Risk of cervical cytological squamous intraepithelial neoplasia (SIL) by joint effect of duration of oral contraceptive (OC) use and C. trachomatis positivity at 18.5 years
| Risk factors | N | SIL | Adjusted SIL* | ||
| n | OR (95% CI) | OR (95% CI) | |||
| CT# | Duration of OC use | ||||
| 0 | 0 | 2746 | 233 | 1 | 1 |
| 0 | 1 | 3675 | 298 | 0.9 (0.8 to 1.1) | 0.9 (0.7 to 1.1) |
| 1 | 0 | 88 | 7 | 0.9 (0.4 to 1.9) | 0.7 (0.3 to 1.7) |
| 1 | 1 | 126 | 11 | 1.0 (0.5 to 1.8) | 0.9 (0.4 to 1.7) |
In duration (0=5 or less than 5 years/short-term OC use, 1= more than 5 years/long-term OC use).
*Adjusted for HPV16/18, condom use last year, smoking and number of sexual partners.
CT, C. trachomatis (0= CT negative, 1=CT positive); HPV, human papillomavirus.