Development of a BMI-Assigned Stunkard Scale for the Evaluation of Body Image Perception Based on Data of the SOS Reference Study

Abstract

Introduction: Stunkard’s figure rating scale is a widely used tool to assess weight status and, more recently, body image perception in people with obesity. However, large population-based studies on Europeans linking this scale’s silhouettes with measured BMI values are lacking. Therefore, we used measured weight and height data from the Swedish Obese Subjects (SOS) reference cohort to assign a mean BMI to each of the 9 Stunkard Scale silhouettes and to define silhouette cutoff values for categorizing people with obesity and overweight. Methods: A total of 1,128 participants from the SOS reference cohort were included (54% females, BMI = 25.2 [ranging from 17.6 to 45.4] ±3.8 kg/m2, and age = 50 [ranging from 36 to 62] ±7 years [means ± standard deviation]). Patients estimated their own body size by choosing a silhouette of the Stunkard Scale. A mean BMI, based on measured weight and height, was assigned to each male and female silhouette of the Stunkard Scale. Measured BMI values were compared with BMI values calculated by simple linear regression analysis. ROC analysis was used to test accuracy of discrimination and the Youden index to assess optimal cutoff. Results: Figure ratings and BMI were strongly correlated in men, r (518) = 0.76, p < 0.001 and women, r (606) = 0.80, p < 0.001. Silhouette selection significantly predicted BMI values in men, β = 16.03, t (518) = 25.30, p < 0.001, and women, β = 12.06, t (606) = 32.98, p < 0.001, and explained a significant proportion of variance in BMI values in men, R2 = 0.55, F (1, 518) = 639.98, p < 0.001, and women, R2 = 0.64, F (1, 606) = 1,087.88, p < 0.001. ROC curve analyses resulted in an optimal cutoff value of 6 for identifying people with obesity and 5 for overweight. Conclusion: Stunkard’s figure rating scale can be used with confidence to assess weight status. Silhouette selection accurately classifies subjects as overweight or obese.

Keywords

• body image perception
• figure rating scale
• stunkard scale