Associations of Relative Fat Mass, a Novel Adiposity Indicator, with Non-Alcoholic Fatty Liver Disease and Cardiovascular Disease: Data from SPECT-China

Purpose: This study aimed to determine the associations of relative fat mass (RFM), a novel adiposity indicator, with the prevalence of non-alcoholic fatty liver disease (NAFLD) and cardiovascular disease (CVD) and compared the disease discriminative ability of RFM with other common adiposity indicators in the general Chinese population. Patients and Methods: This cross-sectional study consisted of 11,532 adult participants from the SPECT-China study (2014-2016). We included RFM and six other adiposity indicators, including body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), visceral adiposity index (VAI), and lipid accumulation product (LAP). Binary logistic regression analysis was used to assess the relationship between adiposity indicators and the prevalence of NAFLD and CVD. The receiver operating characteristic (ROC) curve was used to evaluate the ability to screen NAFLD and CVD. Results: After adjusting for confounding variables, RFM showed a strong association with the prevalence of NAFLD and CVD. In men, each 1-SD (standard deviation) increase in RFM was associated with more than 3-fold increased risk of NAFLD (OR: 4.33, 95% CI: 3.79-4.93) and 66% increased risk of CVD (OR: 1.66, 95% CI: 1.36-2.02); in women, per 1-SD increase in RFM was associated with about 4-fold increased risk of NAFLD (OR: 5.16, 95% CI: 4.62-5.77) and 26% increased risk of CVD (OR: 1.26, 95% CI: 1.08-1.47). ROC analysis showed that RFM and WHtR were the strongest predictors for CVD. Conclusion: RFM was significantly associated with prevalent NAFLD and CVD in Chinese adults and might be considered a simple tool for disease prediction. Further large longitudinal studies are needed to verify our findings.