Anthropometry and body composition in ethnic Japanese and Caucasian adolescent girls: considerations on ethnicity and menarche.

OBJECTIVE: This study aimed to compare the various anthropometric and body composition parameters based on the ethnicity and the absence or presence of menarche. DESIGN: A cross-sectional study with incomplete sampling, using the subject as the evaluation unit. SUBJECTS: The final sample of 550 subjects was composed of 122 Japanese and 179 Caucasian premenarcheal adolescents, and 72 Japanese and 177 Caucasian postmenarcheal adolescents. METHODS: The variables of body composition were measured through the following methods: bioelectrical impedance analysis, near-infrared interactance (NIR), Slaughter cutaneous skinfold equations and body mass index. Weight, height and sitting height were also evaluated. RESULTS: The Japanese pre- and postmenarcheal girls presented lower weight and height values when compared with the Caucasian girls. In general, the Japanese premenarcheal girls presented less fat and fat-free mass than the premenarcheal Caucasian girls. This fact was demonstrated through NIR results. Conversely, the Japanese postmenarcheal adolescents accumulated more fat than their Caucasian counterparts. However, significant differences were solely encountered in the values of cutaneous skinfold percent body fat. With regard to menarche, it was verified that, regardless of ethnicity, all the anthropometric and body composition variables reached higher values among postmenarcheal adolescents when compared with premenarcheal adolescents. CONCLUSION: Different results of weight and height between the ethnic groups may bring back the discussion concerning separate growth curves for different ethnic groups. The results of the body composition analysis indicated high adiposity levels among postmenarcheal adolescents.

Comparison of the body mass index to other methods of body fat evaluation in ethnic Japanese and Caucasian adolescent girls.

OBJECTIVE: The aim of this study was to assess the body mass index (BMI) and its relationship with other methods of body fat evaluation in pre- and post-menarcheal, Japanese and Caucasian female adolescents, using two different cut-off points for obesity: 28% and 30%. DESIGN: A cross-sectional study with incomplete sampling, using the subject as the evaluation unit. SUBJECTS: A total of 436 Japanese and Caucasian female adolescents in two age groups: 10-11 (pre-menarcheal adolescent); and 16-17 (post-menarcheal adolescents). METHODS: For the BMI the cut-off point for thinness was set at the 5th percentile of the BMI distribution of the NCHS reference population and the cut-off point for overweight and obesity was set at the 85th percentile. Body composition was assessed using foot-to-foot bioelectrical impedance analysis (BIA), near-infrared interactance (NIR) and Slaughter skinfold equations (SKI). The statistical comparison of the methods was performed using the kappa agreement test and the McNemar disagreement test. RESULTS: In the 10- and 11-y-old girls, the BMI was considerably and significantly correlated with the other methods. The major agreements were: in Japanese adolescents BMI x NIR=82.3% (cut-off point of 28%), BMI x BIA=85.7% (cut-off point of 30%); in Caucasian adolescents BMI x NIR=80.7% (cut-off point of 28%), BMI x BIA=87.4% (cut-off point of 30%). The disagreement above the diagonal between BMI x NIR was higher within the two groups for both the cut-off points, revealing that the girls identified as obese by the BMI were considered eutrophic by NIR. In the 16- and 17-y-old adolescents, the BMI demonstrated low or no correlation with the other methods. Furthermore, it presented disagreements below the diagonal, revealing that the BMI identified fewer obese subjects than the other methods. CONCLUSION: Among the 10- and 11-y-olds, the BMI presented a good correlation with the other methods, independent of ethnicity. The BMI can therefore be used in place of these methods, although it may underestimate obesity. Among the 16- and 17-y-olds, the BMI presented low or no agreement with the other methods, suggesting that it is probably not a suitable index for this age-group in studies focusing on the identification of obesity. In such cases the choice of one of the other methods, depending on availability, cost or technical experience, may represent a better approach.

Adaptacao do criterio antropometrico para avaliacao do estado nutricional de adolescentes em dois niveis socio-economicos no municipio de Sao Paulo / Adaptation of the criterion anthropometric for evaluation of the nutritional status of adolescents in two socioeconomics levels in the municipality of Sao Paulo

Foi realizada a avaliacao nutricional em 294 adolescentesdo sexo feminino de 11 a 18 anos, sendo 192 estudantes de um colegio de nivel socio-economico alto e 102 residentes em 5 favelas do Municipio de Sao Paulo. A avaliacao foi realizada com base na adequacao em relacao ao percentil 50 das distribuicoes de E/I e P/I. Foi feita uma adaptacao destas duas distribuicoes para avaliacao da relacao P/E. O metodo consistiu em verificar a partir da estatura real, independente da idade cronologica, o peso adequado a esta estatura. Observou-se uma prevalencia maior de baixa estatura nas adolescentes de nivel socio-economico baixo (36,3% vs. 13%). Os dois criterios de avaliacao, P/I e P/E, nao resultaram em grandes diferencas de diagnostico nos adolescentes de alto nivel socio-economico. Nas adolescentes de baixo nivel socio-economico, observou-se um aumento importante na prevalencia de obesidade (4% vs. 23%), e uma reducao na prevalencia de desnutricao atual (48% vs. 18%) quando P/E foi utilizado. A prevalencia de obesidade com baixa estatura foi maior nas adolescentes de baixo nivel. Os resultados sugerem que em paises subdesenvolvidos, onde a desnutricao compromete ocrescimento dos individuos, a avaliacao nutricional pelo P/I pode induzir a um erro de diagnostico com subestimacao da obesidade .