Fatness and Fat Patterning as Independent Anatomical Characteristics of Body Composition: A Study of Urban South African Children

Objective The purpose of this study was to examine the relationship between fat patterning, age and body composition, among urban South African children in Pretoria, Central. Methods Samples for the study comprised 1136 participants (548 boys and 588 girls) and 581 black and 555 white drawn from 12 primary schools in Pretoria Central. Anthropometrical measurements include stature, body mass and eight skinfolds: triceps, subscapular, biceps, supraspinal, abdomen, front thigh, iliac crest and medial calf. Principal components analysis technique was applied to examine the components loadings. An eigenvalue of >1.0 was retained for analysis. Pearson's correlation coefficient was used to determine the relationship of fat patterning scores, age and body composition measures. Findings Three principal components emerged. The first principal component was a size component (fatness), accounting for 62.3% variance. The second component (central-peripheral patterning) accounted for the total variance of 14.1%. The third component (lower trunk-upper extremity) of relative subcutaneous fat distribution, explained about 10.2% of the total residual variance. Overall, the three components account approximately for 87.0% of the total variance. The correlation coefficients indicating probabilities demonstrated that the overall body fatness (PC1), but not PC2 or PC3 was significantly correlated with body mass index (r=0.745, P<0.01), FM (r=0.672, P<0.01), fat-free mass (r=0.583, P<0.01), Percentage body fat (r=0.701, P<0.01) and children's age (r=0.062, P<0.05). Conclusion The central-peripheral and upper-lower body extremity fat patterning components are discernible among the sample of South African children in Pretoria. The results indicated that principal component 1, but not 2 and 3 was significantly correlated with body composition variables and age, suggesting that component 1 is truly an indicator of total body fatness and not fat patterning.