Differing growth responses to nutritional supplements in neighboring health districts of Burkina Faso are likely due to benefits of small-quantity lipid-based nutrient supplements (LNS)

Abstract

Background : Of two community-based trials among young children in neighboring health districts of Burkina Faso, one found that small-quantity lipid-based nutrient supplements (LNS) increased child growth compared with a non-intervention control group, but zinc supplementation did not in the second study. Objectives : We explored whether the disparate growth outcomes were associated with differences in intervention components, household demographic variables, and/or children's morbidity. Methods : Children in the LNS study received 20g LNS daily containing different amounts of zinc (LNS). Children in the zinc supplementation study received different zinc supplementation regimens (Z-Suppl). Children in both studies were visited weekly for morbidity surveillance. Free malaria and diarrhea treatment was provided by the field worker in the LNS study, and by a village-based community-health worker in the zinc study. Anthropometric assessments were repeated every 13-16 weeks. For the present analyses, study intervals of the two studies were matched by child age and month of enrollment. The changes in length-for-age z-score (LAZ) per interval were compared between LNS and Z-Suppl groups using mixed model ANOVA or ANCOVA. Covariates were added to the model in blocks, and adjusted differences between group means were estimated. Results : Mean ages at enrollment of LNS (n = 1716) and Z-Suppl (n = 1720) were 9.4 +/- 0.4 and 10.1 +/- 2.7 months, respectively. The age-adjusted change in mean LAZ per interval declined less with LNS (-0.07 +/- 0.44) versus Z-Suppl (-0.21 +/- 0.43; p<0.0001). There was a significant group by interval interaction with the greatest difference found in 9-12 month old children (p<0.0001). Adjusting for demographic characteristics and morbidity did not reduce the observed differences by type of intervention, even though the morbidity burden was greater in the LNS group. Conclusions : Greater average physical growth in children who received LNS could not be explained by known cross-trial differences in baseline characteristics or morbidity burden, implying that the observed difference in growth response was partly due to LNS