Table 2

Association between academic ability at age 11 and substance use across adolescence (risk ratios and 95% CIs, weighted for survey design)

N=6059Onset of substance use in early adolescence (age 13–17)Persistence of substance use in later adolescence (age 18–20)
Occasional cigarette smoking*Persistent cigarette smoking*Occasional cigarette smokingPersistent cigarette smoking
Academic abilityMinimally adjusted†Additionally adjusted‡Minimally adjusted†Additionally adjusted‡Minimally adjusted†Additionally adjusted‡Minimally adjusted†Additionally adjusted‡
Medium (vs low)0.95 (0.74 to 1.23)§0.96 (0.74 to 1.24)§0.88 (0.69 to 1.11)§0.89 (0.70 to 1.14)§
High (vs low)0.90 (0.71 to 1.14)§0.96 (0.74 to 1.23)§0.58 (0.45 to 0.74)0.62 (0.48 to 0.81)
Occasional regular alcohol use¶Persistent regular alcohol use¶Occasional regular alcohol use*Persistent regular alcohol use**
Medium (vs low)1.58 (1.35 to 1.85)1.39 (1.17 to 1.64)2.07 (1.73 to 2.49)1.82 (1.50 to 2.21)0.85 (0.65 to 1.10)§0.78 (0.59 to 1.02)§1.92 (1.60 to 2.32)1.56 (1.27 to 1.92)
High (vs low)1.53 (1.30 to 1.81)1.25 (1.04 to 1.51)2.24 (1.87 to 2.67)1.83 (1.50 to 2.23)0.94 (0.72 to 1.23)§0.89 (0.66 to 1.20)§3.03 (2.51 to 3.65)2.28 (1.84 to 2.82)
Occasional cannabis use¶Persistent cannabis use¶Occasional cannabis use**Persistent cannabis use**
Medium (vs low)1.29 (1.09 to 1.53)1.25 (1.05 to 1.49)1.60 (1.30 to 1.98)1.53 (1.24 to 1.90)1.48 (1.24 to 1.77)1.37 (1.14 to 1.64)1.98 (1.62 to 2.43)1.81 (1.48 to 2.22)
High (vs low)1.12 (0.94 to 1.32)§1.08 (0.90 to 1.29)§1.32 (1.07 to 1.63)1.22 (0.98 to 1.52)§1.70 (1.41 to 2.05)1.50 (1.22 to 1.83)2.34 (1.93 to 2.84)1.91 (1.57 to 2.34)
  • *Represents substance use data at age 14/15 (2005) to 15/16 (2006).

  • †Adjusted for age and sex.

  • ‡Additionally adjusted for longstanding disability/illness/infirmity, ethnic group, parental occupational social class and parental education.

  • §Represents significance level: p>0.05.

  • ¶Represents substance use data at age 14/15 (2005) to 16/17 (2007).

  • **Represents substance use data at age 18/19 (2009) to 19/20 (2010).