Table 1.
Number of Individuals Providing Data Within Each Age Group
| Age Group
|
||||
|---|---|---|---|---|
| 11 → 15
|
16 → 20
|
21 → 27
|
28 → 34
|
|
| Tobacco Use Frequency | 2,286 | 3,338 | 3,375a | 5,974 |
| Tobacco Use Quantity | 1,465 | 2,465 | 1,837a | 2,035 |
| Alcohol Use Frequency | 2,661 | 5,903 | 7,525 | 4,702 |
| Alcohol Use Quantity | 2,188 | 5,426 | 7,036 | 4,232 |
| Cannabis Use Frequency | 1,196 | 3,195 | 2,768 | 1,249 |
Notes.
a
Because the Wave III assessments of tobacco use frequency and quantity were dropped, these groupings exhibited extremely low covariance coverage with the 28 → 34 year age groupings for all phenotypes. Thus, the 21 → 27 year age groupings for tobacco use were excluded from analyses.