Table 5.
Within-pair contrasts for monozygotic twin pairs discordant for early risky behaviors.
| N (in pairs) | Model 11 | Model 22 | Model 33 | |
|---|---|---|---|---|
| Early Alcohol Experimentation | 135 | 2.62 (1.38– 5.00)* | 3.24 (1.63– 6.43)* | 3.21 (1.54– 6.67)* |
| Early Regular Alcohol Use | 53 | 1.25 (0.49– 3.17) | 1.55 (0.58– 4.12) | 1.55 (0.58– 4.19) |
| Early Nicotine Experimentation | 191 | 1.54 (0.92– 2.58) | 1.61 (0.95– 2.74) | 1.42 (0.82– 2.49) |
| Early Regular Nicotine Use | 95 | 1.07 (0.52– 2.22) | 1.03 (0.48– 2.21) | 0.79 (0.35– 1.77) |
| Early Daily Nicotine Use | 85 | 0.73 (0.34– 1.60) | 0.66 (0.29– 1.47) | 0.49 (0.20– 1.18) |
| Early Cannabis Experimentation | 67 | 1.55 (0.67– 3.59) | 1.42 (0.60– 3.35) | 0.71 (0.26– 1.92) |
| Any Early Nicotine/Cannabis Experimentation | 193 | 1.46 (0.89– 2.41) | 1.51 (0.91– 2.53) | 1.30 (0.76– 2.22) |
| Any Early Substance Experimentation | 198 | 1.81 (1.06– 3.08)* | 1.90 (1.10– 3.30)* | 1.92 (1.10– 3.33)* |
| Early Sex | 84 | 1.31 (0.64– 2.69) | 1.30 (0.62– 2.74) | 1.15 (0.51– 2.61) |
Note. In all comparisons, the non-early using cotwin is the referent group. 95% confidence intervals are presented in parentheses. Statistically significant effects that survive Bonferroni correction (p<.013) are bolded.
*
Significant before Bonferroni correction (p<.05).
1
Unadjusted model.
2
Adjusted for age, BMI, and early menarche.
3
Adjusted for age, BMI, early menarche, and other early risky behaviors (three out of four early alcohol experimentation, early nicotine experimentation, early cannabis experimentation, early sex- excluding the early risky behavior that was used as the exposure variable).