Validation and calibration of self-reported weight and height from individuals in the city of São Paulo

To evaluate the validity of self-reported weight and height measurements among residents of São Paulo, as well as the accuracy of these measurements for determining nutritional status, and to present calibration coefficients. A cross-sectional, population-based study was performed with a sample of 299 adolescents, adults and elderly of both genders, in São Paulo in 2008. Bland-Altman difference plot and intraclass correlation were used to determine agreement between measured and self-reported parameters. Sensitivity and specificity were assessed for overweight, and calibration coefficients were estimated for correction of weight, height and body mass index data. The intraclass correlation was high between self-reported and measured parameters for weight (r > 0,94) and body mass index (BMI) (r > 0,85). The agreement between measured and self-reported weight, height and BMI was good. Sensibility was > 91% and specificity was > 83%. Self-reported weight measurements can substitute measured parameters in this population, in both genders and in the age groups studied. Self-reported height measurements should be used with caution. Calibration coefficients can be used to adjust self-reported measurements.