Background: The issue of neonatal circumcision is controversial, with proponents arguing that it is an important public health measure. Studies have shown conflicting results regarding the effect of circumcision on the risk of sexually transmitted infections (STIs), leading the American Academy of Pediatrics to defer circumcision decisions to parents. Fergusson and colleagues conducted a longitudinal cohort study to determine whether circumcision provides long-term protection against STIs.

The Study: Participants were 510 men from a birth cohort in New Zealand who were evaluated at birth, four months of age, and one year of age, then yearly until 16 years of age, and then at ages 18, 21, and 25 years. Of this sample, 154 (30.2 percent) were circumcised. Self-reported information about acquisition of STIs was obtained at ages 21 and 25 years. STI diagnoses were reported in 2.7 percent of 21-year-olds and in 6.6 percent of 25-year-olds; 1.2 percent reported a diagnosis at both visits. Covariate risk factors included sex partners, unprotected sex, maternal age and education, socioeconomic status, and birth weight.

Results: Using a random effects model, the authors found that uncircumcised participants had a 2.66 greater risk of STIs than circumcised participants. Adjustment for covariate risk factors increased the odds ratio to 3.19. This increase was caused by a stronger positive association between circumcision and risk factors (i.e., higher number of sexual partners and higher rates of unprotected sex). According to another estimate, the authors calculated that if all men were circumcised, this would reduce the STI rate by 48.2 percent.

Conclusion: The authors conclude that, overall, after adjusting for covariates, uncircumcised men have a more than threefold greater risk of contracting STIs than circumcised men. According to the authors, this study provides important longitudinal data supporting the practice of circumcision as a public health measure.