Table 2

 Associations between exposure and outcomes by follow up 1 and between follow up 1 and 2

Exposure (superscript indicates group)Protected first sex by follow up 1Unprotected first sex by follow up 1Protected first sex between follow up 1 and follow up 2Unprotected first sex between follow up 1 and follow up 2
% (n)Unadjusted OR (95% CI)Adjusted OR (95% CI)% (n)Unadjusted OR (95% CI)Adjusted OR (95% CI)% (n)Unadjusted OR (95% CI)Adjusted OR (95% CI)% (n)Unadjusted OR (95% CI)Adjusted OR (95% CI)
Adjustment for all exposures except those within same group. 1, Socioeconomic status group; 2, Expectation group; 3, Confidence group; 4, Knowledge group.
Attitude to schoolp = 0.001p = 0.013p = 0.001p = 0.012p = 0.0125p = 0.028p = 0.683p = 0.177
    Like7.78 (133)111.64 (28)1121.90 (258)113.90 (46)11
    Ambivalent9.71 (105)1.30 (1.03,1.64)1.30 (0.97,1.74)3.05 (33)1.93 (1.20,3.10)2.38 (1.33,4.26)22.52 (166)1.04 (0.87,1.25)1.13 (0.93,1.37)4.61 (34)1.20 (0.79,1.83)1.14 (0.71,1. 82)
    Dislike12.65 (54)1.78 (1.26,2.51)1.70 (1.16,2.51)4.45 (19)2.97 (1.68,5.23)2.66 (1.17,6.06)29.62 (93)1.50 (1.15,1.96)1.59 (1.07,2.25)3.82 (12)1.09 (0.64,1.86)0.49 (0.22,1.08)
Non-privately owned accomodation1p = 0.000p = 0.000p = 0.001p = 0.004p = 0.007p = 0.018p = 0.046p = 0.462
    No7.29 (152)111.82 (38)1122.21 (340)113.92 (60)11
    Yes14.87 (105)2.33 (1.74,3.13)2.09 (1.51,2.90)4.82 (34)2.98 (1.69,5.23)2.34 (1.30,4.19)30.00 (129)1.51 (1.12,2.03)1.55 (1.08,2.22)5.58 (24)1.65 (0.99,2.69)1.25 (0.69,2.26)
Neither parent in full time employment1p = 0.001p = 0.000p = 0.027p = 0.058p = 0.244p = 0.090p = 0.972p = 0.502
    No8.22 (217)112.16 (57)1122.90 (436)114.31 (82)11
    Yes13.20 (54)1.74 (1.25,2.41)1.83 (1.33,2.51)4.16 (17)2.07 (1.07,4.02)1.83 (0.98,3.40)26.14 (69)1.18 (0.89,1.55)1.33 (0.96,1.84)4.17 (11)1.01 (0.59,1.74)0.77 (0.37,1.63)
Expectation of parenting by 202p = 0.0002p = 0.050p = 0.0000p = 0.001p = 0.0006p = 0.061p = 0.003p = 0.061
    No7.77 (146)111.70 (32)1121.38 (314)113.61 (53)11
    Unsure10.09 (91)1.34 (1.01,1.79)1.23 (0.83,1.81)2.55 (23)1.55 (0.90,2.67)1.17 (0.63,2.16)25.67 (143)1.27 (1.01,1.60)1.27 (0.93,1.74)3.95 (22)1.16 (0.76,1.78)0.84 (0.48,1.47)
    Yes12.77 (53)1.83 (1.36,2.46)1.56 (1.09,2.23)5.78 (24)3.77 (2.27,6.24)2.79 (1.58,4.94)31.09 (60)1.80 (1.32,2.43)1.49 (1.02,2.16)8.81 (17)3.04 (1.60,5.77)2.46 (1.07,5.64)
Lack of expectation of education/training at age 202p = 0.001p = 0.346p = 0.0000p = 0.226p = 0.106p = 0.381p = 0.041p = 0.265
    No8.20 (188)112.18 (50)1122.46 (381)113.60 (61)11
    Unsure10.95 (91)1.38 (1.13,1.70)1.19 (0.92,1.55)2.53 (21)1.20 (0.74,1.94)0.93 (0.51,1.68)25.40 (127)1.21 (0.96,1.52)1.11 (0.82,1.50)5.80 (29)1.73 (1.10,2.73)1.55 (0.91,2.65)
    Yes15.12 (13)2.22 (1.17,4.20)1.60 (0.66,3.90)10.47 (9)5.77 (2.75,12.12)2.53 (0.89,7.41)30.00 (9)1.53 (0.70,3.35)1.81 (0.66,4.98)6.67 (2)2.16 (0.51,9.15)1.92 (0.26,14.04)
Confidence in rejecting unwanted sex3p = 0.037p = 0.103p = 0.882p = 0.492p = 0.004p = 0.014p = 0.275p = 0.058
    Low⩽median score7.72 (79)112.25 (23)1120.99 (293)114.30 (60)11
    High>median score10.05 (211)1.15 (1.01,1.32)1.14 (0.97,1.32)2.43 (51)1.02 (0.78,1.33)1.11 (0.83,1.49)28.24 (209)1.21 (1.06,1.38)1.21 (1.04,1.41)3.65 (27).87 (0.67,1.12)0.78 (0.61,1.01)
Confidence communicating about sex3p = 0.000p = 0.000p = 0.001p = 0.008p = 0.000p = 0.000p = 0.005p = 0.052
    Low⩽median score7.72 (79)111.88 (38)1120.99 (293)114.30 (60)11
    High>median score13.08 (143)1.68 (1.44,1.95)1.75 (1.46,2.12)3.39 (37)1.60 (1.23,2.09)1.48 (1.11,1.97)28.24 (209).90 (1.58,2.28)1.79 (1.42,2.25)3.65 (27)1.57 (1.15,2.14)1.41 (1.00,2.00)
Knowledge of emergency contraception timing4p = 0.017p = 0.014p = 0.448p = 0.389p = 0.000p = 0.002p = 0.041p = 0.032
    No8.21 (198)112.36 (57)1120.36 (257)113.65 (46)11
    Yes11.70 (86)1.49 (1.07,2.07)1.51 (1.09,2.09)2.72 (20)1.20 (0.75,1.94)1.27 (0.74,2.16)27.51 (252)1.53 (1.23,1.90)1.48 (1.16,1.90)4.80 (44)1.48 (1.01,2.17)1.58 (1.04,2.39)
Knowledge of contraception and sexual health service access4p = 0.0000p = 0.001p = 0.050p = 0.109p = 0.001p = 0.060p = 0.079p = 0.167
    05.58 (27)112.89 (14)1117.43 (88)112.75 (6)11
    17.09 (111)1.28 (0.91,1.80)0.97 (0.71,1.34)1.79 (28)0.62 (0.36,1.08)0.57 (0.27,1.21)18.80 (113)1.12 (0.71,1.76)0.81 (0.48,1.38)3.16 (19)1.18 (0.45,3.09)0.70 (0.23,2.16)
    214.14 (54)2.80 (1.69,4.64)1.84 (1.06,3.20)3.14 (12)1.20 (0.53,2.71)1.17 (0.47,2.90)23.91 (82)1.56 (1.09,2.22)0.96 (0.64,1.45)4.37 (15)1.78 (0.75,4.21)1.04 (0.35,3.08)
    313.10 (95)2.56 (1.84,3.58)1.73 (1.18,2.53)3.03 (22)1.14 (0.68,1.94)0.96 (0.46,1.97)26.88 (275)1.84 (1.20,2.82)1.25 (0.78,2.00)4.99 (51)2.14 (0.79,5.73)1.40 (0.46,4.31)