TABLE 2.
Steady state compartment masses, transfer rates, and other model-derived parameters for 3 groups of young children1
| Parameter | Bangladesh | Philippines | Guatemala |
|---|---|---|---|
| Compartment masses, μmol | |||
| M(4) | 0.453 | 1.67 | 1.85 |
| M(5) | 0.382 | 0.462 | 0.848 |
| M(6) | 195 | 529 | 1054 |
| M(7) | 3.34 | 4.17 | 7.65 |
| TBS | 198 | 533 | 1062 |
| Transfer rates, μmol/d | |||
| U(3) | 1.22 | 2.56 | 2.83 |
| R(5,4) | 0.974 | 2.04 | 2.26 |
| R(7,5) | 5.31 | 1.42 | 2.60 |
| R(5,7) | 5.31 | 1.42 | 2.60 |
| R(6,5) | 4.70 | 5.68 | 10.4 |
| R(5,6) | 4.23 | 4.68 | 9.32 |
| R(10,6) | 0.480 | 1.03 | 1.14 |
| R(8,5) | 0.497 | 1.02 | 1.14 |
| Absorbed and retained, % | 76.2 | 69.9 | 73.6 |
| Disposal rate, μmol/d | 0.976 | 2.05 | 2.27 |
| Days of stores, d | 203 | 260 | 467 |
| System fractional catabolic rate, d−1 | 0.00492 | 0.00384 | 0.00214 |
Values are compartment masses [M(I), or μmol of vitamin A in compartment I (see Figure 1)] and transfer rates [R(I, J), or the rate of transfer of retinol in compartment J to compartment I each day] calculated using a steady state solution in WinSAAM; TBS = M(6) + M(7) and disposal rate = R(10,6) + R(8,5); the % of ingested vitamin A that was absorbed and retained in stores was calculated as {[R(6,5) + R(7,5)]/[R(6,5) + R(7,5) + R(8,5)] × 0.8} × 100, based on the assumption that 80% of the dose was absorbed; days of vitamin A stores were calculated as TBS/disposal rate and the system fractional catabolic rate was calculated as vitamin A disposal rate/TBS. TBS, total body stores.