Development and initial validation of the multifaceted instrument for body image disturbance (MI-BoD)

Specific facets of body image disturbance have an important role in eating disorder (ED) onset and maintenance yet have been assessed with single items and/or questionnaires predominantly developed in female samples to capture desire for a thinner body. The aim of this multipart study was to develop the multifaceted instrument for body image disturbance (MI-BoD) that will assess body image disturbance across gender and body size. In Study 1, interviews were conducted with 31 ED lived experience experts (45% females) to develop an initial item pool which was then rated for relevance and clarity by 59 international field experts, shortened and refined by the research team, and then rerated by 20 field experts and 91 ED lived experience experts. Of the 477 items developed from interviews, 46 were retained for the initial validation study. In Study 2, the MI-BoD was administered to undergraduate students (N = 937; 84% females), community adolescents (N = 208; 58% females), and individuals with self-reported ED diagnosis (N = 410; 77% females) to assess its preliminary psychometric properties. Exploratory factor analysis revealed six underlying factors, namely, Dissatisfaction, Overvaluation, Preoccupation, Fear of Weight Gain, Body Checking, and Body Exposure. No differential item functioning was detected for most MI-BoD items across gender, weight status, and ED status (symptomatic vs. asymptomatic). Overall, the MI-BoD showed good internal consistency, convergent and divergent validity, concurrent validity, and test-retest reliability. In conclusion, the MI-BoD is a promising tool for assessment of important facets of body image disturbance across gender, body size, and ED symptomatology.