The Study
Shift work and metabolic dysfunction-associated steatotic liver disease: a systematic review of observational studies
This study looked at lots of other studies and found that people who work nights or weird hours seem to have more fatty liver problems — but it doesn’t prove that night work causes it. It’s like noticing that people who eat a lot of candy also get more cavities — maybe candy causes cavities, or maybe they just don’t brush their teeth well. We can’t be sure yet.
Analysis score
Maximum 100 for a systematic review.
Where the score came from
Working nights messes up your body’s internal clock, which can make your liver store too much fat. This is more likely if you work nights often, are young, or stay up late by choice.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 552 / 100
Quality score
Systematic reviews and meta-analyses of cohort studies. They sit above a single cohort study but below a single randomized trial, because the underlying evidence is still observational.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes—this means night workers, especially young women and night owls, should watch their liver health closely.
- 2Shift workers have 20-30% higher risk of fatty liver; those working >3 night shifts a week have 17-18% higher risk than others.
- 3Weight gain explains about one-third of this risk.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
International Archives of Occupational and Environmental Health
Year
2025
Authors
Bingya Ma, Yihang Fan, W. Fan
Related Content
Claims (6)
People who work nights or irregular shifts are more likely to develop a fatty liver condition, especially if they do it for a long time or often — this might be because their body’s internal clock gets messed up.
People in their 20s, especially women who work nights or irregular hours, might be more likely to develop a fatty liver condition than older workers, because their bodies may react more strongly to disrupted sleep schedules.
Working irregular hours or not sleeping well can mess up your body’s internal clock, which in turn hurts your metabolism and liver — making it harder for your body to process food and stay healthy.
People who work nights more than three times a week are more likely to develop a type of liver fat buildup than those who rarely or never work nights — and the more nights they work, the higher the risk.
People who naturally stay up late might be more likely to develop a fatty liver if they work night shifts or irregular hours, because their body clock doesn’t match their work schedule.
People who work irregular shifts tend to gain weight, and that extra weight explains about a third of why they’re more likely to have fat in their liver—but other factors also play a role.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.