Table 4.
Predictors of Hb and two biomarkers of iron status based on both univariate and multiple regression models, as shown by β coefficient (and 95 % confidence interval), among pre-schoolers aged 3–6 years from disadvantaged households, Salvador, Northeast Brazil, August–November 2010
| Univariate β | Multivariate β | 95 % CI | P | |
|---|---|---|---|---|
| Hb† | ||||
| α3·7 Thalassaemia homozygous | −12·29* | −12·19 | −14·78, −9·60 | <0·001 |
| α3·7 Thalassaemia heterozygous | −4·84* | −5·28 | −7·44, −3·11 | 0·001 |
| Hb AS | −0·44 | |||
| Hb AC | −1·00 | |||
| Se | 11·71* | 11·71 | 6·26, 17·17 | 0·001 |
| Retinol (log-transformed) | 7·62* | 5·08 | 0·65, 9·51 | 0·030 |
| Ferritin (log-transformed) | 2·11(*) | 2·35 | −0·76, 5·46 | 0·117 |
| Zn | 0·71* | 0·42 | −0·09, 0·92 | 0·092 |
| AGP > 1 g/l | 0·01(*) | 0·29 | −2·09, 2·68 | 0·779 |
| Serum ferritin (log-transformed)‡ | ||||
| Age | 0·03 | |||
| BMIZ >1 | 0·10* | 0·04 | −0·02, 0·10 | 0·138 |
| AGP > 1 g/l | 0·31* | 0·30 | 0·16, 0·44 | 0·001 |
| Hb AS | 0·07 | |||
| Hb AC | −0·12 | |||
| α3·7 Thalassaemia heterozygous | 0·04 | |||
| α3·7 Thalassaemia homozygous | −0·05 | |||
| Serum sTfR (log-transformed)§ | ||||
| Age | −0·04* | −0·03 | −0·06, 0·01 | 0·086 |
| Sex | 0·04 | |||
| BMIZ >1 | 0·10* | 0·09 | 0·00, 0·17 | 0·050 |
| Helminths | −0·06(*) | −0·06 | −0·14, 0·03 | 0·163 |
| Hb AS | 0·16* | 0·17 | 0·04, 0·31 | 0·020 |
| Hb AC | 0·09 | |||
| α3·7 Thalassaemia heterozygous | 0·03 | |||
| α3·7 Thalassaemia homozygous | 0·01 |
AGP, α1-glycoprotein; BMIZ, BMI Z-score.
All variables with P < 0·2 in the univariate analysis were included in the multivariate regression.
For all binary categorical variables, the reference was the absence of the condition specified.
(*) P < 0·2 based on univariate regression; *P < 0·05 based on univariate regression.
†R 2 for multivariate regression model = 0·242.
‡R 2 for multivariate regression model = 0·098.
§R 2 for multivariate regression model = 0·083.