Fenótipos corporais na adolescência e a maturação sexual

Abstract

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.

Milk consumption, dietary calcium intake and nutrient patterns from adolescence to early adulthood and its effect on bone mass: the 1993 Pelotas (Brazil) birth cohort

“…Yet, the absence of adjustment for sexual maturation also needs to be reported, as well as the impact of physical activity variables, which may interfere with bone mass. However, at their 18th year most of the adolescents were expected to have completed sexual maturation, as menarche age is 12.34 years (95%CI: 12.24; 12.42) (data not shown), and, in boys, studies show that the voice breaking age is at 13 years and Tanner Genital Stage 5 between 14 and 15 years of age 72,73 . About physical activity, the use of IPAQ (valid for epidemiological studies 46 ) may have minimized this limitation.…”

Predictive capacity and cut-off points of adiposity indices for body fat prediction according to adolescent periods

“…In adolescence, body composition varies according to age, sexual maturation and physical growth, with physiological increase of adipose tissue, being higher in females, because this accumulation of body fat is essential for the beginning and maintenance of menstrual cycles and consequently for the reproductive process (2,31) . However, it should be considered that this is an age of many changes and therefore is a critical period for the development of obesity (32,33) . High-calorie eating habits and sedentary lifestyles of adolescents in general may lead to excessive body fat accumulation and obesity (34,35) .…”

Fenótipos corporais na adolescência: é necessário ajustar o índice de massa corporal de acordo com os estágios de maturação sexual?

“…Em um estudo foi aplicada a análise de componentes principais (APC) para estimar diferentes perfis latentes do estado nutricional de adolescentes, que foram denominados fenótipos corporais. Entre os perfis criados, apenas o fenótipos corporais da adiposidade esteve fortemente associado ao IMC, já o fenótipos corporais do crescimento esteve associado ao crescimento físico linear 8 .…”