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.

Accuracy of obesity diagnosis in Brazilian adolescents: comparison of Cole et al and Must et al criteria with DXA percentage of fat mass / Precisión del diagnóstico de obesidad en adolescentes brasileños: comparación de los criterios de COLE y cols. y de MUST y cols. con el porcentaje DXA sobre masa grasa

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 nonobese adolescent in the two cutoff points considered

Objetivos: valorar la precisión de dos de los criterios antropométricos más utilizados, los de Must y los de Cole, para diagnosticar la obesidad en adolescentes comparando el porcentaje de masa grasa determinada por DXA. Metodología: estudio transversal sobre 418 adolescentes (52,4% varones) de un colegio privado de Sao Paulo (Brasil). Se tomaron las medidas antropométricas peso y talla, y se calculó el IMC. Se realizó el análisis de la composición corporal utilizando DXA para detectar el porcentaje de masa grasa. Utilizando el método propuesto por Ellis y Wong (ERM), se crearon dos modelos de regresión linear específicos para el sexo para el porcentaje de grasa en relación con la edad (años). Se realizó la comparación entre ambos métodos mediante el análisis de especificidad y sensibilidad con dos percentiles residuales (Percentil 85 del ERM (ERM85) y percentil 95 del ERM (ERM95)) como puntos de corte estándar. Se ajustó un modelo logístico para estimar las curvas de probabilidad de la clasificación de la obesidad. Resultados: la comparación de los dos criterios clásicos del diagnóstico de la obesidad con el ERM85 y el ERM95 muestra, para las mujeres, las mismas sensibilidades, de 0,50 y 0,20, para ambos criterios. Para los hombres, las sensibilidades del ERM85 fueron 0,61 (Must) y 0,49 (Cole), mientras que las del ERM95 fueron 0,81 (Must) y 0,64 (Cole). Por lo tanto, la probabilidad de que estos dos criterios diagnostiquen la obesidad en adolescentes es elevada cuando realmente no lo son. Conclusión: los criterios de Must y los de Cole fueron similares y presentan fallos en el diagnóstico de la obesidad. En la práctica clínica y los estudios de campo, los criterios antropométricos deberían evaluarse en relación con la precisión diagnóstica junto con otros parámetros clínicos y, cuando sea posible, el análisis del porcentaje de adiposidad. Sin embargo, los criterios antropométricos evaluados son eficaces para la identificación de los adolescentes no obesos con los dos puntos de corte considerados

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.

Plasma total homocysteine in Brazilian overweight and non-overweight adolescents: a case-control study / Homocisteína plasmática total en adolescentes brasileños con y sin sobrepeso: un estudio de casos-control

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 µmol/L; non-overweight: 11.6 µmol/L) higher for boys than for girls (P ≤ 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 (AU)

Objetivo: Probar la hipótesis de que los adolescentes con sobrepeso tienen mayores concentraciones plasmáticas de homocisteína total (tHcy) que los adolescentes sin sobrepeso, y explorar la asociación entre las concentraciones plasmáticas de tHcy con folato, vitamina B12 y algunos factores de riesgo de ECV en ambos grupos. Métodos: Estudio de casos-control realizado en 239 adolescentes de edades entre los 15-19 años, de la ciudad de Sao Paulo, Brasil; 86 tenían sobrepeso y 153 no, emparejados por edad, sexo, estado puberal y socioeconómico. Se midieron tHcy, folato, vitamina B12, perfil lipídico, glucosa, insulina y resistencia a insulina. Resultados: no se hallaron diferencias significativas en las concentraciones de tHcy, folato ni vitamina B12 entre los grupos con y sin sobrepeso. Las medias geométricas de tHcy estaban elevadas en ambos grupos (sobrepeso: 11,8 µmol/l; sin sobrepeso: 11,6 µmol/l), y fueron mayores en los chicos que las chicas (P ≤ 0,001). Se identificó la deficiencia de folatos en el 68,6% de la población total estudiada. El triacilglicerol, el colesterol-LDL y la resistencia a insulina fueron mayores en el grupo de adolescentes con sobrepeso, y el colesterol HDL fue superior en el grupo sin sobrepeso. En el modelo de regresión linear múltiple, en el grupo con sobrepeso, la tHcy se asoció, de forma independiente, con la edad (P = 0,041), el sexo (P = 0,004) y el folato (P = 0,022) y, en el grupo sin sobrepeso, con la edad (P = 0,049), el sexo (P < 0,001), el folato (P = 0,018) y la vitamina B12 (P = 0,030). Conclusiones: la obesidad no fue un factor determinante de las concentraciones de tHcy. La edad, el sexo y el folato fueron determinantes independientes de las concentraciones plasmáticas de tHcy. La prevalencia elevada de deficiencia de folato podría haber sido responsable de las concentraciones elevadas de tHcy en estos adolescentes, aumentando el riesgo de desarrollo futuro de ECV (AU)

[Changes in lipid profile in obese children and adolescents]. / Investigação de alterações no perfil lipídico de criançãs e adolescentes obesos.

Alterations in plasmatic lipid profile are known to be risk factors for atherosclerotic disease and have been associated with obesity. This research was designed in order to study the incidence of these alterations in obese children and adolescents according to two different reference patterns. Analyses of seric levels of Total Cholesterol (CT) and fractions and of Triglycerides (TG) were done. The sample included 74 obese children and adolescents with average age equal to 11 years and 10 months for boys and 10 years and 9 months for girls and with mean weight/height ratio (W/H) equal to 151 and 149% for boys and for girls, respectively. Plasmatic lipid values obtained were classified according to the American Heart Position Statement Circulation (AHPSC) and to Kwiterovich reference patterns. It was observed that patients with abnormal seric HDL-cholesterol (HDL) levels had a significantly greater (W/H) then the other group. It was also noticed that a greater number of individuals presented abnormal or borderline plasmatic lipid levels (91.9%), specially HDL (93.6%) and TG (67.6%), according to Kwiterovich than AHPSC. Obesity showed to be an important factor in determining lipid profile values and should be included as a variable to indicate screening of these lipoproteins in childhood and adolescence.

Comparaçäo de conhecimentos sobre nutriçäo entre mäes de crianças desnutridas e eutróficas / Comparison of knowledge about nutrition between mothers of malnourished and euthophic children

A fim de relacionar os conhecimentos maternos sobre nutriçäo e práticas alimentares com o estado nutricional de crianças menores de 24 meses, 40 mäes de crianças atendidas e/ou internadas no Centro de Referência da Saúde da Mulher e Nutriçäo, Alimentaçäo e Desenvolvimento Infantil da Secretaria de Estado da Saúde e/ou Unidade Básica de Saúde do município de Säo Paulo, nos meses de outubro e novembro de 1993, foram submetidas a um questionário do tipo certo/errado contendo questöes referentes a: conhecimentos de nutriçäo, aleitamento materno, técnica dietética, educaçäo e higiene alimentar. Os resultados foram analisados estatisticamente pelos testes de Fischer e Cochran näo sendo encontradas diferenças significantes entre as mäes de crianças eutróficas(grupo 1) e mäes de desnutridas(grupo 2). Pode-se verificar diferenças de acerto para algumas questöes que näo foram consideradas relevantes à gênese da desnutriçäo...