ORIGINAL RESEARCH article
Front. Public Health
Sec. Occupational Health and Safety
This article is part of the Research TopicTrends in Occupational Health Epidemiology: The Role of Diet, Sleep and Shift Work in Chronic DiseaseView all 19 articles
Association of shift work with metabolic dysfunction-associated fatty liver disease among subway workers
Provisionally accepted
- Wuhan Centre for Disease Prevention and Control, Wuhan, China
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Objective: Inconsistent associations between shift work and metabolic dysfunction-associated fatty liver disease (MAFLD) have been suggested. This study aimed to investigate the association between shift work characteristics and MAFLD in subway workers. Methods: This cross-sectional study was conducted in Wuhan, China, between December 2018 and January 2019, with 9105 subway workers included after excluding participants with missing data on shift work or ultrasonography, with cancer, or with insufficient data to diagnose MAFLD. All participants were on-duty employees, covering various functional positions such as train drivers, station attendants, maintenance technicians, and administrative staff. Information on demographics, occupational history, and lifestyles was collected through standardized questionnaires. We used logistic regression models to estimate the association of shift work duration and types with MAFLD, and restricted cubic spline regression to examine the potential nonlinear relationship. Mediation analyses were employed to evaluate the potential mediating role of body mass index (BMI). Results: Compared with participants with no shift work, the multivariable-adjusted ORs (95% CIs) for those with ≤3, 3-6, and >6 years of shift work were 0.80 (0.68, 0.94), 1.21 (1.04, 1.41), and 1.60 (1.37, 1.88), respectively. A J-shaped relationship between shift work duration and MAFLD (Poverall < 0.001, Pnonlinear = 0.002) was observed, with the likelihood of MAFLD substantially increased after three years of shift work. Compared with participants with no shift work, MAFLD risk increased by 13% (OR:1.13, 95% CI: 0.95, 1.34), 22% (OR: 1.22, 95% CI: 1.05, 1.42), and 21% (OR: 1.21, 95% CI: 1.02, 1.42) for those worked in two-shift, three-shift, and four-shift, respectively. BMI adjustment attenuated these associations, with mediation analyses revealing significant mediation effects: mediation proportion was 48.5% (34.0%, 64.0%) for shift work duration, 42.9% (5.0%, 99.4%) for three-shift, and 47.5% (4.4%, 111.5%) for four-shift systems (all P<0.05). Conclusion: Both shift work duration and rotation systems were associated with MAFLD risk in subway workers, with BMI mediating approximately half of these relationships.
Keywords: Body Mass Index, Cross-sectional study, meidation effect, Metabolic dysfunction-associated fatty liver disease, shift work
Received: 02 Nov 2025; Accepted: 08 Dec 2025.
Copyright: © 2025 Peng, Shi, Liu and He. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Junling Liu
Zhenyu He
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