Prevalence of Extremely Severe Obesity and Metabolic Dysfunction Among US Children and Adolescents

Abstract

Importance: Pediatric obesity is associated with complications such as metabolic dysfunction-associated steatotic liver disease (MASLD), type 2 diabetes, dyslipidemia, and hypertension. However, data on the prevalence of extremely severe obesity in childhood and adolescence and its associated complications are lacking.

Objective: To assess trends in pediatric obesity over time and to investigate the association between obesity degree and comorbidities.

Design, setting, and participants: This cross-sectional study included data from nationally representative samples of pediatric participants aged 2 to 18 years from the National Health and Nutrition Examination Survey (NHANES) from 2008 through 2023. NHANES is a US cross-sectional survey assessing health and nutrition through questionnaires, physical examinations, and laboratory tests.

Exposure: Pediatric obesity, classified as follows: traditional classes 1 to 3 obesity (body mass index [BMI] ≥95th percentile to <160% of the 95th percentile) and extremely severe obesity, comprising class 4 (BMI ≥160% to <180% of 95th percentile) and class 5 (BMI ≥180% of 95th percentile) obesity.

Main outcomes and measures: The main outcomes were national trends in prevalence of obesity classes in childhood and adolescence, stratified by gender, age, and ethnicity and race, and odds of conditions of metabolic dysfunction in each obesity group.

Results: The cohort included 25 847 participants (51% male) with a median age of 10.0 (IQR, 6.00-15.0) years. From 2008 to 2023, the prevalence of pediatric obesity increased, with the highest relative increase of 253.1% observed for extremely severe obesity from 0.32% (95% CI, 0.17%-0.59%) in 2008 to 1.13% (95% CI, 0.78%-1.65%) in 2023. From 2020 to 2023, extremely severe obesity was particularly prevalent among adolescents aged 16 to 18 years (1.99%; 95% CI, 1.31%-2.99%) and non-Hispanic Black participants (2.04%; 95% CI, 1.45%-2.86%). Compared with milder forms of obesity, extremely severe obesity was associated with higher odds of metabolic complications, including MASLD (odds ratio [OR], 6.74; 95% CI, 3.30-15.75), prediabetes or diabetes (OR, 4.94; 95% CI, 3.41-7.14), severe insulin resistance (OR, 8.05; 95% CI, 3.70-17.02), and metabolic syndrome (OR, 1.99; 95% CI, 1.45-2.73).

Conclusions and relevance: In this nationally representative cross-sectional study of US children and adolescents, prevalence of extremely severe obesity significantly increased over time, particularly among older adolescents and non-Hispanic Black participants. Extremely severe obesity was associated with severe metabolic and cardiovascular complications, including MASLD, prediabetes or diabetes, severe insulin resistance, and metabolic syndrome. These findings emphasize the urgent need for public health interventions and policies to address pediatric obesity broadly.

Figure 1.. Prevalence of Pediatric Obesity From 2008 to 2023 Among 25 847 Individuals

Adjusted P values after Holm correction are shown.

Figure 2.. Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD) and Advanced Liver Fibrosis in Children With Extremely Severe Obesity

Adjusted P < .001 for all comparisons after Holm correction in A, B, D, and E and for fibrosis stage 2 or higher in C. A-C, Whiskers indicate 95% CIs. D and E, The box extends from the 25th to 75th percentile, with the center line indicating the median; the bottom whiskers indicate the minimum value of the data that is within 1.5 times the IQR under the 25th percentile, and the top whiskers indicate the maximum value of the data that is within 1.5 times the IQR over the 75th percentile. CAP indicates controlled attenuation parameter.

Figure 3.. Prediabetes, Diabetes, and Severe Insulin Resistance in Children With Extremely Severe Obesity

Adjusted P < .001 for all comparisons after Holm correction. A, E, Whiskers indicate 95% CIs. B-D, The box extends from the 25th to 75th percentile, with the center line indicating the median; the bottom whiskers indicate the minimum value of the data that is within 1.5 times the IQR under the 25th percentile, and the top whiskers indicate the maximum value of the data that is within 1.5 times the IQR over the 75th percentile. HbA_1c indicates glycated hemoglobin; HOMA-IR, Homeostatic Model Assessment of Insulin Resistance (calculated as [fasting insulin (μIU/mL) × fasting glucose (mg/dL)]/405).

Figure 4.. Other Cardiometabolic Risk Factors, Including Metabolic Syndrome, in Children With Extremely Severe Obesity

Adjusted P < .001 for all comparisons after Holm correction. A, Whiskers indicate 95% CIs. B-D, The box extends from the 25th to 75th percentile, with the center line indicating the median; the bottom whiskers indicate the minimum value of the data that is within 1.5 times the IQR under the 25th percentile, and the top whiskers indicate the maximum value of the data that is within 1.5 times the IQR over the 75th percentile. To convert C-reactive protein (CRP) to mg/L, multiply by 10; high-density lipoprotein (HDL) cholesterol to mmol/L, multiply by 0.0259.