Self-Reported versus Measured Height, Weight and Body Mass Index in Spanish Mediterranean Teenagers: Effects of Gender, Age and Weight on Perceptual Measures of Body Image

Abstract

Background: To have a good physical appearance is a determining factor by which adolescents show a tendency to worry excessively about their weight. The aim of this work is to study the possible relationship between actual and perceived body weight, how it is considered and what strategies are followed for weight control among adolescents residing in Valencia. Methods: A sample of 568 students, 325 girls and 243 boys, aged 14–20 years, were selected from public high schools in Valencia. Their height and weight were used to calculate their actual body mass index (BMIO). The subjective perception of their physical measurements (BMIS) was evaluated by means of a questionnaire. The statistical treatment of data was done with commercially available software. Results: There is a relatively large proportion of underweight subjects among the participants of the survey. Differences between the BMIO and BMIS indicate a misperception of height (overestimated) and weight (underestimated) that is greater in girls than in boys. Girls tend to undergo restrictive dietary measures when they consider themselves overweight. A general lack of knowledge about adequate weight was observed. Conclusion: Valencia teenagers show a poor knowledge of their body size and of the weight that should be adequate for their age and tallness.

Validity of self-reported height and weight among adolescents: the importance of reporting capability

“…The average underestimation was relatively small, 0.8 kg for boys and 1.8 kg for girls. This difference by gender is in line with a number of previous studies [6,8,9,21,25-27] while other studies find no differences between boys’ and girls’ reports [5,7,12,14,23,28]. Only among girls, a significant larger systematic underestimation of weight was seen among those who are not weighed recently.…”

“…Study populations of adolescents are often characterised by a substantial proportion of missing values on height and weight [2-4]. Further, weight is often under-reported [5-13] while height tends to be over-reported [5,6,8,10,12,13]. Consequently, BMI is frequently underestimated leading to misclassification as some overweight individuals are classified as being normal weight.…”

Validity and predictors of BMI derived from self-reported height and weight among 11- to 17-year-old German adolescents from the KiGGS study

“…The few studies that have considered self-reports by underweight adolescents confirmed the result of this study, i.e. that underweight adolescents tend to over-report their BMI [10,14]. When measured weight status was not included in the linear regression model, body perception was a major predictor of the quality of self-reports.…”

Differences in Measured and Self-Reported Height and Weight in Dutch Adolescents

“…In our study pupils knew their self-report data would be treated confi dentially and under-or over-reporting would not be noticed either by the school nurse who did the actual measurement or anyone else. In six of the reviewed studies on validity of self-reports, subjects knew self-report would be followed by actual measurement [5,9,15,17] , which sometimes even took place in the same room [12,14] . In a confi dential situation, like in our study, it is possible that adolescents are more likely to under-report their weight.…”

“…Upon the usefulness of self-reported data diff erent conclusions are drawn. In many of the reviewed studies self-report was followed almost directly by an actual measurement, with subjects being aware of this procedure [5,9,12,14,17] . Th is might well have infl uenced the accuracy of the selfreported data and the conclusions drawn from these studies might not be valid for monitor systems which rely solely on self-report data.…”