Validation of self-reported anthropometrics in the Adventist Health Study 2

Maira Bes-Rastrollo,Joan Sabaté,Gary E Fraser,Karen Jaceldo-Siegl

doi:10.1186/1471-2458-11-213

Maira Bes-Rastrollo, Joan Sabaté + Show 2 more

Open Access

https://doi.org/10.1186/1471-2458-11-213

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Abstract

BackgroundRelying on self-reported anthropometric data is often the only feasible way of studying large populations. In this context, there are no studies assessing the validity of anthropometrics in a mostly vegetarian population. The objective of this study was to evaluate the validity of self-reported anthropometrics in the Adventist Health Study 2 (AHS-2).MethodsWe selected a representative sample of 911 participants of AHS-2, a cohort of over 96,000 adult Adventists in the USA and Canada. Then we compared their measured weight and height with those self-reported at baseline. We calculated the validity of the anthropometrics as continuous variables, and as categorical variables for the definition of obesity.ResultsOn average, participants underestimated their weight by 0.20 kg, and overestimated their height by 1.57 cm resulting in underestimation of body mass index (BMI) by 0.61 kg/m2. The agreement between self-reported and measured BMI (as a continuous variable), as estimated by intraclass correlation coefficient, was 0.97. The sensitivity of self-reported BMI to detect obesity was 0.81, the specificity 0.97, the predictive positive value 0.93, the predictive negative value 0.92, and the Kappa index 0.81. The percentage of absolute agreement for each category of BMI (normoweight, overweight, and obese) was 83.4%. After multivariate analyses, predictors of differences between self-reported and measured BMI were obesity, soy consumption and the type of dietary pattern.ConclusionsSelf-reported anthropometric data showed high validity in a representative subsample of the AHS-2 being valid enough to be used in epidemiological studies, although it can lead to some underestimation of obesity.

Highlights

Relying on self-reported anthropometric data is often the only feasible way of studying large populations
We studied the agreement between self-reported and measured anthropometric variables using a randomeffect model intraclass correlation coefficient and the survival agreement plot for body mass index (BMI) proposed by Luiz et al [10] differentiating between negative and positive differences [11]
From 1011 participants in the calibration study, we excluded one hundred participants with missing values, including 911 participants. Those 911 participants were a good representation of the overall AHS-2cohort, except that the validation sample had a slightly higher percentage of soy consumers (Table 1)

Summary

Introduction

Relying on self-reported anthropometric data is often the only feasible way of studying large populations. In this context, there are no studies assessing the validity of anthropometrics in a mostly vegetarian population. The prevalence of overweight and obesity has reached epidemic proportions around the world, in developed countries and in developing countries It has been recognised as a pandemic by the World Health Organization [1]. The causes of obesity are multiple and complex For all these reasons it is important to assess obesity as a risk factor and to study the potential causes of weight gain in large populations

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