Non-linear association between long-term air pollution exposure and risk of metabolic dysfunction-associated steatotic liver disease

• Published in: Environmental health and preventive medicine Vol. 29; p. 7
• Main Authors: Cheng, Wei-Chun, Wong, Pei-Yi, Wu, Chih-Da, Cheng, Pin-Nan, Lee, Pei-Chen, Li, Chung-Yi
• Format: Journal Article
• Language: English
• Published: Japan Japanese Society for Hygiene 01.01.2024; Komiyama Printing Co. Ltd
• Subjects: air pollutants; Air Pollutants - adverse effects; Air Pollutants - analysis; Air Pollution - adverse effects; Air Pollution - analysis; Cross-Sectional Studies; Environmental Exposure - adverse effects; Environmental Exposure - analysis; epidemiologic study; Humans; Liver Diseases; metabolic dysfunction-associated steatotic liver disease (masld); Nitrogen Dioxide; particular matters; Particulate Matter - adverse effects; Particulate Matter - analysis; restricted cubic spline (rcs); risk factors; Restricted cubic spline (RCS); Particular matters; Epidemiologic study; Air pollutants; Metabolic dysfunction-associated steatotic liver disease (MASLD); Risk factors
• ISSN: 1342-078X; 1347-4715
• DOI: 10.1265/ehpm.23-00271

Metabolic Dysfunction-associated Steatotic Liver Disease (MASLD) has become a global epidemic, and air pollution has been identified as a potential risk factor. This study aims to investigate the non-linear relationship between ambient air pollution and MASLD prevalence. In this cross-sectional study, participants undergoing health checkups were assessed for three-year average air pollution exposure. MASLD diagnosis required hepatic steatosis with at least 1 out of 5 cardiometabolic criteria. A stepwise approach combining data visualization and regression modeling was used to determine the most appropriate link function between each of the six air pollutants and MASLD. A covariate-adjusted six-pollutant model was constructed accordingly. A total of 131,592 participants were included, with 40.6% met the criteria of MASLD. "Threshold link function," "interaction link function," and "restricted cubic spline (RCS) link functions" best-fitted associations between MASLD and PM , PM /CO, and O /SO /NO , respectively. In the six-pollutant model, significant positive associations were observed when pollutant concentrations were over: 34.64 µg/m for PM , 57.93 µg/m for PM , 56 µg/m for O , below 643.6 µg/m for CO, and within 33 and 48 µg/m for NO . The six-pollutant model using these best-fitted link functions demonstrated superior model fitting compared to exposure-categorized model or linear link function model assuming proportionality of odds. Non-linear associations were found between air pollutants and MASLD prevalence. PM , PM , O , CO, and NO exhibited positive associations with MASLD in specific concentration ranges, highlighting the need to consider non-linear relationships in assessing the impact of air pollution on MASLD.