Table 1.
Sociodemographic Characteristics by Study Year Among Vaccinated and Unvaccinated Participants
| Characteristic | Study Year 1 (2016) | Study Year 2 (2017) | Study Year 3 (2018) | Associated With Vaccination Status | Associated With HPV | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Unvaccinated (n = 929) | Vaccinated (n = 1098) | Unvaccinated (n = 802) | Vaccinated (n = 944) | Unvaccinated (n = 767) | Vaccinated (n = 899) | |||||||||
| No. | (%) | No. | (%) | No. | (%) | No. | (%) | No. | (%) | No. | (%) | P Valuea | P Value | |
| Age, y, mean (range) | 14.97 (14–15) | 14.96 (14–15) | 15.98 (15–16) | 15.97 (15–16) | 16.97 (16–17) | 16.96 (16–17) | <.0001 | |||||||
| Dutch ethnicity | .7328 | .0468 | ||||||||||||
| Yes | 769 | (82.8) | 926 | (84.3) | 671 | (83.7) | 772 | (81.8) | 651 | (84.9) | 748 | (83.2) | ||
| No | 102 | (11. 0) | 120 | (10.9) | 75 | (9.4) | 97 | (10.3) | 79 | (10.3) | 85 | (9.5) | ||
| Degree of urbanization | .4166 | .1892 | ||||||||||||
| Low | 422 | (45.4) | 476 | (43.4) | 367 | (45.8) | 405 | (42.9) | 359 | (46.8) | 400 | (44.5) | ||
| High | 443 | (47.7) | 558 | (50.8) | 379 | (47.3) | 462 | (48.9) | 371 | (48.4) | 433 | (48.2) | ||
| Highest educational level | .4803 | .1249 | ||||||||||||
| Low | 365 | (39.3) | 437 | (39.8) | 283 | (35.3) | 328 | (34.7) | 275 | (35.9) | 316 | (35.2) | ||
| High | 506 | (54.5) | 609 | (55.5) | 463 | (57.7) | 541 | (57.3) | 450 | (58.7) | 510 | (56.7) | ||
| Ever used contraception | .03 | .0261 | ||||||||||||
| No | 625 | (67.3) | 734 | (66.8) | 416 | (51.9) | 420 | (44.5) | 282 | (36.8) | 275 | (30.6) | ||
| Yes | 246 | (26.5) | 312 | (28.4) | 330 | (41.1) | 449 | (47.6) | 448 | (58.4) | 558 | (62.1) | ||
| Smoking past year | .3544 | .4011 | ||||||||||||
| No | 745 | (80.2) | 910 | (82.9) | 585 | (72.9) | 696 | (73.7) | 523 | (68.2) | 603 | (67.1) | ||
| Yes | 126 | (13.6) | 136 | (12.4) | 161 | (20.1) | 173 | (18.3) | 207 | (27.0) | 230 | (25.6) | ||
| Sexual orientation | .6632 | .5703 | ||||||||||||
| Heterosexual | 822 | (88.5) | 984 | (89.6) | 693 | (86.4) | 808 | (85.6) | 672 | (87.6) | 764 | (85.0) | ||
| Other | 47 | (5.1) | 58 | (5.3) | 50 | (6.2) | 61 | (6.5) | 58 | (7.6) | 67 | (7.5) | ||
| Ever had sexual intercourse | .6947 | .0195 | ||||||||||||
| No | 745 | (80.2) | 921 | (83.9) | 545 | (68.0) | 614 | (65.0) | 400 | (52.2) | 451 | (50.2) | ||
| Yes | 126 | (13.6) | 123 | (11.2) | 201 | (25.1) | 255 | (27.0) | 330 | (43.0) | 382 | (42.5) | ||
| Among sexually active participants only | ||||||||||||||
| Ever used condoms | .6577 | .9772 | ||||||||||||
| No | 14 | (11.1) | 14 | (11.4) | 20 | (10.0) | 18 | (7.1) | 35 | (10.6) | 40 | (10.5) | ||
| Yes | 112 | (88.9) | 109 | (88.6) | 181 | (90.0) | 237 | (92.9) | 295 | (89.4) | 342 | (89.5) | ||
| Age at first sexual intercourse | .5910 | .0270 | ||||||||||||
| <15 y | 68 | (54.0) | 70 | (56.9) | 55 | (27.4) | 62 | (24.3) | 50 | (15.2) | 57 | (14.9) | ||
| ≥15 y | 56 | (44.4) | 51 | (41.5) | 142 | (70.6) | 193 | (75.7) | 277 | (83.9) | 325 | (85.1) | ||
| No. of sex partners in past year | .6992 | .3574 | ||||||||||||
| 1–2 | 113 | (89.7) | 115 | (93.5) | 174 | (86.6) | 221 | (86.7) | 268 | (81.2) | 316 | (82.7) | ||
| ≥3 | 7 | (5.6) | 6 | (4.9) | 15 | (7.5) | 21 | (8.2) | 35 | (10.6) | 45 | (11.8) | ||
| No. of sex partners in lifetime | .7329 | <.0001 | ||||||||||||
| 1–2 | 111 | (88.1) | 108 | (87.8) | 159 | (79.1) | 209 | (82.0) | 250 | (75.8) | 284 | (74.3) | ||
| ≥3 | 15 | (11.9) | 14 | (11.4) | 38 | (18.9) | 45 | (17.6) | 77 | (23.3) | 96 | (25.1) | ||
| Has current sex partner | .9926 | .0238 | ||||||||||||
| No | 44 | (34.9) | 48 | (39.0) | 75 | (37.3) | 80 | (31.4) | 109 | (33.0) | 130 | (34.0) | ||
| Yes | 81 | (64.3) | 75 | (61.0) | 126 | (62.7) | 175 | (68.6) | 220 | (66.7) | 251 | (65.7) | ||
| Condom use with partner | .6802 | .0011 | ||||||||||||
| Never | 12 | (9.5) | 12 | (9.8) | 23 | (11.4) | 30 | (11.8) | 59 | (17.9) | 67 | (17.5) | ||
| Always or sometimes | 64 | (50.8) | 60 | (48.8) | 93 | (46.3) | 135 | (52.9) | 143 | (43.3) | 161 | (42.1) | ||
| Diagnosed with STI past year | .3394 | .0092 | ||||||||||||
| No | 125 | (99.2) | 121 | (98.4) | 196 | (97.5) | 253 | (99.2) | 321 | (97.3) | 373 | (97.6) | ||
| Yes | 1 | (0.8) | 2 | (1.6) | 5 | (2.5) | 2 | (0.8) | 9 | (2.7) | 9 | (2.4) |
Abbreviations: HPV, human papillomavirus; STI, sexually transmitted infection.
a P values for main effect of vaccination status are reported (no time interaction).