Table 4.
Multivariate analysis on the association between risk characteristics and grade, divided by gender
| Risk characteristics | Male | Female | ||||||||
| Grade I | Grade II | Grade III | Grade IV | P value* | Grade I | Grade II | Grade III | Grade IV | P value* | |
| Odds ratios (95% CI)† | Odds ratios (95% CI)† | |||||||||
| Having first sex before university (referred to never or having first sex at university) | 2.08 (1.43–3.02) | 1.79 (1.23–2.59) | 1.89 (1.31–2.75) | 1 | < 0.001 | 7.73 (2.80–21.33) | 4.52 (1.63–12.58) | 4.82 (1.73–13.44) | 1 | < 0.001 |
| Ever had sex with a casual and/or commercial sex partner in previous year‡ (referred to having had only regular partner) | 1.89 (1.03–3.47) | 1.76 (1.01–3.10) | 1.33 (0.78–2.29) | 1 | 0.02 | 2.37 (0.40–14.04) | 2.20 (0.42–11.68) | 1.89 (0.36–9.92) | 1 | 0.33 |
| Having had ≥2 sexual partners in previous year‡ (referred to having had only one partner) | 2.08 (1.16–3.72) | 1.86 (1.08–3.20) | 1.60 (0.96–2.68) | 1 | 0.01 | 0.56 (0.22–1.42) | 0.77 (0.36–1.68) | 0.72 (0.34–1.50) | 1 | 0.26 |
| Never or rarely used condom in previous year‡ (referred to sometimes/often/always used) | 1.87 (1.20–2.90) | 1.39 (0.93–2.08) | 1.14 (0.78–1.66) | 1 | 0.003 | 1.98 (1.04–3.78) | 1.43 (0.82–2.51) | 1.12 (0.66–1.89) | 1 | 0.03 |
| Became aware of sex before high school (referred to becoming aware of sex in high school/at university) | 1.66 (1.45–1.91) | 1.27 (1.11–1.46) | 0.98 (0.86–1.13) | 1 | < 0.001 | 2.11 (1.82–2.45) | 1.37 (1.18–1.59) | 1.19 (1.03–1.39) | 1 | < 0.001 |
| Being exposed to pornographic media ≤16 year-old¶ (referred to never or being exposed ≥ 17 year-old) | 1.66 (1.43–1.93) | 1.12 (0.96–1.30) | 1.02 (0.88–1.19) | 1 | < 0.001 | 3.24 (2.33–4.51) | 2.09 (1.49–2.92) | 1.69 (1.20–2.38) | 1 | < 0.001 |
| Being exposed to pornographic website ≤16 year-old (referred to never or being exposed ≥ 17 year-old) | 6.09 (3.94–9.41) | 3.29 (2.12–5.13) | 1.44 (0.90–2.30) | 1 | < 0.001 | 3.66 (1.07–12.58) | 2.16 (0.61–7.58) | 0.59 (0.13–2.66) | 1 | < 0.01 |
| Disapproved high school students' sex (referred to approved or did not know) | 0.93 (0.80–1.08) | 0.91 (0.78–1.06) | 0.84 (0.72–0.98) | 1 | 0.09 | 0.86 (0.69–1.06) | 1.06 (0.86–1.32) | 0.96 (0.78–1.20) | 1 | 0.27 |
* P value is calculated using linear contrast statistics.
† Odds ratio with 95% confidence interval in parentheses is adjusted for university, faculty, residential area, and family's economic status.
‡ Among students sexually active in the previous year.
¶ Including pornographic novel, magazine, and/or video.