Global trends, projections, and inequalities in overweight and obesity among children and adolescents from 1990 to 2040: a modelling study

Abstract

Background: Evidence remains limited regarding how childhood and adolescent overweight and obesity have evolved across countries at different levels of economic development and how these patterns may change in the future. We therefore characterised global trends from 1990 to 2022, generated projections to 2040, and examined changes in absolute and relative GDP-related inequalities. Methods: We analysed NCD-RisC prevalence estimates for children and adolescents aged 5–19 years in 200 countries and territories. Joinpoint regression was used to assess temporal trends and estimate average annual percentage changes (AAPCs) in prevalence. Bayesian age-period-cohort models were used to project prevalence to 2040. Population-weighted slope index of inequality (SII) and relative concentration index (RCI) were used to quantify absolute and relative inequalities across countries ranked by gross domestic product (GDP). Results: Between 1990 and 2022, global overweight prevalence among children and adolescents approximately doubled, from 5.76% to 11.50%, with an AAPC of 2.18%, whereas obesity prevalence increased more than fourfold, from 1.93% to 8.22%, with an AAPC of 4.62%. By 2040, overweight and obesity prevalence are projected to reach 15.68% and 13.57%, respectively, with corresponding AAPCs of 1.66% and 2.76% during 2023–2040. From 1990 to 2040, overweight and obesity rates rose across all income groups, fastest in low- and middle-income countries and slower in high-income countries (HICs). SII estimates show that overweight disparities between lower- and higher-income countries declined from 15.27% in 1990 to 12.81% in 2022, and then to 9.32% by 2040, while obesity disparities increased from 6.71% to 13.80%, and then to 12.30%. The RCI declined for both outcomes, indicating a reduction in their relative concentration in higher-income countries over time. Conclusions: The global burden of overweight and obesity rose substantially from 1990 to 2022 and is projected to continue increasing through 2040, with the fastest projected growth in low- and middle-income countries and slower growth in HICs. Although the burdens of overweight and obesity remain disproportionately concentrated in higher-income countries, the degree of relative health inequality has gradually diminished over time.