Triglycerides Mediate Body Mass Index and Nonalcoholic Fatty Liver Disease: A Population-Based Study.

INTRODUCTION Nonalcoholic fatty liver disease (NAFLD) is defined by the accumulation of triglycerides (TG). The body mass index (BMI) is associated with NAFLD. This large-scale cohort study was performed to evaluate and quantify the mediating effect of TG on the association between BMI and NAFLD. METHODS In total, 15,943 participants in the Kailuan Group were recruited between 2010 and 2014. The impact of TG on the association between BMI and NAFLD was determined through a mediation analysis. RESULTS BMI was an independent risk factor for incident NAFLD, with OR of 1.416 (95% CI 1.338-1.499) and 1.187 (95% CI 1.137-1.240) in the low-BMI and high-BMI groups, respectively (p < 0.001). The TG level was a risk factor for NAFLD in the high-BMI group, with an OR of 2.775 (95% CI 1.488-5.177; p = 0.001). Positive associations between BMI and the TG level remained in the 2 above mentioned groups after adjusting for confounders (β = 0.072 and 0.032; p < 0.001). The mediation analysis revealed that TG contributed to 26.050% of incident NAFLD in the high-BMI group (p = 0.01). CONCLUSION A high BMI was an independent risk factor for incident NAFLD, and a high TG level was a risk factor in the high-BMI group (BMI ≥24). TG contributes about 25% to incident NAFLD in people with obesity.