Evidence map›Paper›PMID 36558491›Full record

SynthesisNutrients2022

Effect of Oral Iron Supplementation on Cognitive Function among Children and Adolescents in Low- and Middle-Income Countries: A Systematic Review and Meta-Analysis.

Zekun Chen, Huanhuan Yang, Dongqing Wang, Christopher R Sudfeld, Ai Zhao, Yiqian Xin, Jiawen Carmen Chen, Wafaie W Fawzi, Yan Xing, Zhihui Li

Open access · goldAbstract readMeta-AnalysisSystematic Review
PubMed Full text at PMC Publisher
In one paragraph

Synthesis in Nutrients, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 12 papers, 3 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
12citing papers in PubMed, 3 pooled it
6.1field-weighted citation impact, top 3% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

12 citing papers in PubMed, 3 syntheses or guidelines pooled it, 42 citations in OpenAlex.

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4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

10 authors at 5 institutions in 2 countries.

Zekun ChenVanke School of Public Health, Tsinghua University, Beijing 100084, China.
Huanhuan YangVanke School of Public Health, Tsinghua University, Beijing 100084, China.
Dongqing WangDepartment of Global Health and Population, Department of Nutrition, Harvard T.H. Chan School of Public Health, Harvard University, Boston, MA 02115, USA.ORCID 0000-0003-3369-5972
Christopher R SudfeldDepartment of Global Health and Population, Department of Nutrition, Harvard T.H. Chan School of Public Health, Harvard University, Boston, MA 02115, USA.ORCID 0000-0002-3203-3638
Ai ZhaoVanke School of Public Health, Tsinghua University, Beijing 100084, China.
Yiqian XinDuke Global Health Institute, Duke University, Durham, NC 27705, USA.
Jiawen Carmen ChenDepartment of Population and Public Health Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA.
Wafaie W FawziDepartment of Global Health and Population, Department of Nutrition, Harvard T.H. Chan School of Public Health, Harvard University, Boston, MA 02115, USA.
Yan XingDepartment of Pediatrics, Peking University Third Hospital, Beijing 100191, China.
Zhihui LiVanke School of Public Health, Tsinghua University, Beijing 100084, China.
Vanke (China) · CNHarvard University · USDuke University · USPeking University · CNUniversity of Southern California · US

Funding

Sanming Project of Medicine in Shenzhen NO.SZSM202111001
6 · The paper itself

Abstract

backgroundThere is abundant evidence showing that iron deficiency is closely linked with delayed brain development, worse school performance, and behavioral abnormalities. However, evidence on the impact of iron supplementation among children and adolescents in low- and middle-income countries (LMICs) has been inconsistent. This study aims to examine the effect of oral iron supplementation on cognitive function among children and adolescents in LMICs.

methodsA systematic review and meta-analysis was conducted to examine the impact of iron supplementation on cognitive function (including intelligence, attention, short-term memory, long-term memory, and school performance) among children and adolescents aged 5 to 19. We searched PubMed, Embase, Web of Science, CINAHL, and references of related articles published from the inception of the databases to 1 May 2022. Random-effects pooled standardized mean difference (SMD) with 95% confidence intervals (CIs) were calculated to estimate the effect of iron supplementation on cognitive function. We also investigated the heterogeneity of the effects using subgroup and meta-regression analyses. This review was registered with PROSPERO (CRD42020179064).

resultsNine studies with 1196 individual participants from five countries were identified and included. Iron had a positive impact on intelligence test scores among children and adolescents (SMD = 0.47, 95% confidence interval [CI]: 0.10, 0.83). Meta-regression showed that the intelligence test scores improved with increasing the iron supplement dose (odds ratio [CI] = 1.02, 95% CI: 1.00, 1.04). There were no significant effects on attention, short-term memory, long-term memory, or school performance.

conclusionsOral iron intake can improve the intelligence test scores of children and adolescents in LMICs and should be considered for future nutritional interventions.

Indexed as

Developing CountriesIronAdolescentAttentionChildCognitionDietary SupplementsHumansIronchildren and adolescentscognitive functioniron supplementationmeta-analysis

Identifiers

PMID36558491
PMCPMC9783508
OpenAlexW4312195625

What OpenQuestion holds

Textmetadata
LicenceCC BY
Read underepoch 390

Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.