TABLE 3.
Concentrations of maternal and newborn (cord blood plasma) micronutrient status biomarkers, their strength of association, and the ratio of newborn to maternal biomarker concentrations assessed at 32 wk gestation among participants in the JiVitA-3 trial in rural Bangladesh1
| Biomarker | n | Maternal, 32-wk gestation | Cord blood | Cord blood biomarker difference per 1-SD maternal biomarker increment, % (95% CI) | P value | R 2 | Cord:maternal ratio, % (95% CI) |
|---|---|---|---|---|---|---|---|
| Ferritin, µg/L | 317 | 32 (16, 66) | 151 (76, 302) | +2.0 (−8.9, 14.3) | 0.72 | 0.0008 | 4.66 (1.74, 12.45) |
| Folate, nmol/L | 329 | 26 (12, 54) | 59 (37, 93) | +26.8 (19.6, 34.5) | <0.0001 | 0.2657 | 2.28 (1.20, 4.35) |
| Cobalamin, pmol/L | 328 | 163 (113, 233) | 297 (175, 506) | +31.3 (24.6, 38.3) | <0.0001 | 0.2625 | 1.83 (1.15, 2.91) |
| Retinol, µmol/L | 279 | 0.99 ± 0.32 | 0.64 ± 0.23 | +3.5 (−0.4, 7.3) | 0.073 | 0.0100 | 0.64 (0.40, 1.03) |
| 25(OH)D, nmol/L | 330 | 49 (36, 66) | 41 (29, 59) | +26.7 (23.2, 30.3) | <0.0001 | 0.4501 | 0.84 (0.64, 1.10) |
| α-Tocopherol, µmol/L | 279 | 19.9 ± 5.1 | 6.0 ± 2.0 | +8.7 (3.6, 13.7) | 0.0014 | 0.0626 | 0.30 (0.17, 0.54) |
| Zinc, µmol/L | 326 | 9.9 (7.8, 12.4) | 14.9 (12.2, 18.0) | +2.3 (0.5, 4.2) | 0.015 | 0.0141 | 1.57 ± 0.45 |
| Thyroglobulin, µg/L | 279 | 5.1 (1.6, 15.8) | 34.4 (17.0, 69.8) | +20.1 (9.0, 32.2) | 0.0005 | 0.0671 | 6.75 (2.10, 21.66) |
| fT4, pmol/L | 261 | 14.1 ± 1.9 | 15.3 ± 1.7 | +1.5 (0.0, 3.0) | 0.044 | 0.0200 | 1.09 ± 0.18 |
Values for maternal and cord blood biomarkers are averaged across intervention groups and expressed as geometric means (−1-SD, +1-SD), as described for Table 2, or mean ± SD. Percentage difference in cord blood micronutrient biomarkers is expressed per 1-SD increment in maternal values with simple linear regression with maternal biomarkers as independent variables standardized to mean ± SD = 0 ± 1. For biomarkers on the arithmetic scale, percentage difference is calculated from 100 × β1(95% CI)/β0, where β0 is the cord biomarker value at the mean of the maternal distribution and β1 the change per 1-SD maternal biomarker; calculations are 100 × 0.0224 (−0.0023, 0.0471)/0.6442 µmol/L for retinol, 100 × 0.5164 (0.2175, 0.8153)/5.9667 µmol/L for α-tocopherol, and 100 × 0.2324(0.0062, 0.4585)/15.2726 pmol/L for fT4. Percent difference for log10-transformed variables is 10β1 (95% CI): for ferritin, β1 (95% CI) of 0.0087(−0.0407, 0.0582) for a 1-SD increment in maternal ferritin results in a 100.0087(10−0.0407, 100.0582) = 1.020 (0.911, 1.143)-fold change in cord ferritin, or a 2.0 (−8.9, 14.3)% increase. The ratio of cord to maternal biomarker concentrations is expressed as geometric means (−1-SD, +1-SD) or mean ± SD, depending on whether log10-transformation was required to normalize the distribution or not, respectively. fT4, free thyroxine; IFA, iron folic acid; MM, multiple micronutrients; 25(OH)D, 25-hydroxyvitamin D.