biostudies-literatureUnknown13Zhang X<h4>Objective</h4>Air pollution is a major environmental risk to human health, with increasing evidence linking it to non-alcoholic fatty liver disease (NAFLD). However, findings remain inconsistent. This meta-analysis aimed to assess the relationship between air pollutants and the risk of NAFLD.<h4>Methods</h4>PubMed, Embase, and Web of Science were systematically searched for studies published up to March 20, 2025. A random effects model was used to estimate combined odds ratios (ORs) and 95% confidence intervals (95% CIs). Subgroup analysis, sensitivity analysis, funnel plots, and Egger's test were conducted.<h4>Results</h4>A total of 12 studies, including 49,549,903 participants (published between 2022 and 2024), were analyzed. For each 10 μg/m3 increase in pollutants, the ORs were 1.22 (1.16-1.29) for particulate matter with aerodynamic diameter ≤ 2.5 μm (PM_2.5), 1.15 (0.95-1.40) for particulate matter between 2.5 and 10 μm in aerodynamic diameter (PM_{2.5 - 10}), and 1.07 (1.01-1.13) for particulate matter with aerodynamic diameter ≤ 10 μm (PM₁₀). For gaseous pollutants, the ORs were 1.45 (0.92-2.28) for sulfur dioxide (SO₂) and 1.10 (1.06-1.14) for nitrogen dioxide (NO₂). No notable connection emerged between ozone (O₃) or carbon monoxide (CO) and NAFLD. Subgroup analysis revealed stronger associations for PM_2.5, PM₁₀, and NO₂ with NAFLD in developed countries, Europe, and cohort studies, compared to developing countries, Asia, and cross-sectional studies.<h4>Conclusion</h4>This analysis supports a positive relationship between air pollution and NAFLD risk. Geographic region and economic development appear to moderate this association.<h4>Systematic review registration</h4>https://www.crd.york.ac.uk/PROSPERO/view/CRD42024594146, Identifier: CRD42024594146.Frontiers in public health1606959https://www.ebi.ac.uk/biostudies/studies/S-EPMC12401902biostudies-literatureAssociation between air pollution and risk of non-alcoholic fatty liver disease: an updated meta-analysis.PMC12401902Yang XTan LLi XRu SZhang XHu LChai YfalseAssociation between air pollution and risk of non-alcoholic fatty liver disease: an updated meta-analysis.<h4>Objective</h4>Air pollution is a major environmental risk to human health, with increasing evidence linking it to non-alcoholic fatty liver disease (NAFLD). However, findings remain inconsistent. This meta-analysis aimed to assess the relationship between air pollutants and the risk of NAFLD.<h4>Methods</h4>PubMed, Embase, and Web of Science were systematically searched for studies published up to March 20, 2025. A random effects model was used to estimate combined odds ratios (ORs) and 95% confidence intervals (95% CIs). Subgroup analysis, sensitivity analysis, funnel plots, and Egger's test were conducted.<h4>Results</h4>A total of 12 studies, including 49,549,903 participants (published between 2022 and 2024), were analyzed. For each 10 μg/m3 increase in pollutants, the ORs were 1.22 (1.16-1.29) for particulate matter with aerodynamic diameter ≤ 2.5 μm (PM_2.5), 1.15 (0.95-1.40) for particulate matter between 2.5 and 10 μm in aerodynamic diameter (PM_{2.5 - 10}), and 1.07 (1.01-1.13) for particulate matter with aerodynamic diameter ≤ 10 μm (PM₁₀). For gaseous pollutants, the ORs were 1.45 (0.92-2.28) for sulfur dioxide (SO₂) and 1.10 (1.06-1.14) for nitrogen dioxide (NO₂). No notable connection emerged between ozone (O₃) or carbon monoxide (CO) and NAFLD. Subgroup analysis revealed stronger associations for PM_2.5, PM₁₀, and NO₂ with NAFLD in developed countries, Europe, and cohort studies, compared to developing countries, Asia, and cross-sectional studies.<h4>Conclusion</h4>This analysis supports a positive relationship between air pollution and NAFLD risk. Geographic region and economic development appear to moderate this association.<h4>Systematic review registration</h4>https://www.crd.york.ac.uk/PROSPERO/view/CRD42024594146, Identifier: CRD42024594146.2025-01-01T00:00:00Z20252026-05-29T21:28:53.957Z2026-04-08T06:02:02.963ZS-EPMC124019024090492210.3389/fpubh.2025.1606959