Table 2. Hazard Ratios From Univariate and Multivariate Cox Regression to Predict Incident ADHD.
| Characteristic | Hazard ratio (95% CI) | |
|---|---|---|
| Univariate model | Multivariate modela | |
| Race/ethnicity | ||
| White | 1 [Reference] | 1 [Reference] |
| Asian | 0.47 (0.42-0.52) | 0.48 (0.43-0.53) |
| Black | 0.94 (0.87-1.02) | 0.83 (0.77-0.90) |
| Hispanic | 0.84 (0.79-0.90) | 0.77 (0.72-0.82) |
| Other/unknown | 0.73 (0.66-0.81) | 0.73 (0.66-0.82) |
| Female sex | 0.40 (0.38-0.41) | 0.40 (0.38-0.41) |
| Census region | ||
| Northeast | 1 [Reference] | 1 [Reference] |
| Midwest | 0.86 (0.81-0.92) | 0.77 (0.72-0.82) |
| South | 1.13 (1.06-1.20) | 1.06 (1.00-1.13) |
| West | 0.66 (0.62-0.71) | 0.64 (0.60-0.69) |
| Household income, $ | ||
| ≥200 000 | 1 [Reference] | 1 [Reference] |
| 125 000-199 999 | 1.14 (1.08-1.21) | 1.16 (1.09-1.23) |
| 75 000-124 999 | 1.31 (1.24-1.39) | 1.33 (1.26-1.41) |
| 40 000-74 999 | 1.40 (1.32-1.49) | 1.44 (1.35-1.54) |
| <40 000 | 1.52 (1.39-1.65) | 1.57 (1.44-1.71) |
| Other/unknown | 1.22 (1.13-1.32) | 1.29 (1.19-1.39) |
Abbreviation: ADHD, attention-deficit/hyperactivity disorder.
a
The multivariate model included adjustments for sex, region, and household income.