Table 1.
Main characteristics of the study population.
| Total n = 3613 |
CT-Negative History † n = 2780 (76.9%) |
CT-Positive History ‡ n = 833 (23.1%) |
p-Value | |
|---|---|---|---|---|
| Demographic characteristics | ||||
| Age | 0.089 | |||
| Q1: 21–28 years | 923 (25.6) | 703 (25.3) | 220 (26.4) | |
| Q2: 29–31 years | 954 (26.4) | 721 (25.9) | 233 (28.0) | |
| Q3: 32–34 years | 899 (24.9) | 685 (24.6) | 214 (25.7) | |
| Q4: 35–38 years | 837 (23.2) | 671 (24.1) | 166 (19.9) | |
| Migration background (n (%)) | <0.001 | |||
| Western | 3017 (83.5) | 2391 (86.0) | 626 (75.2) | |
| Non-western | 446 (12.3) | 277 (10.0) | 169 (20.3) | |
| Unknown | 150 (4.2) | 112 (4.0) | 38 (4.6) | |
| Educational level # a (n (%)) | <0.001 | |||
| Low and middle | 661 (18.3) | 439 (15.8) | 222 (26.7) | |
| High | 2949 (81.7) | 2339 (84.2) | 610 (73.3) | |
| Infection characteristics | ||||
| Number of CT infections (n (%)) | ||||
| 0 infections | 2780 (76.5) | 2,780 (100.0) | ||
| 1 | 631 (17.5) | 631 (75.8) | ||
| 2 | 166 (4.6) | 166 (19.9) | ||
| ≥3 | 36 (1.0) | 36 (4.3) | ||
| Number of CT tests (n (%)) | <0.001 | |||
| <2 tests | 609 (16.9) | 576 (20.7) | 33 (4.0) | |
| 2 | 994 (27.5) | 852 (30.7) | 142 (17.1) | |
| 3 | 968 (26.8) | 748 (26.9) | 220 (26.4) | |
| >3 | 1042 (28.8) | 604 (21.7) | 438 (52.6) | |
| Years since last CT infection b (median IQR) | 6.0 (4.0–9.0) | 6.0 (4.0–9.0) | ||
| CT symptoms c $ (n (%)) | ||||
| No symptoms | 408 (49.0) | 408 (49.0) | ||
| Symptoms | 425 (51.0) | 425 (51.0) | ||
| Sexual behavior | ||||
| Condom use with steady partner d (n (%)) | 0.001 | |||
| Always, mostly | 309 (8.6) | 260 (9.4) | 49 (5.9) | |
| Sometimes | 583 (16.2) | 439 (15.9) | 144 (17.3) | |
| Never/not often | 1000 (27.8) | 734 (26.5) | 266 (32.0) | |
| At beginning of relationship | 1665 (46.2) | 1301 (47.0) | 364 (43.8) | |
| No steady partners | 45 (1.3) | 36 (1.3) | 9 (1.1) | |
| Condom use with casual partner e (n (%)) | <0.001 | |||
| Always, mostly | 1662 (46.1) | 1313 (47.4) | 349 (42.0) | |
| Sometimes | 1131 (31.4) | 762 (27.5) | 369 (44.4) | |
| Never/not often | 217 (6.0) | 165 (6.0) | 52 (6.3) | |
| No casual partners | 592 (16.4) | 530 (19.1) | 62 (7.5) | |
| Number of lifetime sexual partners (n (%)) | <0.001 | |||
| <6 partners | 1163 (32.2) | 1034 (37.2) | 129 (15.5) | |
| 6–12 | 1243 (34.4) | 956 (34.4) | 287 (34.5) | |
| >12 | 1207 (33.4) | 790 (28.4) | 417 (50.1) | |
| Age of first intercourse (n (%)) | <0.001 | |||
| ≤15 years | 926 (25.6) | 647 (23.3) | 279 (33.5) | |
| 16–17 | 1419 (39.3) | 1076 (38.7) | 343 (41.2) | |
| ≥18 | 1268 (35.1) | 1057 (38.0) | 211 (25.3) | |
| Self-reported gonorrhea infection (n (%)) | <0.001 | |||
| Never | 3555 (98.4) | 2758 (99.2) | 797 (95.7) | |
| At least one | 58 (1.6) | 22 (0.8) | 36 (4.3) | |
| Lifestyle characteristics | ||||
| Smoking status (n (%)) | <0.001 | |||
| Never | 1455 (40.3) | 1205 (43.3) | 250 (30.0) | |
| Occasional | 1813 (50.2) | 1351 (48.6) | 462 (55.5) | |
| Daily | 345 (9.6) | 224 (8.1) | 121 (14.5) | |
| BMI f (median (IQR)) | 22.5 (20.8–24.8) | 22.5 (20.8–24.6) | 22.7 (20.8–25.3) | 0.117 |
Data are medians ± inter quartile ranges (IQR) or numbers and percentages. Percentages might not add up to a total of 100 as values were rounded-up. CT = Chlamydia trachomatis, Q = quartile, BMI = Body Mass Index. † CT-negative history was defined as: no positive Nucleic Acid Amplification Test (NAAT) result during the Chlamydia Screening Implementation study (CSI) [16] and no self-reported positive CT test. ‡ CT-positive history was defined as—at least one NAAT positive result during CSI or self-reported positive CT tests. o Migration background was classified as ‘Western’ if both parents had a Western country of birth (i.e., a country from Europe [excluding Turkey], North-America, Oceania, Indonesia, and Japan), ‘non-Western’ if at least one parent had a non-Western country of birth, and ‘unknown’ if one parent was Western whereas the country of birth of the other parent was unknown or when country of birth of both parents was unknown. # Educational level was categorized by low- and middle-educational level versus high-educational level (low/medium—no education, primary education only, lower general secondary education, and vocational education, high—higher professional education and university education). $ CT symptoms included—vaginal discharge, abdominal pain or pain during intercourse or intermenstrual vaginal bleeding. a missing 3. b missing 3: based on women (n = 833) with a CT-positive history. c based on women (n = 833) with a CT-positive history. d missing 11; e missing 11; f missing 4.