Table 2.
Univariate frailty models
| HR | 95% CI | SEβ | z/χ2 | df | p | |
|---|---|---|---|---|---|---|
| Site* | – | – | – | .470 | 4 | .976 |
| Sex | 2.81 | 1.59 – 4.95 | 0.29 | 3.56 | – | < .001 |
| Ethnicity | – | – | – | 3.59 | 3 | .309 |
| Clinical Probands vs. Clinical Siblings† | 1.95 | 1.27 – 2.98 | 0.22 | 3.07 | .002 | |
| Clinical Probands vs. Controls† | 6.97 | 3.30 – 14.74 | 0.38 | 5.08 | – | < .001 |
| Clinical Siblings vs. Controls† | 3.58 | 1.64 – 7.79 | 0.40 | 3.27 | – | .001 |
| Clinical Probands and Siblings vs. Controls† | 4.99 | 2.40 – 10.40 | 0.37 | 4.30 | – | < .001 |
| Substance Abuse/Dependence Vulnerability‡ | 1.16 | 1.08 – 1.26 | 0.04 | 3.92 | – | < .001 |
| Conduct Disorder Symptoms‡ | 1.18 | 1.12 – 1.25 | 0.03 | 5.68 | – | < .001 |
Note: Each row represents a separate frailty model estimating the contribution of the predictor to mortality hazard on the multiplicative scale while accounting for dependence due to family.
Probands recruited from residential and outpatient treatment facilities for substance abuse and delinquency in the Denver, Colorado area were ascertained in the context of three separate waves of funding, each of which was treated as a separate site in case of cohort-specific differences, resulting in five total sites and four orthogonal contrasts.
Group variables were estimated using orthogonal codes together in a single analysis of deviance (χ2(2) = 39.53, p < .001). We present four contrasts of interest above, though only two contrasts are identifiable in the context of a single model.
Slopes are unstandardized and are to be interpreted relative to unit increases in average abuse/dependence symptoms per substance and in total symptom counts for substance abuse/dependence vulnerability and conduct disorder symptoms, respectively.