Characteristics that modify the effect of small-quantity lipid-based nutrient supplementation on child growth: an individual participant data meta-analysis of randomized controlled trials

Abstract

Background: Meta-analyses have demonstrated that small-quantity lipid-based nutrient supplements (SQ-LNS) reduce stunting and wasting prevalence among infants and young children. Identification of subgroups who benefit most from SQ-LNS may facilitate program design. Objective: Our objective was to identify study-level and individual-level modifiers of the effect of SQ-LNS on child growth outcomes. Methods: We conducted a two-stage meta-analysis of individual participant data from 14 randomized controlled trials of SQ-LNS provided to children 6 to 24 months of age in low- and middle-income countries (n=37,066). We generated study-specific and subgroup estimates of SQ-LNS vs. control and pooled the estimates using fixed-effects models, with random-effects models as sensitivity analyses. We used random effects meta-regression to examine study-level effect modifiers. Heterogeneity was assessed using I2 and Tau2 statistics. Sensitivity analyses were conducted to examine whether results differed depending on inclusion criteria for arms within trials and types of comparisons. Results: SQ-LNS provision decreased stunting (length-for-age z-score < -2) by 12% (relative reduction), wasting (weight-for-length (WLZ) z-score < -2) by 14%, low mid-upper arm circumference (MUAC < 125 mm or MUACZ < -2) by 18%, acute malnutrition (WLZ < -2 or MUAC < 125 mm) by 14%, underweight (weight-for-age z-score < -2) by 13%, and small head size (head-circumference z-score < -2) by 9%. Effects of SQ-LNS on growth outcomes generally did not differ by study-level characteristics including region, stunting burden, malaria prevalence, sanitation, water quality, duration of supplementation, frequency of contact or average reported compliance with SQ-LNS. Effects of SQ-LNS on stunting, wasting, low MUAC and small head size were greater among girls than among boys; effects on stunting, underweight and low MUAC were greater among later-born (vs. first-born) children; and effects on wasting and acute malnutrition were greater among children in households with improved (vs. unimproved) sanitation. Results were similar across sensitivity analyses. Conclusions: The positive impact of SQ-LNS on growth is apparent across a wide variety of study-level contexts. Policy-makers and program planners should consider including SQ-LNS in the mix of interventions to prevent both stunting and wasting. This study was registered at www.crd.york.ac.uk/PROSPERO as CRD42019146592. Keywords: Stunting, wasting, child undernutrition, complementary feeding, nutrient supplements, home fortification