Table 2.
Formulas for body size descriptors used in modelinga
| Body size descriptor | Age or wt range | Formula |
|---|---|---|
| BSA (m2) | All ages | (wt0.5378) × (ht0.3964) × 0.024265 |
| LBM1 (kg) | Age ≤ 5 yr | Total body wt |
| 5 < age < 18 yr | Males, ln(LBM) = −2.8990 + 0.8064 × ln(ht) + 0.5674 × ln(wt) + 0.0000185 × wt2 − 0.0153 × (BMIz)2 + 0.0132 × age | |
| Females, ln(LBM) = −3.8345 + 0.954 × ln(ht) + 0.6515 × ln(wt) − 0.0102 × BMIz2 | ||
| Age ≥ 18 yr | Males, (9.27 × 103 × wt)/(6.68 × 103 + 216 × BMI) | |
| Females, (9.27 × 103 × wt)/(8.78 × 103 + 244 × BMI) | ||
| LBM2 (kg) | Wt < 50 kg | 3.8 × (0.0215 × wt0.6469 × ht0.7236) |
| Wt ≥ 50 kg | Males, 0.407 × wt + 0.267 × ht − 19.2 | |
| Females, 0.252 × wt + 0.473 × ht − 48.3 |
a
In formulas, weight is in kg, height is in cm, and age is in years. LBM1 and LBM2 were constrained to not exceed total body weight. BMIz values are z scores for subjects' body mass index values.