[Body phenotypes in adolescence and sexual maturation]

The study aims to describe body phenotypes estimated by multivariate technique for the assessment of nutritional status in adolescence during the process of sexual maturation. The sample consisted of 833 schoolchildren 10 to 15 years of age, selected by complex sampling in Piracicaba, São Paulo State, Brazil. Body phenotypes were defined by principal components analysis (PCA) based on anthropometric data (body mass, height, skinfolds, and waist circumference), body composition (phase angle measurement by bioelectric impedance), biochemical parameters (triglycerides, glucose, total/LDL cholesterol ratio, hemoglobin), and sexual maturation (self-classification of stages of pubic hair and breasts or genitals). Body phenotypes were: P1adiposity, characterized by a positive association with the variables skinfolds, body mass, and waist circumference; P2puberty, characterized by positive association with stages of pubic hair and breasts in girls or genitals in boys, height, and age; P3biochemical, characterized by positive association with cholesterol, triglycerides, and glucose; and P4muscular, characterized by positive association with phase angle and hemoglobin and negative association with glucose. Only P1adiposity showed a strong association with body mass index, and there was independence between P1adiposity and P2puberty. Our results highlight the independence between biochemical parameters, anthropometry, body composition, and sexual maturation. Body phenotypes can provide the basis for calculating scores on likelihood of obesity based on anthropometric variables and overcoming ambiguity with the use of body mass.