Table 2.
Median values for hydration, density, and constants (C1 and C2) for the paediatric version of Siri's (11) equation, obtained by using the LMS (lambda-mu-sigma) method*.
| Age | Males | Females | ||||||
|---|---|---|---|---|---|---|---|---|
| Hydration % | Density kg/L | C1 | C2 | Hydration % | Density kg/L | C1 | C2 | |
| 5 y | 76.5 | 1.0827 | 5.36 | 4.95 | 76.7 | 1.0837 | 5.33 | 4.92 |
| 6 y | 76.3 | 1.0844 | 5.32 | 4.90 | 76.1 | 1.0865 | 5.27 | 4.85 |
| 7 y | 76.1 | 1.0861 | 5.28 | 4.86 | 75.5 | 1.0887 | 5.22 | 4.79 |
| 8 y | 75.9 | 1.0877 | 5.24 | 4.82 | 75.2 | 1.0900 | 5.19 | 4.76 |
| 9 y | 75.7 | 1.0889 | 5.21 | 4.79 | 75.1 | 1.0909 | 5.17 | 4.74 |
| 10 y | 75.5 | 1.0900 | 5.19 | 4.76 | 75.0 | 1.0916 | 5.15 | 4.72 |
| 11 y | 75.3 | 1.0911 | 5.16 | 4.73 | 75.0 | 1.0924 | 5.13 | 4.70 |
| 12 y | 75.2 | 1.0917 | 5.15 | 4.72 | 74.9 | 1.0937 | 5.10 | 4.67 |
| 13 y | 75.0 | 1.0920 | 5.14 | 4.71 | 74.6 | 1.0954 | 5.07 | 4.63 |
| 14 y | 74.8 | 1.0927 | 5.13 | 4.69 | 74.4 | 1.0975 | 5.02 | 4.58 |
| 15 y | 74.4 | 1.0942 | 5.09 | 4.66 | 74.1 | 1.0996 | 4.98 | 4.53 |
| 16 y | 74.0 | 1.0960 | 5.05 | 4.61 | 73.8 | 1.1011 | 4.95 | 4.49 |
| 17 y | 73.7 | 1.0978 | 5.02 | 4.57 | 73.7 | 1.1020 | 4.93 | 4.47 |
| 18 y | 73.5 | 1.0991 | 4.99 | 4.54 | 73.6 | 1.1027 | 4.92 | 4.46 |
| 19 y | 73.4 | 1.1000 | 4.97 | 4.52 | 73.6 | 1.1031 | 4.91 | 4.45 |
| 20 y | 73.3 | 1.1006 | 4.96 | 4.51 | 73.6 | 1.1035 | 4.90 | 4.44 |
∗C1 is calculated as (D FFM ∗ D FM)/(D FFM − D FM), and C2 is calculated as DFFM /(D FFM − D FM); D FFM and D FM represent fat-free mass density and fat mass density, respectively. % fat mass is calculated as [(C1/Db) – C2] ∗ 100, where Db is measured body density. Adapted from Wells et al. [33].