Multiple micronutrient supplementation during early childhood increases child size at 2 y of age only among high compliers

Background: Micronutrient deficiencies are common, even in middle-income countries. Objective: The objectives were to determine whether multiple micronutrient (MM) supplementation from 3 to 24 mo of age improves growth and whether the effect is modified by MM supplementation during pregnancy. Design: We conducted a randomized, double-blind, controlled trial in central Mexico. Singleton live births (n = 650) from a prenatal MM trial were randomly assigned to receive either MM supplements (1-1.5 times the Recommended Dietary Allowance of vitamins A, B-6, B-12, and C; folic acid; iron; zinc; and other nutrients) or supplements containing similar amounts of iron and vitamin A (Fe-A) within the maternal supplementation groups (MM and iron only) 6 d/wk from 3 to 24 mo of age. Anthropometric measurements were obtained at 3 and 24 mo of age. Results: There was no effect of supplement group on child growth in intention-to-treat analyses. However, infants who consumed MM supplements regularly (greater than the median compliance of 79%) were 0.8 (95% CI: -0.4, 1.9) and 1.6 (95% CI: 0.4, 2.8) cm taller at 24 mo in the maternal MM and iron-only groups, respectively, than were those in the Fe-A group; these differences were 0.2 (95% CI: -1.0, 1.4) and -0.5 (95% CI: -1.7, 0.7) cm among those with compliance below the median. Mean body mass index (in kg/m(2)) was significantly higher in those exposed to iron only in utero and Fe-A during childhood (16.2) than in the other groups (15.8). Conclusions: MM supplements increased the length of children who consumed them regularly from 3 to 24 mo. Strategies that promote compliance through effective delivery of micronutrient interventions are needed. Am J Clin Nutr 2009;89:1125-31.