TABLE 3.
Determinants of fetal femur and humerus z scores in pregnant adolescents1
| Fetal femur z score |
Fetal humerus z score |
|||
| Covariate2 | β ± SE | P | β ± SE | P |
| 25(OH)D <50 nmol/L | −0.1462 ± 0.0738 | 0.049 | −0.1753 ± 0.0784 | 0.027 |
| Calcium intake <1050 mg/d | −0.1655 ± 0.0738 | 0.026 | −0.1341 ± 0.0808 | 0.099 |
| 25(OH)D × calcium intake3 | −0.1628 ± 0.0739 | 0.029 | — | — |
| Maternal race, African American | 0.1744 ± 0.0741 | 0.020 | — | — |
| Maternal height (m) | 0.0203 ± 0.0100 | 0.042 | 0.0166 ± 0.0109 | 0.130 |
| P | <0.0001 | — | 0.007 | — |
| R2 | 0.125 | — | 0.057 | — |
| n | 160 | — | 158 | — |
1
Stepwise multiple linear regression was used to model the determinants of fetal femur and humerus length z scores and to test for an interaction between calcium intake and 25(OH)D status after control for maternal race, height, weight gain, and smoking status. 25(OH)D, 25-hydroxyvitamin D.
2
In stepwise regression, maternal weight gain and smoking status were not significant in models of either bone z scores.
3
Interaction term between maternal calcium intake and 25(OH)D status.