Effect of age-difference between heterosexual partners on risk of cervical cancer and human papillomavirus infection

Abstract

Background: Age difference (Adiff) within a heterosexual couple may influence a woman's risk of being HPV-positive and developing cervical cancer (CC). Methods: We assessed the relationship between Adiff within the first and current sexual partnership and risk of CC and HPV infection in 1495 cases and 1358 control women from 6 countries included in IARC's multicentric case-control study (median age: 48 years). Results: Large Adiff within the first partnerships was associated with increased CC risk (OR≥3 vs. ≤2 years=1.49, CI: 1.26–1.75); this association disappeared after correction for age at first sexual intercourse (OR=1.03, 0.86–1.24). The relationship between Adiff within the current partnership and HPV-positivity was opposite (OR≥3 vs. ≤2 years=0.59, 0.41–0.86) and not affected by adjustment for sexual confounding. The influences of Adiff on CC risk and HPV-positivity were consistent across age groups and countries. Conclusion: The association between CC risk and large Adiff in the first sexual partnership is mostly explained by young age at first intercourse. Conversely, the negative association between Adiff in current partnership and HPV-positivity is probably related to decreased infectiousness of the male partner with age. The study of Adiff in sexual partnerships helps elucidate HPV circulation in different populations. Keywords: Sexual behavior, Age-difference, Assortative mixing, Human papillomavirus (HPV), Cervical cancer