Table 3.
BMD values for umbilical cord blood lead (μg/dL) and maternal blood pressure, comparing Hill, linear, polynomial, and power models.
| Measurement | Hill | Linear | Polynomial | Power |
|---|---|---|---|---|
| Admission SBP
| ||||
| BMD | 1.50 | 2.57 | 0.22 | 1.46 |
| BMDL | 1.42 | 1.57 | 0.07 | 1.42 |
| AIC | 1,840 | 1,838 | 1,840 | 1,838 |
| Admission DBP
| ||||
| BMD | NC | 2.71 | NC | 1.91 |
| BMDL | NC | 1.62 | NC | 1.43 |
| AIC | NC | 1,698 | NC | 1,699 |
| Maximum SBP
| ||||
| BMD | 1.46 | 2.50 | 0.15 | 1.45 |
| BMDL | 1.41 | 1.55 | 0.06 | 1.41 |
| AIC | 1,895 | 1,897 | 1,895 | 1,893 |
| Maximum DBP
| ||||
| BMD | 1.50 | 2.95 | 0.15 | 1.47 |
| BMDL | 1.43 | 1.71 | 0.06 | 1.43 |
| AIC | 2,009 | 2,009 | 2,009 | 2,007 |
NC, no calculation. BMD values were generated with Benchmark Dose Software using the geometric mean for umbilical cord blood and adjusted maternal blood pressure (derived from models presented in Table 2) for each lead quartile. Average SDs for blood pressure were 15.1 mmHg (SBP admission), 11.9 mmHg (DBP admission), 16.7 mmHg (SBP maximum), and 20.4 mmHg (DBP maximum). The AIC is a unitless measure of model fit.