Delayed intercourse after menarche linked to higher risk of HPV infection

Contrary to previous reports, women who first have sexual intercourse more than 3 years after menarche are at increased risk for human papillomavirus (HPV) infection than women who have intercourse sooner, new research shows.

“This finding is biologically plausible,” note Dr. Stuart I. Collins, from the University of Birmingham in the UK, and colleagues, “given that the life cycle of HPV is dependent on host cell replication and differentiation, which are characteristic of squamous metaplasia occurring in the cervical transformation zone.” HPV targets basal cells in the transformation zone, which increases in size with time after menarche, the team explains. As noted, previous research based on cross-sectional studies reached an entirely different conclusion: that sexual intercourse soon after menarche increases the risk of HPV infection. However, Dr. Collins’ team notes that in these studies, subjects were first evaluated several years after first intercourse, whereas in their study no more than 1 year had transpired. Thus, the likelihood of methodologic issues was reduced. The new findings, which appear in the International Journal of Cancer for April 10, are based on a study of 474 adolescent women with a sexual history of one partner. A total of 145 women became HPV positive.On univariate analysis, longer interval between menarche and first intercourse, age at first intercourse, partner age, and sexually experienced partner were all risk factors for HPV infection. Multivariate analysis confirmed that first sexual intercourse more than 3 years after menarche raised the risk of HPV infection by 58% compared with earlier intercourse.”Our observations suggest that postponement of first intercourse will not reduce a woman’s risk of acquiring an HPV infection, and that the risk is high, even among those engaged in low-risk sexual behavior,” the researchers conclude. (Source: Int J Cancer 2005;114:498-500., March 2005)