Table 2.
Correlations Between Study Variables
| Tobacco use F | Tobacco use Q | Alcohol use F | Alcohol use Q | Cannabis use F | Age of initiation | ||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
|
|||||||||||||||||||||
| 11–15 | 16–20 | 28–34 | 11–15 | 16–20 | 28–34 | 11–15 | 16–20 | 21–27 | 28–34 | 11–15 | 16–20 | 21–27 | 28–34 | 11–15 | 16–20 | 21–27 | 28–34 | Tobacco | Alcohol | Cannabis | |
|
|
|||||||||||||||||||||
| Tobacco use F | |||||||||||||||||||||
| 11–15 | -- | ||||||||||||||||||||
| 16–20 | 0.63 | -- | |||||||||||||||||||
| 28–34 | 0.46 | 0.51 | -- | ||||||||||||||||||
| Tobacco use Q | |||||||||||||||||||||
| 11–15 | 0.63 | 0.47 | 0.29 | -- | |||||||||||||||||
| 16–20 | 0.53 | 0.65 | 0.37 | 0.61 | -- | ||||||||||||||||
| 28–34 | 0.22 | 0.28 | 0.54 | 0.36 | 0.42 | -- | |||||||||||||||
| Alcohol use F | |||||||||||||||||||||
| 11–15 | 0.36 | 0.26 | 0.24 | 0.18 | 0.26 | 0.10 | -- | ||||||||||||||
| 16–20 | 0.08 | 0.27 | 0.18 | 0.03 | 0.15 | 0.02 | 0.22 | -- | |||||||||||||
| 21–27 | 0.01 | 0.08 | 0.18 | −0.09 | −0.03 | −0.05 | 0.06 | 0.27 | -- | ||||||||||||
| 28–34 | 0.01 | 0.002 | 0.17 | −0.07 | −0.04 | −0.11 | 0.10 | 0.16 | 0.49 | -- | |||||||||||
| Alcohol use Q | |||||||||||||||||||||
| 11–15 | 0.29 | 0.21 | 0.18 | 0.24 | 0.25 | 0.06 | 0.30 | 0.13 | 0.005 | 0.002 | -- | ||||||||||
| 16–20 | 0.11 | 0.21 | 0.17 | 0.14 | 0.16 | 0.06 | 0.14 | 0.36 | 0.15 | 0.09 | 0.22 | -- | |||||||||
| 21–27 | 0.13 | 0.14 | 0.21 | 0.16 | 0.11 | 0.07 | 0.09 | 0.18 | 0.31 | 0.13 | 0.14 | 0.27 | -- | ||||||||
| 28–34 | 0.12 | 0.16 | 0.29 | 0.04 | 0.14 | 0.14 | 0.08 | 0.17 | 0.19 | 0.24 | 0.19 | 0.19 | 0.34 | -- | |||||||
| Cannabis use F | |||||||||||||||||||||
| 11–15 | 0.41 | 0.33 | 0.12 | 0.25 | 0.20 | 0.001 | 0.33 | 0.18 | −0.05 | 0.07 | 0.22 | 0.03 | 0.08 | 0.02 | -- | ||||||
| 16–20 | 0.13 | 0.30 | 0.22 | 0.15 | 0.18 | 0.07 | 0.09 | 0.27 | 0.14 | 0.14 | 0.11 | 0.14 | 0.11 | 0.13 | 0.30 | -- | |||||
| 21–27 | 0.12 | 0.20 | 0.28 | 0.07 | 0.14 | 0.08 | 0.09 | 0.07 | 0.02 | 0.11 | 0.15 | 0.11 | 0.11 | 0.12 | 0.20 | 0.34 | -- | ||||
| 28–34 | −0.03 | 0.03 | 0.25 | 0.06 | 0.09 | 0.13 | 0.14 | 0.01 | 0.02 | −0.07 | 0.11 | 0.09 | 0.04 | 0.08 | 0.02 | 0.12 | 0.45 | -- | |||
| Age of initiation | |||||||||||||||||||||
| Tobacco | −0.18 | −0.20 | −0.17 | −0.25 | −0.28 | −0.21 | −0.22 | −0.07 | 0.02 | 0.05 | −0.19 | −0.13 | −0.10 | −0.11 | −0.11 | −0.11 | −0.11 | −0.07 | -- | ||
| Alcohol | −0.21 | −0.18 | −0.20 | −0.14 | −0.13 | −0.08 | −0.33 | −0.20 | −0.16 | −0.11 | −0.20 | −0.17 | −0.14 | −0.15 | −0.16 | −0.11 | −0.12 | −0.05 | 0.42 | -- | |
| Cannabis | −0.30 | −0.24 | −0.18 | −0.23 | −0.22 | −0.08 | −0.27 | −0.13 | −0.01 | 0.04 | −0.24 | −0.14 | −0.10 | −0.11 | −0.11 | −0.18 | −0.21 | −0.15 | 0.42 | 0.44 | -- |
Notes. Correlations among initiation, among quantity, and between initiation and quantity variables are Pearson coefficients. Correlations between frequency variables are polychoric coefficients. Correlations between initiation and frequency and between frequency and quantity variables are Spearman coefficients. F=frequency, Q=quantity, 11–15=11–15 years, 16–20=16–20 years, 21–27=21–27 years, 28–34=28–34 years.