Table 4.

Multivariable analysis of CIS in relation to HPV-16 status in first smear, stratified by smoking attributes at first smear

VariableHPV-16 statusNo. cases/controlsAdjusted OR* (95% CI)Pinteraction
Smoking duration (y)
    0Negative91/160Reference0.03
Positive28/114.8 (2.2-10.3)
    <5Negative49/52Reference
Positive12/43.3 (1.0-11.2)
    ≥5Negative128/134Reference
Positive67/235.9 (8.6-150.2)
Smoking intensity (pack-years)
    0Negative91/160Reference0.12
Positive28/114.8 (2.2-10.2)
    <2.5Negative86/84Reference
Positive30/47.9 (2.6-23.7)
    ≥2.5Negative91/102Reference
Positive49/226.9 (6.3-114.6)
  • * ORs are adjusted for age at first smear, number of years between date of smear and diagnosis, current oral contraceptive use, and parity as categorized in Table 1. Number of sex partners before first smear was included as a continuous variable.