RESUMEN
Adiposity and distribution of body fat are important issues in the prediction of degenerative diseases. Measurements of weight, height, circumferences of thigh, waist and hip; triceps, biceps, subscapular and suprailiac skinfolds; body mass index (BMI), centripetal index (CI), waist/hip (WHR), waist/thigh (WTR) ratios and sigma skinfold thickness (sigma SK) were performed in 836 youths (373 males, 463 females) aged 11, 13 and 15 years. Analysis method included Student t test, ANOVA, Principal Component Analysis and simple linear regression model, with sigma skinfold thickness as independent variable. The sample was divided in two groups (A and B) according with Graffar-MÚndez Castellano methodology. Sexual dimorphism in adiposity and differences in body fat distribution were found with a tendency towards peripherical distribution for girls and centripetal for boys. Group A (higher stratum) showed higher values of skinfolds in both trunk and extremities, and a more peripherical distribution than his peers from group B. First component from extremity/trunk and second component from upper/inferior trunk distribution explained 40.2 and 32.7 of the variability respectively. CI and WHR appear dependent from BMI, WHR showed independence from BMI, although significant differences was found by social stratum, reflecting differences in fat topography in boys and girls from group B. These results confirm more adiposity in group A and a tendency towards central distribution in group B. Studies of body fat distribution during these age should include waist/thigh ratio.