TABLE 3.
Risk factors for poor iron status in Chilean infants at age 12 according to iron supplementation status1
| Risk factor | Anemia | Iron deficiency anemia | Iron deficiency without anemia | Iron deficiency total |
|---|---|---|---|---|
| No added iron | ||||
| Boys vs girls | 2.46 (1.57, 3.86)2,3 | 3.16 (1.82, 5.47)3 | 1.55 (1.01, 2.39)4 | 1.99 (1.37, 2.89)3 |
| Gestational age (1-wk decrease) | 1.19 (0.97, 1.44) | 1.40 (1.11, 1.78)3 | 1.25 (1.00, 1.55)4 | 1.31 (1.10, 1.56)3 |
| Birth weight (100-g decrease) | 1.75 (0.94, 3.28)5 | 2.23 (1.06, 4.69)4 | 1.42 (0.77, 2.61) | 1.55 (0.91, 2.64)5 |
| Hemoglobin at 6 mo (10-g/L decrease) | 1.86 (1.47, 2.35)3 | 1.77 (1.34, 2.33)3 | 1.16 (0.92, 1.47) | 1.38 (1.13, 1.68)3 |
| Weight gain (1-kg/y increase) | 1.07 (0.86, 1.33) | 1.57 (1.17, 2.10)3 | 1.52 (1.23, 1.89)3 | 1.51 (1.24, 1.83)3 |
| Maternal education (1-y decrease) | 1.19 (1.10, 1.28)3 | 1.23 (1.12, 1.36)3 | 1.07 (0.97, 1.18)5 | 1.13 (1.04, 1.22)3 |
| Socioeconomic status index (1-SD increase) | 1.35 (1.07, 1.71)3 | 1.49 (1.11, 2.00)3 | 1.00 (0.76, 1.31) | 1.17 (0.95, 1.46) |
| Cow milk intake (100-mL increase) | 0.96 (0.85, 1.08) | 0.96 (0.82, 1.12) | 1.02 (0.91, 1.15) | 1.01 (0.92, 1.11) |
| Discrimination power (c-statistic)6 | 0.74 | 0.80 | 0.66 | 0.72 |
| Overall P | <0.0001 | <0.0001 | <0.0001 | <0.0001 |
| Abnormal/total (n)7 | 138/528 | 120/371 | 155/406 | 275/526 |
| Low iron supplementation | ||||
| Boys vs girls | 1.39 (0.54, 3.58) | 0.97 (0.34, 2.77) | 0.63 (0.41, 0.97)4 | 0.66 (0.44, 1.00)4 |
| Hemoglobin at 6 mo (10-g/L decrease) | 2.84 (1.56, 5.16)3 | 3.27 (1.70, 6.31)3 | 1.52 (1.19, 1.95)3 | 1.63 (1.28, 2.07)3 |
| Formula intake (100-mL increase) | 1.28 (0.97, 1.70)5 | 1.23 (0.90, 1.69) | 1.03 (0.92, 1.17) | 1.05 (0.93, 1.19) |
| Discrimination power (c-statistic)6 | 0.77 | 0.79 | 0.63 | 0.64 |
| Overall P | 0.001 | 0.001 | 0.001 | <0.001 |
| Abnormal/total (n)7 | 20/403 | 17/247 | 145/375 | 162/392 |
| High iron supplementation | ||||
| Boys vs girls | 1.80 (0.74, 4.38) | 2.02 (0.71, 5.71) | 1.31 (0.84, 2.05) | 1.40 (0.91, 2.13) |
| Birth weight (100-g decrease) | 1.75 (0.54, 5.68) | 3.89 (0.93, 16.39)5 | 1.99 (1.06, 3.75)4 | 2.18 (1.20, 3.95)3 |
| Hemoglobin at 6 mo (10-g/L decrease) | 2.21 (1.36, 3.59)3 | 2.28 (1.31, 3.97)3 | 1.51 (1.18, 1.92)3 | 3.81 (0.56, 25.76)3 |
| Weight gain (1-kg/y increase) | 0.66 (0.41, 1.06)5 | 0.64 (0.37, 1.13) | 1.07 (0.87, 1.30) | 1.02 (0.83, 1.26) |
| Accelerating weight gain (1-SD difference) | 1.82 (1.20, 2.75)3 | 2.10 (1.30, 3.38)3 | 0.88 (0.70, 1.11) | 3.41 (0.59, 19.79) |
| Formula intake (100-mL increase) | 0.76 (0.63, 0.93)3 | 0.83 (0.68, 1.03)5 | 0.95 (0.86, 1.04) | 0.93 (0.85, 1.01)5 |
| Discrimination power (c-statistic)6 | 0.83 | 0.84 | 0.63 | 0.65 |
| Overall P | <0.0001 | <0.0001 | <0.001 | <0.0001 |
| Abnormal/total (n)7 | 28/715 | 21/595 | 110/684 | 131/705 |
1
The odds ratios (ORs) for logistic regression coefficients were calculated to reflect the unit change shown in parentheses after each risk factor; 95% CIs that do not include 1 are statistically significant, according to the chi-square test.
2
OR; 95% CI in parentheses (all such values).
3
P ≤ 0.01.
4
P ≤ 0.05.
5
P ≤ 0.10.
6
Discrimination power (defined as ability of the model to correctly classify infants for a given iron status outcome) was measured by using the area under the receiver operating characteristic curve (41).
7
The numbers are slightly low because of missing data for ≥1 predictors.