Association between Dietary Niacin Intake and Nonalcoholic Fatty Liver Disease: NHANES 2003-2018

Evidence regarding the association between dietary niacin intake and nonalcoholic fatty liver disease (NAFLD) is limited. The objective of this study was to examine the association of dietary niacin intake with NAFLD. Subjects aged 20 years and older who participated in the National Health and Nutrition Examination Survey (NHANES) 2003-2018 were included in this study. Dietary niacin intake was assessed by two 24-h dietary recalls. NAFLD was defined using the United States fatty liver index (US-FLI). Weighted logistic regression models and restricted cubic splines were used to examine the association between dietary niacin and NAFLD. Of the 12,355 participants in this study, 4378 had NAFLD. There is no evident nonlinear relationship between dietary niacin intake and the presence of NAFLD in the restricted cubic spline regression (p_overall < 0.001; p_{non-linearity} = 0.068). The multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for NAFLD were 0.84 (0.68-1.03), 0.80 (0.65-0.97), and 0.69 (0.55-0.85), respectively, when comparing the second, third, and fourth quartiles of niacin intake levels to the lowest quartile (p_trend = 0.001). Stratified analysis revealed that the effect of niacin intake on NAFLD varied in the group with or without hypertension (p_interaction = 0.033). In conclusion, our results indicate that higher dietary niacin intake may be associated with a lower likelihood of NAFLD.