Table 3.
Unadjusted and adjusted logistic regression results: likelihood (ORs and 95% CIs) of having completed less than 16 years of education among twins with varying substance risk factors.
| Substance Risk Factor | Full Sample1 | Concordant High Risk2 |
High Risk Twin from Disc. Pairs2 |
Low Risk Twin from Disc. Pairs2 |
Significant Covariates |
|---|---|---|---|---|---|
| Unadjusted | |||||
| Early Drinker |
1.69 (1.45 – 1.97) |
1.77a,b (1.39 – 2.23) |
1.87a (1.54 – 2.28) |
1.53b (1.27 – 1.85) |
n/a |
| Daily Nicotine Use |
2.34 (2.04 – 2.68) |
2.87a (2.40 – 3.43) |
2.01b (1.60 – 2.53) |
1.50c (1.21 – 1.87) |
n/a |
| Early Cannabis Use |
2.42 (1.78 – 3.27) |
3.01 (1.74 – 5.20) |
2.15 (1.51 – 3.06) |
1.76 (1.27 – 2.45) |
n/a |
| Cannabis Initiation |
1.39 (1.22 – 1.58) |
1.67a (1.40 – 1.99) |
1.22b (1.01 – 1.47) |
1.31b (1.09 – 1.59) |
n/a |
| Alcohol Dependence |
1.72 1.50 – 1.97) |
2.10a (1.69 – 2.60) |
1.52b (1.27 0 1.83) |
1.18c (0.99 – 1.40) |
n/a |
| Nicotine Dependence |
1.95 (1.71 – 2.22) |
2.54a (2.11 – 3.05) |
1.80b (1.49 – 2.17) |
1.55c (1.30 – 1.86) |
n/a |
| Cannabis Dependence |
1.47 (1.12 – 1.94) |
1.86 (1.03 – 3.36) |
1.36 (1.00 – 1.84) |
1.42 (1.05 – 1.94) |
n/a |
| Any Illicit Drug Dep. |
1.85 (1.44 – 2.37) |
2.11 (1.31 – 3.38) |
1.78 (1.34 – 2.36) |
1.41 (1.08 – 1.83) |
n/a |
| Adjusted 3 | |||||
| Early Drinker |
1.62 (1.39 – 1.89) |
1.68a,b (1.32 – 2.13) |
1.80b (1.48 – 2.20) |
1.49b (1.24 – 1.80) |
SEA |
| Daily Nicotine Use |
2.26 (1.97 – 2.59) |
2.76a (2.30 – 3.31) |
1.97b (1.57 – 2.48) |
1.48c (1.19 – 1.85) |
--- |
| Early Cannabis Use |
2.36 (1.74 – 3.21) |
3.01 (1.73 – 5.23) |
2.10 (1.47 – 3.00) |
1.74 (1.25 – 2.42) |
SEA |
| Cannabis Initiation |
1.34d (1.17 – 1.52) |
1.59a (1.33 – 1.91) |
1.18b (0.98 – 1.43) |
1.29b (1.07 – 1.57) |
SEA |
| Alcohol Dependence |
1.64 (1.43 – 1.89) |
1.99a (1.61 – 2.48) |
1.45b (1.21 – 1.75) |
1.15c (0.97 – 1.37) |
SEA |
| Nicotine Dependence |
1.88 (1.64 – 2.14) |
2.45a (2.03 – 2.96) |
1.73b (1.43 – 2.09) |
1.52b (1.27 – 1.83) |
--- |
| Cannabis Dependence |
1.34 (1.01 – 1.77) |
1.62 (0.89 – 2.95) |
1.27 (0.93 – 1.73) |
1.38 (1.02 – 1.89) |
CD, SEA |
| Any Illicit Drug Dep. |
1.72 (1.33 – 2.22) |
1.91 (1.18 – 3.08) |
1.69 (1.26 – 2.26) |
1.38 (1.06 – 1.80) |
CD, SEA |
1
Within-individual odds of having lower educational attainment based on substance risk status;
2
Within-risk-group odds ratio relative to pairs concordant for low risk;
3
All adjusted models included four covariates: depression (DEPR), conduct disorder (CD), Southeast Asia service (SEA), and post-traumatic stress disorder (PTSD).
a, b, c
risk groups with different superscripts are significantly different;
d
CD and SEA significant for this full sample OR; other full sample covariates matched the covariates for the analyses within-risk-group