Effect of Iron-Containing Micronutrient Powders on Growth and Malaria-Induced Anaemia Among Preschool Children in Ghana: A Cluster-Randomized, Double-Blind, Placebo-Controlled Trial

Background: Affecting 40% of infants and young children worldwide, anaemia in sub-Saharan Africa hampers cognitive and physical development, often in ways that cannot be reversed. Iron-based micronutrient powders (MNPs) are recommended to combat anaemia, but concerns remain about their safety and effectiveness in malaria-endemic areas. We evaluated the impact of iron-based MNPs on growth measurements and malaria-related anaemia among preschool children in Ghana. Methods: We conducted a secondary analysis of a cluster-randomized, double-blind, placebo-controlled trial in the Bono Region, Ghana. Children aged 6-35 months (n=1,958) received daily MNP containing 12·5mg elemental iron or placebo for five months. Anthropometric indices, haemoglobin, and malaria parasitaemia were assessed at baseline and endline. Adjusted analysis of covariance (ANCOVA) models estimated effects on height-for-age (HAZ), weight-for-age (WAZ), and weight-for-height (WHZ) z scores. Binomial regression with identity link estimated risk differences for malaria-induced anaemia. Cluster-robust standard errors were applied at the compound level, and intracluster correlation coefficients (ICCs) were estimated. Results: 1,815 (92·7%) children completed the endline survey, but 1,806 were included in the final analysis. Baseline characteristics were balanced between groups. Iron-containing MNP had no significant effect on endline HAZ (β=0·026, p=0·609), WAZ (β=-0·015, p=0·719), or WHZ (β=-0·035, p=0·463). However, the intervention reduced the risk of malaria-induced anaemia (risk difference 0·050, 95% CI 0·004-0·096; p=0·032). Female sex was associated with higher HAZ (β=0·149, p=0·005). Conclusion: Iron-containing MNP did not improve short-term growth but was associated with a modest reduction in malaria-induced anaemia. These findings support the safe use of iron fortification in malaria-endemic settings while underscoring the need for integrated strategies to address persistent growth faltering and gender specificity. TRIAL REGISTRATION clinicaltrialsgov Identifier: NCT01001871. Registered 27/10/2009, http://www.ClinicalTrials.gov/NCT01001871 .