Sample size and selection of participants
We considered a 0·25 The children for neurodevelopment assessments were contacted in a consecutive manner, that is, as and when they completed their anthropometric and biochemical assessments in the primary trial at 12 months of age. The family members of these children were approached for their consent for participation in the neurodevelopment assessments at 12 and 24 months of age. For infants who could not be contacted at 12 months of age because the family members had temporarily moved out of the study area at the time of house visit or in those who had crossed the window period of +4 weeks at the time they were approached for inclusion in this study, the study team visited the house at the time of anthropometric assessments at 15 months of age and obtained written informed consent for neurodevelopment assessments at 24 months of age. Such children did not have their 12 months neurodevelopment assessments but were eligible for assessments at 24 months.