Table 5.
Results of Cox proportional hazards (PH) regression analyses predicting transition from first cigarette use to nicotine dependence onset as a function of youth’s and mother’s experience of social class discrimination: White youth
| Baseline Model HR (95% CI) |
Adjusted Model HR (95% CI) |
|
|---|---|---|
| Social Class Discrimination | ||
| Youth | 1.14 (0.79-1.64) | 0.81 (0.53-1.24) |
| Mother | 1.27 (0.87-1.85) | 1.46 (0.96-2.22) |
| Socioeconomic Status Indicators | ||
| Household income a | ||
| Low | 1.03 (0.69-1.53) | 1.14 (0.75-1.75) |
| High | 1.10 (0.74-1.62) | 1.15 (0.79-1.66) |
| Mother’s education level b | ||
| < High school | 2.17 (1.37-3.44) | 1.55 (0.92-2.59) |
| > High school | ||
| ND onset ≤ age 18 c | 0.88 (0.64-1.22) d | 1.08 (0.70-1.68) |
| ND onset ≥ age 19 c | 0.57 (0.36-0.89) | |
| Father’s education level b | ||
| < High school | 0.99 (0.69-1.42) | 0.75 (0.50-1.12) |
| > High school | 0.70 (0.46-1.07) | 0.54 (0.34-0.85) |
| Psychosocial/Psychiatric Risk Factors and Family History | ||
| Youth alcohol use | - | 3.06 (1.62-5.75) |
| Youth cannabis use | 3.40 (2.22-5.22) | |
| Youth major depressive disorder | - | |
| ND onset ≤ age 18 c | 2.51 (1.59-3.96) | |
| ND onset ≥ age 19 c | 1.35 (0.75-2.40) | |
| Youth conduct disorder | - | 1.01 (0.61-1.67) |
| Youth childhood physical abuse/harsh punishment or neglect | - | 1.38 (1.00-1.90) |
| Youth childhood sexual abuse | - | 1.55 (0.98-2.45) |
| Mother regular smoker (lifetime) | 1.17 (0.78-1.76) | |
| Father regular smoker (lifetime) | - | |
| ND onset ≤ age 16 c | 0.71 (0.39-1.28) | |
| ND onset ≥ age 17 c | 1.04 (0.64-1.67) |
HR=hazard ratio; CI=confidence interval; ND=nicotine dependence; bold indicates significant at p<0.05
a
comparison group=middle household income
b
comparison group=high school level education
c
risk period-specific hazard ratios generated to adjust for violation of PH assumption
d
only one value reported because PH assumption was not violated in this model. Both models included gender, age at last interview, family risk group, and age at first cigarette.