Association of Myosteatosis with Nonalcoholic Fatty Liver Disease, Severity, and Liver Fibrosis Using Visual Muscular Quality Map in Computed Tomography (Diabetes Metab J 2023;47:104-17)

Article information

Diabetes Metab J. 2023;47(2):304-305

Publication date (electronic) : 2023 March 15

doi : https://doi.org/10.4093/dmj.2023.0058

Hwi Seung Kim¹, Hong-Kyu Kim^,2, Chang Hee Jung^,3,4

¹Department of Internal Medicine, Department of Internal Medicine, Chung-Ang University Gwangmyeong Hospital, Chung-Ang University College of Medicine, Gwangmyeong, Korea

²Department of Health Screening and Promotion Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea

³Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea

⁴Asan Diabetes Center, Asan Medical Center, Seoul, Korea

Corresponding authors: Hong-Kyu Kim https://orcid.org/0000-0002-7606-3521 Department of Health Screening and Promotion Center, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Korea E-mail: hkkim0801@amc.seoul.kr

Chang Hee Jung https://orcid.org/0000-0003-4043-2396 Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Korea E-mail: chjung0204@gmail.com

We appreciate Dr. Roh’s comments on our recent article, “Association of myosteatosis with nonalcoholic fatty liver disease, severity, and liver fibrosis using visual muscular quality map in computed tomography” [1]. We are also grateful for the additional opportunity to discuss different views on this topic.

We agree with Dr. Roh’s remarks on the findings of our study, as they clearly reflect and emphasize the background of our study. Regarding the relationship between nonalcoholic fatty liver disease (NAFLD) and sarcopenia, previous studies primarily focused on low skeletal muscle mass as a possible risk factor for NAFLD [2-4]. As Dr. Roh mentioned, the reverse relationship was demonstrated for the first time in her recently published article, in which elderly people with high hepatic steatosis index and fatty liver index showed increased risk of low muscle mass and low muscle strength (measured as handgrip strength) [5]. The complexity of liver-muscle crosstalk is noted, as sarcopenia and NAFLD share common pathophysiologic mechanisms, which may explain the mutual associations between the two. These mechanisms include insulin resistance, chronic inflammation, and changes in regulation of myokines and hepatokines [6].

Additionally, Dr. Roh discussed the emphasis on low muscle strength in the updated definition of sarcopenia. Dr. Roh’s recent study (mentioned above) measured handgrip strength to evaluate muscle strength [5]. We measured muscle quality by measuring skeletal muscle attenuation on computed tomography (CT). Muscle with low attenuation represented lipid-rich and poor quality muscle. As more studies start to evaluate muscle strength and quality, we look forward to more consistent results being obtained through well-controlled longitudinal studies on muscle and liver health in near future.

With respect to myosteatosis, we have looked into its association with various cardiometabolic diseases, all of which have shown consistent results. Other than NAFLD, poor quality muscle was associated with an increased prevalence of hypertension [7], dyslipidemia (not yet published), type 2 diabetes mellitus [8], and subclinical coronary atherosclerosis [9]. Dr. Roh recommended that future studies seek to identify optimal cutoffs for muscle fat; however, our study group recently presented sex-specific diagnostic cutoff points for myosteatosis based on T-scores measured by CT and suggested normal attenuation muscle area (NAMA) divided by total abdominal muscle area (TAMA), the so-called NAMA/TAMA index, as a new index for good quality muscle and myosteatosis [10]. This could provide useful information about myosteatosis, muscle quality, and associated cardiometabolic risk in people with previous abdominal CT scans in future studies.

Once more, we thank Dr. Roh for her comprehensive review and valuable comments.