Table 4.
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: Black youth
| Baseline Model HR (95% CI) |
Adjusted Model HR (95% CI) |
|
|---|---|---|
| Social Class Discrimination | ||
| Youth | ||
| x Mother’s education ≤ High school | 0.69 (0.41-1.19) | 1.15 (0.73-1.82) |
| x Mother’s education > High school | ||
| ND onset ≤ age 18 a | 1.53 (1.03-2.26) b | 0.31 (0.09-1.07) |
| ND onset ≥ age 19 a | 0.72 (0.42-1.22) | |
| Mother | ||
| x Low household income | 1.36 (0.86-2.15) | 1.21 (0.76-1.94) |
| x Middle household income | 0.27 (0.12-0.59) | 0.29 (0.13-0.63) |
| x High household income | 1.20 (0.49-2.91) | 0.90 (0.38-2.10) |
| Socioeconomic Status Indicators | ||
| Household income c | ||
| Low | ||
| ND onset ≤ age 18 a | 0.87 (0.45-1.68) | 0.63 (0.38-1.03) b |
| ND onset ≥ age 19 a | 0.46 (0.26-0.79) | |
| High | 0.53 (0.30-0.96) | 0.56 (0.30-1.06) |
| Mother’s education level d | ||
| < High school | 0.86 (0.53-1.39) | 1.05 (0.64-1.72) |
| > High school | 0.72 (0.43-1.22) | 0.82 (0.51-1.31) |
| Father’s education level d | ||
| < High school | 0.88 (0.60-1.29) | 0.74 (0.50-1.08) |
| > High school | ||
| ND onset ≤ age 17 a | 0.59 (0.36-0.97) b | 0.46 (0.23-0.90) |
| ND onset > age 18 a | 0.92 (0.46-1.82) | |
| Psychosocial/Psychiatric Risk Factors and Family History | ||
| Youth alcohol use | - | 3.87 (2.14-7.00) |
| Youth cannabis use | 2.85 (1.66-4.87) | |
| Youth major depressive disorder | - | 1.52 (1.02-2.26) |
| Youth conduct disorder | - | 0.96 (0.64-1.44) |
| Youth childhood physical abuse/harsh punishment or neglect | - | 1.30 (0.86-1.97) |
| Youth childhood sexual abuse | - | 1.14 (0.74-1.76) |
| Mother regular smoker (lifetime) | 0.95 (0.66-1.36) | |
| Father regular smoker (lifetime) | - | 1.23 (0.79-1.90) |
HR=hazard ratio; CI=confidence interval; ND=nicotine dependence; bold indicates significant at p<0.05; x indicates that separate hazard ratios were estimated for different levels of a variable in a significant interaction
risk period-specific hazard ratios generated to adjust for violation of PH assumption
only one value reported because PH assumption was not violated in this model
comparison group=middle household income
comparison group=high school level education. Both models included gender, age at last interview, family risk group, and age at first cigarette.