The role of individual and contextual economic factors in obesity among adolescents: A cross-sectional study including 143160 participants from 41 countries

Background To our knowledge, no previous study has examined the role of index of economic freedom (IEF) in the prevalence of excess weight and obesity in adolescents. The aim of this study was to determine the association between both individual and contextual economic factors and the prevalence of overweight and obesity (i.e. excess weight) or obesity in adolescents from different countries. Methods A cross-sectional study was carried out using data from the 2017/2018 wave of the Health Behaviour School-Aged Children study. Body mass index z-score was determined following the International Obesity Task Force criteria and, subsequently, excess weight and obesity were computed. The Family Affluence Scale was used to assess socioeconomic status. The index of IEF was used to estimate the benefits of economic freedom, both for individuals and for society as a whole. Results An inverse association was shown between socioeconomic status (SES) and excess weight or obesity, with adolescents with high SES and medium SES being less likely to have excess weight compared to adolescents with low SES (medium SES: odds ratio (OR)=0.79; 95% confidence interval (CI)=0.77–0.82, P<0.001; high SES: OR=0.65; 95% CI=0.62–0.68, P<0.001). For obesity, lower odds were also found for adolescents with medium SES (medium SES: OR=0.74; 95% CI=0.69–0.80, P<0.001) or high SES (high SES: OR=0.55; 95% CI=0.49–0.61, P<0.001), in comparison with their counterparts with low SES. On the other hand, it was observed a lower likelihood of having excess weight and obesity in mostly unfree countries (excess weight: OR=0.72; 95% CI=0.51–1.00, P=0.052; obesity: OR=0.60; 95% CI=0.39–0.92, P=0.019) compared to free/mostly free countries. These results remained significant after adjusting for several sociodemographic and lifestyle covariates. Conclusions Both individual and contextual factors seem to have a crucial role in the prevalence of excess weight and obesity in adolescents.