Cross-national time trends in adolescent body weight perception and the explanatory role of overweight/obesity prevalence

Introduction Body weight perception (BWP) is associated with health behaviors. Current evidence points to an increase over time in both actual and perceived weight status among adolescents, however there is limited evidence on time trends in BWP in cross-national samples of adolescents. Therefore, the aims of this study were to examine time trends in BWP between 2002 and 2018 among adolescents from 41 countries and regions, including gender and country differences and to explore the role of changes over time in country-level overweight/obesity prevalence in these trends. Methods Data were used from five cycles (2002, 2006, 2010, 2014, 2018) of the repeated cross-sectional Health Behavior in School-Aged Children (HBSC) study (n = 746,121; mean±standard deviation age 13.7 ± 1.6 years, 51.0% girls). Multilevel logistic models estimated cross-national linear time trends in adolescent BWP (correct perception, underestimation, or overestimation), adjusted for gender, age, and family affluence. Next, we tested whether country-level changes over time overweight/obesity prevalence could explain these trends in BWP among adolescents. Results Correct weight perception increased over time among girls, while it decreased among boys. Underestimation of weight status increased, and overestimation of weight status decreased over time among both genders, with stronger trends for girls. Furthermore, country differences in trends in both BWP and overweight/obesity were found. Changes over time in country-level overweight/obesity prevalence could not explain these trends. Conclusion The linear increase over time in correct weight perception and the decrease in overestimation may have a positive effect on unhealthy weight reduction behaviors among adolescents. However, the increase in underestimation could signal a need for interventions to strengthen correct weight perception among adolescents. Several implications for policy and practice are discussed.