The Global Spread of Severe Obesity in Toddlers, Children, and Adolescents: A Systematic Review and Meta-Analysis

Introduction: Severe obesity among children and adolescents has emerged as a public health concern in multiple places around the world. Methods: We searched the Medline database for articles on severe obesity rates in children published between January 1960 and January 2020. For studies with available prevalence rates for an early and a more recent time period, the relative increase in prevalence was imputed. Results: In total, 874 publications were identified, of which 38 contained relevant epidemiological data. Rates of severe obesity varied significantly according to age, gender, geographic area, and the definition of severe obesity. The highest rates of class II and III obesity in the USA according to the Centers of Disease Control cut-off were 9.5% and 4.5%, respectively. Seventeen studies reported prevalence rates in at least two time periods. Data for 9,190,718 individuals showed a 1.71 (95% CI, 1.53-1.90) greater odds for severe obesity in 2006-2017 (N = 5,029,584) versus 1967-2007 (N = 4,161,134). In an analysis limited to studies from 1980s with a minimum follow-up of 20 years, a 9.16 (95% CI, 7.76-10.80) greater odds for severe obesity in recent versus earlier time was found. An analysis limited to studies from 2000, with a follow-up of 5-15 years, a 1.09 (95% CI, 0.99-1.20) greater odds was noted when comparing (2011-2017; N = 4,991,831) versus (2000-2011; N = 4,134,340). Conclusion: Severe pediatric obesity is escalating with a marked increase from the 1980s and a slower rate from 2000.