Fatty Liver Index and Skeletal Muscle Density

Abstract

Accumulation of fat in the liver and skeletal muscle is associated with obesity and poor health outcomes. Liver steatosis is a characteristic of non-alcoholic fatty liver disease (NAFLD) and myosteatosis, of poor muscle quality in sarcopenia. In this study of 403 men (33–96 years), we investigated associations between the fatty liver index (FLI) and muscle density, as markers of fat accumulation in these organs. We also investigated associations between the FLI and parameters of sarcopenia, including DXA-derived appendicular lean mass (ALM) and handgrip strength by dynamometry. Muscle density was measured using pQCT at the radius and tibia. FLI was calculated from BMI, waist circumference, and levels of triglycerides and gamma-glutamyltransferase. There was a pattern of decreasing muscle density across increasing quartiles of FLI. After adjusting for age and lifestyle, mean radial muscle density in Q4 was 2.1% lower than Q1 (p < 0.001) and mean tibial muscle density was 1.8% lower in Q3 and 3.0% lower in Q4, compared to Q1 (p = 0.022 and < 0.001, respectively). After adjusting for age and sedentary lifestyle, participants in the highest FLI quartile were sixfold more likely to have sarcopenia. In conclusion, our results suggest that fat accumulation in the liver co-exists with fat infiltration into skeletal muscle.

Moderate-Intensity Exercise Enhances Mitochondrial Biogenesis Markers in the Skeletal Muscle of a Mouse Model Affected by Diet-Induced Obesity

“…Obesity has numerous detrimental systemic effects on the body, contributing to the development of the metabolic syndrome, including type 2 diabetes mellitus (T2DM), Alzheimer’s disease, various types of cancer, and cardiovascular diseases. Along with these systemic effects, fat accumulation in vital organs such as the liver (hepatic steatosis), skeletal muscle (myosteatosis), and heart (obesity cardiomyopathy) can adversely impact its respective tissue and lead to poor health outcomes [ 28 ]. Notably, an inverse correlation between fatty liver index and muscle density was reported in a population-based prospective cohort study of both male and female subjects [ 28 ].…”

Effect of progressive resistance training with weight loss compared with weight loss alone on the fatty liver index in older adults with type 2 diabetes: secondary analysis of a 12-month randomized controlled trial

“…Future studies may also consider a more comprehensive assessment of body composition, including muscle adiposity, as there is evidence that individuals with high muscle fat are more likely to have higher liver fat. 49 …”

“…Given most previous studies report liver fat as the primary outcome, capacity for more meaningful comparison between other PRT-related studies was also limited. Future studies may also consider a more comprehensive assessment of body composition, including muscle adiposity, as there is evidence that individuals with high muscle fat are more likely to have higher liver fat 49…”

Osteosarcopenia in NAFLD/MAFLD: An Underappreciated Clinical Problem in Chronic Liver Disease

“…Additional cross-sectional and retrospective studies have further confirmed the independent association between sarcopenia and NAFLD [ 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 ], NAFLD severity [ 35 , 37 , 43 ], fibrosis [ 36 , 40 , 44 , 45 , 46 , 47 ] and fibrosis severity [ 36 , 48 , 49 ].…”