Estudo de calibração do questionário de frequência alimentar para adolescentes - QFAA a ser utilizado em um estudo de coorte de escolares de Piracicaba, SP / Calibration study of Adolescents Food Frequency Questionnaire – AFFQ to Piracicaba students cohort, SP

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

Background - A major limitation in usual diet assessment is the measurement error. Calibration approaches have been proposed to minimize its effects and to correct risk estimates. Calibration could be defined as a method which determines a relation between rank orders of two instruments by linear regression. Objective – to apply a calibration strategy in nutrient intake datas obtained by Adolescents Food Frequency Questionnaire (AFFQ), by using a calibration factor obtained by linear regression. Methodology – 74 boys and girls (10 to 14 years old) enrolled at a public school of Piracicaba were assessed. Values of energy intake higher than 6000Kcal and adolescents older than 14 years were excluded. Demographic and anthropometric data, sexual maturation and dietary intake (assessed by food frequency questionnaire and 24-hour recall) were examined. Dietary data intakes were adjusted by energy and, only 24-hour recall data were adjusted by within-person variance. Descriptive statistics, one way ANOVA, Pearson correlation coefficients and linear regression were performed. Results - 71,6% were girls. The calibrated values were similar to the reference data, with a reduction of standard deviation values. Linear regression coefficients (λ) ranged from -0,05 (iron) to 0,28 (vitamin C). Conclusion – The methodology used to calibrate dietary data was capable to reduce measurement error. Although it was not able to eliminate error completely, it is an approach that can be used to obtain less unbiased estimates.

ASSUNTO(S)

linear regression diet saúde pública dieta measurement error adolescente calibração erro de medida public health regressão linear calibration adolescent

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