Obesity drives high rates of chronic disease in US adolescents and young adults

 Key Takeaways: 

• A new JAMA Pediatrics study found obesity is linked to a substantial proportion of chronic health conditions in US adolescents and young adults, with the highest impact seen in liver steatosis and type 2 diabetes.
• Among young adults with obesity, nearly 79% of type 2 diabetes cases were attributable to excess weight, while almost half of adolescent liver steatosis cases were linked to obesity.
• Researchers emphasise the need for early prevention and treatment strategies, including behavioural, surgical, and pharmacological interventions, to mitigate long-term health and economic consequences.
  

Rising prevalence of obesity and chronic disease

The prevalence of obesity among adolescents and young adults in the United States continues to rise and is closely linked with a growing burden of obesity-related conditions (ORCs). A study recently published in JAMA Pediatrics has provided one of the most comprehensive analyses to date, showing that obesity accounts for a substantial share of several chronic health conditions in this population.

Researchers conducted a cross-sectional analysis using pooled data from the National Health and Nutrition Examination Survey (NHANES) between 2013 and 2023. The study population included 4199 adolescents aged 12–17 years and 3200 young adults aged 18–25 years. These participants represented approximately 56 million people nationwide. Individuals who were pregnant or underweight were excluded.

How the study was conducted

Body mass index (BMI) was classified into three categories: normal weight, overweight, and obesity, according to standard clinical definitions. Investigators identified obesity-related conditions using consensus definitions and the data available from NHANES. Conditions examined included:

• Prediabetes and type 2 diabetes
• Hypertension
• Dyslipidaemia
• Asthma
• Stress urinary incontinence
• Liver steatosis
• Kidney hyperfiltration
• Probable obstructive sleep apnoea
  

Relative risks for each condition were calculated by comparing individuals with obesity or overweight to those with normal BMI, while adjusting for factors such as age, sex, insurance status, access to health care, and survey cycle. The researchers then estimated population attributable fractions (PAFs), which indicate the proportion of each condition that could be attributed to overweight or obesity.

Study findings

Among adolescents, 18.7% had overweight and 22.3% had obesity. Among young adults, 25.8% had overweight and 29.7% had obesity. Prevalence of obesity-related conditions varied widely — from 0.3% for type 2 diabetes in adolescents to 36.4% for liver steatosis in young adults.

The analysis showed that obesity made a striking contribution to the overall disease burden:

• Adolescents – Six of seven measured conditions showed significant PAFs due to obesity, ranging from 10.2% for asthma to 49.6% for liver steatosis.
• Young adults – Eight of nine conditions showed significant obesity-attributable fractions, ranging from 10.4% for asthma to 78.9% for type 2 diabetes.
  

Overweight status also contributed to disease burden, though to a lesser extent. For adolescents, PAFs due to overweight ranged from 6.2% for asthma to 13.1% for liver steatosis. In young adults, overweight contributed to 10.0% of hypertension cases and 21.0% of liver steatosis cases.

The study authors concluded: “Large portions of ORCs in US adolescents and young adults may be attributable to obesity and, to a lesser extent, overweight.”

Implications for prevention and treatment

The findings underscore the critical role of obesity in the early development of chronic disease. The researchers highlighted that obesity-related conditions arising in adolescence or young adulthood increase the risk of more severe disease later in life.

They noted: “These PAFs can inform estimates of the potential impact of expanding access to behavioural, surgical, and pharmacotherapeutic interventions, including glucagon-like peptide-1 receptor agonists, on reducing ORCs in US youth.”

Limitations

The study acknowledged several limitations. Its cross-sectional design assumed causality between obesity and obesity-related conditions, which cannot be proven definitively. Reliance on self-reported data introduced the risk of recall bias, and there was a possibility of misclassifying diabetes subtypes. The researchers also noted the potential for confounding factors, such as independent precursors that may contribute to both obesity and associated conditions.

Conclusion

Obesity remains a major driver of chronic disease among adolescents and young adults in the United States. While overweight status contributes to some extent, obesity accounts for much larger proportions of conditions such as liver steatosis, hypertension, and type 2 diabetes.

The authors emphasised that intervening early in life — through prevention and treatment strategies — may reduce both the long-term health impact and the associated economic burden of these conditions.

CCH Insight:

The findings of this study are, in a way, quite shocking – the fact that large numbers of young people have liver disease, prediabetes and hypertension, conditions that were once associated with the later stages of life. However, the rising prevalence of child and adolescent obesity over recent decades means this has been sadly predictable, and it is a ticking time-bomb in terms of chronic diseases, disability, premature mortality and health and social care costs. As the authors stated, it is vital that obesity is addressed from the earliest opportunity, including access to GLP-1 medications.