Evidence
This page contains a snapshot of featured content which highlights evidence addressing key clinical questions including areas of uncertainty. Please see the main topic reference list for details of all sources underpinning this topic.
BMJ Best Practice evidence tables
Evidence tables provide easily navigated layers of evidence in the context of specific clinical questions, using GRADE and a BMJ Best Practice Effectiveness rating. Follow the links at the bottom of the table, which go to the related evidence score in the main topic text, providing additional context for the clinical question. Find out more about our evidence tables.
This table is a summary of the analysis reported in a Cochrane Clinical Answer that focuses on the above important clinical question.
Confidence in the evidence is high or moderate to high where GRADE has been performed and there is a trade off between benefits and harms of the intervention.
Population: Otherwise healthy children aged 6 months to 12 years of age ᵃ
Intervention: Zinc
Comparison: No zinc or placebo
| Outcome | Effectiveness (BMJ rating)? | Confidence in evidence (GRADE)? |
|---|---|---|
Height (median follow-up: 26 weeks [assessed with cm or height‐for‐age z-scores]) | Favors intervention ᵇ | Moderate |
All-cause mortality (median follow-up: 26 weeks) | No statistically significant difference ᶜ | High |
Incidence of all‐cause diarrhea (median follow-up: 26 weeks) | Favors intervention | Moderate |
Incidence of lower respiratory tract infection (median follow-up: 26 weeks) | No statistically significant difference | High |
Incidence of malaria at 24–47 weeks | No statistically significant difference | GRADE assessment not performed for this outcome |
Participants with ≥1 adverse effect | Occurs more commonly with zinc compared with no zinc or placebo (favors comparison) | GRADE assessment not performed for this outcome |
Participants with ≥1 vomiting episode at mean 48 hours | Occurs more commonly with zinc compared with no zinc or placebo (favors comparison) | High |
Note The Cochrane review which underpins this Cochrane Clinical Answer (CCA) noted that the benefits, harms, and costs of zinc in a specific setting should be considered before using this intervention. The Cochrane review concluded that the benefits of preventive zinc supplementation may outweigh the harms in regions where zinc deficiency is high. ᵃ Children from low‐ and middle‐income countries in Asia, Latin America, and the Caribbean or sub‐Saharan Africa. Half the studies included a co‐intervention given to both groups (iron, copper, folic acid, vitamin A, or multivitamin supplements). ᵇ The CCA noted that the difference in height was slight (SMD 0.12, 95% CI 0.09 to 0.14) and appeared to be greater in older children (5–13 year olds > 1–5 year olds > 6–12 month olds). The Cochrane review underlying this CCA also found that in subgroup analyses, there was no effect of zinc on height in the group also receiving iron supplementation. ᶜ The CCA also included mortality due to specific causes and found no statistically significant difference between treatment groups. See the CCA for more details.
This evidence table is related to the following section/s:
Cochrane Clinical Answers
Cochrane Clinical Answers (CCAs) provide a readable, digestible, clinically focused entry point to rigorous research from Cochrane systematic reviews. They are designed to be actionable and to inform decision making at the point of care and have been added to relevant sections of the main Best Practice text.
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