Self-perceived body image, dissatisfaction with body weight and nutritional status of Brazilian adolescents: a nationwide study

Objectives: The purpose of this study was to evaluate the agreement and risk factors for underestimation and overestimation between nutritional status and self-perceived body image and to assess the prevalence and associated factors for dissatisfaction with body weight among Brazilian adolescents. Methods: Students aged 12-17 years participating in the Study of Cardiovascular Risk in Adolescents ("ERICA"), a multicenter, cross-sectional, school-based country-wide study, were included (n=71,740). Variables assessed as covariates were sex, age, skin color, socioeconomic status, and common mental disorders (screened by the General Health Questionnaire, GHQ-12). Multinomial logistic regression was used to explore the association between covariates and combinations between self-perceived body image and body mass index (agreement, underestimation and overestimation). The associations between dissatisfaction with body weight and exposure variables were investigated using multivariable Poisson regression models. Results: Approximately 66% students rightly matched their body mass index with self-perceived weight (kappa coefficient was 0.38 for boys and 0.35 for girls). Agreement was higher among younger students and adolescents from low income households. Male sex, older age, and GHQ-12 score >= 3 were associated with weight overestimation. Prevalence of dissatisfaction with body weight was 45.0% (95% CI: 44.0-46.0), and higher among girls, older adolescents, those with underweight or overweight/obesity, as well as those who were physically inactive and with GHQ-12 >= 3. Conclusions: Most of the sample rightly self-perceived their body image according to body mass index. Students with body image misperception and those dissatisfied with their weight were more likely to present a positive screening for common mental disorders. (C) 2018 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda.