How Prevalent Is Extremely Severe Obesity Among U.S. Children and Adolescents, and What Are Its Health Consequences?

Short Summary

This nationally representative study analyzed 25,847 U.S. children and adolescents from NHANES (2008–2023) to assess extremely severe obesity (BMI ≥160% of the 95th percentile). Prevalence rose from 0.32% in 2008 to 1.13% in 2023, a 253% increase, peaking among adolescents (1.99%) and non-Hispanic Black youth (2.04%). Extremely severe obesity was strongly linked to metabolic complications: MASLD (OR 6.74), prediabetes/diabetes (OR 4.94), severe insulin resistance (OR 8.05), and metabolic syndrome (OR 1.99). These findings highlight urgent public health needs.

The Policy Scientist’s Perspective

Childhood obesity is a critical policy challenge with far-reaching health and economic consequences. This article makes a useful contribution by documenting the prevalence of extremely severe obesity and associated metabolic risks, a focus often missing from broader obesity research. The NHANES data are high quality for descriptive purposes, but the reliance on cross-sectional regression means the study identifies associations rather than causal effects, and important controls—such as socioeconomic status, food environment, and health-care access—are limited. Published in JAMA Pediatrics, it is credible and consistent with prior research. The findings underscore the need for prevention policies emphasizing early intervention, access to healthy foods, and equitable health-care delivery, while future longitudinal and causal inference research could better guide targeted solutions.

Full Citation and Link to Article

Münte, E., Zhang, X., Khurana, A., & Hartmann, P. (2025). Prevalence of extremely severe obesity and metabolic dysfunction among US children and adolescents. JAMA Network Open, 8(7), e2521170. https://doi.org/10.1001/jamanetworkopen.2025.21170

Extended Summary

Central Research Question

The study investigates how prevalent extremely severe pediatric obesity has become in the U.S. between 2008 and 2023 and whether this condition is associated with heightened risks of metabolic and cardiovascular complications compared with lower obesity classes or no obesity. The authors specifically focus on class 4 (BMI ≥160% to <180% of the 95th percentile) and class 5 (BMI ≥180% of the 95th percentile) obesity among children and adolescents.

Previous Literature

Childhood obesity rates have been rising globally, with the World Health Organization noting that over 390 million individuals aged 5 to 19 were overweight or obese in 2022. U.S. classifications traditionally stop at severe obesity (classes 2 and 3), but little evidence exists on the prevalence and implications of extremely severe obesity. Prior work has already linked childhood obesity with metabolic dysfunction–associated steatotic liver disease (MASLD), type 2 diabetes, hypertension, and dyslipidemia, but few studies have stratified these risks by obesity severity. Some research highlights racial and ethnic disparities, showing higher prevalence among non-Hispanic Black and Hispanic children, but the relationship between extreme obesity and comorbidities had not been systematically examined at the national level until this study.

Data

The analysis used National Health and Nutrition Examination Survey (NHANES) data from 2008 to 2023. This nationally representative dataset included 25,847 children aged 2–18 years. Participants underwent physical exams, laboratory tests, imaging studies, and completed questionnaires. Data included BMI, liver imaging (FibroScan), fasting glucose and insulin levels, lipid profiles, and blood pressure. Self-reported race and ethnicity were included to examine disparities, with groups categorized as Mexican American, non-Hispanic Black, non-Hispanic White, Other Hispanic, and multiracial/other race.

Methods

Obesity was classified by BMI relative to the age- and sex-specific 95th percentile: class 1 (≥95th to <120%), class 2 (≥120% to <140%), class 3 (≥140% to <160%), class 4 (≥160% to <180%), and class 5 (≥180%). The primary outcomes were prevalence trends of obesity classes and associations with comorbidities: MASLD, prediabetes/diabetes, insulin resistance, and metabolic syndrome. Logistic regressions adjusted for demographics were used to estimate odds ratios. Noninvasive measures such as FibroScan assessed liver steatosis and fibrosis. The study followed STROBE guidelines for cross-sectional studies.

Findings/Size Effects

The prevalence of pediatric obesity increased across all categories, with extremely severe obesity rising most sharply: from 0.32% in 2008 to 1.13% in 2023—a 253% increase. Overall obesity reached 22.5% in 2023. Extremely severe obesity was more common among adolescents (16–18 years, 1.99%) and non-Hispanic Black participants (2.04%). Logistic regression showed significantly higher risks for metabolic dysfunction:

• MASLD: 84.6% prevalence among extremely severe obesity vs. 44.5% (classes 1–3) and 2.8% (no obesity). Odds ratio (OR) 6.74 compared to classes 1–3.

• Advanced liver fibrosis: 23.1% prevalence in classes 4–5 vs. 2.9% in classes 1–3. OR 10.0.

• Prediabetes/Diabetes: 46.8% prevalence vs. 15.1% in classes 1–3 and 6.0% with no obesity. OR 4.94.

• Severe insulin resistance: 40.6% prevalence vs. 7.8% in classes 1–3. OR 8.05.

• Metabolic syndrome: 53.8% prevalence vs. 36.9% in classes 1–3 and 4.4% in no obesity. OR 1.99.

Biomarkers supported these associations: children with extreme obesity had higher HbA1c (median 5.6% vs. 5.3%), fasting insulin (median 43.4 μIU/mL vs. 21.8), HOMA-IR (median 10.2 vs. 5.3), larger waist circumference (median 124.2 cm vs. 88.1), lower HDL cholesterol (41 vs. 54 mg/dL), and higher blood pressure and C-reactive protein levels than peers. Notably, 100% of class 4–5 participants met insulin resistance thresholds.

Conclusion

This study documents a sharp rise in extremely severe obesity among U.S. children and adolescents, particularly in older teens and non-Hispanic Black youth, with dramatic increases in related metabolic and cardiovascular complications. The findings underscore the urgency of early interventions to reduce obesity prevalence, address disparities, and manage comorbidities. Policy recommendations include targeted prevention, education, and equitable access to effective treatments—including prioritization of scarce weight loss medications like GLP-1 receptor agonists for this highest-risk group. Future research should use longitudinal and interventional designs to better understand long-term outcomes and test targeted therapies.