Development and validation of the body image scale for youth (BISY)

BACKGROUND: Body dissatisfaction has been known as an important public health concern that can influence the physical and psycho-social health of adolescents. Hence, health professionals need a valid and reliable tool to assess this problem and its related factors in youth. This study aims to develop and assess the psychometric properties of an indigenous scale for the evaluation of body image and to investigate its association with body weight status among Iranian adolescents. METHODS: This study was conducted on 857 adolescents who completed the body image scale for Youth (BISY) and self-reported their body weight and height. Face, content, and construct validity methods were used to assess the validity of the BISY. Exploratory factor analysis (EFA) was used to assess construct validity. Moreover, the internal consistency of the scale was assessed by calculating Cronbach’s alpha coefficient (α), and test–retest reliability was examined using the intra-class correlation coefficient (ICC). To compare the BISY scores across sex and body weight status groups, the Independent samples t-test and the analysis of variance (ANOVA) or Welch tests were used, respectively. RESULTS: Mean age and body mass index (BMI) of participants were 16.5 ± 1.1 years and 22.4 ± 4.5 kg/m(2), respectively. The EFA showed a 10-factor construct which explained 57% of the variance. The Cronbach’s alpha coefficient for overall items of the scale was 0.896 and ranged from 0.42 to 0.92 for subscales. The test–retest reliability result was acceptable for the BISY (ICC = 0.805). The ICC values ranged from 0.753 to 0.990 for BISY subscales. The BISY total score was significantly higher in girls compared to boys (34.8 ± 12.7 vs. 31.3 ± 10.2; p < 0.001). In girls, the BISY total score was significantly lower in normal-weight girls compared to their overweight (p = 0.009), and obese (p = 0.012) counterparts. This difference was not observed in boys. CONCLUSION: These findings support the reliability and validity of the BISY for the assessment of body image in Iranian adolescents; this scale can be applied as an appropriate tool for the assessment of body image in adolescents in related future studies. Current findings highlight considering body image as an important aspect of intervention programs targeting overweight and obesity in adolescents, specifically girls. PLAIN ENGLISH SUMMARY: Negative body image has been known as an important public health concern that can adversely influence different aspects of adolescents’ health. Hence, a valid and reliable tool is necessary to identify adolescents at risk of developing negative body image and its related disorders. There is a lack of an indigenous scale that can comprehensively assess body image and its related factors in Iranian adolescents; hence, the current study aimed to develop and assess the psychometric properties of an indigenous scale for evaluation of body image and further investigate the association between body image and body weight status among Iranian adolescents. The current findings support the reliability and validity of the BISY. In addition, more negative body images were observed in girls compared to boys and in overweight/obese girls compared to their normal-weight counterparts. Therefore, promoting a healthy body image should be incorporated as an important component of future health promotion programs to address obesity, eating disorders, and other health-related concerns among adolescents, specifically girls. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s40337-022-00657-z.