Table 3.
Simple and multiple regression models of predictors of Hb concentration and anemia 1.
| Independent Variables | Dependent Variable: Hb Concentration (g/L2) | Dependent Variable: Anemia (Hb < 110 g/L) | ||||||
|---|---|---|---|---|---|---|---|---|
| Bivariate Relationships | Adjusted Model | Bivariate Relationships | Adjusted Model | |||||
| β (SE) | p | β (SE) | p 2 | OR (95% CI) | p | OR (95% CI) | p 2 | |
| Age, months | 25.4 (14.4) | 0.088 | 24.7 (11.0) | 0.033 | 0.972 (0.949–0.997 | 0.026 | 0.963 (0.938–0.990) | 0.007 |
| Male | −598 (331) | 0.080 | -- | 0.25 | 0.76 (0.45–1.28) | 0.30 | -- | 0.48 |
| Hb AS | −138 (368) | 0.71 | -- | 0.15 | 2.01 (1.01–4.02) | 0.047 | 2.14 (1.13–4.07) | 0.020 |
| Hb SS | −6960 (1020) | <0.0001 | −6790 (880) | <0.0001 | >999 (>999–>999) 5 | <0.0001 | >999 (>999–>999) | <0.001 |
| α+thalassemia heterozygote | −149 (341) | 0.67 | -- | 0.31 | 0.81 (0.46–1.42) | 0.47 | -- | 0.71 |
| α+thalassemia homozygote | −1470 (490) | 0.006 | −1270 (440) | 0.007 | 4.31 (1.03–17.93) | 0.045 | -- | 0.11 |
| Malaria | −2050 (690) | 0.006 | −1760 (620) | 0.008 | 2.62 (1.10–6.27) | 0.030 | 2.80 (1.03–7.64) | 0.045 |
| Adjusted RBP 3 < 0.83 µmol/L | −1360 (430) | 0.004 | −620 (299) | 0.048 | 2.00 (1.09–3.67) | 0.026 | -- | 0.13 |
| Adjusted ferritin 3 < 12 µg/L | −1270 (310) | 0.0003 | −1170 (330) | 0.001 | 2.46 (1.38–4.41) | 0.002 | 2.08 (1.03–4.17) | 0.040 |
| Low adjusted plasma zinc 3,4 | −425 (399) | 0.30 | -- | 0.99 | 1.26 (0.68–2.32) | 0.46 | -- | 0.90 |
| Plasma CRP, mg/L | −334 (129) | 0.015 | -- | 0.71 | 1.05 (1.01–1.09) | 0.015 | 1.05 (1.01–1.09) | 0.014 |
| Plasma AGP, g/L | −1520 (550) | 0.010 | −1290 (470) | 0.010 | 2.46 (1.16–5.21) | 0.019 | -- | 0.44 |
| Plasma folate, nmol/L | 18.4 (8.1) | 0.03 | -- | 0.27 | 0.975 (0.962–0.989) | 0.0003 | 0.976 (0.961–0.991) | 0.002 |
| Plasma vitamin B12, pmol/L | 1.45 (0.38) | 0.0007 | 0.984 (0.312) | 0.004 | 0.999 (0.998–1.000) | 0.012 | -- | 0.078 |
1 Analysis conducted using SAS PROC SURVEYREG and SURVEYLOGISTIC, for hemoglobin concentration (n = 266; R2 = 0.34 for final model) and anemia (n = 273 for final model), respectively. AGP, α1-acid glycoprotein; CRP, C-reactive protein; Hb, hemoglobin; OR, odds ratio. 2 For variables removed from the model, p-values indicate the adjusted p-value at the step at which the variable was removed from the model. For variables retained in the final model, the p-value reflects the final adjusted model (with all non-significant variables removed). 3 Values adjusted for inflammation by regression analysis to values equivalent to those at CRP and AGP concentrations of 0.14 mg/L CRP and 0.52 g/L AGP (the 10th percentile among individuals with CRP < 5 and AGP < 1). 4 Low plasma zinc defined as <65 µg/dL for AM samples and < 57 µg/dL for PM samples [23], after adjusting for inflammation as noted above. 5 All children with the HbSS genotype were anemic.