Reliability and validity of body weight and body image perception in children and adolescents from the South American Youth/Child Cardiovascular and Environmental (SAYCARE) Study

Abstract

ObjectiveTo assess the reliability and validity of body weight (BW) and body image (BI) perception reported by parents (in children) and by adolescents in a South American population.DesignCross-sectional study. BW perception was evaluated by the question, ‘Do you think you/your child are/is: severely wasted, wasted, normal weight, overweight, obese?’ BI perception was evaluated using the Gardner scale. To evaluate reliability, BW and BI perceptions were reported twice, two weeks apart. To evaluate validity, the BW and BI perceptions were compared with WHO BMI Z-scores. Kappa and Kendall’s tau-c coefficients were obtained.SettingPublic and private schools and high schools from six countries of South America (Argentina, Peru, Colombia, Uruguay, Chile, Brazil).ParticipantsChildren aged 3–10 years (n 635) and adolescents aged 11–17 years (n 400).ResultsReliability of BW perception was fair in children’s parents (κ=0·337) and substantial in adolescents (κ=0·709). Validity of BW perception was slight in children’s parents (κ=0·176) and fair in adolescents (κ=0·268). When evaluating BI, most children were perceived by parents as having lower weight. Reliability of BI perception was slight in children’s parents (κ=0·124) and moderate in adolescents (κ=0·599). Validity of BI perception was poor in children’s parents (κ=−0·018) and slight in adolescents (κ=0·023).ConclusionsReliability of BW and BI perceptions was higher in adolescents than in children’s parents. Validity of BW perception was good among the parents of the children and adolescents with underweight and normal weight.

Level of agreement between objectively determined body composition and perceived body image in 6- to 8-year-old South African children: The Body Composition–Isotope Technique study

“…In our study, the consistency of agreement between actual fat ness as assessed using the DDM and perceived body size using silhouettes was very poor (κ = 0.083; p = 0.053), hence the low level of concordance between the silhouettes and the DDM. The validity of the girls' perceived body weight compared with objectively measured body fatness in our study demonstrated a fair agreement, and this finding is different from previous studies on the body weight perceptions of children's parents from Mexico [62] and South America [41]. A study from Chile [63] reported poor concordance between nutritional status, perceived with a seven-figure scale, and real BMI (κ = 0.031, T c = 0.275), and their finding was similar to the one for boys in our study (κ = 0.040, T c = 053).…”

“…The observed poor agreement between BMI category and body size perception measured by silhouettes in our study is similar to the findings of the Youth/Child Cardiovascular and Environmental (SAYCARE) multi-country study, carried out in seven South American cities (Buenos Aires, Lima, Medellín, Montevideo, Santiago, São Paulo, and Teresina) with 1035 children and adolescents aged 3 to 17 years, which reported that the correlation between children's body size self-evaluation outcome and their objectively measured BMI was lower before the age of 8 years [41]. The potential methodological errors associated with using silhouette choice in younger children as a reason for low correlation has been highlighted [62,64].…”

“…Children were not allowed to eat or drink anything apart from the light snack that was provided after completion of the sample collection, but they were permitted to go to the bathroom to void their bladders at any time. At each saliva sampling, the child was given a ball of cotton wool to rotate in the mouth until well soaked; the wet cotton wool was then transferred into a syringe to squeeze out the saliva into a plastic vial that was immediately capped to avoid evaporation [41]. For children who could not wet their cotton wool balls after several attempts, an alternative approach was used; such children were asked to spit directly into the vial.…”

“…In another study by Descamps reported that almost one-third of adolescents misperceived their body weight, with girls being more likely than boys to have body size misperceptions (27.3% of boys vs 42.2% of girls) [39]. Body image in children is frequently determined by figural stimuli such as silhouettes [40,41]. Most of these figure scales show figure contours and avoid showing race characteristics such as hair and skin color, making the instruments reliable, valid, and suitable for use among different ethnic groups [42].…”

Association between body weight misperception and dietary patterns in Brazilian adolescents: Cross-sectional study using ERICA data

“…The ability to compare this prevalence with other Latin American countries is limited, as studies with body image perception or (dis)satisfaction are more common in these countries. In a study carried out in seven South American cities to establish the reliability and validity of instruments to measure body image, researchers found that 15.4% of normal weight adolescents underestimated their weight and 11.5% overestimated their weight [ 70 ]. In other territories, the rates of weight underestimation and overestimation ranged between 12.4% and 27.0% in China [ 71 ], 17.8% and 9.8% in Italy [ 72 ], 22.8% and 15.7% in South Korea [ 9 ], 29.1% and 11.6% in the United States [ 42 ], and 30.8% and 28.4% in Iran [ 39 ].…”