Table 3.
Univariable and multivariable analyses of Chlamydia trachomatis (CT) IgG antibody status stratified for women with a CT-negative and a CT-positive history.
| Positive CT IgG Antibody Status | ||||
|---|---|---|---|---|
| CT-Negative History † | CT-Positive History ‡ | |||
| CT IgG Antibody Positivity n/N | 207/2768 | 337/830 | ||
| Crude | Adjusted | Crude | Adjusted | |
| Variable | OR (95% CI) | aOR (95% CI) | OR (95% CI) | aOR (95% CI) |
| Age | ||||
| Q1: 21–28 years * | 1 | 1 | ||
| Q2: 29–31 years | 0.95 (0.63–1.44) | 1.11 (0.76–1.63) | ||
| Q3: 32–34 years | 1.05 (0.70–1.58) | 1.09 (0.74–1.60) | ||
| Q4: 35–38 years | 1.33 (0.90–1.97) | 1.27 (0.84–1.91) | ||
| Migration background o | ||||
| Western * | 1 | 1 | 1 | 1 |
| Non-Western | 2.19 (1.49–3.21) | 2.22 (1.49–3.29) | 1.47 (1.04–2.06) | 1.38 (0.97–1.96) |
| Unknown | 2.03 (1.13–3.64) | 2.10 (1.16–3.83) | 1.81 (0.94–3.49) | 1.98 (1.00–3.91) |
| Educational level # a | ||||
| Low and middle * | 1 | 1 | 1 | |
| High | 0.50 (0.36–0.70) | 0.58 (0.41–0.82) | 0.84 (0.61–1.14) | |
| Number of CT infections | ||||
| 1 * | 1 | 1 | ||
| ≥2 | 2.35 (1.71–3.25) | 2.28 (1.64–3.17) | ||
| Number of CT tests | ||||
| <2 tests * | 1 | 1 | ||
| 2 | 0.77 (0.51–1.17) | 1.06 (0.49–2.30) | ||
| 3 | 1.07 (0.72–1.61) | 0.93 (0.44–1.97) | ||
| >3 | 1.14 (0.75–1.73) | 1.11 (0.54–2.30) | ||
| Years since last CT infection b | ||||
| <2 years * | 1 | |||
| 2–5 | 0.73 (0.44–1.21) | |||
| >5 | 0.65 (0.41–1.03) | |||
| CT symptoms $ c | ||||
| No symptoms * | 1 | |||
| Symptoms | 1.14 (0.86–1.50) | |||
| Condom use with steady partner d | ||||
| Always, mostly * | 1 | 1 | ||
| Sometimes | 1.10 (0.63–1.95) | 1.45 (0.75–2.80) | ||
| Never/not often | 0.84 (0.49–1.44) | 0.96 (0.52–1.79) | ||
| At beginning of relationship | 0.99 (0.60–1.63) | 0.87 (0.47–1.59) | ||
| No steady partners | 1.10 (0.31–3.87) | 1.16 (0.28–4.86) | ||
| Condom use with casual partner e | ||||
| Always, mostly * | 1 | 1 | ||
| Sometimes | 1.32 (0.96–1.82) | 0.99 (0.73–1.33) | ||
| Never/not often | 0.65 (0.31–1.35) | 1.00 (0.55–1.81) | ||
| No casual partners | 0.79 (0.52–1.20) | 1.21 (0.71–2.09) | ||
| Number of lifetime sexual partners | ||||
| <6 partners * | 1 | 1 | 1 | |
| 6–12 | 1.68 (1.19–2.39) | 1.76 (1.22–2.53) | 0.90 (0.58–1.37) | |
| >12 | 1.64 (1.14–2.37) | 1.81 (1.23–2.68) | 1.17 (0.78–1.75) | |
| Age at first intercourse | ||||
| ≤15 years * | 1 | 1 | 1 | |
| 16–17 | 0.70 (0.50–0.98) | 0.75 (0.53–1.07) | 0.83 (0.60–1.15) | |
| ≥18 | 0.56 (0.39–0.80) | 0.62 (0.42–0.90) | 0.96 (0.67–1.38) | |
| Self-reported gonorrhea infection | ||||
| Never * | 1 | 1 | ||
| At least one | 2.78 (0.93–8.30) | 2.11 (1.08–4.17) | ||
| Smoking status | ||||
| Never * | 1 | 1 | 1 | |
| Occasional | 1.07 (0.79–1.45) | 0.73 (0.54–1.00) | 0.70 (0.51–0.97) | |
| Daily | 1.96 (1.24–3.08) | 1.36 (0.88–2.10) | 1.17 (0.75–1.84) | |
| BMI f | ||||
| Healthy weight (18.5–25) * | 1 | 1 | 1 | |
| Underweight (<18.5) | 0.76 (0.27–2.11) | 0.76 (0.27–2.14) | 0.58 (0.24–1.40) | |
| Overweight (25–30) | 1.15 (0.78–1.69) | 1.09 (0.73–1.62) | 1.19 (0.83–1.69) | |
| Obese (≥30) | 2.33 (1.49–3.65) | 1.81 (1.13–2.91) | 1.81 (1.10–2.97) | |
OR—odds ratio, aOR—adjusted odds ratio, CI—confidence interval, CT—Chlamydia trachomatis, IgG—Immunoglobulin G, Q—quartile, BMI—Body Mass Index. Factors associated (p < 0.10) in the univariable analyses were included in the multivariable analysis. Significant (p < 0.05) results are presented in bold. * Reference category. † 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 tests’. ‡ CT-Positive history was defined as ‘at least one NAAT positive result during CSI or self-reported positive CT test’. 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 (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.