Determinants for Ct IgG seropositivity among women and men aged 15–39 years old in the Netherlands in 1996, 2007 and 2017
| Characteristics | Women | Men | ||||
| Weighted Ct IgG positive | Univariable | Multivariable | Weighted Ct IgG positive | Univariable | Multivariable | |
| N (%) | OR (95% CI) | aOR (95% CI) | N (%) | OR | aOR (95% CI) | |
| Total | 224 (10.5) | 126 (5.8) | ||||
| Study round | ||||||
| 1996 | 92 (12) | 1 | 1 | 34 (4.4) | 1 | |
| 2007 | 61 (9) | 0.7 (0.5 to 1.0) | 1.3 (0.7 to 2.5) | 50 (7.0) | 1.6 (0.9 to 2.8) | |
| 2017 | 70 (10) | 0.8 (0.6 to 1.2) | 1.5 (0.7 to 3.1) | 41 (6.0) | 1.3 (0.8 to 2.3) | |
| Age group | ||||||
| 15–24 years | 59 (7.5) | 1 | 1 | 44 (5.6) | 1 | |
| 25–39 years | 166 (12.3) | 1.7 (1.2 to 2.4) | 3.0 (1.6 to 5.6) | 82 (6.0) | 1.1 (0.7 to 1.1) | |
| Age×study round 2007 | 0.4 (0.2 to 0.9)* | |||||
| Age×study round 2017 | 0.4 (0.2 to 0.9)* | |||||
| Migration background† | ||||||
| Western | 167 (9.5) | 1 | 1 | 84 (4.6) | 1 | 1 |
| Non-Western | 57 (15.3) | 1.7 (1.1 to 2.7) | 2.1 (1.3 to 3.5) | 41 (12.3) | 2.9 (1.7 to 5.1) | 3.3 (1.7 to 6.1) |
| Level of urbanisation | ||||||
| Very (low) | 67 (10.3) | 1 | 31 (4.4) | 1 | ||
| Moderate and high | 157 (10.6) | 1.0 (0.8 to 1.4) | 95 (6.5) | 1.5 (1.0 to 2.4) | ||
| Level of education‡ | ||||||
| High | 54 (9.8) | 1 | 30 (5.2) | 1 | ||
| Moderate and low | 163 (11.1) | 1.1 (0.8 to 1.6) | 93 (6.3) | 1.2 (0.7 to 2.0) | ||
| STI diagnosed ever§ | ||||||
| No | 177 (9.6) | 1 | 1 | 102 (5.3) | 1 | |
| Yes | 32 (27.6) | 3.6 (2.3 to 5.7) | 3.3 (2.0 to 5.4) | 13 (17.6) | 3.7 (1.8 to 7.8)†† | |
| Age at first time sex | ||||||
| <18 | 106 (12.8) | 1 | 1 | 47 (7.4) | 1 | 1 |
| ≥18 | 74 (10.1) | 0.8 (0.5 to 1.1) | 0.7 (0.5 to 1.0) | 43 (5.5) | 0.7 (0.4 to 1.2) | 0.7 (0.4 to 1.3) |
| Number of recent sexual partners** | ||||||
| 0–1 | 175 (10.8) | 1 | 1 | 84 (5.7) | 1 | |
| ≥2 | 17 (19.1) | 2.0 (1.1 to 3.4) | 2.3 (1.3 to 4.1) | 10 (7.8) | 1.3 (0.7 to 2.7) | |
| Regular partner¶ | ||||||
| Yes | 89 (9.7) | 1 | 54 (6.4) | 1 | ||
| No | 38 (9.1) | 0.9 (0.6 to 1.4) | 30 (6.0) | 0.9 (0.5 to 1.7) | ||
| Condom use with regular partner¶ | ||||||
| Always | 15 (8.8) | 1 | 11 (7.0) | 1 | ||
| Sometimes/never | 70 (10.6) | 1.3 (0.6 to 2.5) | 41 (6.2) | 0.9 (0.4 to 2.1) | ||
An extra category was created for missing data so that these could be included in the analyses. Missing data are not shown. Missing data are a mix of ‘I don't know’, ‘I don't want to say’ and not filled in. Missing values included in the analysis as a separate category (ORs not shown).
ORs with p values of <0.05 are indicated in bold.
*P=0.024 for the interaction term ‘age group×study round 2007’; p=0.027 for the interaction term ‘age group×study round 2017’.
†Migration background was combined into Western (Dutch and Western non-Dutch (West European countries, Australia, North America, Indonesia and Japan)) and non-Western (Morocco and Turkey, SAN and non-Western (other countries)).
‡Education was classified as theoretical (higher professional education, university-level education) or practical (all other educations).
§1996: chlamydia, hepatitis B, gonorrhoea, herpes, HPV, syphilis; 2007 and 2017: chlamydia, hepatitis B, gonorrhoea, herpes, genital warts (HPV), syphilis, HIV.
¶Data not collected in 1996, univariable association from 2007 and 2017 data only. Not included in multivariable model.
**1996: reported number of partners in the past year; 2007 and 2017: reported number of partners in the past 6 months.
††Variables could not be tested in multivariable model due to low numbers (<15 cases per group).
aOR, adjusted OR; Ct, Chlamydia trachomatis; HIV, human immunodeficiency virus; HPV, human papillomavirus; SAN, Suriname, Aruba and the former Dutch Antilles; STI, sexually transmitted infection.