Age of diagnosis of squamous cell cervical carcinoma and early sexual experience.

BACKGROUND Given the established links among young age at first intercourse (AFI), number of sex partners, high-risk human papillomavirus infection, and squamous cell cervical cancer (SCC), we hypothesized that women diagnosed with SCC at younger ages would be more likely to report young AFI than women diagnosed later in life. METHODS We performed a population-based investigation among invasive SCC cases who were diagnosed between 1986 and 2004, were ages 22 to 53 years, and lived in the metropolitan Seattle-Puget Sound region (n = 333). Using multivariate linear regression, we estimated coefficients and 95% confidence intervals (95% CI) to assess the association between age at SCC diagnosis and AFI (<15, 15-18, > or =19 years) and number of sex partners at age <20 years (0, 1, 2-4, 5-14, > or =15), accounting for birth year and other factors. Interactions were assessed using the likelihood ratio test. RESULTS The interval between AFI and SCC diagnosis ranged from 4 to 35 years. In a multivariate model, compared with SCC cases reporting AFI > or =19, the mean age of diagnosis was 3.1 years younger for SCC cases reporting AFI <15 (95% CI, -5.8 to -0.5) and 2.6 years younger for SCC cases reporting AFI 15 to 18 (95% CI, -4.6 to -0.6). Although number of sex partners at age <20 years was associated with age at SCC diagnosis in a crude analysis, the association was not independent of AFI. However, in the AFI > or =19 and <15 groups, differences in effect were seen by number of sex partners at age <20 years (P(interaction) = 0.08), with the association remaining strong and significant only in the AFI <15 group that had > or =2 partners at age <20 years (coefficient, -4.2; 95% CI, -6.3 to -2.1). CONCLUSION Among younger and middle-aged women with SCC, early age of diagnosis was associated with early AFI, although the effect appeared to be modified by number of sex partners at age <20 years.