• Journal of the Korean Society of Physical Medicine
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• v.18 no.4
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• pp.37-45
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• 2023

PURPOSE: The coexistence of age-related skeletal muscle mass loss and obesity poses a substantial health risk for individuals because it combines the detrimental effects of muscle mass reduction associated with aging and the health complications from obesity. This study aimed to identify the incidence rate and key influencing elements among Korean men in their thirties. METHODS: A cross-sectional study involving 934 male participants was performed using complex sampling analysis. Various influencing elements were investigated, including age, height, weight, body mass index, waist circumference, skeletal muscle mass index, smoking and drinking behaviors, systolic and diastolic blood pressure, fasting glucose levels, triglyceride, and cholesterol levels. RESULTS: The incidence rate was 2.90%. The key influencing elements were age, height, weight, body mass index, waist circumference, skeletal muscle index, systolic blood pressure, fasting glucose, triglyceride, and total cholesterol (p < .05). CONCLUSION: This study identified the incidence rate and key influencing element for CALSMO among Korean younger community-dwelling men.

• Journal of the Korean Society of Physical Medicine
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• v.18 no.3
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• pp.1-9
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• 2023

PURPOSE: This study examined the prevalence and specific risk factors in males aged 40-49 years with the coexistence of age-related loss of skeletal muscle mass and obesity (CALSMO). METHODS: The current study analyzed the data obtained from a cross-sectional study involving a sample of 1,218 men who resided in the community and fell within the age range of 40 to 49 years. Multiple risk factors were examined: age, height, weight, body mass index, waist circumference, skeletal muscle mass index, smoking and drinking habits, systolic and diastolic blood pressure, fasting glucose levels, and triglyceride and cholesterol levels. All data were analyzed via complex sampling analysis. RESULTS: The coexistence of age-related loss of skeletal muscle mass and obesity in males was 2.94% (95% CI: 2.06-4.17). The clinical risk factors were low height, high weight, body mass index, waist circumference, skeletal muscle index, systolic blood pressure, diastolic blood pressure, and fast glucose (p < .05). CONCLUSION: The study identifies the prevalence and risk factors for CALSMO among adults in the community. These findings contribute to the existing literature on CALSMO and highlight potential risk factors associated with CALSMO development in males aged 40-49 years.

• Journal of the Korean Society of Physical Medicine
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• v.18 no.2
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• pp.13-21
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• 2023

PURPOSE: This study examined the specific clinical risk factors in middle-aged men with age-related loss of skeletal muscle mass (ALSMM). METHODS: The present research analyzed the data from a cross-sectional study of 1,564 community-dwelling participants aged between 40 to 49 years old. The participants were screened for ALSMM. The study examined various risk factors, including age, height, weight, body mass index, waist circumference, skeletal muscle mass index, smoking and drinking status, systolic and diastolic blood pressure, fasting glucose levels, and triglyceride and cholesterol levels. RESULTS: The risk factors of ALSMM were height, body mass index, waist circumference, skeletal muscle mass index, systolic blood pressure, diastolic blood pressure, drinking status, fasting glucose, and triglyceride levels (p < .05). The weight, triglyceride, and smoking status variables were non-significant (p > .05). CONCLUSION: The risk factors for ALSMM among community-dwelling adults were determined. These results are expected to contribute to the existing literature on ALSMM and provide potential risk factors associated with the development of ALSMM in middle-aged males.

• Journal of the Korean Society of Physical Medicine
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• v.18 no.4
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• pp.67-75
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• 2023

PURPOSE: This study aimed to identify the clinical factors that contribute to age-related loss of skeletal muscle mass (ALSMM) among young Korean male adults. METHODS: This was a cross-sectional study involving 955 men aged between 20-29 years. They underwent screening to assess the ALSMM. The study examined a variety of factors, including age, height, weight, body mass index (BMI), waist circumference (WC), skeletal muscle mass index (SMI), lifestyle-related habits such as smoking and drinking status, systolic and diastolic blood pressure (SBP/DBP), fasting blood glucose (FBG) levels, as well as the serum triglyceride and total cholesterol (TC) levels. RESULTS: The variables that displayed significant associations with ALSMM were height, weight, BMI, WC, SMI, FBG, TC, DBP, and alcohol consumption (p < .05). Serum triglyceride levels, SBP, and smoking status did not exhibit statistical significance (p > .05). CONCLUSION: The study identified the contributing factors associated with the ALSMM in community-dwelling young adult males. These findings would enrich the current body of literature on ALSMM and provide potential risk factors associated with its development in young Korean males.

• Journal of the Korean Society of Physical Medicine
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• v.19 no.3
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• pp.47-54
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• 2024

PURPOSE: This study aimed to identify the potential clinically predictive indicators of the age-related loss of skeletal muscle mass (ALSMM) in middle-aged women. METHODS: The data from a cross-sectional study involving 2,066 community-dwelling female participants aged 40 to 49 years were analyzed. Complex sampling analyses were used to ensure a nationally representative analysis, incorporating the individual weights provided by KNHANES. This approach accounted for the stratified, clustered, and multistage probability sampling design of the survey. The participants were screened for ALSMM, and various potential predictive indicators were assessed, including age, height, weight, body mass index, waist circumference, skeletal muscle mass index, smoking and drinking status, systolic and diastolic blood pressure, fasting glucose levels, triglyceride levels, and cholesterol levels. RESULTS: Significant potential predictive indicators for ALSMM included height, weight, body mass index, waist circumference, skeletal muscle mass index, and fasting glucose (p < .05). The systolic blood pressure, diastolic blood pressure, triglyceride levels triglyceride, and drinking and smoking status were found to be non-significant variables (p > .05). CONCLUSION: The study identified the potential predictive indicators for ALSMM among community-dwelling middle-aged women. These findings enhance the current understanding of ALSMM and highlight the potential predictive indicators associated with its development in middle-aged women.

• Journal of the Korean Society of Physical Medicine
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• v.19 no.1
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• pp.31-41
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• 2024

PURPOSE: This study examined the distribution dynamics and proposed determinants, including morphological measurements, clinical laboratory tests, and lifestyle factors among young Korean men aged 20 to 29 years with the coexistence of age-related loss of skeletal muscle mass and obesity (CALSMO). METHODS: Six hundred and sixty-six participants were divided into two groups based on their skeletal muscle mass index, with 12 individuals categorized in the CALSMO group and the remaining 654 in the normal group. The proposed determinants variables consisted of three main components: morphological measurements, clinical laboratory tests, and lifestyle factors. The morphological measurement variables were height, weight, body mass index, waist circumference, and skeletal muscle mass index. The clinical laboratory tests were fasting glucose, triglyceride, total cholesterol levels, and systolic and diastolic blood pressure. The lifestyle factors considered were alcohol consumption and tobacco use. Complex sampling analysis was performed for the evaluation. RESULTS: The distribution dynamics were determined to be 1.81(1.02-3.18) %. Morphological factors, such as height, weight, body mass index, waist circumference, and skeletal muscle mass index, showed significant differences (p < .05). The clinical laboratory test variables, specifically the fasting glucose, triglyceride, and total cholesterol levels, also exhibited significant differences (p < .05). The lifestyle factor, alcohol consumption, also showed a significance (p < .05). CONCLUSION: This study provides insights into the distribution dynamics. The proposed determinants in young Korean individuals with CALSMO are height, weight, body mass index, waist circumference, skeletal muscle mass index, fasting glucose, triglyceride, total cholesterol levels, and alcohol consumption.

• Nutrition Research and Practice
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• v.12 no.3
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• pp.222-232
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• 2018

BACKGROUND/OBJECTIVES: Since gain or loss of skeletal muscle mass is a gradual event and occurs due to a combination of lifestyle factors, assessment of dietary factors related to skeletal muscle is complicated. The aim of this study was to investigate the changes in total energy intake according to the level of skeletal muscle mass. SUBJECTS/METHODS: A total of 8,165 subjects ${\geq}30years$ of age from the Korean National Health and Nutrition Examination Surveys (KNHANES) 2008-2011 were included in the analysis, and multivariate-adjusted regression analyses were performed to analyze the association of the quartiles of sarcopenia index (SI) with energy intake of the study population after adjusting for age and metabolic parameters. RESULTS: The increase in SI quartile was in proportion to the gradual decrease in systemic lipids and the anthropometric measurement of fat accumulation (P < 0.001). Subjects in higher SI quartiles tended to consume more total energy and energy-producing nutrients than those in lower quartiles (P < 0.001). After age, body weight, alcohol consumption, and metabolic parameters were adjusted in the analysis, total energy intake gradually increased according to the increase in SI quartile, and the association between total energy intake and SI was more pronounced in men. However, the risk (odd ratio) of having a low SI was not affected by any single macronutrient intake. CONCLUSION: In this study, total energy intake was positively associated with SI and relative skeletal mass in both men and women. However, no significant association or a weak association was observed between any single macronutrient intake and skeletal muscle mass. The data indicated that acquiring more energy intake within the normal range of energy consumption may help to maintain skeletal muscle mass.

• Osteoporosis and Sarcopenia
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• v.3 no.3
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• pp.117-122
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• 2017

Sarcopenia is the degenerative loss of muscle mass and function with aging. Recently sarcopenia was recognized as a clinical disease by the International Classification of Disease, 10th revision, Clinical Modification. An imbalance between protein synthesis and degradation causes a gradual loss of muscle mass, resulting in a decline of muscle function as a progress of sarcopenia. Many mechanisms involved in the onset of sarcopenia include age-related factors as well as activity-, disease-, and nutrition-related factors. The stage of sarcopenia reflecting the severity of conditions assists clinical management of sarcopenia. It is important that systemic descriptions of the disease conditions include age, sex, and other environmental risk factors as well as levels of physical function. To develop a new therapeutic intervention needed is the detailed understanding of molecular and cellular mechanisms by which apoptosis, autophagy, atrophy, and hypertrophy occur in the muscle stem cells, myotubes, and/or neuromuscular junction. The new strategy to managing sarcopenia will be signal-modulating small molecules, natural compounds, repurposing of old drugs, and muscle-specific microRNAs.

• Fisheries and Aquatic Sciences
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• v.26 no.6
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• pp.406-422
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• 2023

Sarcopenia is an age-related, progressive skeletal muscle disorder involving the loss of muscle mass and strength. Previous studies have shown that γ-aminobutyric acid (GABA) from fermented oysters aids in regulatory T cells (Tregs) cell expansion and function by enhancing autophagy, and concomitantly mediate muscle regeneration by modulating muscle inflammation and satellite cell function. The fermentation process of oysters not only increases the GABA content but also enhances the content of branched amino acids and free amino acids that aid the level of protein absorption and muscle strength, mass, and repair. In this study, the effect of GABA-enriched fermented sarco oyster extract (FSO) on reduced muscle mass and functions via Treg modulation and enhanced autophagy in aged mice was investigated. Results showed that FSO enhanced the expression of autophagy markers (autophagy-related gene 5 [ATG5] and GABA receptor-associated protein [GABARAP]), forkhead box protein 3 (FoxP3) expression, and levels of anti-inflammatory cytokines (interleukin [IL]-10 and transforming growth factor [TGF]-β) secreted by Tregs while reducing pro-inflammatory cytokine levels (IL-17A and interferon [IFN]-γ). Furthermore, FSO increased the expression of IL-33 and its receptor IL-1 receptor-like 1 (ST2); well-known signaling pathways that increase amphiregulin (Areg) secretion and expression of myogenesis markers (myogenic factor 5, myoblast determination protein 1, and myogenin). Muscle mass and function were also enhanced via FSO. Overall, the current study suggests that FSO increased autophagy, which enhanced Treg accumulation and function, decreased muscle inflammation, and increased satellite cell function for muscle regeneration and therefore could decrease the loss of muscle mass and function with aging.

• BMB Reports
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• v.48 no.11
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• pp.595-596
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• 2015

Skeletal muscle exhibits a loss of muscle mass and function with age. Decreased regenerative potential of muscle stem/progenitor cells is a major underlying cause of sarcopenia. We analyzed microRNAs (miRNA) that are differentially expressed in young and old myoblasts, to identify novel intrinsic factors that play a degenerative role in aged skeletal muscle. miR-431, one of decreasing miRNAs in old myoblasts, improved the myogenic differentiation when overexpressed in old myoblast, but suppressed their myogenic capability in knockdowned young myoblasts. We found that miR-431 directly binds to 3` untranslated regions (UTR) of Smad4 mRNA, and decreases its expression. Given that SMAD4 is one of the downstream effectors of TGF-β, a well-known degenerative signaling pathway in myogenesis, the decreased miR-431 in old myoblast causes SMAD4 elevation, thus resulting in defective myogenesis. Exogenous expression of miR-431 greatly improved the muscle regeneration in the cardiotoxin-injured hindlimb muscle of old mice by reducing SMAD4 levels. Since the miR-431 seed sequence is conserved in human SMAD4 3'UTR, miR-431 regulates the myogenic capacity of human skeletal myoblasts in the same manner. Our results suggest that age-associated miR-431 is required for the maintenance of the myogenic capability in myoblasts, thus underscoring its potential as a therapeutic target to slow down muscle aging.