Table 4.
Clearance of new HPV infections a and associated factors among girls who reported having had sex at any time during follow-up (unit of analysis is the infection)
| Number cleared/person-years (rate/100 pys) | Crude HR (95% CI) | Adjusted HR (95% CI) | |
|---|---|---|---|
| Sociodemographic (enrolment) | |||
| Age at enrolment | P = 0.03 | ||
| 15 years | 8/6.1 (132.2) | 1 | |
| 16 years | 18/22.7 (79.3) | 0.09 (0.01-0.74) | |
| Religion | P = 0.08 | P = 0.21 | |
| Christian | 25/23.1 (108.3) | 1 | 1 |
| Muslim | 1/4.8 (20.8) | 0.39 (0.13-1.13) | 0.53 (0.20-1.43) |
| Other | 0/0.9 (0.0) | – | – |
| Socioeconomic status score (tertiles) | P = 0.10 | P = 0.12 | |
| Low | 16/15.3 (104.6) | 1 | 1 |
| Middle | 7/8.0 (87.6) | 0.81 (0.22-3.02) | 0.73 (0.37-1.45) |
| High | 3/5.5 (54.9) | 0.35 (0.13-0.93) | 0.40 (0.14-1.09) |
| Sociodemographic (time-varying) | |||
| Current residence | P = 0.10 | P = 0.24 | |
| Urban | 13/15.2 (85.4) | 1 | 1 |
| Rural | 13/12.9 (101.0) | 2.23 (0.85-5.85) | 0.44 (0.11-1.71) |
| Current occupation | P = 0.88 | P = 0.56 | |
| School | 6/7.8 (77.0) | 1 | 1 |
| Work | vocational training | 0/0.1 (0.0) | – | – |
| Not working | 20/20.8 (96.0) | 0.90 (0.24-3.38) | 1.55 (0.34-7.09) |
| Currently married | P = 0.25 | P = 0.46 | |
| No | 21/23.8 (88.3) | 1 | 1 |
| Yes | 5/5.0 (100.3) | 0.44 (0.11-1.78) | 0.60 (0.15-2.33) |
| Alcohol since most recent visit | P = 0.35 | P = 0.35 | |
| No | 24/27.5 (87.2) | 1 | 1 |
| Yes | 2/1.2 (164.0) | 2.45 (0.37–16.28) | 2.45 (0.37-16.28) |
| Behavioural (time-varying) | |||
| Total partners ever | P = 0.58 | P = 0.16 | |
| 1 | 18/17.6 (102.6) | 1 | 1 |
| 2 | 4/5.4 (73.8) | 0.84 (0.17-4.05) | 0.26 (0.04-1.53) |
| 3+ | 4/5.7 (70.7) | 0.60 (0.23-1.57) | 0.84 (0.35-2.01) |
| Number of times had sex in the past 3 months | P = 0.14 | P = 0.14 | |
| 0 | 13/11.0 (118.4) | 1 | 1 |
| 1 | 0/6.2 (0.0) | – | – |
| 2+ | 13/11.5 (112.7) | 0.21 (0.02-1.69) | 0.21 (0.02-1.69) |
| Most recent male sexual partner was circumcised | P = 0.06 | P = 0.18 | |
| No | 15/13.7 (109.7) | 1 | 1 |
| Yes | 11/14.4 (76.3) | 0.38 (0.14-1.04) | 0.56 (0.24-1.30) |
| Don't know b | 0/0.5 (0.0) | – | – |
| Most recent sexual partner was in concurrent relationship | |||
| No | 17/18.2 (93.3) | – | – |
| Yes | 0/1.6 (0.0) | – | – |
| Don't know b | 9/8.8 (102.1) | – | – |
| Used condom at last sex | |||
| No | 26/26.9 (96.8) | – | – |
| Yes | 0/1.8 (0.0) | – | – |
| Partner put saliva on penis | P = 0.75 | P = 0.75 | |
| No | 18/22.0 (81.8) | 1 | 1 |
| Yes | 3/2.0 (150.7) | 0.88 (0.40-1.92) | 0.88 (0.40-1.92) |
| Don't know b | – | – | – |
| Partner used vaseline for sex | |||
| No | 21/23.0 (91.3) | – | – |
| Yes | 0/1.0 (0.0) | – | – |
| Time had known most recent partner before sex | P = 0.13 | P = 0.89 | |
| < 1 month | 7/7.4 (94.9) | 1 | 1 |
| 1-6 months | 17/17.2 (98.6) | 2.05 (0.64-6.53) | 0.98 (0.30-3.15) |
| 6+ months | 2/3.8 (52.1) | 0.82 (0.17-4.01) | 0.72 (0.09-5.54) |
| Cleansed vagina in past 3 months c | P = 0.02 | P = 0.30 | |
| No | 19/15.9 (119.4) | 1 | 1 |
| Yes | 7/12.8 (54.5) | 0.26 (0.08-0.83) | 0.49 (0.13-1.87) |
a New infection defined as first positive test for the specific HPV type, among those not infected at enrolment or before reported sexual debut. Girls with gaps >180 days in observation time are censored at latest available HPV result before the gap. All P -values are from likelihood ratio tests.
b ‘Don’t know’ responses considered missing data and not included in analysis.
c Vaginal cleansing is cleaning inside the vagina with water, soap or other products using fingers or a cloth.