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Table 1 Study population characteristics of the CT1 and CT2 chlamydia prevalence studies

From: Prevalence estimates of genital Chlamydia trachomatis infection in Belgium: results from two cross-sectional studies

  CT1 study CT2 study
Total (N = 770) CT negative (N = 759) CT positive (N = 11) Total (N = 763) CT negative (N = 753) CT positive (N = 10)
Median age of participants, years (IQR) 40 (30, 51) 40 (30, 51) 31 (30, 39) 43 (33, 50) 43 (33, 50) 44 (30, 52)
Median age women, years (IQR) 40 (30, 50) 40 (30, 50) 32 (30, 42) 42 (33, 50) 42 (33, 50) 45 (36, 51)
Median age men, years (IQR) 41 (30, 52) 41 (30, 52) 30 (27, 31) 44 (34, 51) 44 (35, 51) 41 (32, 48)
Age group
 16–29 y/o—18–29 y/o 181 (24%) 178 (24%) 3 (27%) 125 (16%) 122 (16%) 3 (30%)
 30–44 y/o 279 (36%) 274 (36%) 5 (45%) 299 (39%) 297 (39%) 2 (20%)
 45–59 y/o 310 (40%) 307 (40%) 3 (27%) 339 (44%) 334 (44%) 5 (50%)
Gender
 Male 348 (45%) 343 (45%) 5 (45%) 351 (46%) 348 (46%) 3 (30%)
 Female 422 (55%) 416 (55%) 6 (55%) 412 (54%) 405 (54%) 7 (70%)
Nationality
 Belgian 639 (84%) 630 (84%) 9 (90%)
 Other than Belgian 124 (16%) 123 (16%) 1 (10%)
Education
 No diploma or primary education 28 (4%) 28 (4%) 0 (0%) 30 (4%) 30 (4%) 0 (0%)
 Lower secondary education 45 (6%) 45 (6%) 0 (0%) 73 (10%) 71 (9%) 2 (20%)
 Higher secondary education 175 (23%) 172 (23%) 3 (27%) 225 (29%) 223 (30%) 2 (20%)
 Higher education (academic or outside University) 456 (59%) 449 (59%) 7 (64%) 382 (50%) 379 (50%) 3 (30%)
 No answer 66 (9%) 65 (9%) 1 (9%) 53 (7%) 50 (7%) 3 (30%)
Health literacy
 Low 25 (3%) 24 (3%) 1 (10%)
 Limited 209 (27%) 207 (27%) 2 (20%)
 Sufficient 472 (62%) 466 (62%) 6 (60%)
 No answer 57 (7%) 56 (7%) 1 (10%)
Civil status
 Single (never married) 220 (29%) 215 (29%) 5 (50%)
 Married or legal cohabitation 461 (60%) 460 (61%) 1 (10%)
 Divorced (not remarried) 78 (10%) 74 (10%) 4 (40%)
 Widowed (not remarried) 4 (1%) 4 (1%) 0 (0%)
Sexual intercourse in the last 12 months
 Yes 635 (82%) 625 (82%) 10 (91%) 600 (79%) 593 (79%) 7 (70%)
 No 68 (9%) 67 (9%) 1 (9%) 103 (13%) 101 (13%) 2 (20%)
 No answer 62 (8%) 62 (8%) 0 (0%) 60 (8%) 59 (8%) 1 (10%)
Nr. of sexual partner in the last 12 months
 One 532 (69%) 526 (69%) 6 (55%) 541 (71%) 535 (71%) 6 (60%)
 Two 38 (5%) 38 (5%) 0 (0%) 25 (3%) 24 (3%) 1 (10%)
 Three 34 (4%) 34 (4%) 0 (0%) 21 (3%) 21 (3%) 0 (0%)
 Four or more 27 (4%) 24 (3%) 3 (27%) 11 (1%) 11 (1%) 0 (0%)
 No answer 136 (18%) 134 (18%) 2 (18%) 165 (22%) 162 (22%) 3 (30%)
The last sexual partner was…
 A steady partner 557 (72%) 552 (73%) 5 (45%)
 A casual partner 74 (10%) 70 (9%) 4 (36%)
 No answer 136 (18%) 134 (18%) 2 (18%)
Condom use during last intercourse
 No 525 (68%) 518 (68%) 7 (64%) 510 (67%) 503 (67%) 7 (70%)
 Yes 88 (12%) 88 (12%) 0 (0%)
 Yes, the whole time 65 (8%) 64 (8%) 1 (9%)
 Yes, but not the whole time 44 (6%) 43 (6%) 1 (9%)
 No answer 136 (18%) 134 (18%) 2 (18%) 165 (22%) 162 (22%) 3 (30%)
First sexual intercourse before age 15
 Yes 33 (5%) 33 (5%) 0 (0%) 32 (4%) 31 (4%) 1 (10%)
 No 672 (95%) 661 (95%) 11 (100%) 631 (83%) 623 (83%) 8 (80%)
 No answer 65 (8%) 65 (9%) 0 (0%) 100 (13%) 99 (13%) 1 (10%)
Median age at first sexual intercourse, years (IQR) 18 (16, 20) 18 (16, 20) 19 (18, 19) 18 (16, 20) 18 (16, 20) 17 (16, 18)
Ever been tested for any STI
 Yes 278 (36%) 272 (36%) 6 (55%)
 No 412 (54%) 408 (54%) 4 (36%)
 No answer 60 (8%) 59 (8%) 1 (9%)
Ever been diagnosed with chlamydia
 Yes 27 (4%) 27 (4%) 0 (0%)
 No 686 (89%) 675 (89%) 11 (100%)
 No answer 57 (7%) 57 (8%) 0 (0%)
Sexual orientation for men
 Men who are attracted to men only/mostly/as much as to women 29 (8%) 29 (8%) 0 (0%)
Testing for HIV in the past 12 months
 Yes 53 (7%) 52 (7%) 1 (10%)
 No 655 (86%) 647 (86%) 8 (80%)
 No answer 55 (7%) 54 (7%) 1 (10%)
Ever been tested for HIV
 Yes 303 (40%) 300 (40%) 3 (30%)
 No 405 (53%) 399 (53%) 6 (60%)
 No answer 55 (7%) 54 (7%) 1 (10%)
Testing for other STI than HIV in the past 12 months
 Yes 60 (8%) 59 (8%) 1 (10%)
 No 608 (80%) 600 (80%) 8 (80%)
 No answer 95 (12%) 94 (12%) 1 (10%)
Ever been tested for other STI than HIV
 Yes 321 (42%) 318 (42%) 3 (30%)
 No 347 (45%) 341 (45%) 6 (60%)
 No answer 95 (12%) 94 (12%) 1 (10%)
  1. CT: Chlamydia trachomatis; IQR: interquartile range; y/o: years of age; STI: sexually transmitted infection; Nr.: number; HIV: human immunodeficiency virus