AbstractBackgroundThe connection between vitamin D to non-alcoholic fatty liver disease (NAFLD) is still unclear. Herein, the relationship of vitamin D with NAFLD and liver fibrosis (LF) detected by vibration controlled transient elastography was investigated in US adults.MethodsThe National Health and Nutrition Examination Survey of 2017–2018 was employed for our analysis. Participants were categorized as having either vitamin D deficiency (<50 nmol/L) or vitamin D sufficiency (≥50 nmol/L). A controlled attenuation parameter score of ≥ 263 dB/m was employed to define NAFLD. Significant LF was identified by the liver stiffness measurement value of ≥ 7.9 kPa. Multivariate logistic regression was adopted to explore the relationships.ResultsAmong the 3407 participants, the prevalence of NAFLD and LF was 49.63% and 15.93% respectively. Compared to participants without NAFLD, no significant difference in serum vitamin D was observed in NALFD participants (74.26 vs. 72.24 nmol/L;p= 0.21). Using multivariate logistic regression analysis, no obvious connection of vitamin D status to NAFLD (sufficiency vs. deficiency, OR 0.89, 95%CI 0.70–1.13) was discovered. However, among NAFLD participants, the sufficiency of vitamin D represents a lower LF risk (OR 0.56, 95%CI 0.38–0.83). When evaluated in quartiles, in comparison to the lowest quartile, high vitamin D represents low LF risk in a dose-dependent manner (Q2 vs. Q1, OR 0.65, 95%CI 0.37–1.14; Q3 vs. Q1, OR 0.64, 95%CI 0.41–1.00; Q4 vs. Q1, OR 0.49, 95%CI 0.30–0.79).ConclusionsNo relationship was found between vitamin D and CAP-defined NAFLD. However, a positive connection of the high serum vitamin D to the reduced LF risk was found among NAFLD subjects.Key messages:Our study found no relationship between vitamin D and CAP-defined NAFLD in US adults.High serum vitamin D was inversely associated with liver fibrosis in a dose-dependent manner among NAFLD participants.