Daytime Physical Activity Linked to Lower MAFLD Risk in Adolescents: AJPC Study, December 2025

The Rising Burden of Pediatric Metabolic Liver Disease

Metabolic Dysfunction–Associated Fatty Liver Disease (MAFLD), formerly NAFLD, is a growing global health concern, particularly among adolescents. Its prevalence is estimated at 7.4% worldwide and 8.53% in Asia, with evidence suggesting that pediatric MAFLD often progresses more aggressively than adult disease, leading to earlier fibrosis and cirrhosis. Because pharmacologic treatments for children remain limited and controversial, lifestyle modification, especially achieving 7%–10% weight loss, remains the cornerstone of therapy. Given today’s declining adolescent physical activity levels and rising sedentary behavior, the study used objective wearable device–based activity measurements, rather than imprecise self-reported questionnaires, to investigate the link between physical activity and MAFLD risk in youth.

Study Overview

This cross-sectional study analyzed 5,705 adolescents aged 12–19 years from the NHANES database (3,666 from 2003–2006 and 2,039 from 2011–2014). Physical activity was objectively assessed using wearable accelerometers—ActiGraph AM-7164 worn at the hip (2003–2006) and ActiGraph GT3X+ worn on the wrist (2011–2014)—requiring separate data processing. Activity levels were categorized into quartiles and evaluated for daytime (7 AM–7 PM) and nighttime (8 PM–6 AM) periods. MAFLD was diagnosed per International Expert Consensus using the Hepatic Steatosis Index (HSI > 36) plus criteria for excess adiposity, type 2 diabetes, or metabolic dysfunction. Weighted multivariable logistic regression models, adjusted for age, sex, race, and family income, examined the association between physical activity and MAFLD.

The Key Findings from the Study are:

• The overall prevalence of MAFLD was 22.6% in the 2003–2006 cycle and 20.0% in the 2011–2014 cycle. In the 2003–2006 cycle, higher total physical activity levels were strongly and consistently associated with lower odds of MAFLD.

• A clear dose–response trend was evident across quartiles. Specifically, participants in the highest physical activity quartile (Q4) had 60% lower odds of MAFLD overall compared with the lowest quartile (Q1).

• Both daytime and nighttime activity in Q4 were significantly protective, with daytime activity showing a slightly stronger association.

• Subgroup analysis in the 2003–2006 cycle indicated that females exhibited a stronger inverse relationship between physical activity and MAFLD risk than males. In contrast, the analysis of the 2011–2014 cycle found no significant association between physical activity and MAFLD risk after full adjustment.

Clinical Inference: Focusing Interventions on Daytime Movement

These findings underscore that physical activity remains the cornerstone of pediatric MAFLD management, with daytime activity showing the strongest protective effect. Concentrating exercise between 7 AM and 7 PM may be especially beneficial, likely because nighttime activity can disrupt circadian rhythms and worsen metabolic health. Clinically, pediatric specialists and cardiologists should emphasize daytime movement and high-intensity interventions among adolescents to improve the overall cardio-metabolic health of the youth in the community.

Reference: Wang R, You C, Dong Z, Zheng Q, Zheng X, Zhou L, Wang X, Zhang L, Zhang H. Wearable device–measured physical activity and risk of MAFLD in adolescents. American Journal of Preventive Cardiology. 2025 Nov 3:101345.

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