Maternal multiple micronutrient supplementation and other biomedical and socioenvironmental infl uences on children’s cognition at age 9–12 years in Indonesia: follow-up of the SUMMIT randomised trial

Background Brain and cognitive development during the fi rst 1000 days from conception are aff ected by multiple biomedical and socioenvironmental determinants including nutrition, health, nurturing, and stimulation. An improved understanding of the long-term infl uence of these factors is needed to prioritise public health investments to optimise human development. Methods We did a follow-up study of the Supplementation with Multiple Micronutrients Intervention Trial (SUMMIT), a double-blind, cluster-randomised trial of maternal supplementation with multiple micronutrients (MMN) or iron and folic acid (IFA) in Indonesia. Of 27 356 live infants from birth to 3 months of age in 2001–04, we re-enrolled 19 274 (70%) children at age 9–12 years, and randomly selected 2879 from the 18 230 who were attending school at a known location. Of these, 574 children were oversampled from mothers who were anaemic or malnourished at SUMMIT enrolment. We assessed the eff ects of MMN and associations of biomedical (ie, maternal and child anthropometry and haemoglobin and preterm birth) and socioenvironmental determinants (ie, parental education, socioeconomic status, home environment, and maternal depression) on general intellectual ability, declarative memory, procedural memory, executive function, academic achievement, fi ne motor dexterity, and socioemotional health. The SUMMIT trial was registered, number ISRCTN34151616. Findings Children of mothers given MMN had a mean score of 0·11 SD (95% CI 0·01–0·20, p=0·0319) higher in procedural memory than those given IFA, equivalent to the increase in scores with half a year of schooling. Children of anaemic mothers in the MMN group scored 0·18 SD (0·06–0·31, p=0·0047) higher in general intellectual ability, similar to the increase with 1 year of schooling. Overall, 18 of 21 tests showed a positive coeffi cient of MMN versus IFA (p=0·0431) with eff ect sizes from 0·00–0·18 SD. In multiple regression models, socioenvironmental determinants had coeffi cients of 0·00–0·43 SD and 22 of 35 tests were signifi cant at the 95% CI level, whereas biomedical coeffi cients were 0·00–0·10 SD and eight of 56 tests were signifi cant, indicating larger and more consistent impact of socioenvironmental factors (p