Summary of findings 2. Micronutrient or macronutrient supplementation interventions in children versus no intervention, or placebo to reduce stunting (height‐for‐age, length velocity, and length at 12 months).

Micronutrient or macronutrient supplementation interventions in children versus no intervention, or placebo to reduce stunting (HFA, length velocity, and length at 12 months)
Patient or population: children under 5 years old Settings: poor urban slums Intervention: micronutrient or macronutrient supplementation Comparison: no intervention or placebo
Outcomes	Relative effect (95% CI)	No of participants (studies)	Certainty of the evidence (GRADE)	Comments
Height‐for‐age (z‐score)	No evidence of an effect: MD –0.02 (–0.06 to 0.02)	2601 (3)	⊕⊕⊝⊝ Lowa	Iannotti 2014; Oelofse 2003; Taneja 2010
Height‐for‐age (z‐score) Length gain (6 months)	Unclear effect: change in height‐for‐age z‐score and length were not significantly different among the groups.	653 (1)	⊕⊕⊝⊝ Lowb	Rahman 2002
Height‐for‐age (%) at 18 months, 21 months Length gain	Unclear effect	324 (1)	⊕⊕⊕⊝ Moderatec	Radhakrishna 2013
Length velocity (change in cm since start of supplementation)	Unclear effect: controlling for initial anthropometric status, sex, and age at the beginning of supplementation, and for additional covariates (feeding practices, maternal characteristics, socioeconomic variables, and initial presupplementation morbidity rates) Unclear effect: baseline to 2 months, baseline to 4 months, and baseline to 6 months.	315 (1)	⊕⊕⊝⊝ Lowd	Begin 2008
Length velocity (cm/month)	Effect: MD 0.22 (0.02 to 0.43)	75 (1)	⊕⊝⊝⊝ Very lowe	Moursi 2003
Length (cm) at 12 months	Effect: MD 2.3 (no CI provided)	100 (1)	⊕⊕⊝⊝ Lowf	Sur 2003
CI: confidence interval; MD: mean difference. GRADE Working Group grades of evidence High certainty: further research is very unlikely to change our confidence in the estimate of effect. Moderate certainty: further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low certainty: further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. Very low certainty: we are very uncertain about the estimate.

^aThe overall risk of bias was high for Oelofse 2003 and Iannotti 2014, and moderate for Taneja 2010. We downgraded two levels for bias and inconsistency. Refer to Appendix 14 for more details. Therefore, the overall GRADE was low.
 ^bThe overall risk of bias was high. We downgraded two levels for bias and indirectness of evidence (geographical coverage). Refer to Appendix 14 for more details. Therefore, the overall GRADE was low.
 ^cThe overall risk of bias was moderate and there was no evidence that bias had significantly influenced the results of the intervention. We downgraded one level for indirectness of evidence (geographical coverage). Refer to Appendix 14 for more details. Therefore, the overall GRADE was moderate.
 ^dThe overall risk of bias was high. We downgraded two levels for bias and indirectness of evidence (geographical coverage). Refer to Appendix 14 for more details. Therefore, the overall GRADE was low.
 ^eThe overall risk of bias was high. We downgraded three levels for bias, indirectness of evidence (geographical coverage), and precision, Refer to Appendix 14 for more details. Therefore, the overall GRADE was very low.
 ^fThe overall risk of bias was moderate. We downgraded two levels for indirectness of evidence (geographical coverage) and precision. Refer to Appendix 14 for more details. Therefore, the overall GRADE was low.