Table 3.

Hazard ratios for the association between HPV exposure and squamous cervical lesions (SIL or CIN) in cohort analyses based on different exposure time and outcome definitions

Time zero* defined atHPV exposure status defined atOutcome definitionHPV exposure statusIncidence rate per 1,000 women-months (95% CI)Hazard ratio§ (95% CI)
Screening or 1st HPV infection eventScreening or 1st HPV infection eventCytology onlyNegative0.5 (0.2-1.1)1.0 (reference)
Only LR-HPV types4.6 (1.7-12.3)10.1 (2.6-38.5)
HR-HPV, non-16/1810.4 (7.3-14.9)21.0 (7.8-56.8)
HPV 16 or 1812.4 (7.9-19.4)24.6 (8.8-68.6)
Biopsy + cytologyNegative0.2 (0.0-0.7)1.0 (reference)
Only LR-HPV types4.6 (1.7-12.3)28.3 (5.0-159.2)
HR-HPV, non-16/189.0 (6.2-13.1)50.9 (11.5-225.4)
HPV 16 or 1813.0 (8.4-19.9)66.2 (14.9-295.1)
ScreeningLast visit or 1st abnormality or lesion eventCytology onlyNegative0.6 (0.3-1.1)1.0 (reference)
Only LR-HPV types7.7 (3.9-15.4)14.4 (5.5-37.4)
HR-HPV, non-16/1811.4 (8.5-15.2)19.8 (9.6-40.7)
HPV 16 or 1815.1 (10.7-21.3)26.4 (12.4-55.8)
Biopsy + cytologyNegative0.6 (0.3-1.2)1.0 (reference)
Only LR-HPV types6.3 (3.0-13.1)10.7 (4.1-28.3)
HR-HPV, non-16/1810.3 (7.5-14.0)15.6 (7.8-31.6)
HPV 16 or 1813.0 (9.0-18.7)20.8 (10.0-43.2)
  • * For the calculation of time to lesion event. The exit visit was the one with an incident lesion, or the last visit, for women who did not develop any lesions during follow-up. See Table 1 for details.

  • By design, at screening, all women were HR-HPV negative. For the first set above, HPV exposure status was based on the type found in the first HPV infection event or, if negative up to exit visit, on the status at screening. For the second set, exposure status was based on the last observation for each woman or on the HPV type associated with the incident lesion during follow-up. See Table 1 for details.

  • Does not take into account changes in status during follow-up. LR-HPV events at screening were not included as exposure outcome. For the second set, HPV-negative women may have been HPV positive at a previous instance during follow-up but cleared their infection before exit (last visit without lesion event or first instance of lesion event). See text for details on categories of HPV positivity.

  • § Adjusted for age, race, and study region.

  • Hierarchical use of cytology and biopsy diagnoses: cytology results replaced by biopsy results when biopsy was done.