Table 4.
Zinc with iron compared with zinc alone (all outcomes)
| Outcomes | Trials | People | ES (95% CI), fixed effects | Heterogeneity I2; χ2 (p Value) |
|---|---|---|---|---|
| All-cause mortality | 1 (13%) | 323 (17%) | Risk=0.33 (0.01 to 8.31) | Not applicable |
| Hospitalisation | ||||
| All-cause | 1 (13%) | 399 (21%) | Risk=0.92 (0.45 to 1.89) | Not applicable |
| Due to diarrhoea | 1 (13%) | 399 (21%) | Risk=0.99 (0.25 to 3.88) | Not applicable |
| Diarrhoea | ||||
| Incidence (all-cause) | 5 (63%) | 1530 (81%) | Risk=1.10 (1.03 to 1.18) | 76%; 16.92 (p=0.002) |
| Prevalence (all-cause) | 1 (13%) | 399 (21%) | Rate=0.90 (0.79 to 1.06) | Not applicable |
| Incidence (severe) | 1 (13%) | 323 (17%) | Rate=0.78 (0.59 to 1.04) | Not applicable |
| Lower respiratory tract infection | ||||
| Incidence | 3 (38%) | 1065 (56%) | Risk=0.93 (0.83 to 1.04) | 21%; 2.52 (p=0.28) |
| Malaria | ||||
| Incidence | 1 (13%) | 410 (22%) | Rate=0.86 (0.59 to 1.24) | Not applicable |
| Growth | ||||
| Height | 5 (63%) | 1517 (80%) | SMD=0.06 (−0.04 to 0.16) | 0%; 3.54 (p=0.47) |
| Weight | 4 (50%) | 910 (48%) | SMD=0.12 (−0.01 to 0.25) | 0%; 2.29 (p=0.51) |
| Weight-to-height ratio | 4 (50%) | 514 (27%) | SMD=−0.06 (−0.07 to 0.19) | 0%; 1.36 (p=0.71) |
| Prevalence of stunting | 2 (25%) | 462 (24%) | Risk=0.92 (0.85 to 0.99) | 45%; 1.82 (p=0.18) |
| Adverse events | ||||
| Study withdrawal | 2 (25%) | 557 (29%) | Risk=1.41 (0.91 to 2.18) | 0%; 0.08 (p=0.78) |
| Biological indicators | ||||
| Zn concentration | 8 (100%) | 1337 (70%) | SMD=0.16 (0.05 to 0.27) | 61%; 17.84 (p=0.01) |
| Zn deficiency (prevalence) | 3 (38%) | 350 (18%) | Risk=1.42 (0.75 to 2.68) | 5%; 2.10 (p=0.35) |
| Haemoglobin concentration | 8 (100%) | 1341 (71%) | SMD=−0.23 (−0.34 to −0.12) | 79%; 33.53 (p<0.0001) |
| Anaemia (prevalence) | 3 (38%) | 482 (25%) | Risk=0.78 (0.67 to 0.92) | 0%; 1.25 (p=0.54) |
| Fe concentration | 6 (75%) | 945 (50%) | SMD=−1.79 (−1.99 to −1.56) | 99%; 927.92 (p<0.00001) |
| Fe deficiency (prevalence) | 2 (25%) | 248 (13%) | Risk=0.12 (0.04 to 0.32) | 87%; 8.00 (p=0.005) |
| Cu concentration | 2 (25%) | 353 (19%) | SMD=−0.06 (−0.27 to 0.15) | 0%; 0.11 (p=0.74) |
Effects favour intervention (ie, zinc rather than iron; zinc plus iron rather than zinc alone) when the relative risk is reduced (RR<1) or the standardised difference is positive (SMD>0).
ES, effect size; Rate, rate ratio; Risk, risk ratio; SMD, standardised mean difference.