Role of infant feeding practice, sex, and age on fatness and subcutaneous fat distribution in infancy: Longitudinal analysis of multiple skinfold measurements

Abstract

The aim of this study was to determine whether subcutaneous fatness and fat distribution differ on the basis of feeding practice and sex during the first 6 months of life. Longitudinal principal components analysis (PCA) was done on skinfolds measured at five sites in 45 breast-fed and 41 formula-fed infants. The first component represented fatness, the second component change in fatness, and the third component upper body/lower body fat distribution. Analysis of the components indicated that fatness and the proportion of lower body fat were greater in breast-fed than in formula-fed infants; however, when race was included as a predictor, the differences in lower body fat did not persist. The interpretation of components and the group differences were confirmed by repeated measures analysis of variance (ANOVA) on the sum of skinfolds (fatness) or simple skinfold ratios (fat distribution). Group differences for fatness and upper body/lower body fat persisted when race was included as a predictor. Longitudinal PCA of another indicator, the Rohrer index, suggested that fatness was greater in formula-fed than breast-fed infants. Collectively, these findings suggest that formula-fed infants have less subcutaneous fat than breast-fed infants; however, formula-fed infants may have either more internal fat or more lean body mass. Am. J. Hum. Biol. 9:179–190, 1997. © 1997 Wiley-Liss, Inc.