Table 3.
Factors associated with risk of the first CIN1+ or CIN2+ (multivariable Cox proportional-hazards analysis)
| Covariate | Category | CIN1+ | CIN2+ | ||||||
|---|---|---|---|---|---|---|---|---|---|
| No. of women (N = 982) | No. of women with CIN1+ (N = 50) | HR (95% CI) | p-value | No. of women (N = 982) | No. of women with CIN2+ (N = 29) | HR (95% CI) | p-value | ||
| Region | Europe | 644 | 35 | 1 | 644 | 21 | 1 | ||
| Asia Pacific | 168 | 6 | 2.99 (1.03-8.70) | 0.0441 | 168 | 3 | 0.76 (0.20-2.93) | 0.6942 | |
| Latin America | 76 | 3 | 1.18 (0.34-4.05) | 0.7932 | 76 | 1 | 0.57 (0.07-4.37) | 0.5869 | |
| North America | 94 | 6 | 1.93 (0.80-4.68) | 0.1439 | 94 | 4 | 1.73 (0.58-5.18) | 0.3238 | |
| 0.1480 | 0.6452 | ||||||||
| Age at first sexual intercourse | ≥18 years | 801 | 41 | 1 | 801 | 26 | 1 | ||
| 15-17 years | 181 | 9 | 0.46 (0.21-1.02) | 0.0545 | 181 | 3 | 0.18 (0.05-0.64) | 0.0086 | |
| 0.0545 | 0.0086 | ||||||||
| Number of lifetime sexual partners1 | 1 | 800 | 9 | 1 | 800 | 5 | 1 | ||
| 2-3 | 537 | 15 | 1.73 (0.72-4.15) | 0.2213 | 537 | 10 | 1.93 (0.63-5.92) | 0.2529 | |
| ≥4 | 245 | 26 | 5.60 (2.28-13.77) | 0.0002 | 248 | 14 | 4.02 (1.24-13.05) | 0.0203 | |
| 0.0001 | 0.0504 | ||||||||
| Cumulative duration of hormone use for contraception or other indication1 | No use | 804 | 3 | 1 | Not included | ||||
| 1-12 months | 786 | 13 | 3.61 (0.94-13.86) | 0.0614 | |||||
| 13-48 months | 707 | 32 | 3.84 (1.00-14.77) | 0.0502 | |||||
| >48 months | 102 | 2 | 6.09 (0.89-41.63) | 0.0653 | |||||
| 0.2157 | |||||||||
| Tobacco exposure (number of pack-years)1 | <0.5 | 862 | 36 | 1 | Not included | ||||
| ≥0.5 | 177 | 14 | 1.44 (0.76-2.74) | 0.2622 | |||||
| 0.2622 | |||||||||
| Previous cervical HPV infection1 | No | 974 | 2 | 1 | 975 | 1 | 1 | ||
| Yes | 431 | 48 | 35.70 (8.47-150.50) | <0.0001 | 432 | 28 | 42.30 (5.61-318.63) | 0.0003 | |
| <0.0001 | 0.0003 | ||||||||
1Time-varying covariates. The number of women represents the number of observations that appeared at least once during the follow-up period. One woman can be counted in several categories. The number of events (CIN1+ or CIN2+) corresponds to the value recorded at the most recent visit before the endpoint.
Values in italics are the global p-value.
History of Chlamydia trachomatis (CIN1+ and CIN2+), cumulative duration of hormone use (CIN2+), marital/partner status (CIN1+ and CIN2+) and tobacco exposure (CIN2+) were not included in the multivariable analyses because p-values of >0.2 were obtained in the univariate analyses. The covariates of number of sexual partners during the past 12 months and hormone use or not for contraception or another indication were not included in the multivariable analyses because of overlap with the covariates of number of lifetime sexual partners and cumulative duration of hormone use or other indication, respectively.
CI: confidence interval; CIN: cervical intraepithelial neoplasia; HPV: human papillomavirus; HR: hazard ratio.