Long-term exposure to air pollution and prevalent nonalcoholic fatty liver disease

Clara Matthiessen; Lina Glaubitz; Sarah Lucht; Julia Kälsch; Tom Luedde; Raimund Erbel; Andreas Stang; Börge Schmidt; Scott L Friedman; Ali Canbay; Lars P Bechmann; Barbara Hoffmann

doi:10.1097/EE9.0000000000000268

Long-term exposure to air pollution and prevalent nonalcoholic fatty liver disease

Environ Epidemiol. 2023 Aug 31;7(5):e268. doi: 10.1097/EE9.0000000000000268. eCollection 2023 Oct.

Authors

Clara Matthiessen¹, Lina Glaubitz¹, Sarah Lucht^{1

2}, Julia Kälsch³, Tom Luedde⁴, Raimund Erbel⁵, Andreas Stang^{5

6}, Börge Schmidt⁵, Scott L Friedman⁷, Ali Canbay⁸, Lars P Bechmann⁸, Barbara Hoffmann¹

Affiliations

¹ Institute of Occupational, Social, and Environmental Medicine, Centre for Health and Society, Medical Faculty, Heinrich-Heine University Düsseldorf, Germany.
² Cardinal Health, Dublin, Ohio.
³ Department of Gastroenterology and Hepatology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany.
⁴ Department of Gastroenterology, Hepatology and Infectious Diseases, University Hospital of Duesseldorf, Germany.
⁵ Institute of Medical Informatics, Biometry and Epidemiology (IMIBE), University Hospital Essen, University of Duisburg-Essen, Essen, Germany.
⁶ School of Public Health, Department of Epidemiology Boston University, Boston, Massachusetts.
⁷ Division of Liver Diseases, Icahn School of Medicine at Mount Sinai, New York City, New York.
⁸ Department of Internal Medicine, University Hospital Knappschaftskrankenhaus, Ruhr-University Bochum, Bochum, Germany.

Abstract

Background: Nonalcoholic fatty liver disease (NAFLD) is a disease characterized by lipid accumulation within hepatocytes, ranging from simple steatosis to steatohepatitis, in the absence of secondary causes of hepatic fat accumulation. Although air pollution (AP) has been associated with several conditions related to NAFLD (e.g., metabolic syndrome, type 2 diabetes mellitus), few studies have explored an association between AP and NAFLD. The aim of the study was to investigate whether exposure to AP is associated with NAFLD prevalence.

Methods: We used baseline cross-sectional data (2000-2003) of the Heinz-Nixdorf-Recall cohort study in Germany (baseline n = 4,814), a prospective population-based cohort study in the urbanized Ruhr Area. Mean annual exposure to size-fractioned particulate matter (PM₁₀, PM_2.5, PM_coarse, and PM_2.5abs), nitrogen dioxide, and particle number was assessed using two different exposure models: a chemistry transport dispersion model, which captures urban background AP exposure on a 1 km² grid at participant's residential addresses, and a land use regression model, which captures point-specific AP exposure at participant's residential addresses. NAFLD was assessed with the fatty liver index (n = 4,065), with NAFLD defined as fatty liver index ≥60. We estimated ORs of NAFLD per interquartile range of exposure using logistic regression, adjusted for socio-demographic and lifestyle variables.

Results: We observed a NAFLD prevalence of 31.7% (n = 1,288). All air pollutants were positively associated with NAFLD prevalence, with an OR per interquartile range for PM_2.5 of 1.11 (95% confidence interval [CI] = 1.00, 1.24) using chemistry transport model, and 1.06 (95% CI = 0.94, 1.19) using the land use regression model, respectively.

Conclusion: There was a positive association between long-term AP exposure and NAFLD.

Keywords: FIB-4; Fatty liver index; NAFLD; NO2; Particulate matter.