The association between non-alcoholic fatty liver disease with blood selenium level based on the NHANES 2017-2020

The present study aims to investigate the relationship between blood selenium and NAFLD. Data were obtained from the National Health and Nutrition Examination Survey (2017-2020), a total of 3940 eligible participants were included in this study. Multivariable logistic regression, subgroup analyses, and smooth curve fitting assessed the blood selenium-NAFLD relationship. A piecewise linear regression model identified potential thresholds. Model robustness was evaluated using multiple imputation. Among 3,940 participants, NAFLD prevalence was 45% (n = 1,173). Compared to the lowest blood selenium quartile (Q1: 103.10-169.49 µg/L), the adjusted odds ratios for NAFLD were 1.44 (95% CI: 1.16-1.78; P < 0.01) in Q3 (184.56-201.29 µg/L) and 1.26 (95% CI: 1.02-1.57; P = 0.035) in Q4 (201.30-562.23 µg/L) after full covariate adjustment (Q2 was non-significant). Each 1-standard deviation increase in log-transformed blood selenium corresponded to an adjusted odds ratios of 1.16 (95% CI: 1.08-1.26) for NAFLD. Gender significantly modified this association (P for interaction < 0.05). Adjusted smooth curve fitting demonstrated a significant non-linear positive dose-response relationship (P for non-linearity = 0.026). Elevated blood selenium concentration is significantly associated with an increased risk of NAFLD in US adults, exhibiting a non-linear dose-response pattern. This finding requires confirmation in future prospective cohort studies. Such association, if confirmed, will be of considerable public health relevance given the epidemic of NAFLD.