Variables | Categories | Non-participants | Participants | Significance of difference |
---|---|---|---|---|
N | Â | 73 | 450 | Â |
Mean age in years (std) | Â | 21.1 (3.6) | 20.6 (2.4) | ns |
Years in higher education (std) | Â | 2.3 (1.3) | 3.0 (1.5) | 0.001 |
 |  | N (%) | N (%) |  |
Higher Education Institution | A | 15 (20.5) | 114 (25.3) | ns |
 | B | 29 (39.7) | 180 (40.0) | ns |
 | C | 29 (39.7) | 156 (34.7) | ns |
Ireland is not usual country of residence | Â | 4 (5.5) | 28 (6.2) | ns |
Current user of oral contraceptive pill | Â | 39 (55.6) | 269 (59.8) | ns |