Background: Physical activity (PA) has long been considered a key strategy in the management of sarcopenia. To our knowledge, this is the first study to examine domain-specific physical activity, including leisure-time and occupational activities, in relation to possible sarcopenia (PS) among middle-aged and older adults. Methods: We analyzed a total of 15,819 adults aged ≥40 years. PS was defined on the basis of handgrip strength (males <28 kg and females <18 kg) according to the Asian Working Group for Sarcopenia. The Global Physical Activity Questionnaire was used to evaluate domain-specific PA, including weekly leisure-time or occupational moderate-to-vigorous PA (MVPA). MVPA was classified into three categories: no activity, 1–149 min/week, and ≥150 min/week. Parameters potentially related to PS or PA were included as covariates: age, sex, household income, education, medication, alcohol and smoking habits, nutritional status, and body weight. Results: Compared with participants with no leisure-time MVPA, those with 1–149 min/week and ≥150 min/week of leisure-time MVPA had odds ratios (95% confidence intervals) of 0.64 (0.54, 0.74) and 0.60 (0.52, 0.68) for PS, respectively (p<0.001 for both). However, occupational MVPA was not significantly related to PS. Subgroup analyses stratified by sex, age, and sedentary time revealed no significant heterogeneity (all p-values for interactions >0.05). Conclusion These findings demonstrate that PS is inversely related to leisure-time PA but not to occupational PA among middle-aged and older adults, suggesting that PA programs that focus specifically on leisure-time activities may be necessary to prevent and manage possible sarcopenia.

Background: Muscle–liver crosstalk plays an important role in the development and progression of non-alcoholic fatty liver disease (NAFLD). The measurement of muscle echo-intensity during ultrasonography is a realtime, non-invasive method of assessing muscle quality. In this retrospective study, we investigated the significance of poor muscle quality (namely, a greater mass of non-contractile tissue, including intramuscular fat) as a risk factor for advanced liver fibrosis and considered whether it may represent a useful tool for the diagnosis of advanced liver fibrosis. Methods: We analyzed data from 307 patients with NAFLD (143 men and 164 women) who visited the University of Tsukuba Hospital between 2017 and 2022. The patients were stratified into the following tertiles of muscle quality according to their muscle echo-intensity on ultrasonography: modest (84.1 arbitrary units [A.U.]), intermediate (97.4 A.U.), and poor (113.6 A.U.). We then investigated the relationships between muscle quality and risk factors for advanced liver fibrosis and calculated appropriate cutoff values. Results: Patients with poor muscle quality showed a significant, 7.6-fold greater risk of liver fibrosis compared to those with modest muscle quality. Receiver operating characteristic curve analysis showed that muscle quality assessment was as accurate as the fibrosis-4 index and NAFLD fibrosis score in screening for liver fibrosis and superior to the assessment of muscle quantity and strength, respectively. Importantly, a muscle echo-intensity of ≥92.4 A.U. may represent a useful marker of advanced liver fibrosis. Conclusion Muscle quality may represent a useful means of identifying advanced liver fibrosis, and its assessment may become a useful screening tool in daily practice.

Background: Muscle–liver crosstalk plays an important role in the development and progression of non-alcoholic fatty liver disease (NAFLD). The measurement of muscle echo-intensity during ultrasonography is a realtime, non-invasive method of assessing muscle quality. In this retrospective study, we investigated the significance of poor muscle quality (namely, a greater mass of non-contractile tissue, including intramuscular fat) as a risk factor for advanced liver fibrosis and considered whether it may represent a useful tool for the diagnosis of advanced liver fibrosis. Methods: We analyzed data from 307 patients with NAFLD (143 men and 164 women) who visited the University of Tsukuba Hospital between 2017 and 2022. The patients were stratified into the following tertiles of muscle quality according to their muscle echo-intensity on ultrasonography: modest (84.1 arbitrary units [A.U.]), intermediate (97.4 A.U.), and poor (113.6 A.U.). We then investigated the relationships between muscle quality and risk factors for advanced liver fibrosis and calculated appropriate cutoff values. Results: Patients with poor muscle quality showed a significant, 7.6-fold greater risk of liver fibrosis compared to those with modest muscle quality. Receiver operating characteristic curve analysis showed that muscle quality assessment was as accurate as the fibrosis-4 index and NAFLD fibrosis score in screening for liver fibrosis and superior to the assessment of muscle quantity and strength, respectively. Importantly, a muscle echo-intensity of ≥92.4 A.U. may represent a useful marker of advanced liver fibrosis. Conclusion Muscle quality may represent a useful means of identifying advanced liver fibrosis, and its assessment may become a useful screening tool in daily practice.

Background: Muscle–liver crosstalk plays an important role in the development and progression of non-alcoholic fatty liver disease (NAFLD). The measurement of muscle echo-intensity during ultrasonography is a realtime, non-invasive method of assessing muscle quality. In this retrospective study, we investigated the significance of poor muscle quality (namely, a greater mass of non-contractile tissue, including intramuscular fat) as a risk factor for advanced liver fibrosis and considered whether it may represent a useful tool for the diagnosis of advanced liver fibrosis. Methods: We analyzed data from 307 patients with NAFLD (143 men and 164 women) who visited the University of Tsukuba Hospital between 2017 and 2022. The patients were stratified into the following tertiles of muscle quality according to their muscle echo-intensity on ultrasonography: modest (84.1 arbitrary units [A.U.]), intermediate (97.4 A.U.), and poor (113.6 A.U.). We then investigated the relationships between muscle quality and risk factors for advanced liver fibrosis and calculated appropriate cutoff values. Results: Patients with poor muscle quality showed a significant, 7.6-fold greater risk of liver fibrosis compared to those with modest muscle quality. Receiver operating characteristic curve analysis showed that muscle quality assessment was as accurate as the fibrosis-4 index and NAFLD fibrosis score in screening for liver fibrosis and superior to the assessment of muscle quantity and strength, respectively. Importantly, a muscle echo-intensity of ≥92.4 A.U. may represent a useful marker of advanced liver fibrosis. Conclusion Muscle quality may represent a useful means of identifying advanced liver fibrosis, and its assessment may become a useful screening tool in daily practice.

Moderate to vigorous physical activity is associated with improving insulin resistance in overweight and obese adults. However, effect of light physical activity on insulin resistance remains to be fully elucidated. The purpose of this study was to investigate the effect of light physical activity on insulin resistance in overweight and obese men. Thirty-seven overweight and obese middle-aged men (28.9 ± 1.8 kg/m², 51.0 ± 8.8 years) participated in this study. They took part in the lifestyle intervention (calorie restricted diet and exercise) for 12 weeks. Anthropometric parameters, fasting glucose, HbA1c, fasting insulin, and HOMA-IR were assessed at baseline and post intervention. Physical activity was objectively measured using a triaxial accelerometer at baseline and during intervention. Light physical activity (+17.7 min/day) and moderate-vigorous physical activity (+33.2 min/day) increased significantly, while body weight (-12.4 kg), fasting glucose (-9.5 mg/ml), fasting insulin (-4.2 μU/ml), and HOMA-IR (-1.1) decreased significantly. The change in light physical activity from baseline to during intervention were inversely related to change in fasting insulin (r = 0.18, P = 0.02) and change in HOMA-IR (r = -0.16, P = 0.03), after adjustment for several confounders. These results suggest that an increase of light physical activity improves insulin resistance in overweight and obese men.