Table 5.

Incidence of new HPV-16 infection and its association with new sexual partners stratified by level of IgG serologic response against HPV-16 at enrollment

Tertile of seroreactivityN*Women-monthsIncidence rate per 1,000 women-months (95% CI)Crude RR (95% CI)Adjusted RR (95% CI)
Lowest64644,7721.6 (1.3–2.1)1.7 (0.8–3.6)1.2 (0.5–2.6)
Middle64544,0041.7 (1.3–2.1)2.6 (1.4–4.9)2.1 (1.1–4.0)
Highest61137,9962.1 (1.7–2.6)3.0 (1.6–5.3)3.0 (1.6–5.3)

NOTE: Analysis restricted to women who were HPV-16 DNA–negative at enrollment. Ludwig-McGill cohort, Brazilian women (1993–2004).

  • *N = number of women. Serologic data at enrollment were available for 2,034 women, of whom 1,974 were HPV-16 DNA–negative at enrollment. The analysis was restricted to 1,902 women who had multiple follow-up visits. Imbalance in frequencies by seroreactivity because proportionally more women who were HPV-16 DNA–positive were excluded from the highest tertile of seroreactivity.

  • RRs and their respective 95% CIs obtained via Cox regression modeling with time-dependent covariates. Referent group: women who reported not having a new sexual partner.

  • Adjusted for empirical confounders. See text for details.