Agreement Between Actual and Perceived Body Weight in Adolescents and Their Weight Control Behaviors

To investigate the agreements between actual and perceived body weight status among adolescents and to identify the associations of disagreements with their weight control behaviors.

This study used the secondary data of a sample survey (n=13,871) of the Seoul Student Health Examination among middle and high schools in 2010. Agreements between actual (underweight, normal, overweight, and obese, according to 2007 Korean National Growth Charts) and perceived body weight status (underweight, normal, overweight, and obese) were examined using Chi-square and Cohen's kappa agreement, and then multinomial logistic regression including gender, grade, and attempt of weight control or method of weight control was done.

Agreements between actual and perceived body weight status were only 45.2%, and disagreements were up to 54.8%, including mild over- (20.4%), severe over- (1.8%), mild under- (29.5%), and severe under-estimation (3.1%). The kappa coefficient of agreement was only 0.19. The odds ratios on severe over-estimated perception were 1.59 (95% CI, 1.22-2.07) in female subjects, 1.78 (95% CI, 1.36-2.34) in diet control behaviors, and 1.53 (95% CI, 1.18-2.00) in exercise. The odds ratios on severe under-estimated perception were only 0.40 (95% CI, 0.32-0.50) in female subjects but 5.77 (95% CI, 3.68-9.06) in taking medication.

There were associations of body weight control behaviors with disagreements of actual and perceived weight status. Therefore, further study is needed to identify the weight disagreement-related factors and to promote the desired weight control behaviors for adolescents.