Table 2.
Subgroup Analyses of the Effects of Iron Supplementation on Intelligence in Children and Adolescents.
| Subgroup Analyses | Heterogeneity Test | Pooled SMD Values (95% CI) |
Pooled SMD Values’ Tests Statistic | |||
|---|---|---|---|---|---|---|
| q | d.f. | I 2 | Z | p | ||
| Sex | ||||||
| Whole population | 116.61 | 8 | 93.1% | 0.67 (0.12, 1.22) | 2.38 | 0.017 |
| Male | 2.83 | 2 | 29.3% | 0.64 (0.14, 1.13) | 2.53 | 0.011 |
| Female | 1.64 | 1 | 39.1% | 0.50 (−0.11, 1.11) | 1.62 | 0.106 |
| Age, year | ||||||
| ≤11 | 47.32 | 6 | 87.3% | 0.29 (−0.03, 0.61) | 1.75 | 0.08 |
| >11 | 56.39 | 6 | 89.4% | 1.18 (0.33, 2.04) | 2.7 | 0.007 |
| Dose, mg/day | ||||||
| <60 | 23.98 | 6 | 75.0% | 0.38 (−0.06, 0.81) | 1.71 | 0.088 |
| ≥60 | 97.44 | 6 | 93.8% | 0.91 (0.38, 1.45) | 3.37 | 0.001 |
| Duration, month | ||||||
| <4 | 12.24 | 3 | 75.5% | 0.34 (−0.19, 0.86) | 1.26 | 0.208 |
| ≥4 | 112.71 | 9 | 92.0% | 0.81 (0.38, 1.25) | 3.66 | <0.001 |
| Iron status | ||||||
| Anemia | 43.98 | 5 | 88.6% | 1.01 (0.34, 1.68) | 2.97 | 0.003 |
| Non-anemia | 28.26 | 5 | 82.3% | 0.68 (0.17, 1.18) | 2.63 | 0.009 |
Abbreviation: d.f., degree of freedom.