Preconception micronutrient supplementation positively affects child intellectual functioning at 6 y of age: A randomized controlled trial in Vietnam

Background: Although there is growing evidence on the role of preconception nutrition for birth outcomes, very few studies have evaluated the long-term effects of nutrition interventions during the preconception period on offspring cognitive outcomes. Objective: We evaluate the impact of preconception weekly multiple micronutrients (MMs) or iron and folic acid (IFA) supplementation compared with folic acid (FA) alone on offspring intellectual functioning at age 6-7 y. Methods: We followed 1599 offspring born to women who participated in a double-blinded randomized controlled trial of preconception supplementation in Vietnam. Women received weekly supplements containing either 2800 mu g FA only, 60 mg iron and 28(X) mu g FA, or MMs (15 micronutrients including IFA) from baseline until conception, followed by daily prenatal IFA supplements until delivery. We used the Wechsler Intelligence Scale for Children to measure full-scale IQ (FSIQ) and 4 related domains of intellectual functioning [Verbal Comprehension Index (VCI), Perceptual Reasoning Index (PRI), Working Memory Index (WMI), and Processing Speed Index (PSI) scores] at 6-7 y. Group comparisons were done using ANOVA tests for all children and the subgroup born to women who consumed the supplements >= 26 wk before conception (per-protocol analyses). Results: The final sample with data at 6-7 y (n = 1321) was similar for baseline maternal and offspring birth characteristics and age at follow-up by treatment group. Compared with the offspring in the FA group. those in the MM group had higher FSIQ (beta = 1.7; 95% CI: 0.1. 3.3). WMI (beta = 1.7; 95% CI: 0.2, 3.2), and PSI (beta = 2.5; 95% CI: 0.9, 4.1). Similar findings were observed in the per-protocol analyses. There were no significant differences by treatment group for VCI and PRI. Conclusions: Preconception supplementation with MMs improved certain domains of intellectual functioning at age 6-7 y compared with FA. These findings suggest the potential for preconception micronutrient interventions to have long-term benefits for offspring cognition.