Familial aggregation of subcutaneous fat patterning: Principal components of skinfolds in the Québec family study

Abstract

Familial resemblance was examined for each of the principal components arising from an analysis of six skinfolds (triceps, biceps, subscapular, abdominal, suprailiac, and medial calf) measured in 1,237 participants of the Québec Family Study. Most of the phenotypic variance among the skinfolds (83%) was accounted for by the first two principal components. Examination of the skinfold loadings on each principal component, as well as intraindividual cross‐trait correlations with other body composition and fat pattern measures (body mass index; total fat mass and fat‐free mass estimated from body density obtained through underwater weighing; the sum of six skinfolds; and the ratio of trunk to extremity skinfolds) support the interpretation of the first component as a general measure of adiposity and the second component as a trunk‐extremity contrast. Parent‐child and sibling correlations for each of the two principal components indicate that familial effects reach 46% (general) and 52% (trunk‐extremity). Although the eigenvalues for the remaining four principal components (accounting for 17% of the variance) are <1.0, it is noteworthy that each exhibits significant familial resemblance (31–60%). Further, the intraindividual correlations for the additional four components with the other body size indicators are quite low, suggesting that they capture somewhat different aspects of relative fat distribution. © 1996 Wiley‐Liss, Inc.

Findings from the Quebec Family Study on the Etiology of Obesity: Genetics and Environmental Highlights

“…The familial aggregation of subcutaneous fat patterning was also investigated in QFS by performing a principal component analysis of six skinfolds that led to the identification of two principal components. The heritability of the first component (PC1), indexing total adiposity, reached 46 %, while the heritability of the second component (PC2), contrasting trunk-to-extremity skinfolds, reached 52 % [ 7 ]. The heritability of abdominal fat measured by computed tomography was first reported in QFS and results showed significant genetic effects for abdominal fat after adjustment for total body fatness with heritability estimates ranging from 42 % for subcutaneous abdominal fat to 56 % for abdominal visceral fat [ 8 ].…”

A statistical investigation into the sharing of common genetic factors between blood pressure and obesity phenotypes in nuclear families from the Greater Bilbao (Spain)

“…Factors extracted from a factor analysis could represent features that contain a higher degree of genetic variance than the original variables separately [15]. This methodology is widely used in the study of correlated measures as circumferences or skinfold thickness [16][17][18]. Finally, Heath-Carter [19] somatotype provides a more generalized approach to body types and summarizes body shape in three basic components: endomorphy, mesomorphy and ectomorphy (fatness and leanness, musculoskeletal development for the individual's height and linearity-related component, respectively).…”