Table 1. Descriptive data on body composition, substance use, and covariates, by sample and data collection wave (N = 704).
| Combined sample | IDEA sample | ECHO sample | ||||
|---|---|---|---|---|---|---|
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| Baseline | Follow-up | Baseline | Follow-up | Baseline | Follow-up | |
| Body composition, M (SD) | ||||||
| BMI z-score | 0.40 (1.02) | 0.42 (1.00) | 0.28 (0.95)a | 0.30 (0.96)a | 0.52 (1.04)a | 0.53 (1.01)a |
| Percent body fat | 21.46 (10.48) | 22.17 (10.28) | 20.33 (10.02)a | 21.37 (9.68) | 22.47 (10.68)a | 22.84 (10.68) |
| Substance use (proportion) | ||||||
| Cigarette use | 5.1% | 15.0% | 7.0%b | 17.9%b | 3.3%b | 12.0%b |
| Alcohol use | 11.7% | 36.8% | 18.6%a | 44.8%a | 5.0%a | 29.3%a |
| Marijuana use | 3.1% | 13.1% | 4.1% | 16.0%a | 2.2% | 10.1%a |
| Covariates | ||||||
| Age, M (SD) | 14.68 (1.83) | 16.65 (1.85) | 15.40 (1.70)a | 17.38 (1.73)a | 13.99 (1.67)a | 15.91 (1.68)a |
| Female | 51.1% | 50.7% | 51.5% | |||
| White | 86.4% | 93.6%a | 79.4%a | |||
| Pubertal status, M (SD) | 2.90 (.73) | 3.04 (.67) | 2.77 (0.76) | |||
| Parent education, M (SD) | 4.96 (1.14) | 4.99 (1.12) | 4.92 (1.00) | |||
| Weight satisfaction, M (SD) | 3.41 (1.01) | 3.45 (1.02) | 3.38 (1.00) | |||
a
Comparison of studies differed significantly p < 0.001
b
Comparison of studies differed significantly p ≤ 0.05