Table 4.
Relationship of baseline biomarker categories and the occurrence of clinical outcomes at delivery among Tanzanian pregnant women who did not receive iron supplements
| Anemia at delivery | Higher cutoff iron deficiency (hID) at delivery | Regression-corrected iron deficiency (rID) at delivery | Higher cutoff iron deficiency anemia (hIDA) at delivery | Regression-corrected iron deficiency anemia (rIDA) at delivery | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Biomarker | n/N1 | Multivariate RR (95% CI)2 | n/N | Multivariate RR (95% CI) | n/N | Multivariate RR (95% CI) | n/N | Multivariate RR (95% CI) | n/N | Multivariate RR (95% CI) |
| Hemoglobin | ||||||||||
| ≥110g/Lc | 245/495 | 0.59 (0.49, 0.70) | 224/482 | 0.82 (0.61, 1.09) | 180/488 | 0.94 (0.67, 1.32) | 119/464 | 0.56 (0.38, 0.81) | 99/470 | 0.73 (0.47, 1.13) |
| Zinc protoporphyrin (ZPP) | ||||||||||
| <70 mmol/Lc | 72/120 | 0.93 (0.72, 1.20) | 57/127 | 0.95 (0.50, 1.79) | 45/127 | 1.16 (0.50, 2.72) | 38/117 | 0.75 (0.36, 1.53) | 31/117 | 0.97 (0.37, 2.52) |
| Hepcidin | ||||||||||
| >13.3μg/Lc | 87/182 | 0.96 (0.43, 2.15) | 78/178 | 0.59 (0.18, 2.01) | 60/179 | 0.59 (0.13, 2.60) | 41/174 | 0.99 (0.21, 4.68) | 33/175 | 0.45 (0.05, 3.74) |
| >4.3μg/Ls | 87/182 | 0.61 (0.39, 0.95) | 78/178 | 0.78 (0.44, 1.38) | 60/179 | 0.73 (0.37, 1.44) | 41/174 | 0.79 (0.35, 1.81) | 33/175 | 0.50 (0.19, 1.36) |
| >1.8μg/Lj | 87/182 | 0.58 (0.41, 0.81) | 78/178 | 0.99 (0.62, 1.58) | 60/179 | 1.06 (0.62, 1.81) | 41/174 | 0.51 (0.26, 0.99) | 33/175 | 0.54 (0.26, 1.13) |
| >1.6μg/Lk | 87/182 | 0.51 (0.35, 0.73) | 78/178 | 1.00 (0.62, 1.64) | 60/179 | 1.06 (0.60, 1.88) | 41/174 | 0.50 (0.26, 0.97) | 33/175 | 0.55 (0.26, 1.17) |
| Transferrin receptor (sTfR) | ||||||||||
| <4.4mg/Lc | 88/186 | 0.97 (0.51, 1.87) | 81/183 | 1.01 (0.35, 2.86) | 62/184 | 0.83 (0.29, 2.40) | 40/179 | 0.98 (0.22, 4.34) | 33/180 | 0.80 (0.18, 3.59) |
Cut-off is conventional;
Cut-off at 95% sensitivity for regression-corrected ID;
Cut-off identified using Youden Index for regression corrected ID;
Cut-off identified using Youden Index for regression-corrected IDA;
P-value <0.05;
P-value<0.01;
P-value <0.001
Values in column are number of events/number of observations.
Log-binomial regression models were estimated to obtain the RR of clinical outcomes. RR > 1 implies the outcome is more likely to occur as the biomarker level increases. RR < 1 implies the outcome is less likely as the biomarker level increases. Multivariate models were adjusted for age (18 – 25, 26 – 35 and >36 years), gestational age at enrollment (weeks), years of formal education (0 – 7 years, 8 – 11 years and ≥12 years), number of household assets(0 – 1, 2 – 3 and 4 – 5), consumption of meat (<75g, ≥75g per week), season of enrolment [December – March (long rains), April – May (harvest), June – September (post-harvest) and October – November (short rains)], multiple gestation (yes, no), and clinic attended.