Metabolic associated fatty liver disease (MAFLD) is a new concept proposed in 2020. This study aimed to explore the relationship between serum 25-hydroxy vitamin D (25(OH)D) level and MAFLD based on a population survey dataset (the third National Health and Nutrition Examination Surveys of the United States). Multivariate logistic regression was used to estimate the odds ratio (OR) of serum 25(OH)D level for MAFLD. A total of 12,878 participants were included in this analysis. Among them, 4,027 (31.27%) cases were diagnosed with MAFLD and 8,851 (66.40%) were without MAFLD (non-MAFLD). Patients with vitamin D sufficiency and insufficiency totaled 6,983 (54.22%) and 5,895 (45.78%), respectively. The incidence of MAFLD and the grade of hepatic steatosis were both significantly higher in vitamin D insufficiency group. Multivariate analysis showed that vitamin D insufficiency was an independent risk factor for MAFLD after adjusted for other confounders (OR: 1.130, 95%CI: 1.035 to 1.234). In MAFLD population, the average serum 25(OH)D level decreased with the numbers of metabolic risks in MAFLD cases. Serum 25(OH)D level was not associated with the severity of fibrosis or steatosis in MAFLD group. In Conclusion, lower serum 25(OH)D level is associated with higher prevalence of MAFLD in general population. No relationship was found between serum 25(OH)D level and the severity of hepatic steatosis or fibrosis in MAFLD.

代谢相关脂肪性肝病（MAFLD）是2020年提出的新概念。本研究基于人口调查数据集（第三次全国人美国健康和营养检查调查）。多变量逻辑回归用于估计血清 25(OH)D 水平对 MAFLD 的比值比 (OR)。该分析共包括 12,878 名参与者。其中，4027例（31.27%）确诊为MAFLD，8851例（66.40%）无MAFLD（非MAFLD）。维生素 D 充足和不足的患者总数分别为 6,983 (54.22%) 和 5,895 (45.78%)。维生素D不足组MAFLD的发生率和肝脂肪变性的分级均显着升高。多变量分析表明，在校正其他混杂因素后，维生素 D 不足是 MAFLD 的独立危险因素（OR：1.130，95%CI：1.035 至 1.234）。在 MAFLD 人群中，平均血清 25(OH)D 水平随着 MAFLD 病例代谢风险的增加而降低。MAFLD组血清25(OH)D水平与纤维化或脂肪变性的严重程度无关。总之，较低的血清 25(OH)D 水平与一般人群中较高的 MAFLD 患病率相关。未发现血清 25(OH)D 水平与 MAFLD 中肝脂肪变性或纤维化的严重程度之间存在相关性。平均血清 25(OH)D 水平随着 MAFLD 病例代谢风险的增加而降低。MAFLD组血清25(OH)D水平与纤维化或脂肪变性的严重程度无关。总之，较低的血清 25(OH)D 水平与一般人群中较高的 MAFLD 患病率相关。未发现血清 25(OH)D 水平与 MAFLD 中肝脂肪变性或纤维化的严重程度之间存在相关性。平均血清 25(OH)D 水平随着 MAFLD 病例代谢风险的增加而降低。MAFLD组血清25(OH)D水平与纤维化或脂肪变性的严重程度无关。总之，较低的血清 25(OH)D 水平与一般人群中较高的 MAFLD 患病率相关。未发现血清 25(OH)D 水平与 MAFLD 中肝脂肪变性或纤维化的严重程度之间存在相关性。