Effect of micronutrient supplement on health and nutritional status of schoolchildren: study design

Abstract

Objective We tested the hypothesis that supplementation with a micronutrient-fortified beverage improves micronutrient status and physical and mental development in apparently healthy schoolchildren. Methods The study was carried out in middle-income students in two residential schools that catered to children from a semi-urban population near Hyderabad, India. Included were 869 children who were 6 to 16 y of age in grades 1 to 10. Because children at each grade were distributed across two classrooms (clusters) and were homogeneous, each grade was considered to consist of a matched pair. There were thus 10 pairs available for the study. Classes in each grade were randomized to receive a micronutrient-enriched beverage or a placebo without added micronutrients. The study was double blinded and the duration was 14 mo, with supervised feeding of the micronutrient-enriched beverage. The effect of the micronutrients on the outcome variables growth, biochemical status, mental function, and bone health were assessed. Results The number of matched pairs varied between seven and eight, and the required number of children per treatment group ranged from 32 in the case of bone heath to 177 for body weight. The power of the outcome variables ranged from 74% to 100% and was adequate for successful pairing. The effect assessed at the end of supplementation showed that the intervention was beneficial. Conclusions Designing an intervention, choosing outcome variables, and implementing the protocol in a typical Indian school setting were achieved.