Impact of Double-Fortified Salt with Iron and Iodine on Hemoglobin, Anemia, and Iron Deficiency Anemia: A Systematic Review and Meta-Analysis

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Impact of Double-Fortified Salt with Iron and Iodine on Hemoglobin, Anemia, and Iron Deficiency Anemia: A Systematic Review and Meta-Analysis

Ramírez-Luzuriaga et al., 2018 | Adv Nutr | Meta Analysis

Citation

Ramírez-Luzuriaga María J, Larson Leila M, ... Martorell Reynaldo. Impact of Double-Fortified Salt with Iron and Iodine on Hemoglobin, Anemia, and Iron Deficiency Anemia: A Systematic Review and Meta-Analysis. Adv Nutr. 2018-May-01;9(3):207-218. doi:10.1093/advances/nmy008

Abstract

Double-fortified salt (DFS) containing iron and iodine has been proposed as a feasible and cost-effective alternative for iron fortification in low- and middle-income countries (LMICs). We conducted a systematic review and meta-analysis from randomized and quasi-randomized controlled trials to 1) assess the effect of DFS on biomarkers of iron status and the risk of anemia and iron deficiency anemia (IDA) and 2) evaluate differential effects of DFS by study type (efficacy or effectiveness), population subgroups, iron formulation (ferrous sulfate, ferrous fumarate, and ferric pyrophosphate), iron concentration, duration of intervention, and study quality. A systematic search with the use of MEDLINE, EMBASE, Cochrane, Web of Science, and other sources identified 221 articles. Twelve efficacy and 2 effectiveness studies met prespecified inclusion criteria. All studies were conducted in LMICs: 10 in India, 2 in Morocco, and 1 each in Côte d'Ivoire and Ghana. In efficacy studies, DFS increased hemoglobin concentrations [standardized mean difference (SMD): 0.28; 95% CI: 0.11, 0.44; P < 0.001] and reduced the risk of anemia (RR: 0.59; 95% CI: 0.46, 0.77; P < 0.001) and IDA (RR 0.37; 95% CI: 0.25, 0.54; P < 0.001). In effectiveness studies, the effect size for hemoglobin was smaller but significant (SMD: 0.03; 95% CI: 0.01, 0.05; P < 0.01). Stratified analyses of efficacy studies by population subgroups indicated positive effects of DFS among women and school-age children. For the latter, DFS increased hemoglobin concentrations (SMD: 0.32; 95% CI: 0.03, 0.60; P < 0.05) and reduced the risk of anemia (SMD: 0.48; 95% CI: 0.34, 0.67; P < 0.001) and IDA (SMD: 0.37; 95% CI: 0.25, 0.54; P < 0.001). Hemoglobin concentrations, anemia prevalence and deworming at baseline, sample size, and study duration were not associated with effect sizes. The results indicate that DFS is efficacious in increasing hemoglobin concentrations and reducing the risk of anemia and IDA in LMIC populations. More effectiveness studies are needed.

Key Findings

More effectiveness studies are needed.

Outcomes Measured

  • Requires manual extraction

Population

Field Value
Population See abstract
Sample Size See abstract
Age Range See abstract
Condition deficiency

MeSH Terms

  • Adult
  • Anemia
  • Anemia, Iron-Deficiency
  • Child
  • Developing Countries
  • Female
  • Food, Fortified
  • Hemoglobins
  • Humans
  • Iodine
  • Iron
  • Iron Deficiencies
  • Iron, Dietary
  • Male
  • Pregnancy
  • Sodium Chloride, Dietary

Evidence Classification

  • Level: Meta Analysis
  • Publication Types: Journal Article, Meta-Analysis, Systematic Review
  • Vertical: iron

Provenance

Source extracted via PubMed E-utilities API on 2026-04-09