Table 2.

Baseline risk factors for acquisition of cervical HPV infection

Subjects * n (=972)High-risk HPVLow-risk HPV Any HPV
Events n (=284)Hazard ratio § (95% CI)PtrendEvents n (=286)Hazard ratio § (95% CI)PtrendEvents n (=570)Hazard ratio § (95% CI)Ptrend
Age (y)
    <25267123114237
    25–34250660.48 (0.36–0.65)710.56 (0.42–0.76)1370.52 (0.42–0.64)
    35–44198350.30 (0.20–0.44)290.27 (0.18–0.41)640.29 (0.22–0.38)
    45–54180140.15 (0.09–0.26)120.14 (0.08–0.26)260.15 (0.10–0.22)
    ≥557750.12 (0.05–0.30)<.000170.19 (0.09–0.40)<.0001120.15 (0.09–0.27)<.0001
Ethnicity
    Japanese112222042
    Caucasian383931.01 (0.64–1.60)881.07 (0.66–1.75)1811.04 (0.74–1.45)
    Hawaiian130220.74 (0.41–1.33)240.91 (0.50–1.65)460.82 (0.54–1.24)
    Filipino5590.55 (0.25–1.19)120.82 (0.40–1.71)210.68 (0.40–1.15)
    Other292971.05 (0.66–1.66)891.10 (0.67–1.80)1861.07 (0.77–1.50)
Income
    <7,50022310272174
    7,500–19,999222490.62 (0.44–0.87)480.86 (0.60–1.24)970.72 (0.56–0.92)
    20,000–49,999246450.56 (0.39–0.80)611.12 (0.78–1.61)1060.78 (0.61–1.01)
    ≥50,000248320.48 (0.32–0.71)<.0001350.77 (0.51–1.17)0.51670.60 (0.45–0.80)0.001
Age at menarche
    <122125267119
    12258590.94 (0.65–1.37)570.70 (0.50–1.00)1160.81 (0.63–1.04)
    13251580.88 (0.61–1.28)520.61 (0.43–0.88)1100.73 (0.56–0.95)
    ≥14249721.30 (0.91–1.85)0.20570.79 (0.55–1.12)0.151291.01 (0.79–1.29)0.91
No. pregnancies
    None403117133250
    1186641.38 (1.02–1.86)410.75 (0.53–1.06)1051.04 (0.83–1.31)
    2123241.20 (0.75–1.90)210.84 (0.52–1.36)451.01 (0.72–1.40)
    ≥3259381.13 (0.78–1.64)0.34380.88 (0.61–1.28)0.37761.00 (0.77–1.30)0.99
Age at first sexual intercourse
    <162195941100
    16–17287831.18 (0.85–1.65)731.49 (1.02–2.19)1561.31 (1.02–1.68)
    18–19246601.25 (0.87–1.79)722.16 (1.47–3.18)1321.62 (1.25–2.10)
    ≥20204381.06 (0.71–1.61)0.57461.83 (1.19–2.82)0.0003841.38 (1.03–1.85)0.003
No. lifetime sexual partners
    <211171522
    2–5314943.62 (1.68–7.80)821.45 (0.83–2.51)1762.14 (1.37–3.33)
    ≥65201383.33 (1.56–7.11)0.031321.46 (0.86–2.49)0.282702.05 (1.33–3.17)0.02
Oral contraceptive use at baseline
    Never175514495
    Ever7971920.75 (0.55–1.03)1890.87 (0.63–1.21)3810.81 (0.65–1.01)
    Past user465760.69 (0.48–0.99)770.81 (0.56–1.18)1530.74 (0.57–0.97)
    Current user 3321160.80 (0.58–1.11)1120.92 (0.65–1.30)2280.86 (0.68–1.09)
Years of oral contraceptive pill use
    Never used3129198189
    <2 y91260.85 (0.55–1.31)230.71 (0.45–1.12)490.78 (0.57–1.06)
    2–4 y214540.73 (0.53–1.02)520.67 (0.48–0.94)1060.70 (0.55–0.89)
    5–9 y191450.70 (0.49–0.99)370.53 (0.37–0.78)820.61 (0.47–0.79)
    ≥10 y163270.74 (0.47–1.18)0.04230.56 (0.35–0.90)0.0003500.65 (0.46–0.90)<.0001
Hormonal cream use at baseline
    Never880228217445
    Past user6380.56 (0.28–1.15)80.60 (0.29–1.22)160.58 (0.35–0.96)
    Current user 2971.83 (0.86–3.89)82.14 (1.07–4.31)151.98 (1.19–3.31)
Tobacco smoking history
    Never611160162322
    Ever361830.96 (0.74–1.26)710.80 (0.61–1.06)1540.88 (0.73–1.07)
    Past216420.88 (0.63–1.24)330.67 (0.46–0.98)750.78 (0.60–1.00)
    Current 145411.07 (0.76–1.50)380.97 (0.68–1.38)791.02 (0.80–1.30)
Alcohol history
    Never529138122260
    Ever4431051.02 (0.79–1.32)1111.22 (0.94–1.58)2161.12 (0.93–1.34)
    Past205300.65 (0.44–0.96)411.00 (0.70–1.42)710.81 (0.62–1.06)
    Current 238751.33 (1.00–1.76)701.40 (1.04–1.87)1451.36 (1.11–1.67)
History of tubal ligation
    No841223218441
    Yes131201.66 (0.96–2.86)151.07 (0.60–1.91)351.34 (0.90–2.00)
Condom use by a sexual partner at baseline
    No698135133268
    Yes 2741081.37 (1.05–1.80)1001.33 (1.02–1.75)2081.35 (1.12–1.64)
Spermicide use at baseline
    No840201192393
    Yes 132421.05 (0.75–1.47)411.12 (0.79–1.58)831.08 (0.85–1.38)
History of anal sex
    Never794185182367
    Ever178581.14 (0.85–1.53)511.03 (0.75–1.41)1091.08 (0.87–1.34)
    Past113331.10 (0.76–1.59)311.06 (0.73–1.55)641.08 (0.83–1.41)
    Current 63251.22 (0.81–1.86)190.96 (0.59–1.54)441.09 (0.80–1.49)
  • * The number of subjects who completed the questionnaire and at least two clinical visits.

  • Includes undetermined-risk HPV types.

  • The number of 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.