23. Results of included systematic reviews: adolescent children (aged 11 to 18 years).
| Review | Comparison | Outcome | Number of studies; number of participants | Results | GRADE assessment |
| Supplementation | |||||
|
Fernández‐Gaxiola 2019 Intermittent iron supplementation for reducing anaemia and its associated impairments in adolescent and adult menstruating women |
Intermittent iron supplementation (alone or with any other micronutrients) versus no supplementation or placebo | Hb (g/L) | 15 trials; 2886 women | MD 5.19, 95% CI 3.07 to 7.32 (P < 0.001), significant increase in Hb levels for women receiving intermittent iron supplementation | Moderate |
| Anaemia | 11 trials; 3135 women | RR 0.65, 95% CI 0.49 to 0.87 (P = 0.0038), significant reduction in anaemia for women receiving intermittent iron supplementation | Low | ||
| IDA | 1 trial; 97 women | RR 0.07, 95% CI 0.00 to 1.16, no evidence of a difference | Low | ||
| ID | 3 trials; 624 women | RR 0.50, 95% CI 0.24 to 1.04, no evidence of a difference | Low | ||
| Any adverse side effect | 3 trials; 630 women | RR 1.98, 95% CI 0.31 to 12.72, no evidence of a difference | Moderate | ||
| Intermittent iron supplementation versus daily iron supplementation | Hb (g/L) | 10 trials; 2127 women | MD 0.43, 95% CI −1.44 to 2.31, no evidence of a difference | Low | |
| Anaemia | 8 trials; 1749 women | RR 1.09, 95% CI 0.93 to 1.29, no evidence of a difference | Moderate | ||
| ID | 1 trial; 198 women | RR 4.30, 95% CI 0.56 to 33.20, no evidence of a difference | Very low | ||
| Any adverse side effect | 6 trials; 1166 women | RR 0.41, 95% CI 0.21 to 0.82 (P = 0.011), significant reduction in any adverse side effects for women receiving intermittent iron supplementation versus iron supplementation | Low | ||
|
Neuberger 2016 Oral iron supplements for children in malaria‐endemic areas |
Iron versus placebo/no treatment | Hb (g/L) | 16 trials, 5261 children 7 trials, 2481 anaemic children at baseline 9 trials, 2780 non anaemic children at baseline 12 trials, 2462 children |
MD 7.50, 95% CI 4.80 to 10.10, significant increase in Hb concentration at the end of treatment for children receiving iron supplementation MD 9.50, 95% CI 3.80 to 15.10, significant increase in Hb concentration at the end of treatment for anaemic children receiving iron supplementation MD 6.10, 95% CI 3.80 to 8.50, significant increase in Hb concentration at the end of treatment for non anaemic children receiving iron supplementation MD 6.70, 95% CI 4.20 to 9.20 (P<0.001), significant improvement in haemoglobin from the baseline at end of treatment |
Not assessed |
| Anaemia (as defined in the trial) | 15 trials, 3784 children | RR 0.63, 95% CI 0.49 to 0.82, significant reduction in anaemia for children receiving iron supplementation | Not assessed | ||
| Iron plus folic acid versus placebo | Hb (g/L) | 1 trial, 124 children | MD 9.00, 95% CI 5.10 to 12.90, significant increase in Hb concentration at the end of treatment for children receiving iron plus folic acid supplementation | Not assessed | |
| Anaemia (as defined in the trial) | 3 trials, 633 children | RR 0.49, 95% CI 0.25 to 0.99, significant reduction in anaemia for children receiving iron plus folic acid supplementation | Not assessed | ||
| Iron plus antimalarial versus placebo | Hb (g/L) | 1 trial, 151 children | MD 9.10, 95% CI 4.70 to 13.50, significant increase in Hb concentration at the end of treatment for children receiving iron plus antimalarial supplementation | Not assessed | |
| Anaemia (as defined in the trial) | 2 trials, 295 children 1 trial, 420 children |
RR 0.44, 95% CI 0.28 to 0.70, significant reduction in anaemia at the end of treatment for children receiving iron plus antimalarial supplementation RR 0.37, 95% CI 0.26 to 0.54, significant reduction in anaemia at the end of follow‐up for children receiving iron plus antimalarial supplementation |
Not assessed | ||
|
Salam 2016 Interventions to improve adolescent nutrition: a systematic review and meta‐analysis |
Iron or iron folic acid supplementation alone or in combination with other micronutrient supplementation versus control | Hb (g/L) | Not reported | MD 1.94, 95% CI 1.48 to 2.41, significant increase in Hb concentration for adolescents receiving supplementation | Not assessed |
| Anaemia | 11 trials; 11,861 adolescents | RR 0.69, 95% CI 0.62 to 0.76, significant reduction in anaemia for adolescents receiving supplementation | Moderate | ||
| Nutritional supplementation and counselling versus control | IDA | 1 trial; 14 pregnant adolescents | RR 0.34, 95% CI 0.13 to 0.89, significant reduction in IDA for pregnant adolescents receiving nutritional supplementation and counselling | Low | |
|
Salam 2020 Effects of preventive nutrition interventions among adolescents on health and nutritional status in low‐ and middle‐income countries |
Daily iron supplementation with or without folic acid versus placebo/no supplementation/no fortification | Anaemia | 1 trial, 1160 participants | RR 1.04, 95% CI 0.88 to 1.24, no significant reduction in anaemia for participants receiving daily iron supplementation with or without folic acid versus placebo/no supplementation/no fortification | Low |
| Weekly iron supplementation with or without folic acid versus placebo/no supplementation/no fortification | Anaemia | 1 trial, 1274 participants | RR 1.07, 95% CI 0.91 to 1.26, no significant reduction in anaemia for participants receiving weekly iron supplementation with or without folic acid versus placebo/no supplementation/no fortification | Low | |
| Iron supplementation with or without folic acid versus no supplementation | Hb (g/L) | 4 trials, 1020 participants | MD 0.42 g/L, 95% CI 0.13 to 0.71, significant increase in Hb concentration for participants receiving iron supplementation with or without folic acid compared to no supplementation | Low | |
| Fortification | |||||
|
Salam 2020 Effects of preventive nutrition interventions among adolescents on health and nutritional status in low‐ and middle‐income countries |
MMN fortification versus no fortification | Hb (g/L) | 2 trials, 1102 participants | MD −0.10 g/L, 95% CI ‐0.88 to 0.68, no significant increase in Hb concentration for participants receiving MMN fortification compared to no fortification | Low |
CI: confidence interval; Hb: haemoglobin; ID: iron deficiency; IDA: iron deficiency anaemia; MD: mean difference; MMN: multiple micronutrient; RR: risk ratio.