Body phenotypes and sexual maturation in Brazilian and US adolescents: evidence for a change in BMI category.

OBJECTIVE

Our study aimed to describe body phenotypes (BP) estimated by multivariate analysis and their association with body mass.

DESIGN

BP were defined based on demographic variables, anthropometric data (body mass, height, skinfolds and circumferences), body composition (phase angle measured by bioelectrical impedance analysis), biochemical parameters (TAG, glucose, total cholesterol ratio/LDL, Hb and sexual maturation (pubic hair and breasts or gonads). ANOVA was performed to verify the differences between skin colour and the stages of pubertal development, BP, body composition, anthropometric and biochemical variables.

SETTING

Cities of São Paulo-SP, Piracicaba-SP and Florianópolis-SC from Brazil and the United States.

PARTICIPANTS

9269 adolescents aged between 10 and 15 years old.

RESULTS

The composition of BP was similar in all surveys, which are: BP1 was composed by skinfolds, body mass and circumferences variables; BP2 by pubic hair, breast in girls or gonad in boys, height and age; BP3 by cholesterol, TAG and glucose; and BP4 by phase angle, Hb and glucose (negative loading). There was a strong correlation (r = 0·9, P < 0·001) between BP1 and BMI.

CONCLUSION

We highlighted independence observed between biochemical parameters, anthropometry, body composition and sexual maturation. BP may support the calculation of scores for diagnosis of obesity based on anthropometric variables and overcome ambiguity in the isolated use of BMI.