The Impact of Nutrition-Specific and Nutrition-Sensitive Interventions on Hemoglobin Concentrations and Anemia: A Meta-review of Systematic Reviews

Abstract

Anemia is a multifactorial condition arising from inadequate nutrition, infection, chronic disease, and genetic-related etiologies. Our aim was to assess the impact of nutrition-sensitive and nutrition-specific interventions on hemoglobin (Hb) concentrations and anemia to inform the prioritization and scale-up of interventions to address the multiple causes of anemia. We performed a meta-review synthesis of information by searching multiple databases for reviews published between 1990 and 2017 and used standard methods for conducting a meta-review of reviews, including double independent screening, extraction, and quality assessment. Quantitative pooling and narrative syntheses were used to summarize information. Hb concentration and anemia outcomes were pooled in specific population groups (children aged <5 y, school-age children, and pregnant women). Methodological quality of the systematic reviews was assessed using Assessing the Methodological Quality of Systematic Reviews (AMSTAR) criteria. Of the 15,444 records screened, we identified 118 systematic reviews that met inclusion criteria. Reviews focused on nutrition-specific interventions (96%). Daily and intermittent iron supplementation, micronutrient powders, malaria treatment, use of insecticide-treated nets (ITNs), and delayed cord clamping were associated with increased Hb concentration in children aged <5 y. Among children older than 5 y, daily and intermittent iron supplementation and deworming, and in pregnant women, daily iron-folic acid supplementation, use of ITNs, and delayed cord clamping, were associated with increased Hb concentration. Similar results were obtained for the reduced risk of anemia outcome. This meta-review suggests the importance of nutrition-specific interventions for anemia and highlights the lack of evidence to understand the influence of nutrition-sensitive and multifaceted interventions on the condition.

Keywords: anemia; hemoglobin concentration; meta-review; nutrition interventions; systematic review.

FIGURE 1

Anemia causal framework.

FIGURE 2

Flow diagram.

FIGURE 3

Forest plots of intervention effects (and 95% CI) on hemoglobin concentration, by age groups: <5 y, ≥5 y, and pregnant women. DCC, delayed cord clamping; Hb, hemoglobin; IFA, iron-folic acid; ITN, insecticide-treated nets; MD, mean difference; MNP, micronutrient powders.

FIGURE 4

Forest plots of intervention effects (and 95% CI) on anemia, by age groups: <5 y, ≥5 y, and pregnant women. DCC, delayed cord clamping; IFA, iron-folic acid; ITN, insecticide-treated nets; MNP, micronutrient powders.