RESUMEN
BACKGROUND: Body composition assessment in the first 2 y of life provides important insights into child nutrition and health. The application and interpretation of body composition data in infants and young children have been challenged by a lack of global reference data. OBJECTIVES: We aimed to develop body composition reference charts of infants aged 0-6 mo based on air displacement plethysmography (ADP) and those aged 3-24 mo based on total body water (TBW) by deuterium dilution (DD). METHODS: Body composition was assessed by ADP in infants aged 0-6 mo from Australia, India, and South Africa. TBW using DD was assessed for infants aged 3-24 mo from Brazil, Pakistan, South Africa, and Sri Lanka. Reference charts and centiles were constructed for body composition using the lambda-mu-sigma method. RESULTS: Sex-specific reference charts were produced for FM index (FMI), FFM index (FFMI), and percent FM (%FM) for infants aged 0-6 mo (n = 470 infants; 1899 observations) and 3-24 mo (n = 1026 infants; 3690 observations). When compared with other available references, there were observable differences but similar patterns in the trajectories of FMI, FFMI, and %FM. CONCLUSIONS: These reference charts will strengthen the interpretation and understanding of body composition in infants across the first 24 mo of life.