Circumcision Status and Risk of Sexually Transmitted Infection in Young Adult Males: An Analysis of a Longitudinal Birth Cohort

Abstract

Controversy continues about whether neonatal circumcision could help to prevent the acquisition of sexually transmitted infections (STIs). The present study was based on data obtained during a 25-year longitudinal follow-up investigation of a birth cohort of New Zealand children. A total of 1265 children born in mid-1977 were evaluated three times in the first year of life, annually up to age 16 years, and again at ages 18, 21, and 25 years. Uncircumcised males were at increased risk of STI at ages 18–21 and 21–25 years. Use of a random effects model, fitted to repeated-measures data, yielded an odds ratio (OR) for STI that was 2.66 times higher in uncircumcised than in circumcised males (95% confidence interval [CI], 1.17–6.11). The risk of STI at ages 18–25 years could not be related to measures of childhood social background or birth weight. The risk was, however, related to both the number of sex partners and engaging in unprotected sex. Adjusting for covariate factors by logistic regression analysis increased the degree of association between circumcision status and STIs. The adjusted OR was 3.19 (95% CI, 1.32–7.75). It was estimated that, if all members of the cohort had been circumcised, the overall rate of STI would decline by 48%. The nonadjusted association between reported Chlamydia infection and circumcision status was similar to that for overall STI, but was not statistically significant because of the small number of cases. Circumcision appears to protect against STIs in the teenage and young adult years. In the present study the risk of STI was nearly halved in circumcised males. In the context of public health, long-term benefit from routine neonatal circumcision will have to be weighed against the cost of the procedure.