Dietary Niacin Intake and Mortality Among Individuals With Nonalcoholic Fatty Liver Disease

Importance Evidence regarding the effect of dietary niacin intake on the risk of mortality among patients with nonalcoholic fatty liver disease (NAFLD) is scarce. Objective To examine the association of dietary niacin intake with all-cause mortality and cardiovascular disease (CVD) mortality among individuals with NAFLD. Design, Setting, and Participants This cohort study used data from the National Health and Nutrition Examination Survey (2003-2018). In total, 4315 adults aged 20 years or older with NAFLD were included, with NAFLD defined using the United States Fatty Liver Index. Exposure Dietary niacin intake levels. Main Outcomes and Measures Weighted Cox proportional hazards models and restricted cubic splines were used to estimate hazard ratios and 95% CIs for all-cause and CVD mortality. Data were analyzed March 1 to September 1, 2023. Results This cohort study included data from 4315 participants in the analysis (mean [SD] age, 52.5 [16.2] years; 1670 participants ≥60 years [weighted, 30.9%]; 2351 men [weighted, 55.0%]). During a median (IQR) follow-up of 8.8 (4.6-11.8) years, 566 deaths were recorded, of which 197 were attributed to CVD. Compared with participants with a niacin intake of 18.4 mg or lower (the lowest tertile), the multivariable-adjusted hazard ratios for participants with a niacin intake of 26.7 mg or higher (the highest tertile) were 0.70 (95% CI, 0.50-0.96) for all-cause mortality ( P = .03 for trend) and 0.65 (95% CI, 0.35-1.20) for CVD mortality ( P = .16 for trend). Conclusions and Relevance Findings from this cohort study suggest that higher dietary niacin intake may be associated with lower risk of all-cause mortality among individuals with NAFLD. There was no evident inverse association between dietary niacin intake and the risk of CVD mortality.