Table 3.
Conditional Growth Mixture Models Including a Covariate
| Model 3a: included early heroin use |
Model 3b: included early alcohol use |
Model 3c: included ethnicity |
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Increased | Decreased Late |
Decreased Early |
Moderate | Increased | Decreas ed Late |
Decrease d Early |
Moderate | Increased | Decreased Late |
Decreased Early |
Moderate | |
| Means | ||||||||||||
| Intercept (I) | 1.05** | 1.94** | 2.27** | 2.52** | −0.27 | 2.56** | 2.49** | 0.78 | 1.28* | 1.91** | 2.21* | 1.69** |
| Slope (S) | 0.28** | 0.29** | −0.02 | −0.29** | −0.32* | −0.40* | −0.33 | 0.16 | 0.14 | 0.08 | −0.25 | 0.34 |
| Quadratic (Q) | −0.01** | −0.03** | −0.05** | 0.02** | 0.04** | 0.03 | −0.03 | −0.08 | −0.01 | −0.07** | 0.01 | −0.04 |
| I on early use | 1.06** | −0.49 | −1.12 | 0.61 | 1.83** | −0.76* | 0.06 | 1.50** | -- | -- | -- | -- |
| S on early use | −0.47** | 0.06 | 0.72* | −0.60 | 0.41** | 0.71** | −0.13 | 0.28 | -- | -- | -- | -- |
| Q on early use | 0.03** | 0.01 | −0.02 | −0.01 | −0.04** | −0.06** | 0.05* | −0.02* | -- | -- | -- | -- |
| I on Hispanic | -- | -- | -- | -- | -- | -- | -- | -- | 0.12 | 0.13 | 0.69 | 1.20 |
| S on Hispanic | -- | -- | -- | -- | -- | -- | -- | -- | −8.22** | 0.13 | −1.84** | 0.30 |
| Q on Hispanic | -- | -- | -- | -- | -- | -- | -- | -- | 0.06 | 0.20 | 0.03 | −0.75* |
| I on Black | -- | -- | -- | -- | -- | -- | -- | -- | 3.06** | 0.10 | 1.09** | −0.41 |
| S on Black | -- | -- | -- | -- | -- | -- | -- | -- | −0.004 | 0.04 | −0.04 | 0.06* |
| Q on Black | -- | -- | -- | -- | -- | -- | -- | -- | −0.12** | 0.03 | −0.07** | 0.04 |
| Variance1 | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Intercept | 0.46** | 0.46** | 0.46** | 0.46** | 0.41** | 0.41** | 0.41** | 0.41** | 0.43** | 0.43** | 0.43** | 0.43** |
| Residual Variance | 2.19** | 2.19** | 2.19** | 2.19** | 2.23** | 2.23** | 2.23** | 2.23** | 2.22** | 2.22** | 2.22** | 2.22** |
| Logit of probability of class membership | ||||||||||||
| Mean logit | 0.11 | −0.23 | −0.96** | -- | −0.80 | −0.58 | −0.96 | -- | 0.12 | −0.60 | −0.02 | -- |
| Membership on early Use |
1.25 | 1.55** | 1.43** | -- | 3.02** | 2.14 | 1.86* | -- | -- | -- | -- | -- |
| Membership on Hispanic |
-- | -- | -- | -- | -- | -- | -- | -- | 0.07 | 0.77 | −1.21 | -- |
| Membership on Black | -- | -- | -- | -- | -- | -- | -- | -- | −3.03 | −0.16 | −0.72 | -- |
| Mortality % | 43.8 | 44.0 | 36.2 | 35.7 | 42.1 | 43.8 | 32.3 | 39.5 | 39.5 | 41.0 | 33.3 | 46.7 |
| Number of subjects (%) in each class |
162 (34) | 125 (27) | 58 (12) | 126 (27) | 209 (44) | 121 (26) | 65 (14) | 76 (16) | 185 (39) | 100 (21) | 66 (14) | 120 (25) |
| Goodness of fit | ||||||||||||
| Bayesian (BIC) | 24655.03 | 24660.9 | 24793.89 | |||||||||
| LMR LRT | p=0.038 | p=0.44 | p=0.362 | |||||||||
1
Variances of Slope and Quadratic were constrained to zero.
*
p <0.05
**
p <0.01