Accuracy of obesity diagnosis in Brazilian adolescents: comparison of Cole et al and Must et al criteria with DXA percentage of fat mass.

OBJECTIVES: to assess the accuracy of the two most used anthropometric criteria: Must and Cole to diagnose obesity in adolescence comparing with percentage of fat mass determined by DXA. METHODOLOGY: cross-sectional study with 418 adolescents (52.4% males) attending a private school in São Paulo/Brazil. Anthropometric measures of height and weight were taken and BMI was calculated. Analysis of body composition was performed using the DXA to detect percentage of fat mass. Using the method proposed by Ellis & Wong (ERM) two sex-specific linear regression models of fat percentage for age in years were fitted. The comparison between the methods was carried out through the analyses of specificity and sensitivity with two residual percentiles as cutoff points (ERM85th and ERM95th) as standards. A logistic model was fitted to estimate the probability curves of obesity classification. RESULTS: the comparison of the two classic criteria for the diagnosis of obesity with the ERM85th and ERM 95th, yields for females the same sensitivities of 0.50 and 0.20 for both criteria. For males sensitivities for ERM 85th were 0.61 (Must) and 0.49 (Cole); while for ERM95th the sensitivities were 0.81 (Must) and 0.64 (Cole). Therefore, there are high probabilities that those criteria diagnose adolescents as obese, when actually they are not. CONCLUSION: the Must and Cole criteria were similar and present flaws for the diagnosis of obesity. In clinical practice and field studies anthropometric criteria should be evaluated as to the diagnostic accuracy along with other clinical parameters and, when feasible, the analysis of fatness percentage. However, the anthropometric criteria evaluated are efficient in the identification of non-obese adolescent in the two cutoff points considered.

Plasma total homocysteine in Brazilian overweight and non-overweight adolescents: a case-control study.

OBJECTIVE: To test the hypothesis that overweight adolescents have higher plasma total homocysteine (tHcy) levels than non-overweight adolescents and to explore the association between plasma tHcy levels with folate, vitamin B12 and some risk factors for CVD in both groups. METHODS: A case-control study conductec with 239 adolescentes aged 15-19 years in the city of São Paulo, Brazil; 86 overweight and 153 non-overweight frequency matched by age, gender, pubertal and socioeconomic status. tHcy, folate, vitamin B12, lipid profile, glucose, insulin and insulin resistance were measured. RESULTS: No significant differences were found in tHcy, folate and vitamin B12 levels between overweight and non-overweight groups. The geometric means of tHcy were elevated in both groups (overweight: 11.8 micromol/L; non-overweight: 11.6 micromol/L) higher for boys than for girls (P < or = 0.001). Folate deficiency was identified in 68.6% of total studied population. Triacylglycerol, LDL cholesterol, insulin resistance were higher and HDL cholesterol was lower in overweight that non-overweight adolescents. In the multiple linear regression model, in overweight group, tHcy was independently associated with age (P = 0.041), sex (P = 0.004) and folate (P = 0.022) and in non-overweight group, with age (P = 0.049), sex (P < 0.001), folate (P = 0.018) and vitamin B12 (P = 0.030). CONCLUSIONS: Obesity was not a determinant factor of tHcy levels. Age, sex and folate were independent determinants of plasma tHcy levels. The high prevalence of folate deficiency may have been responsible for the elevated tHcy levels in these adolescents, increasing the risk for future development of CVD.

Estudo Psicológico de crianças e adolescentes obesos / Psychological study of the obesity childrens and adolescents

O presente estudo oferece uma compreensäo dos aspectos psicogênicos e psicodinâmicos do processo evolutivo da obesidade por excesso de ingestäo calórica e propöe uma avaliaçäo psicodiagnóstica participativa e mobilizadora para o tratamento necessário.O estudo baseou-se nas avaliaçöes de 134 casos atendidos no Ambulatório Multiprofissional de Obesidade Infantil da EPM, em 1992/93...