Table 5.
Risk equation with age at quitting incorporated into smoking status variable (Model 2)
| Variable | Parameter Estimate | Standard Error | Chi-Square | P value | Hazard Ratio | 95% CI | |
|---|---|---|---|---|---|---|---|
| Sex | 0.5967 | 0.1133 | 27.7286 | <.0001 | 1.816 | 1.454 | 2.268 |
| Age | 0.0730 | 0.0070 | 107.9667 | <.0001 | 1.076 | 1.061 | 1.091 |
| Sbp | 0.0140 | 0.0036 | 14.7801 | 0.0001 | 1.014 | 1.007 | 1.021 |
| Dbp | -0.0172 | 0.0069 | 6.1574 | 0.0131 | 0.983 | 0.970 | 0.996 |
| Total/HDL ratio | 0.2148 | 0.0354 | 36.7663 | <.0001 | 1.240 | 1.157 | 1.329 |
| Diabetes | 0.7941 | 0.1520 | 27.2897 | <.0001 | 2.213 | 1.642 | 2.981 |
| Trglycerides | -0.0016 | 0.0005 | 8.2076 | 0.0042 | 0.998 | 0.997 | 0.999 |
| Current smoker | 0.7248 | 0.1505 | 23.1684 | <.0001 | 2.064 | 1.537 | 2.773 |
| Age at quitting | |||||||
| <37 | 0.0708 | 0.1474 | 0.2307 | 0.6310 | 1.073 | 0.804 | 1.433 |
| > = 37 | 0.4578 | 0.1435 | 10.1778 | 0.0014 | 1.581 | 1.193 | 2.094 |
| Test | Total | Event | Censored | % Censored | |||
| 3751 | 383 | 3368 | 89.79 | ||||
| Chi-Square | DF | P value | |||||
| Likelihood Ratio | 448.6297 | 10 | <.0001 | ||||
| Hosmer Lemeshow | 11.3628 | 9 | 0.2516 | ||||
| Modified HL | 10.5026 | 9 | 0.3113 | ||||
| Estimate | SE | 95% CI | |||||
| C statistic | 0.8085 | 0.0108 | 0.7873, 0.8296 | ||||
Note: The reference categories for sex, diabetes and the smoking variable are female, no diabetes and never smoker respectively.