Editor’s Note: Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most common chronic liver disease in children aged 2 to 19, affecting approximately 1 in 10 children. Recently, a research team led by Dr. Jeffrey B. Schwimmer from the University of California, San Diego School of Medicine and Rady Children's Hospital, San Diego, published a systematic review examining the effects of exercise interventions on MASLD in children. The study aims to assess the impact of exercise on pediatric MASLD and provide scientific evidence to guide clinical management.The Growing Burden of MASLD in Children
The prevalence of MASLD is significantly higher among children with obesity, affecting about one in four obese children. The condition is more common in boys than in girls and more prevalent among adolescents compared to younger children. Additionally, there are notable racial and ethnic differences, with the highest prevalence observed in children from South America and Asia.
MASLD encompasses a spectrum of disease severity, ranging from simple steatosis (fat accumulation in the liver) to metabolic dysfunction-associated steatohepatitis (MASH), which can progress to serious liver complications such as cirrhosis and hepatocellular carcinoma. Beyond liver-related complications, MASLD is also linked to metabolic and cardiovascular diseases, including type 2 diabetes. Given these risks, developing evidence-based interventions for MASLD is crucial.
The Role of Exercise in MASLD Management
Currently, in the absence of approved pharmacological treatments, lifestyle modifications—primarily dietary improvements and increased physical activity—are the cornerstone of MASLD management. While studies have shown that lifestyle interventions aimed at weight loss can modestly reduce liver fat content and alanine aminotransferase (ALT) levels in children with MASLD, the specific effects of exercise as a standalone treatment remain unclear.
A major challenge in understanding the impact of exercise on MASLD is that most studies combine exercise with broader lifestyle interventions, making it difficult to isolate its independent effects. Furthermore, existing studies vary significantly in terms of exercise type, frequency, intensity, and duration, making it challenging to establish standardized exercise recommendations for MASLD patients.
Systematic Review of Exercise Interventions for Pediatric MASLD
To address these gaps, Dr. Jeffrey B. Schwimmer’s team conducted a comprehensive systematic review to evaluate the impact of exercise interventions on liver health in children diagnosed with MASLD or at high risk due to overweight or obesity. The review aimed to consolidate current evidence and identify areas requiring further research.
The researchers systematically searched multiple databases, including CENTRAL, PubMed, Embase, Web of Science, CINAHL, and Google Scholar, on June 5–6, 2023, and updated the search on August 8, 2024. Eligible studies included English-language research on children aged 0 to 19 diagnosed with MASLD or at high risk due to excess weight, specifically evaluating the effects of exercise interventions on liver fat accumulation or liver-related biomarkers. The risk of bias was assessed using the RoB2 and ROBINS-I tools, and data extraction was performed independently by two reviewers.
After screening 1,578 unique records, 16 studies with a total of 998 children were included in the final analysis. The studies consisted of:
- 7 studies comparing exercise interventions with non-exercise control groups
- 3 uncontrolled exercise intervention studies
- 2 studies comparing exercise plus lifestyle intervention with lifestyle intervention alone
- 9 studies comparing different types of exercise interventions
Among the 11 studies that assessed liver fat content, 5 reported absolute reductions of 1% to 3%. However, among the 9 studies that evaluated liver enzyme levels, no significant changes were observed.
Expert Insights
Dr. Jeffrey B. Schwimmer: “Currently, the evidence supporting exercise as a treatment for pediatric MASLD remains limited, and methodological challenges persist in existing studies. There is an urgent need for high-quality future research to establish clear, evidence-based exercise guidelines for effective MASLD management.”
As our understanding of pediatric MASLD continues to evolve, future research should focus on identifying the most effective exercise parameters, including the optimal type, frequency, intensity, and duration. These insights will be crucial in shaping clinical practice and providing more targeted recommendations for MASLD management. Additionally, increasing public awareness and educating parents and children about MASLD and its prevention strategies will be key in reducing its prevalence.
