| Middle school students (N = 1594) | High school students (N = 1900) | University students (N = 1257) | Total1 (N = 4751) | c2 | p | ||||||||||||
| N | % | N | % | N | % | N | % | ||||||||||
| Ever had sexual intercourse (N = 4693) | 1237.17 | .000 | |||||||||||||||
| Yes | 206 | 13.2 | 542 | 29.0 | 947 | 75.3 | 1695 | 36.1 | |||||||||
| No | 1360 | 86.8 | 1328 | 71.0 | 310 | 24.7 | 2998 | 63.9 | |||||||||
| Only participants who reported having had their first sexual intercourse (N = 1695) | |||||||||||||||||
| Middle school students (N = 194) | High school students (N = 537) | University students (N = 947) | Total1 (N = 1678) | c2 | p | ||||||||||||
| N | % | N | % | N | % | N | % | ||||||||||
| Condom use at 1st sexual intercourse (N = 1492) | 20.39 | .000 | |||||||||||||||
| Yes | 129 | 91.5 | 382 | 94.6 | 818 | 86.4 | 1329 | 89.1 | |||||||||
| No | 12 | 8.5 | 22 | 5.4 | 129 | 13.6 | 163 | 10.9 | |||||||||
| Having had sexual intercourse under the influence of alcohol or drugs (N = 1569) | 106.39 | .000 | |||||||||||||||
| Yes | 32 | 16.5 | 56 | 11.2 | 309 | 35.3 | 397 | 25.3 | |||||||||
| No | 162 | 83.5 | 443 | 88.8 | 567 | 64.7 | 1172 | 74.7 | |||||||||