Assuntos
Humanos , Lactente , Composição Corporal , Nutrição Materna , Nutrição do Lactente , Leite HumanoRESUMO
A correct diagnosis of obesity requires estimating body composition since it is linked to excess fat. Therefore it is necessary to have practical and sensitive methods of measurement. The aim of this study was to develop and validate bioelectrical impedance (BIA) and anthropometric equations to estimate fat mass (FM) and fat-free mass (FFM). Anthropometric measurements, BIA and deuterium dilution technique as the reference standard were performed in 191 children (4-6 years). Two equations were developed using multiple regression models and were validated in a subsample. Bland and Altman was applied to evaluate the bias differences between the means of both methods. The BIA equation was FFM (kg)= 2,089 + (0,346 * Fieight²/Resistance) + (0,312 * Weight) + (0,660 * Sex); with R2= 0.92, SRMSE 0,67 kg, bias 0,140 kg and precision 0,73 kg. The anthropometric equation was FM (kg)= 0.841 + (0,408 * Weight) + (0,137 * Subscapular-Skinfolds-Thickness) + (0,104 * Tricipital-Skinfolds-Thickness) - (0,764 * Sex) - (0,054 * Feight); with R2= 0.89, SRMSE 0,68 kg, bias -0,01 kg and precision 0,76 kg. The equations validated had a good predictive capacity and can be especially useful in epidemiological studies.
Un correcto diagnóstico de obesidad requiere estimar la composición corporal pues ésta se vincula al exceso de grasa, siendo necesario disponer de métodos prácticos y sensibles para su medición. El objetivo fue desarrollar y validar ecuaciones antropométricas y de bio-impedancia para estimar masa grasa (MG) y masa libre de grasa (MLG). Se realizaron mediciones antropométricas, de bio-impedancia y se aplicó la técnica de dilución con óxido de deuterio como patrón oro a 191 preescolares. Se desarrollaron dos ecuaciones utilizando modelos de regresión múltiple y se validaron en una submuestra. Se aplicó Bland-Altman para evaluar el sesgo entre las diferencias de las medias de ambos métodos. Las ecuaciones diseñadas fueron: MLG (kg)= 2,089 + (0,346* Talla²/Resistencia) + (0,312* Peso) + (0,660* Sexo); con R2= 0,92; SRMSE 0,67kg; sesgo 0,140 kg y precisión 0,73 kg; y MG (kg)= 0,841 + (0,408* Peso) + (0,137* Pliegue Subescapular) + (0,104* Pliegue Tricipital) - (0,764* Sexo) - (0,054* Talla) con R2= 0,89; SRMSE 0. 68.kg, sesgo -0,01 kg y precisión 0,76 kg. Las ecuaciones validadas tienen adecuada capacidad predictiva. Pueden ser especialmente útiles en estudios epidemiológicos.
Assuntos
Humanos , Composição Corporal , Antropometria , Impedância Elétrica , Obesidade Infantil , Criança , PrevisõesRESUMO
OBJECTIVE: To assess the reproducibility and validity among adults in the Southern Cone of Latin America (Argentina, Chile and Uruguay) of a self-administered FFQ to be used in the CESCAS I Study, an ongoing observational prospective cohort study to detect and follow up CVD and their risk factors, as well as in other epidemiological studies. DESIGN: Relative validity of the FFQ was evaluated by comparing nutrient and selected food group intakes with those from three 24 h recalls (24HR) administered over 6 months. The FFQ was administered at baseline (FFQ1) and again after 3 months (FFQ2). SETTING: Primary-care centres in Argentina, Chile and Uruguay. SUBJECTS: Adults (n 147) aged 21-74 years. RESULTS: Reproducibility (FFQ1 v. FFQ2): the intra-class correlation coefficients for nutrients ranged from 0·52 (potassium) to 0·74 (fat). Validity (FFQ1 v. the average of three 24HR): the Pearson correlations for energy-adjusted nutrients ranged from 0·39 (thiamin and cholesterol) to 0·59 (carbohydrate). Joint classification: overall, 66 % of participants in the lowest 24HR quintile were in the lowest one or two FFQ1 quintiles, and 62 % of those in the highest 24HR quintile were in the highest one or two FFQ1 quintiles. On average, only 4 % were misclassified into extreme quintiles. CONCLUSIONS: The FFQ version for the Southern Cone seems to present moderate to acceptable relative validity and reliability for its use in the CESCAS I Study to measure dietary exposure.
