Table 2

 Unadjusted and adjusted odds ratios of starting current smoking for the first time at year 8, year 9, year 10 and year 11 as a function of being a year 7 “one time trier” in relation to never smoking

Unadjusted odds OR (95% CI)Year 8 (n = 1900)Year 9 (n = 1721)Year 10 (n = 1514)Year 11 (n = 1283)
Year 7 Smoking
    Never tried1111
    Tried just once7.0*** (4.36 to 11.10)3.0*** (1.89 to 4.67)2.1** (1.27 to 3.41)1.1 (0.53 to 2.09)
Adjusted odds OR (95% CI)Year 8 (n = 1888)Year 9 (n = 1709)Year 10 (n = 1503)Year 11 (n = 1273)
*p<0.05; **p<0.01; ***p<0.0005.
Year 7 smoking
    Never tried1111
    Tried just once6.3*** (3.80 to 10.53)2.9*** (1.79 to 4.73)2.1** (1.22 to 3.51)1.0 (0.49 to 2.02)
Covariates
Sex
        Boys1111
        Girls2.8*** (1.68 to 4.59)2.0*** (1.37 to 2.85)1.4 (0.97 to 1.90)1.2 (0.83 to 1.71)
Deprivation0.94 (0.78 to 1.14)1.0 (0.86 to 1.15)0.90 (0.79 to 1.03)1.1 (0.96 to 1.28)
Ethnicity
    White1111
    Black1.0 (0.54 to 1.87)0.41** (0.24 to 0.73)0.45** (0.26 to 0.77)0.40*** (0.21 to 0.65)
    Asian0.91 (0.37 to 2.23)0.41* (0.20 to 0.83)0.62 (0.35 to 1.09)0.60 (0.32 to 1.03)
    Other0.96 (0.20 to 4.52)0.46 (0.11 to 2.00)0.40 (0.09 to 1.72)0.65 (0.19 to 2.23)
Parental smoking
    Neither smoke1111
    Father smokes0.96 (0.48 to 1.90)1.3 (0.81 to 2.06)1.4 (0.95 to 2.21)1.3 (0.83 to 2.07)
    Mother smokes2.1 (1.00 to 4.22)1.8* (1.00 to 3.18)1.5 (0.81 to 2.72)1.3 (0.69 to 2.63)
    Both smoke2.9** (1.52 to 5.42)1.2 (0.61 to 2.17)1.8* (1.06 to 3.19)0.73 (0.35 to 1.54)
Conduct problems score1.1 (0.94 to 1.22)1.1 (0.98 to 1.21)1.1* (1.00 to 1.22)1.1** (1.04 to 1.27)