Summary of findings
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect (95% CI) | Number of participants (studies) | Quality of the evidence (GRADE) | |
|---|---|---|---|---|---|
| Assumed risk | Corresponding risk | ||||
| Control | Zinc | ||||
| All-cause mortality Follow-up: 17–72 weeks | Low | RR 0.95 (0.86 to 1.05) | 138 302 (13 studies) | ⊕⊕⊕⊕ High | |
| 2400/1 000 000 | 2280/1 000 000 (2064 to 2520) | ||||
| High | |||||
| 34 900/1 000 000 | 33 155/1 000 000 (30 014 to 36 645) | ||||
| Mortality due to all-cause diarrhoea Follow-up: 52–69 weeks | Low | RR 0.95 (0.69 to 1.31) | 132 321 (4 studies) | ⊕⊕⊕⊝ Moderate† | |
| 800/1 000 000 | 760/1 000 000 (552 to 1048) | ||||
| High | |||||
| 3000/1 000 000 | 2850/1 000 000 (2070 to 3930) | ||||
| Mortality due to LRTI Follow-up: 52–69 weeks | Low | RR 0.86 (0.64 to 1.15) | 132 063 (3 studies) | ⊕⊕⊕⊝ Moderate† | |
| 1200/1 000 000 | 1032/1 000 000 (768 to 1380) | ||||
| High | |||||
| 3000/1 000 000 | 2580/1 000 000 (1920 to 3450) | ||||
| Mortality due to malaria Follow-up: 46–69 weeks | Low | RR 0.90 (0.77 to 1.06) | 42 818 (2 studies) | ⊕⊕⊕⊝ Moderate† | |
| 7400/1 000 000 | 6660/1 000 000 (5698 to 7844) | ||||
| High | |||||
| 14 200/1 000 000 | 12 780/1 000 000 (10 934 to 15 052) | ||||
| Incidence of all-cause diarrhoea Follow-up: 12–72 weeks | Low | RR 0.87 (0.85 to 0.89) | 15 042 (35 studies) | ⊕⊕⊝⊝ Low‡§ | |
| 20 000/1 000 000 | 17 400/1 000 000 (17 000 to 17 800) | ||||
| High | |||||
| 1 770 000/1 000 000 | 1 539 900/1 000 000 (1 504 500 to 1 575 300) | ||||
| Incidence of LRTI Follow-up: 12–52 weeks | Low | RR 1.00 (0.94 to 1.07) | 9610 (12 studies) | ⊕⊕⊕⊕ High | |
| 30 000/1 000 000 | 30 000/1 000 000 (28 200 to 32 100) | ||||
| High | |||||
| 370 000/1 000 000 | 370 000/1 000 000 (347 800 to 395 900) | ||||
| Incidence of malaria Follow-up: 24–47 weeks | Low | RR 1.05 (0.95 to 1.15) | 2407 (4 studies) | ⊕⊕⊕⊝ Moderate¶ | |
| 140 000/1 000 000 | 147 000/1 000 000 (133 000 to 161 000) | ||||
| High | |||||
| 2 950 000/1 000 000 | 3 097 500/1 000 000 (2 802 500 to 3 392 500) | ||||
| Height Follow-up: 10–60 weeks | The mean height in the control groups was −1 HAZ | The mean height in the intervention groups was 0.1 HAZ better (0 to 0.2 better) | SMD 0.09 (0.06 to 0.13) | 13 669 (51 studies) | ⊕⊕⊕⊝ Moderate** |
| Participants with one vomiting episode Follow-up: 24–52 weeks | Low | RR 1.29 (1.14 to 1.46) | 35 192 (4 studies) | ⊕⊕⊕⊕ High | |
| 17 500/1 000 000 | 22 575/1 000 000 (19 950 to 25 550) | ||||
| High | |||||
| 300 600/1 000 000 | 387 774/1 000 000 (342 684 to 438 876) | ||||
GRADE working group grades of evidence.
High quality: further research is very unlikely to change our confidence in the estimate of effect.
Moderate quality: further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
Low quality: 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 quality: we are very uncertain about the estimate.
*The basis for the assumed risk (eg, the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% CI) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).
†Few deaths were observed overall.
‡I2=88%.
§Trim-and-fill analysis suggests that the effect may be overestimated due to publication bias.
¶I2=44%.
**I2=86%.
LRTI, lower respiratory tract infection; SMD, standardised mean difference.