Predictive Utility of Anthropometric Based Cut-offs in Assessing Excess Adiposity among Preschool Children in a Multiethnic Population

ABSTRACT Objective: Screening for childhood obesity is a necessary step in developing appropriate and effective interventions. We evaluated the diagnostic performance of various recommended international anthropometric cut-offs based on body mass index (BMI), waist circumference (WC), waist-to-height ratio (WHtR), triceps skinfold (TSF), and mid-upper arm circumference (MUAC) in predicting excess adiposity (body fat ≥ 25%) in a random sample of Trinidadian preschoolers. Methods: After obtaining written parental consent, weight, height, WC, TSF, and MUAC were measured in 596 children using standard procedures. These were used to calculate BMI for age, WHtR, TSF-for-age z-scores, and MUAC-for-age z-scores. Percentage body fat was measured using a Tanita-531 foot-to-foot bioelectrical impedance analyser (BIA). Sensitivities, specificities and area under the receiver-operating curve analysis and predictive values were then computed in reference to BIA estimates. Results: The prevalence of excess adiposity was 12.2% and 5.1% among males and females, respectively. Sensitivities for the various cut-offs ranged from 20.0% to 75.0% and 57.1% to 96.9% among males and females, respectively. WHO-BMI recommended cut-offs and those based on MUAC z-scores had significantly higher sensitivities in females than in males. TSF z-scores had significantly lower sensitivities compared to those based on BMI and WHtR among males. Similarly, specificities ranged from 81.3% to 99.9% and 79.8% to 99.9% among males and females, respectively. In girls, cut-offs based on TSF z-scores had a higher likelihood ratio than cut-offs from Centers for Disease Control, International Obesity Task Force and WHtR. Diagnostic performance was not associated with ethnicity. Conclusion: Our results suggest that diagnostic performance was associated with gender and the cut-offs used; however, it was not associated with ethnicity.

Development and validation of a simplified height-specific blood pressure cutoffs table for screening hypertension in Chinese children and adolescents / 中华预防医学杂志

Objective@#To develop and validate a simplified height-specific blood pressure cutoffs table for screening hypertension in Chinese children and adolescents.@*Methods@#We developed a simplified height-specific blood pressure cut offs table according to Chinese Blood Pressure Reference for Children and Adolescents aged 7-18 years (WS/T 610-2018) (hereafter referred to as "complex definition"). Populations from Early Warning, Diagnosis and Treatment of Children Cardiovascular Disease Project ("Ji′nan sample") and Shandong Children Cardiovascular Cohort Study Project ("Zibo sample") were used as validation populations for evaluating the screening effect of the simplified table for elevated blood pressure and hypertension in children and adolescents.@*Results@#We developed simplified height-specific blood pressure cutoffs table including 7 height groups and 28 cutoffs. Both Ji′nan and Zibo samples were selected by convenient sampling method, and the former included 7 233 participants aged 7 to 17 years, among whom 3 790 (52.4%) were boys. Latter population included 1 277 participants aged 7 to 11 years, among whom 681 (53.3%) were boys. The simplified table performed well for identifying elevated blood pressure in Ji′nan sample, with values of area under the receiver operating curve (AUC) (95%CI), sensitivity, specificity, and Kappa statistic as 0.96 (0.95-0.97), 93.0%, 98.5% and 0.91, respectively, which were similar with results in Zibo sample [the values were 0.92 (0.90-0.95), 87.0%, 98.0% and 0.85, respectively]. The simplified table also performed well for identifying hypertension in Ji′nan sample with values of AUC (95%CI), sensitivity, specificity, and Kappa statistic as 0.92 (0.91-0.94), 86.9%, 98.1% and 0.85, respectively, which were similar with results in Zibo sample [the values were 0.94 (0.91-0.96), 88.2%, 98.9% and 0.88, respectively].@*Conclusion@#Screening for elevated and high blood pressure based on simplified height-specific blood pressure cutoffs table is easy to use and it shows satisfying effect.

Puntos de corte de 17-hidroxiprogesterona en la detección de Hiperplasia Suprarrenal Congénita / Cut offs levels of 17-hydroxyprogesterone in screening of Congenital Adrenal Hyperplasia / Pontos de corte da 17-hidroxiprogesterona na detecção de Hiperplasia Adrenal Congênita

El presente estudio investiga la utilidad de determinar puntos de corte ajustados según la edad gestacional y el peso al nacer de neonatos (2-100 días) en la cuantificación de 17-hidroxiprogesterona en muestras de sangre seca en papel de filtro. Se analizaron los resultados de 6.266 determinaciones realizadas en el marco del Programa Nacional de Fortalecimiento de la Detección Precoz de Enfermedades Congénitas. Los datos se dividieron en cuatro grupos; Grupo 1: recién nacido pretérmino con bajo peso; Grupo 2: recién nacido pretérmino con peso normal; Grupo 3: recién nacido a término con bajo peso y Grupo 4: recién nacido a término con peso normal. Se establecieron puntos de corte diferentes a partir del cálculo del percentilo 99 de la distribución de frecuencias. Basado en este análisis se realizó la comparación de la tasa de resultados falsos positivos que se obtuvieron según el punto de corte establecido por el fabricante y los obtenidos en el estudio. Los nuevos puntos de corte obtenidos fueron: 217,72 nmol/L, 102,14 nmol/L, 61,62 nmol/L y 82,38 nmol/L para los grupos 1, 2, 3 y 4 respectivamente. Se evidenció una tasa total de falsos positivos del 1% con los nuevos puntos de corte, significativamente menor a la tasa del 6,2% obtenida al utilizar el punto de corte del fabricante. Esto puso en evidencia que el uso de puntos de corte adecuadamente establecidos para la población en estudio reduce significativamente las complicaciones derivadas de las repeticiones de análisis y eventualmente la tasa de recitaciones, lo cual es una importante contribución a la Salud Pública.

The present work studies the usefulness of determining adjusted cut-offs for the quantification of 17-hydroxyprogesterone in dried blood samples on filter paper, taking into account the gestational age and weight of the neonates. The results of 6266 determinations made within the framework of the National Program of Strengthening Early Detection of Congenital Disease were analysed. Data were divided into groups, Group 1: early established from the calculation of the 99 percentiles of the frequency distribution. New cutoff points were: 217.72 nmol/L, 102.14 nmol/L, 61.62 nmol/L and 82.38 nmol/L for groups 1, 2, 3 and 4 respectively. It showed a total rate of 1% false positives with the new cut-off points, which was significantly lower than the rate of 6.2% obtained using the manufacturer's cutoff. This revealed that the use of properly established cut-offs for the study of population reduces significantly the complications derived fromn analysis repetitions and eventually the recitation rate, which is an important contribution to Public Health.

O presente estudo investiga a utilidade de determinar pontos de corte estabelecidos conforme a idade gestacional e o peso ao nascer de neonatos (2-100 dias) na quantificação da 17-hidroxiprogesterona em amostras de sangue seco em papel filtro. Foram analisados os resultados de 6.266 determinações feitas no âmbito do Programa Nacional de Fortalecimento da Detecção Precoce de Doenças Congênitas. Os dados foram divididos em quatro grupos; Grupo 1: recém-nascido pré-termo com baixo peso, Grupo 2: recém-nascido pré-termo com peso normal, Grupo 3: recém-nascido a termo com baixo peso e Grupo 4: recém-nascido a termo com peso normal e foram estabelecidos pontos de corte diferentes a partir do cálculo do percentil 99 da distribuição de frequências. Com base nesta análise foi realizada a comparação da taxa de resultados falsos positivos obtidos conforme o ponto de corte estabelecido pelo fabricante e os obtidos no estudo. Os novos pontos de corte obtidos foram: 217,72 nmol/L, 102,14 nmol/L, 61,62 nmol/L e 82,38 nmol/L para os grupos 1, 2, 3 e 4, respectivamente. Tornou-se evidente uma taxa total de 1% de falsos positivos, com os novos pontos de corte significativamente menor do que a taxa de 6,2% obtida utilizando o ponto de corte do fabricante. Isto revelou que o uso de pontos de corte de forma adequada estabelecidos para a população em estudo reduz significativamente as complicações decorrentes das repetições de análises e eventualmente a taxa de repetição de novos encontros, o que é uma importante contribuição para a saúde pública.

Pontos de corte para a aptidão cardiorrespiratória e a triagem de fatores de risco para doenças cardiovasculares na infância / Cardiorespiratory fitness cut offs points and cardiovascular risk factors screening at infancy

O principal objetivo deste estudo foi analisar a validade e propor novos pontos de corte para aptidão cardiorrespiratória de escolares de sete a 12 anos de idade. A amostra foi constituída por 1.413 escolares. A aptidão cardiorrespiratória foi medida através do teste de corrida/caminhada de nove minutos. O colesterol total e as pressões arterial sistólica e diastólica foram medidas e através delas foram criadas referências de fatores de risco para doenças cardiovasculares. Através da curva receiver operating characteristic entre a aptidão cardiorrespiratória e as referências de fatores de risco para doenças cardiovasculares foram identificados os valores dos pontos de corte. Adicionalmente foi utilizada a análise bivariada seguida do cálculo de razão de chances (odds ratio-OR) para identificar quanto os indivíduos que não atenderam os pontos de corte propostos tinham a mais de chance de apresentar fatores de risco para doenças cardiovasculares. Os resultados indicaram que, dentre as propostas analisadas, a que foi sugerida neste estudo apresentou melhores ajustamentos entre sensibilidade e especificidade. Os resultados da análise bivariada mostraram que indivíduos que não atenderam os pontos de corte propostos têm maiores chances de apresentarem fatores de risco para doenças cardiovasculares.

The main objective of the study was to analyze and propose news cardiorespiratory fitness cut offs points for 7 to 12-year old school students. The sample was composed of 1,413 students. Cardiorespiratory fitness was measured by the 9-minutes walking/running test. Total cholesterol and systolic and diastolic blood pressure were measured and with their results cardiovascular risk factors reference were designed. The Receiver Operating Characteristic curve between cardiorespiratory fitness and cardiovascular risk factors reference identified the cut offs point values. The bivariate analysis and odds ratio (OR) calculation was used to identify to what extent the individuals that did not reach the proposed cut offs points could show cardiovascular risk factors. The results showed that the cut offs points suggested in this study presented the best balance between sensibility and specificity. The bivariate analysis results showed increased chance of cardiovascular risk for the individuals that did not reach the cut offs points compared to those individuals who did.