The highest protective effect of circumcision was observed at the glans, irrespective of the viral types (low-risk and high-risk HPV types).
Incidence of HPV infection
The association between circumcision and HPV infection incidence in males was reported by nine studies. Similar to the prevalence findings, circumcision significantly reduced the risk of incident HPV infection at the glans. This association remained unchanged when stratified by low-risk and high-risk HPV types.
Clearance of HPV infection
The association between circumcision and HPV infection clearance in males was reported by seven studies.
In these studies, circumcision significantly increased both the rate and risk of HPV infection clearance at the glans. This occurred irrespective of the types of HPV (low-risk or high-risk).
HPV infection outcomes in females
A total of six studies investigated the association between male circumcision and HPV infection outcomes in female partners of circumcised males. In these studies, circumcision significantly reduced the risk of prevalent high-risk HPV infections and the incidence rate of high-risk HPV infections in female partners.
A similar but non-significant trend was also reported for prevalent infections and the incidence rate of low-risk HPV infections.
This systematic review and meta-analysis indicate that male circumcision has significant protective effects against the prevalence, incidence, and clearance of HPV infections at the glans penis.
Circumcision also protects female partners of circumcised males against contracting HPV infection.
As mentioned in the article, circumcision is believed to protect against sexually transmitted infections by changing keratinization and the local immune environment of the penis.
The current systematic review suggests that male circumcision might act as a potential preventive intervention, especially in regions where HPV-related cancers are highly prevalent, and anti-HPV vaccination is not available.
Shapiro, S. et al. (2023) “Association between male circumcision and human papillomavirus infection in males and females: a systematic review, meta-analysis, and meta-regression”, Clinical Microbiology and Infection. doi: 10.1016/j.cmi.2023.03.028. https://www.sciencedirect.com/science/article/abs/pii/S1198743X23001490