Publications

BACKGROUND: Accurate assessment of body composition during infancy is an important marker of early growth. This study aimed to develop anthropometric  models to predict body composition in 3-24-month-old infants from diverse  socioeconomic settings and ethnic groups. METHODS: An observational,  longitudinal, prospective, multi-country study of infants from 3 to 24 months  with body composition assessed at three monthly intervals using deuterium  dilution (DD) and anthropometry. Linear mixed modelling was utilized to generate  sex-specific fat mass (FM) and fat-free mass (FFM) prediction equations, using  length(m), weight-for-length (kg/m), triceps and subscapular skinfolds and South  Asian ethnicity as variables. The study sample consisted of 1896 (942  measurements from 310 girls) training data sets, 941 (441 measurements from 154  girls) validation data sets of 3-24 months from Brazil, Pakistan, South Africa  and Sri Lanka. The external validation group (test) comprised 349 measurements  from 250 (185 from 124 girls) infants 3-6 months of age from South Africa,  Australia and India. RESULTS: Sex-specific equations for three age categories  (3-9 months; 10-18 months; 19-24 months) were developed, validated on same  population and externally validated. Root mean squared error (RMSE) was similar  between training, validation and test data for assessment of FM and FFM in boys  and in girls. RMSPE and mean absolute percentage error (MAPE) were higher in  validation compared to test data for predicting FM, however, in the assessment of  FFM, both measures were lower in validation data. RMSE for test data from South  Africa (M/F-0.46/0.45 kg) showed good agreement with validation data for  assessment of FFM compared to Australia (M/F-0.51/0.33 kg) and  India(M/F-0.77/0.80 kg). CONCLUSIONS: Anthropometry-based FFM prediction  equations provide acceptable results. Assessments based on equations developed on  similar populations are more applicable than those developed from a different  population.