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.