Table 1.
Demographic characteristics of the 714 NCANDA subjects with usable baseline scans and 526 subjects with at least 3 usable scans by year 4. Two subgroups of 76/76 subjects that were matched on age, sex and scanner type were drawn from the 526 longitudinal cohort.
| Whole Longitudinal | Matched Longitudinal | ||||||
|---|---|---|---|---|---|---|---|
| No-to-low | Transitioner | Moderate-to-heavy | No-to-low | Moderate-to-heavy | |||
| # of adolescents (Boys/Girls) | 259(120/139) | 182(88/94) | 85(40/45) | 76(38/38) | 76(38/38) | ||
| Age | Girls | 15.6±2.3 | 16.9±2.1 | 18.4±2.0 | 17.7±2.0 | 18.1±2.0 | |
| Boys | 15.3±2.4 | 16.7±2.0 | 18.3±1.7 | 17.9±1.9 | 18.2±1.7 | ||
| Scanner (GE/Siemens) | 157/102 | 129/53 | 56/29 | 47/29 | 47/29 | ||
| Pubertal Development Scale | 3.14±0.7 | 3.37±0.6 | 3.63±0.4 | 3.54 ±0.5 | 3.60±0.4 | ||
| Parental education (years) | 16.66±2.4 | 17.10±2.4 | 17.18±2.3 | 16.7 ±2.0 | 17.2± 2.3 | ||
| Days of drinking lifetime (by year 4) | Girls | 2.8±7.2 | 56.1±68.6 | 127.3±93.6 | 3.2±5.3 | 72.8±58.4 | |
| Boys | 3.4±8.2 | 59.2±75.6 | 166.7±157.6 | 3.2±6.3 | 102.1±107.0 | ||
| Days of drinking between baseline and last visit | Girls | 2.6±6.8 | 54.5±67.3 | 123.4±96.0 | 6.1 ±10.8 | 94.7±70.0 | |
| Boys | 3.1±7.5 | 57.5±73.1 | 123.4±118.9 | 6.1 ±10.8 | 125.47±120.8 | ||
| Nicotine | # of cigarettes lifetime | 0.71±7.6 | 79.9±803.7 | 95.4 ±283.3 | 1.7 ±13.8 | 92.7 ±276.7 | |
| # of cigarettes between baseline and last visit | 0.64±7.5 | 79.4±803.6 | 81.8 ±260.2 | 0.64±7.5 | 81.1 ±260.3 | ||
| Marijuana | days lifetime | 1.78±16.9 | 62.95±145.7 | 157.3 ±350.0 | 1.99 ±16.3 | 174.4 ±366.5 | |
| days between baseline and last visit | 1.67±16.7 | 61.86±144.7 | 106.14±235.1 | 1.84 ±16.0 | 117.80 ±246.1 | ||