Table 4.

Baseline risk factors for clearance of cervical HPV infection

High-risk HPVLow-risk HPV *Any HPV
Subjects n (=128)Events n (=162)Hazard ratio § (95% CI)PtrendSubjects n (=126)Events n (=170)Hazard ratio § (95% CI)PtrendSubjects n (=185)Events n (=332)Hazard ratio § (95% CI)Ptrend
Age (y)
    <255063415167114
    25–3436380.90 (0.64–1.27)37440.98 (0.70–1.38)48820.94 (0.74–1.20)
    35–4419180.95 (0.59–1.54)21201.12 (0.77–1.64)30381.03 (0.76–1.40)
    ≥4513151.65 (0.97–2.81)0.2714161.62 (0.98–2.67)0.1023311.63 (1.14–2.34)0.05
Ethnicity
    Japanese131412141628
    Caucasian44471.05 (0.66–1.69)47580.86 (0.54–1.34)681050.99 (0.71–1.37)
    Hawaiian12131.06 (0.56–2.00)14140.94 (0.51–1.71)18271.02 (0.65–1.59)
    Filipino651.06 (0.43–2.59)551.22 (0.40–3.69)8101.12 (0.58–2.14)
    Other43551.45 (0.88–2.39)35400.82 (0.51–1.32)58951.11 (0.79–1.57)
Income
    <7,500425229365288
    7,500–19,99929290.66 (0.43–1.01)26281.55 (0.99–2.43)41570.92 (0.67–1.26)
    20,000–49,99927301.05 (0.71–1.55)33400.99 (0.69–1.42)41700.98 (0.75–1.27)
    ≥50,00013151.00 (0.58–1.72)0.8618201.15 (0.75–1.78)0.9324351.07 (0.76–1.49)0.80
Age at menarche
    <12283233414273
    1233391.39 (0.94–2.06)31350.97 (0.65–1.43)44741.16 (0.88–1.52)
    1322260.68 (0.44–1.05)27280.96 (0.65–1.40)39540.78 (0.59–1.05)
    ≥1433361.87 (1.23–2.85)0.1922270.85 (0.55–1.32)0.4941631.27 (0.96–1.69)0.56
No. pregnancies
    None5059607278131
    132371.00 (0.70–1.42)20230.59 (0.40–0.86)39600.77 (0.60–0.99)
    212140.85 (0.48–1.52)11100.63 (0.36–1.10)17240.72 (0.48–1.07)
    ≥324240.66 (0.35–1.26)0.2022260.65 (0.34–1.23)0.0734500.63 (0.40–0.98)0.02
Age at first sexual intercourse
    <16233419213355
    16–1740470.80 (0.54–1.19)37401.80 (1.18–2.74)56871.11 (0.84–1.48)
    18–1933290.77 (0.46–1.28)35471.84 (1.21–2.82)47761.18 (0.86–1.63)
    ≥2022240.78 (0.49–1.25)0.3222231.14 (0.71–1.82)0.5632470.92 (0.67–1.27)0.77
No. lifetime sexual partners
    <25476910
    2–542460.71 (0.29–1.75)36420.82 (0.45–1.50)59880.79 (0.46–1.35)
    ≥669810.80 (0.34–1.89)0.7867810.66 (0.37–1.19)0.08961620.76 (0.45–1.28)0.44
Oral contraceptive use at baseline
    Never252921193448
    Ever931051.24 (0.86–1.79)921121.14 (0.78–1.65)1342171.20 (0.93–1.57)
    Past user42391.43 (0.94–2.18)45461.03 (0.67–1.59)65851.23 (0.91–1.66)
    Current user 51661.14 (0.77–1.68)47661.24 (0.83–1.84)691321.18 (0.89–1.57)
Years of oral contraceptive pill use
    Never used444742406387
    <2 y12111.25 (0.73–2.14)15150.85 (0.54–1.33)20261.03 (0.73–1.46)
    2–4 y23331.24 (0.82–1.86)22311.08 (0.72–1.62)32641.16 (0.87–1.56)
    5–9 y23240.74 (0.48–1.13)20250.76 (0.50–1.14)31490.75 (0.56–1.00)
    ≥10 y16190.92 (0.56–1.52)0.3814201.09 (0.67–1.78)0.7822390.99 (0.69–1.40)0.36
Hormonal cream use at baseline
    Never110124105121157245
    Past user450.86 (0.40–1.84)550.69 (0.29–1.60)6100.78 (0.44–1.36)
    Current user 450.51 (0.24–1.08)355.05 (2.14–11.90)5100.90 (0.50–1.61)
Tobacco smoking history
    Never79957694110189
    Ever39390.94 (0.67–1.33)37370.82 (0.57–1.19)58760.89 (0.70–1.13)
    Past20140.60 (0.35–1.01)20200.99 (0.57–1.72)33340.76 (0.53–1.09)
    Current 19251.40 (0.95–2.05)17170.71 (0.47–1.07)25421.02 (0.77–1.35)
Alcohol history
    Never6981616395144
    Ever49531.07 (0.79–1.45)52681.14 (0.85–1.53)731211.12 (0.91–1.37)
    Past21170.87 (0.54–1.40)24270.96 (0.66–1.39)32440.93 (0.70–1.24)
    Current 28361.19 (0.84–1.67)28411.31 (0.93–1.84)41771.26 (0.99–1.59)
History of tubal ligation
    No110125103120153245
    Yes890.79 (0.42–1.49)10111.43 (0.85–2.40)15201.05 (0.69–1.60)
Condom use at baseline
    No69787375109153
    Yes 49561.19 (0.88–1.60)40560.93 (0.68–1.26)591121.07 (0.86–1.32)
Spermicide use at baseline
    No9911196106144217
    Yes 19231.38 (0.88–2.17)17251.02 (0.69–1.50)24481.19 (0.89–1.59)
History of anal sex
    Never941048999133203
    Ever24301.30 (0.89–1.90)24320.60 (0.43–0.84)35620.90 (0.71–1.15)
    Past17221.40 (0.94–2.09)13180.55 (0.36–0.85)22400.91 (0.67–1.22)
Current 781.09 (0.54–2.22)10130.65 (0.43–0.98)12210.87 (0.62–1.23)
  • * Includes undetermined-risk HPV types.

  • The number of subjects who completed the questionnaire and at least two clinical visits.

  • The number of cleared incident HPV infections during the study period.

  • § Adjusted for age of participants at study entry.

  • Use within the last 4 mo before the first clinical visit.