Blood and urine manganese exposure in non-alcoholic fatty liver disease and advanced liver fibrosis: an observational study

Manganese was the key activator of biological enzymes-mediated metabolic diseases (Mets)-associated pathophysiological process. Non-alcoholic fatty liver disease (NAFLD), which was the hepatic manifestation of Mets, development remained a mystery. We aimed to explore the association between blood/urine manganese exposure and NAFLD and liver fibrosis diagnosed by vibration-controlled transient elastography (VCTE). All data were extracted from National Health and Nutrition Examination Survey database (2017–2018). A total of 3580 participants with blood manganese data were enrolled and divided into four groups according to the quartile of blood manganese exposure level. In multiple logistic regression models, the higher blood manganese exposure level (groups 2, 3, and 4) had a significant positive association with NAFLD ( β = 1.58, 1.30, and 1.69). In subgroup analysis, the main inversely correlation between blood manganese and NAFLD was found in participants with normal/high body mass index and high blood manganese exposure level. Moreover, in 1179 participants with urine manganese data, urine manganese exposure level presented as significantly associated with advanced liver fibrosis in models 1 and 2 ( β = 2.00 and 2.02). This study showed that manganese exposure level was positively associated with NAFLD and advanced liver fibrosis among the US population. We suggested that manganese exposure level was a biomarker of the development of NAFLD.