Agreement between self-assessment of body image and measured body mass index in the Brazilian adult population.

ABSTRACT

Silhouettes are used in the self-assessment of one's body size, shape and satisfaction. This technique can be helpful in intervention studies and in household studies in which body size measurements are not feasible. Despite its popularity, few studies have validated the Stunkard Figure Rating Scale (SFRS) to assess body image (BI) or nutritional status (NS). The present study assessed the agreement between self-assessment of BI by SFRS and measured BMI in adults from a national household survey in Brazil (n = 11247; 57.2% women, aged 20-99y). The subjects were asked to choose a silhouette from the SFRS that most resembled their current status prior to measures of body mass and stature. BMI-derived NS was then matched to the SFRS. The prevalence of overweight and obesity (OB) was 34.4 and 19.0%, respectively. Weighted kappa between SFRS and BMI was 0.45 and 0.43 and Spearman's correlation coefficient was 0.64 and 0.59 for women and men, respectively. Sex-specific receiver operating curves indicated that the silhouettes correctly (area under the curve > 0.80) identified OB and underweight (UW). In conclusion, SFRS provides only reasonable results when estimating the BMI distribution but it works well to identify OB and UW in the Brazilian adult population.