Maria Aparecida Zanetti Passos

Body mass index percentiles in adolescents of the city of São Paulo, Brazil, and their comparison with international parameters

OBJECTIVE To describe the percentile distribution of body mass index (BMI) in school adolescents, by gender and age, comparing them with international parameters. SUBJECTS AND METHODS The study included 8,020 adolescents aged 10-15 years from 43 schools in the city of São Paulo, southeastern Brazil. BMI values of the study sample were distributed in percentiles and compared to international parameters (CDC, Must and cols. and Cole and cols.). RESULTS Both male and female adolescents aged 10 to 14 years showed BMI cut-offs over the international parameters, especially in the P50-P85 percentile range. At the age of 15, the observed values were very similar to reference data; however, BMI values in the 95th percentile were much higher than international parameters. CONCLUSIONS The study results show how important it is to use adequate BMI values for Brazilian adolescents aged 10-15 since international parameters may not reflect the actual nutritional status of this group.

PONTOS DE CORTE DE CIRCUNFERÊNCIA DA CINTURA DE ACORDO COM O ESTADIAMENTO PUBERAL PARA IDENTIFICAR SOBREPESO EM ADOLESCENTES

ABSTRACT Objective: To establish waist circumference cut off points according to pubertal staging to identify overweight in adolescents. Methods: Longitudinal study approved by the Ethics Research Committee and conducted with 557 adolescents, aged 10 to 15 years old, selected from public schools. Waist, arm, neck and hip circumferences, body fat percentage, body mass index (BMI), height and blood pressure were measured. Pubertal staging was evaluated by Tanner self assessment scale. The Receiver Operating Characteristic Curve (ROC curve) was used to determine predictive power, sensitivity, specificity and waist circumference cut off points to detect overweight. Results: There was a positive correlation between waist circumference and weight, BMI, upper arm and hip circumferences, waist-to-hip ratio and blood pressure in both sexes. Cut off points for waist circumference according to pubertal stage as related to overweight in adolescents with the best performances in ROC curve were: 71.65 cm for prepubescent girls, 67.90 cm for pubescent girls, 70.25 cm for post pubescent girls, and 66.45 cm for pubescent boys. Age, weight, height, BMI, body fat percentage, arm and hip circumferences were associated to altered waist circumference. Conclusions: The establishment of cut off points for waist circumference according to pubertal staging was proven a good means to identify overweight. These cut off points can be considered reliable for the Brazilian adolescent population, as the isolated use of chronological age in adolescents may underestimate their nutritional status.

Artigo OriginalReference curves of the body fat index in adolescents and their association with anthropometric variablesCurvas de referência do índice de adiposidade corporal de adolescentes e sua relação com variáveis antropométricas

Objectives To develop reference curves for the body fat index (BFI) in the pediatric population, in adolescents from the city of Sao Paulo, Brazil, and verify their association with body mass index and body fat percentage.

Use of Sound Devices by Teenagers

Objective: To verify the use of electronic device (iPods, MP3s, cell phones, and PCs) by teenagers who are students in public schools of São Paulo, Brazil. Method: Carried out in a school in São Paulo/Brazil in 2011 and involving students from 10 to 17 years. The sample answered a questionnaire containing questions which referred to electronic devices: type of phones (external, internal, and occlusive), times and places used, elevated volume. Chi-square was done and considered P < .05. Results: Among the 249 teenagers studied, 55.8% were girls, the average age was 12.6 years (±1.42 years). Use of phones: 89.9% girls and 73.6% boys (P = .01). Type: 17% external, 18.9% internal, and 64.1% occlusive. Time of usage: cell phone, - >1 h/d by 26.4% girls and 38.3% boys (P = .03); iPod/MP3, - >1 h/d by 26.4% girls and 18.5% boys (P = .06). Related to the places: 50% streets, 87% home, 45% car, 31% subway, 47% bus, and 21% park. Elevated volume in cell phone: 28% by girls and 35.8% by boys (P = .83); in iPod/MP3, 16.7% and 25.9% (P = .06) for girls and boys, respectively. Conclusion: The elevated percentage of teenagers using electronic devices in an inadequate way points to the necessity of concerning the topic as a way to avoid risks and future auditory loss.