Table 4

Zinc with iron compared with zinc alone (all outcomes)

OutcomesTrialsPeopleES (95% CI), fixed effectsHeterogeneity
I2; χ2 (p Value)
All-cause mortality1 (13%)323 (17%)Risk=0.33 (0.01 to 8.31)Not applicable
Hospitalisation
All-cause1 (13%)399 (21%)Risk=0.92 (0.45 to 1.89)Not applicable
Due to diarrhoea1 (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
Incidence3 (38%)1065 (56%)Risk=0.93 (0.83 to 1.04)21%; 2.52 (p=0.28)
Malaria
Incidence1 (13%)410 (22%)Rate=0.86 (0.59 to 1.24)Not applicable
Growth
Height5 (63%)1517 (80%)SMD=0.06 (−0.04 to 0.16)0%; 3.54 (p=0.47)
Weight4 (50%)910 (48%)SMD=0.12 (−0.01 to 0.25)0%; 2.29 (p=0.51)
Weight-to-height ratio4 (50%)514 (27%)SMD=−0.06 (−0.07 to 0.19)0%; 1.36 (p=0.71)
Prevalence of stunting2 (25%)462 (24%)Risk=0.92 (0.85 to 0.99)45%; 1.82 (p=0.18)
Adverse events
Study withdrawal2 (25%)557 (29%)Risk=1.41 (0.91 to 2.18)0%; 0.08 (p=0.78)
Biological indicators
Zn concentration8 (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 concentration8 (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 concentration6 (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 concentration2 (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.