Recent trends in overweight and obesity in adolescents aged 12 to 15 years across 21 countries

Background There is limited information on recent country-specific trends in the prevalence of overweight and obesity in adolescents. Objective We aimed to identify country-specific trends in overweight and obesity in a study of 137 995 adolescents aged 12 to 15 years from 21 countries based on Global School-Based Student Health Surveys from 2005 to 2017. Methods The World Health Organization criteria were used to define paediatric overweight and obesity. The weighted country-specific prevalence of and trends in overweight and obesity across the survey years were evaluated. Random- or fixed-effect meta-analyses were used to calculate pooled trends across 21 countries. Results A significant upward trend was observed in the prevalence of overweight and obesity in 10 countries, whereas a significant downward trend was observed in 2 countries (p(s) < 0.05). The pooled prevalence of overweight and obesity in the first and last surveys was 24.8% and 27.7%, respectively. A significant upward pooled trend was observed in the prevalence of overweight and obesity across 21 countries (odds ratios [95% confidence intervals]: 1.22 [1.11, 1.35]). An increasing trend in the prevalence of overweight and obesity was specifically observed in high-, upper-middle- and lower-middle-income countries. Conclusion This study confirms a significant upward trend in the prevalence of overweight and obesity in 12- to 15-year-old adolescents, thus emphasizing the urgent need for interventions to mitigate overweight and obesity in this demographic.