Table 2.
Parameter estimates for models of benzene metabolites (corresponding to Equations 1 and 2) for 263 nonsmoking female subjects.
| Bootstrap resampling (n = 1,000)
|
||||
|---|---|---|---|---|
| Model | Parameter | Original model estimate (SE) | Median | 2.5th, 97.5th percentiles |
| One pathway (Equation 1) | Y0 (μM) | 94.64 (4.774) | 94.68 | 85.76, 104.1 |
| Ymax (μM) | 8,253 (2,877) | 8,252 | 4,602, 15,169 | |
| X50 (ppm) | 120.3 (47.49) | 119.7 | 58.76, 251.6 | |
| Ymax:X50 (μM/ppm) | 68.60 | 69.08 | 56.01, 84.84 | |
| Two pathways (Equation 2) | Y0 (μM) | 87.20 (5.244) | 86.30 | 60.13, 95.94 |
| Ymax,1 (μM) | 14,637 (10,321) | 14,742 | 7,554, 60,992 | |
| X50,1 (ppm) | 300.6 (260.6) | 301.2 | 121.5, 1,743 | |
| Ymax,2 (μM) | 80.06 (67.26) | 77.75 | 32.17, 209.6 | |
| X50,2 (ppm) | 0.5938 (0.9616) | 0.5756 | 0.0030, 2.765 | |
| Ymax,1:X50,1 (μM/ppm) | 48.69 | 48.91 | 32.98, 68.23 | |
| Ymax,2:X50,2 (μM/ppm) | 134.8 | 142.7 | 45.84, 18,672 | |
Abbreviations: Y, level of total metabolites (μM), X, benzene air concentration (ppm); Y0, background level of Y; Ymax,i, maximum value of Y given the ith metabolic pathway; X50,i, X corresponding to 50% of Ymax,i.