Table 1.
Sample characteristics (results shown as n (percentages) unless otherwise indicated).
| Any Early Substance Experimentation (n=1393–1403) | No Early Substance Experimentation (n=2118–2134) | p | |
|---|---|---|---|
| Sample Characteristics | |||
| Age (mean (sd)) | 21.73 (0.09) | 21.52 (0.08) | .07 |
| Monozygotic | 740 (53.46) | 1178 (55.20) | .40 |
| BMI (mean (sd)) | 24.63 (0.20) | 23.87 (0.14) | .001 |
| BMI Categories | .01 | ||
| Underweight | 75 (5.37) | 157 (7.38) | |
| Normal Weight | 851 (60.92) | 1344 (63.19) | |
| Overweight | 255 (18.25) | 373 (17.54) | |
| Obese | 216 (15.46) | 253 (11.89) | |
| Early Menarchea | 305 (21.82) | 390 (18.41) | .02 |
| Early Sexb | 264 (18.95) | 57 (2.67) | <.0001 |
| Eating Disorder Symptoms | |||
| Binge Eating | 51 (3.66) | 46 (2.17) | .01 |
| Compensatory Behaviors | 370 (26.45) | 369 (17.30) | <.0001 |
| Purging Behaviors | 166 (11.87) | 146 (6.84) | <.0001 |
| Non-purging Behaviors | 321 (22.94) | 325 (15.23) | <.0001 |
| Bulimic Behaviors | 382 (27.40) | 385 (18.19) | <.0001 |
| Substance Use History | |||
| Early Alcohol Experimentationc | 527 (37.59) | --- | --- |
| Early Regular Alcohol Used | 144 (10.30) | --- | --- |
| Early Nicotine Experimentatione | 1257 (89.59) | --- | --- |
| Early Regular Nicotine Usef | 407 (29.11) | --- | --- |
| Early Daily Nicotine Useg | 297 (21.20) | --- | --- |
| Early Cannabis Experimentationh | 242 (17.29) | --- | --- |
| Any Early Nicotine/Cannabis Experimentationi | 1281 (91.30) | --- | --- |
Note. sd = standard deviation; BMI = body mass index. Statistically significant effects are bolded.
a
Age of onset of menarche before age 12.
b
First consensual sexual intercourse before age 15.
c
Ever having a full drink of alcohol before age 15.
d
Having an alcoholic drink on at least six separate days or dinking at least one drink each week for eight weeks in a row before age 16.
e
Ever smoking before age 15.
f
Smoking at least once per week for at least two months in a row before age 16.
g
Smoking daily or nearly every day for at least two months in a row before age 16.
h
Ever using cannabis before age 15.
i
Ever using nicotine or cannabis before age 15.