1 Social Determinants of Health Research Center, Qazvin University of Medical Sciences, Qazvin, Iran.

2 Children Growth Research Center, Qazvin University of Medical Sciences, Qazvin, Iran.

3 Department of Rehabilitation Sciences, Faculty of Health and Social Sciences, Hong Kong Polytechnic University, Hung Hom, Hong Kong.

4 Department of Physical Education, Imam Khomeini International University: Qazvin 34149-16818, Iran.

5 5Department of Community Nutrition, National Nutrition and Food Technology Research Institute, Faculty of Nutrition and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran.


Background: Identifying and investigating the factors influencing self-efficacy and eventually health related quality of life (HRQoL) can be an important step toward the prevention and treatment of the obesity. The aim of the study was to compare weight self-efficacy and HRQoL among normal-weight, overweight and obese Iranian adolescents.
Materials and Methods
In this case-control study, 118 obese and overweight adolescents (case group) and 118 adolescents with normal weight (control group) were recruited. Adolescent's anthropometric characteristics were measured. The Weight Efficacy Lifestyle Questionnaire (WEL), pediatric quality of life inventory (PedsQLTM 4.0) and self-reported physical activity were completed by the adolescents.
Results: Multivariate logistic regression adjusting for various confounders indicated that overweight and obese adolescents were less likely to be physically active (adjusted odds ratio, AOR= 0.66; 95% confidence interval [CI], 0.48 to 0.911), had lower ability to cope with social pressure (AOR= 0.54; 95% CI, 0.32 to 0.93), involved in less positive activities (AOR= 0.53; 95% CI, 0.37 to 0.75), and felt more negative emotions (AOR= 0.23; 95% CI, 0.14 to 0.36) than their normal-weight counterparts. Moreover, obese and overweight adolescents were more likely to report deteriorated quality of life in all PedsQL subscales than those with normal weight P<0.05). The results of the mediation analysis indicated that negative emotions mediated the relationship between adolescents’ weight status and HRQoL (Z =-5.79, P<0.001). 
Conclusion: Weight management programs should focus on increasing adolescent’s control on situations related to negative emotions to improve their HRQoL.