Table 2 Characteristics of students who were retained in the study and those who were lost to follow-up (n = 1302)

N

%

N

%

Sex

   Male^a

298

40.3%

272

48.3%

< 0.01

   Female

441

59.7%

291

51.7%

Ethnicity^a

   Dutch

446

60.4%

272

48.3%

< 0.001

   Non-Dutch

293

39.6%

291

51.7%

Has a steady relationship^a

   Yes

372

50.8%

265

48.8%

0.26

   No

360

49.2%

278

51.2%

Experience with vaginal intercourse^a

   Yes

472

63.9%

350

62.3%

0.56

   No

267

36.1%

212

37.7%

Experience with anal intercourse^a

   Yes

73

9.9%

68

12.2%

0.21

   No

665

90.1%

490

87.8%

Subgroup of students with experience in vaginal intercourse:

Total n of subsample

Number of lifetime partners vaginal intercourse^b

731^c

n = 731

   1

129

30.7%

79

25.4%

< 0.05

   2

46

18.1%

47

15.1%

   3-5

138

32.9%

88

28.3%

   6+

77

18.3%

92

29.6%

Number of partners vaginal intercourse in past 2 months^b n = 755

755^d

0.46

   0

102

23.8%

79

24.2%

   1

279

65.2%

191

58.4%

   2+

47

11.0%

57

17.4%

Condom use in last vaginal intercourse^a

   Yes

214

48.2%

152

45.5%

0.25

   No

230

51.8%

182

54.5%

Consistent condom use in past 2 months^a

   Yes

103

35.3%

79

33.9%

0.41

   No

189

64.7%

154

66.1%