Beyond prevention: A rightward shift in the distribution of weight-for-height following supplementation with SQ-LNS to children aged 6-23 months in post-conflict settings of Tigray, Ethiopia - A Non-Randomized Cluster Trial

Introduction Acute malnutrition in children aged 6-23 months remains critical in Tigray, Ethiopia, where global acute malnutrition (GAM) rates have reached emergency levels. Small-quantity lipid-based nutrient supplements (SQ-LNS) show promise for prevention, but evidence from post-conflict settings is limited. Objective This study evaluated SQ-LNS effectiveness in preventing acute malnutrition and rightward shifting in the distribution of weight-for-height among young children in post-conflict Tigray, Ethiopia. Methods A non-randomized cluster trial enrolled 8,442 children aged 6-23 months across four districts. The intervention group (n=6,838) received daily 20g SQ-LNS sachets for six months plus behavior change communication; the control group (n=1,604) received standard nutrition programming. Primary outcomes were acute malnutrition prevalence (WHZ < -2 or MUAC < 12.5cm) and distribution of weight-for-height z-scores. Data were collected biweekly and analyzed using longitudinal comparisons and difference-in-differences (DiD) estimation. Results Acute malnutrition declined from 22.1% to 4.2% in the intervention group (17.9 percentage point reduction) versus 19.6% to 11.4% in controls (8.2-point reduction). Mean WHZ scores increased from -0.35 to +0.33 in the intervention group (gain of +0.68 z-scores), while controls improved from -0.79 to -0.63 (gain of +0.16). The net intervention effect (DiD) showed a 4.9 percentage point reduction in WHZ-defined GAM and a 9.7-point reduction in MUAC-defined GAM. Mean WHZ and MUAC increased significantly more in the intervention group (DiD: +0.52 z-scores and +3.88 mm, respectively). Critically, the entire WHZ distribution shifted rightward, indicating population-level nutritional improvement, not merely reduced caseloads. Conclusions Six months of daily SQ-LNS effectively prevented acute malnutrition and shifted the entire weight-for-height distribution rightward among young children in post-conflict Tigray. Benefits extended beyond treatment, lifting whole-population nutritional status and building resilience. Findings support SQ-LNS inclusion in post-conflict nutrition packages and highlight the importance of assessing distributional outcomes, not just prevalence, when evaluating nutritional interventions. Trial registration number This trial was registered as NCT06103084.