Relating body mass index to figural stimuli: population-based normative data for Caucasians

OBJECTIVE: To establish body mass index (BMI) norms for standard figural st imuli using a large Caucasian population-based sample. In addition, we soug ht to determine the effectiveness of the figural stimuli to identify indivi duals as obese or thin. DESIGN: All Caucasian twins born in Virginia between 1915 and 1971 were ide ntified by public birth record. In addition, 3347 individual twins responde d to a letter published in the newsletter of the American Association of Re tired Persons (AARP). All adult twins (aged 18 and over) from both of these sources and their family members were mailed a 16 page 'Health and Lifesty le' questionnaire. SUBJECTS: BMI and silhouette data were available on 16 728 females and 11 3 66 males ranging in age from 18- 100. MEASUREMENTS: Self-report information on height-weight, current body size, desired body size and a discrepancy score using standard figural stimuli. RESULTS: Gender- and age-specific norms are presented linking BMI to each o f the figural stimuli. Additional norms for desired body size and discrepan cy scores are also presented. Receiver operating curves (ROC) indicate that the figural stimuli are effective in classifying individuals as obese or t hin. CONCLUSIONS: With the establishment of these norms, the silhouettes used in standard body image assessment can now be linked to BMI. Differences were observed between women and men in terms of desired body size and discrepanc y scores, with women preferring smaller sizes. The figural stimuli are a ro bust technique for classifying individuals as obese or thin.