Effects of nutrition-specific interventions to prevent and control nutritional anemia in infants, children and adolescents: a systematic review and network meta-analysis of randomized controlled trials

Background: Anemia is a prevalent health issue among children and adolescents worldwide, with malnutrition being one of the most common causes. Nutrition-related anemia can be prevented or controlled through targeted interventions.

Objective: This study aimed to evaluate the effects of nutrition interventions on ferritin concentration, hemoglobin concentration, anemia prevalence, and nutritional anemia prevalence in infants, children, and adolescents-and to compare outcomes by intervention and age group using network meta-analysis of randomized controlled trials (RCTs).

Methods: Web of Science, PubMed, Scopus, EBSCO, the Cochrane Library, CNKI, VIP Database, and WANFANG Database were comprehensively searched to identify RCTs on the effects of nutrition interventions (micronutrient supplementation, macronutrient supplementation, and nutrition education) until September 30, 2023. Two groups of researchers screened the literature and extracted data based on set inclusion and exclusion criteria. Reviewers used the Cochrane tool for assessing risk-of-bias in RCTs and used the Grading of Recommendations, Assessment, Development, and Evaluation for evaluating the strength of evidence for inclusion in network meta-analysis. The study population was categorized into infants and preschool children (6-59 months), school-aged children (6-11 years), and adolescents (12-18 years). The study evaluated the mean difference, risk ratio, and 95% credible interval of outcomes for each intervention across different age groups using network meta-analysis.

Results: Sixty-one RCTs were included in this analysis. In network meta-analysis, micronutrient supplementation, macronutrient supplementation, and nutrition education were found to have significant effects on hemoglobin in infants and preschool children. Lipid-based nutrient supplementation resulted in the highest increase in hemoglobin, while multiple micronutrient supplementation resulted in the largest reduction in risk of anemia and iron deficiency anemia (IDA). In school-aged children, iron supplementation increased hemoglobin, while micronutrient supplementation also increased hemoglobin and reduced anemia risk. In adolescents, iron supplementation improved hemoglobin and lowered anemia risk.

Conclusions: The effectiveness of nutrition interventions in improving nutritional anemia varies across intervention types and age groups. Micronutrient and iron supplementation consistently improved hemoglobin levels and related indicators, with evidence quality ranging from low to moderate. MMN and LNS had positive effects on hemoglobin and anemia in infants and preschool children, which is supported by low to moderate quality evidence. For adolescents, while micronutrient and iron supplementation showed positive effects, the overall evidence quality was generally low, highlighting the need for further high-quality clinical research to validate these findings.