Link between plasma trans-fatty acid and fatty liver is moderated by adiposity

Background: The prevalence of non-alcoholic fatty liver disease (NAFLD) is rising. This increase may be associated with obesity. It has been suggested that trans-fatty acids (TFAs) play an important role in non-communicable diseases. Aim: We examined the link between liver tests, fatty liver index (FLI) and plasma TFAs. Furthermore, we evaluated the impact of adiposity on this link. Methods: The National Health and Nutrition Examination Survey (NHANES) was used to obtain the data on TFAs and liver function biomarkers. We took account of complex NHANES data, masked variance and weighting methodology. Results: Of the 4252 participants, 46.4% were men. The mean age was 50.6 years overall; 51.3 years for men and 49.8 years for women (p = 0.206). In a fully adjusted model (demographic and clinical factors), FLI increased as trans-9-hexadecenoic acid and trans-11-octadecenoic acid levels increased; FLI was 38.1 and 42.3 for the first quarter (Q1) of trans-9-hexadecenoic acid and trans-11-octadecenoic acid, respectively, reaching 65.1 and 69.3 for the highest quarters (Q4) (p < 0.001 for all comparisons). Multivariable logistic regression showed for all four studied TFAs, the likelihood of NAFLD (determined by FLI) increased with increasing TFAs levels (quartiles) in a stepwise manner (p < 0.001 for all comparisons). Based on moderation analysis, a strong impact of body mass index (BMI) on the link between FLI and TFAs was observed. Conclusions: Our results suggest a direct significant association between plasma TFAs, liver tests and NAFLD (assessed by FLI). Furthermore, BMI was shown to mediate this relationship. These findings highlight the importance of avoiding TFAs consumption in order to minimize cardiometabolic risk