Mediators of the Association Between Age of First Sexual Intercourse and Subsequent Human Papillomavirus Infection

Objective: Previous studies have demonstrated that early age of first sexual intercourse is associated with human papillomavirus (HPV) infection. The objective of this study was to identify a set of risk behaviors and partner characteristics that mediate the association between age of first sexual intercourse and subsequent HPV infection in adolescent and young adult women.

Methods: Female university students completed surveys and underwent HPV testing every 6 months for up to 3 years. HPV-positive participants were matched to HPV-negative participants (252 pairs, total N = 504). Associations were examined between risk behaviors/partner characteristics and both age of first sexual intercourse and HPV infection. Those variables associated with either age of first sexual intercourse or HPV infection were entered into a generalized estimating equation (to account for the matched study design) modeling the association between age of first sexual intercourse and HPV infection.

Results: Mean age of first sexual intercourse was 16.7 (+/-1.8) years, and early age of first sexual intercourse was associated significantly with HPV infection (beta = -0.20; odds ratio: 0.82; 95% confidence interval: 0.74-0.90). The association was mediated by number of sexual partners in the past 6 months, history of sexually transmitted infection, alcohol and drug use related to sexual behaviors, and partner's number of sexual partners.

Conclusion: A set of behavioral risk factors and partner characteristics partially mediate the association between age of first sexual intercourse and subsequent HPV infection.