Effect of Exercise Habit on Skeletal Muscle Mass Varies with Protein Intake in Elderly Patients with Type 2 Diabetes: A Retrospective Cohort Study

Unveiling the detrimental vicious cycle linking skeletal muscle and COVID-19: A systematic review and meta-analysis

OBJECTIVE

Skeletal muscle catabolism supports multiple organs and systems during severe trauma and infection, but its role in COVID-19 remains unclear. This study investigates the interactions between skeletal muscle and COVID-19.

METHODS

The PubMed, EMbase, and The Cochrane Library databases were systematically searched from January 2020 to August 2023 for cohort studies focusing on the impact of skeletal muscle on COVID-19 prevalence and outcomes, and longitudinal studies examining skeletal muscle changes caused by COVID-19. Skeletal muscle quantity (SMQN) and quality (SMQL) were assessed separately. The random-effect model was predominantly utilized for statistical analysis.

RESULTS

Seventy studies with moderate to high quality were included. Low SMQN/SMQL was associated with an increased risk of COVID-19 infection (OR = 1.62, p < 0.001). Both the low SMQN and SMQL predicted COVID-19-related mortality (OR = 1.53, p = 0.016; OR = 2.18, p = 0.001, respectively). Mortality risk decreased with increasing SMQN (OR = 0.979, p = 0.009) and SMQL (OR = 0.972, p = 0.034). Low SMQN and SMQL were also linked to the need for intensive care unit/mechanical ventilation, increased COVID-19 severity, and longer hospital stays. Significant skeletal muscle wasting, characterized by reduced volume and strength, was observed during COVID-19 infection and the pandemic.

CONCLUSIONS

This study reveals a detrimental vicious circle between skeletal muscle and COVID-19. Effective management of skeletal muscle could be beneficial for treating COVID-19 infections and addressing the broader pandemic. These findings have important implications for the management of future virus pandemics.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42023395476.

The Vicious Cycle of Type 2 Diabetes Mellitus and Skeletal Muscle Atrophy: Clinical, Biochemical, and Nutritional Bases

Today, type 2 diabetes mellitus (T2DM) and skeletal muscle atrophy (SMA) have become increasingly common occurrences. Whether the onset of T2DM increases the risk of SMA or vice versa has long been under investigation. Both conditions are associated with negative changes in skeletal muscle health, which can, in turn, lead to impaired physical function, a lowered quality of life, and an increased risk of mortality. Poor nutrition can exacerbate both T2DM and SMA. T2DM and SMA are linked by a vicious cycle of events that reinforce and worsen each other. Muscle insulin resistance appears to be the pathophysiological link between T2DM and SMA. To explore this association, our review (i) compiles evidence on the clinical association between T2DM and SMA, (ii) reviews mechanisms underlying biochemical changes in the muscles of people with or at risk of T2DM and SMA, and (iii) examines how nutritional therapy and increased physical activity as muscle-targeted treatments benefit this population. Based on the evidence, we conclude that effective treatment of patients with T2DM-SMA depends on the restoration and maintenance of muscle mass. We thus propose that regular intake of key functional nutrients, along with guidance for physical activity, can help maintain euglycemia and improve muscle status in all patients with T2DM and SMA.

Diet, exercise, and pharmacotherapy for sarcopenia in people with diabetes

Diabetes prevalence is increasing rapidly in older people, and sarcopenia is prevalent as a novel complication, particularly in patients with type 2 diabetes mellitus (T2DM). Therefore, sarcopenia prevention and treatment in these people is necessary. Diabetes accelerates sarcopenia through several mechanisms, such as hyperglycemia, chronic inflammation and oxidative stress. The effects of diet, exercise, and pharmacotherapy on sarcopenia in patients with T2DM need to be considered. In diet, low intake of energy, protein, vitamin D, and ω-3 fatty acid are associated with sarcopenia risk. In exercises, although intervention studies in people, especially older and non-obese patients with diabetes, are few, accumulating evidence shows the usefulness of exercise, particularly resistance exercise for muscle mass and strength, and aerobic exercise for physical performance in sarcopenia. In pharmacotherapy, certain classes of anti-diabetes compounds have possibility of preventing sarcopenia. However, much data on diet, exercise, and pharmacotherapy were obtained in obese and non-elderly patients with T2DM, demanding actual clinical data on non-obese and older patients with diabetes.

Prognostic value of creatinine-to-cystatin c ratio in patients with type 2 diabetes mellitus: a cohort study

BACKGROUND

The serum creatinine-to-cystatin C ratio (Scr/Scys) has been suggested as a surrogate marker of muscle mass and a predictor of adverse outcomes in many diseases. However, the prognostic value of Scr/Scys in patients with type 2 diabetes mellitus (T2DM) is unknown. The aim of this study is to assess the prognostic value of Scr/Scys in patients with T2DM.

METHODS

In this retrospective observational study, we enrolled 3668 T2DM patients undergoing coronary angiography (CAG). Serum creatinine (Scr) and serum cystatin C (Scys) levels were measured at admission. The study population was separated into low muscle mass (low-MM) and normal muscle mass (normal-MM) groups by Scr/Scys cut-off point. The association between muscle mass and long-term all-cause mortality was examined using Cox regression analysis.

RESULTS

During a median follow-up of 4.9 (3.0-7.1) years, a total of 352 (9.6%) patients died. The mortality was higher in patients with low-MM as compared with patients with normal-MM (11.1% vs. 7.3%; p < 0.001). Low muscle mass was associated with increased risk for long-term all-cause mortality, regardless of whether Scr/Scys were used as a continuous variable (adjusted hazard ratio: 1.08 [95% confidence interval (CI) 1.03 to 1.13]; p = 0.009) or a categorial variable (adjusted hazard ratio: 1.36 [95% CI 1.03 to 1.75]; p = 0.021).

CONCLUSION

Low muscle mass assessed by Scr/Scys was associated with increased risk of long-term all-cause mortality in diabetic patients.

Effects of Smoking on the Gut Microbiota in Individuals with Type 2 Diabetes Mellitus

Smoking affects eating habits; however, few studies on smoking and the gut microbiota have reported the effects of diet in detail. This cross-sectional study aimed to determine the association between smoking and the gut microbiota, considering the impact of smoking on dietary intake. Dietary habits and the composition of the gut microbiota were assessed in 195 men with type 2 diabetes (164 non-current smokers and 31 current smokers) using a brief self-administered diet history questionnaire and 16S ribosomal RNA gene sequencing of fecal samples. The data were compared according to the current smoking status of the participants. Current smokers had high alcohol and sugar/sweetener intake and low fruit intake. The proportion of the Coprococcus genus was higher among current smokers. Multiple regression analysis adjusted for current smoking, age, exercise habits, alcohol intake, sugar and sweetener intake, and fruit intake showed that smoking was associated with the proportion of the Coprococcus genus. Current smoking was associated with both dietary intake and composition of the gut microbiota. Although dietary intake should be considered when investigating the association between smoking and the gut microbiota, the results suggest that the direct effect of smoking is more significant.

Osteosarcopenia and Long-COVID: a dangerous combination

SARS-CoV-2 has caused a global pandemic and an unprecedented public health crisis, infecting more than 580 million people worldwide. Moreover, recent evidence has suggested the emergence of a new syndrome known as Long-COVID, a term used to describe a diverse set of physical and mental symptoms that persist after a diagnosed SARS-CoV-2 infection. Epidemiological data have identified myalgias, muscle and joint dysfunction, and bone fragility as common sequelae in patients with moderate and severe forms of this disease. Significant musculoskeletal dysfunction has also been detected in some healed patients, although knowledge about pathophysiological mechanisms of Long-COVID is still rather scarce. In this context, SARS-CoV-2 infection has been suggested to amplify the effects of aging on the musculoskeletal system by aggravating the osteosarcopenic state. Based on this evidence, our review focused on the muscle and bone tissue alterations induced by SARS-CoV-2 infection and Long-COVID, summarizing the current knowledge on the underlying biological mechanisms and highlighting the need for a multidisciplinary approach to predict the musculoskeletal targets and long-term consequences of COVID-19 disease.

Impact of Eating Speed on Muscle Mass in Older Patients With Type 2 Diabetes: A Prospective Study of KAMOGAWA–DM Cohort

Background and Aims

Maintenance of muscle mass is important for sarcopenia prevention. However, the effect of eating speed, especially fast, normal, or slow speed, on muscle mass changes remains unclear. Therefore, the purpose of this prospective study was to investigate the effect of eating speed on muscle mass changes in patients with type 2 diabetes (T2DM).

Methods

This study included 284 patients with T2DM. Based on a self–reported questionnaire, participants were classified into three groups: fast–, normal–, and slow–speed eating. Muscle mass was assessed using a multifrequency impedance body composition analyzer, and skeletal muscle mass (SMI) decrease (kg/m²/year) was defined as [baseline SMI (kg/m²)–follow–up SMI (kg/m²)] ÷ follow–up duration (year). The rate of SMI decrease (%) was defined as [SMI decrease (kg/m²/year) ÷ baseline SMI (kg/m²)] × 100.

Results

The proportions of patients with fast–, normal–, and slow–speed eating were, respectively, 50.5%, 42.9%, and 6.6% among those aged <65 years and 40.4%, 38.3%, and 21.3% among those aged ≥65 years. In patients aged ≥65 years, the rate of SMI decrease in the normal (0.85 [95% confidence interval, CI: −0.66 to 2.35]) and slow (0.93 [95% CI −0.61 to 2.46]) speed eating groups was higher than that in the fast speed eating group (−1.08 [95% CI −2.52 to 0.36]). On the contrary, there was no difference in the rate of SMI decrease among the groups in patients aged <65 years. Compared with slow speed eating, the adjusted odds ratios of incident muscle loss [defined as rate of SMI decrease (%) ≥0.5%] due to fast– and normal–speed eating were 0.42 (95% CI 0.18 to 0.98) and 0.82 (95% CI 0.36 to 2.03), respectively.

Conclusion

Slow–speed eating is associated with a higher risk of muscle mass loss in older patients with T2DM.

Relationship between eosinophils counts and muscle mass decline in older people with type 2 diabetes: A prospective study of the KAMOGAWA-DM cohort

Sarcopenia has become an important issue in older individuals with type 2 diabetes. However, no previous studies investigated the relationship between eosinophil count and muscle mass decline. In this prospective cohort study, we aimed to investigate this relationship in older people with type 2 diabetes. Impedance body composition was used to assess body composition and skeletal muscle mass index (SMI, kg/m²) was calculated as appendicular muscle mass (kg)/height squared (m²). The decrease in SMI (kg/m² per year) was calculated as (baseline SMI [kg/m²] - follow-up SMI [kg/m²]) divided by the follow-up period (years). The rate of SMI decrease (%) was calculated as follows: (decrease in SMI [kg/m² per year] ÷ baseline SMI [kg/m²]) × 100; muscle mass decline was defined as the rate of SMI decrease of ≥0.5%. Complete blood counts, including eosinophil counts, were also measured. Among 141 participants, 54.6% experienced muscle mass decline during mean (standard deviation)19.4 (7.3) months of follow-up. The eosinophil counts of participants with muscle mass decline were higher than those of participants without muscle mass decline (216.5 [147.8] vs. 158.6 [113.1] cells/mm³, p = 0.004). Eosinophil counts were negatively associated with the rate of SMI decrease according to Spearman's rank correlation coefficient (r = 0.182, p = 0.031). According to logistic regression analyses, there was the relationship between eosinophil counts and incident muscle mass decline after adjusting for covariates (odds ratio of Δ 1 incremental of logarithm (eosinophil counts) 2.04 (95% confidence interval 1.15-3.61, p = 0.011). This study showed that eosinophil counts are associated with incident muscle mass decline. If an individual with type 2 diabetes has high eosinophil counts in blood tests, then it is necessary to pay more attention to the possibility of progression of muscle atrophy.

Skeletal muscle as a treatment target for older adults with diabetes mellitus: The importance of a multimodal intervention based on functional category

Although the lifespan of people with diabetes has increased in many countries, the age-related increase in comorbidities (sarcopenia, frailty and disabilities) and diabetic complications has become a major issue. Diabetes accelerates the aging of skeletal muscles and blood vessels through mechanisms, such as increased oxidative stress, chronic inflammation, insulin resistance, mitochondrial dysfunction, genetic polymorphism (fat mass and obesity-associated genes) and accumulation of advanced glycation end-products. Diabetes is associated with early onset, and progression of muscle weakness and sarcopenia, thus resulting in diminished daily life function. The type and duration of diabetes, insulin section/resistance, hyperglycemia, diabetic neuropathy, malnutrition and low physical activity might affect muscular loss and weakness. To prevent the decline in daily activities in older adults with diabetes, resistance training or multicomponent exercise should be recommended. To maintain muscle function, optimal energy and sufficient protein intake are necessary. Although no specific drug enhances muscle mass and function, antidiabetic drugs that increase insulin sensitivity or secretion could be candidates for improvement of sarcopenia. The goals of glycemic control for older patients are determined based on three functional categories through an assessment of cognitive function and activities of daily living, and the presence or absence of medications that pose a hypoglycemic risk. As these functional categories are associated with muscle weakness, frailty and mortality risk, providing multimodal interventions (exercise, nutrition, social network or support and optimal medical treatment) is important, starting at the category II stage for maintenance or improvement in daily life functions. Geriatr Gerontol Int 2022; ••: ••-••.

Factors associated with dropout from physical function assessment programs among participants receiving maintenance hemodialysis: A retrospective observational cohort study

We aimed to investigate the factors associated with dropout from a physical function assessment program among participants receiving outpatient hemodialysis (HD). The participants were divided into continuation and dropout groups and followed up for 3 years after the initial physical function assessment. Multivariate logistic regression analyses were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the dropout group to determine the factors associated with dropout from the physical function assessment program. The continuation and dropout groups included 43 and 58 participants, respectively. The continuation group had a significantly higher self-efficacy (SE) and age than the dropout group (p = 0.001, p = 0.047). Multivariate logistic regression analysis indicated that only SE (OR: 1.202, 95% CI: 1.082-1.334) remained a significant predictor after adjustment (p < 0.05). There is a need to evaluate SE to prevent dropout from physical functioning assessment programs.

Vitamin Intake and Loss of Muscle Mass in Older People with Type 2 Diabetes: A Prospective Study of the KAMOGAWA-DM Cohort

The aim of this prospective cohort study was to examine the relationships between the intakes of various vitamins and the loss of muscle mass in older people with type 2 diabetes (T2DM). The change in skeletal muscle mass index (SMI, kg/m²) (kg/m²/year) was defined as follows: (SMI at baseline (kg/m²) - SMI at follow-up (kg/m²))/follow-up period (year). The rate of SMI reduction (%) was calculated as follows (the change in SMI (kg/m²/year)/SMI at baseline (kg/m²)) × 100. The rate of SMI reduction ≥ 1.2% was considered as the loss of muscle mass. Among 197 people with T2DM, 47.2% of them experienced the loss of muscle mass at the 13.7 ± 5.2 month follow-up. Vitamin B1 (0.8 ± 0.3 vs. 0.8 ± 0.3 mg/day, p = 0.031), vitamin B12 (11.2 ± 8.3 vs. 13.4 ± 7.5 μg/day, p = 0.049), and vitamin D (16.5 ± 12.2 vs. 21.6 ± 13.0 μg/day, p = 0.004) intakes in people with the loss of muscle mass were significantly lower than those without. Vitamin D intake was related to the loss of muscle mass after adjusting for sex, age, exercise, alcohol, smoking, body mass index, SMI, glucagon-like peptide-1 agonist, sodium glucose cotransporter-2 inhibitor, insulin, HbA1c, creatinine, energy intake, and protein intake (adjusted odds ratio 0.93, 95% confidence interval: 0.88-0.97, p = 0.003). This study showed that vitamin D intake was related to the loss of muscle mass in older people with T2DM. Vitamin B12 intake tended to be related to the loss of muscle mass, although vitamin A, vitamin B2, vitamin B6, vitamin C, and vitamin E intake were not related.

Effect of COVID-19 Pandemic on the Change in Skeletal Muscle Mass in Older Patients with Type 2 Diabetes: A Retrospective Cohort Study

Background: The aim of this study was to investigate the effect of the coronavirus disease (COVID-19) pandemic restrictions on the change in muscle mass in older patients with type 2 diabetes (T2D), who were not infected with COVID-19. Methods: In this retrospective cohort study, data were obtained from outpatients who underwent bioelectrical impedance analysis at least twice before April 2020 and at least once thereafter. Skeletal muscle mass index (SMI, kg/m²) was calculated as appendicular muscle mass (kg) divided by height squared (m²). Change in SMI (kg/m²/year) was calculated as (follow-up SMI-baseline SMI/follow-up period). The differences between the changes in SMI before and after the start of the COVID-19 pandemic were evaluated using paired t test. Results: This study recruited 56 patients, with a mean (SD) age of 75.2 (7.1) years. SMI changed from 6.7 (0.9) to 6.8 (0.9) kg/m² before the COVID-19 pandemic, whereas SMI changed from 6.8 (0.9) to 6.6 (0.9) kg/m² after the start of the COVID-19 pandemic. SMI decreased after the start of the COVID-19 pandemic compared with before the pandemic (-0.117 (0.240) vs. 0.005 (0.289) kg/m²/year, p = 0.049). This decrease was observed in men (-0.159 (0.257) vs. 0.031 (0.325) kg/m²/year, p = 0.038), patients with poor glycemic control (-0.170 (0.264) vs. 0.031 (0.285) kg/m²/year, p = 0.042), and those with a long diabetes duration (-0.153 (0.229) vs. 0.082 (0.291) kg/m², p = 0.049). Conclusions: The COVID-19 pandemic restrictions caused muscle mass loss in older patents with T2D. Actions, including recommendation of exercise and adequate diet intake, are needed to prevent loss of muscle mass.

Sarcopenia Is Associated With a Risk of Mortality in People With Type 2 Diabetes Mellitus

BACKGROUND

Sarcopenia has reportedly been associated with increased risk of mortality in general populations. However, few studies have investigated the association between sarcopenia and mortality in older people with type 2 diabetes mellitus (T2D). This study aimed to investigate the effect of sarcopenia on incident all-cause mortality in older people with T2D.

METHODS

Low muscle strength were set at handgrip strength <28 kg for men and <18 kg for women, and low skeletal muscle mass index (SMI), evaluated using the impedance body composition analyzer, were set at SMI <7.0 kg/m² for men and <5.7 kg/m² for women. People who had both low muscle strength and low SMI were diagnosed with sarcopenia. Due to a low incidence of all-cause mortality, the propensity score was used. The propensity score was evaluated using multivariable logistic regression models with the following parameters: age, sex, duration of diabetes, history of heart disease, history of cancer, smoking, exercise, alcohol, sodium-glucose cotransporter-2 inhibitor, glucagon-like peptide-1 receptor agonist, insulin, corticosteroid, hypertension, body mass index, glycosylated hemoglobin A1c, triglycerides, and creatinine, and the C-statistic was 0.89.

RESULTS

In this prospective cohort study, 396 people with an average age and duration of diabetes of 71.3 (6.3) years and 16.3 (11.3) years, respectively, were included. Of those included, 14.6% had sarcopenia. During the average 40.5 (16.5) months of follow-up, 13 people (6 out of the 338 without sarcopenia and 7 out of the 58 with sarcopenia) died. Incident rate were 5.1/1000 person years of follow-up in people without sarcopenia and 41.3/1000 person years of follow-up in people with sarcopenia. According to Cox regression analysis, sarcopenia was associated with all-cause mortality (adjusted hazard ratio: 6.12, 95% confidence interval: 1.52-24.7, p = 0.011).

CONCLUSION

Sarcopenia is associated with incident all-cause mortality in older outpatients with T2D.

Sarcopenia: An underlying treatment target during the COVID-19 pandemic

The role of skeletal muscle mass in modulating immune response and supporting metabolic stress has been increasingly confirmed. Patients with sarcopenia, characterized by reduced muscle mass and muscle strength, were reported to have poor immune response and metabolic stress when facing acute infection, major surgeries, and other attacks. Based on empirical data, patients with sarcopenia are speculated to have increased infection rates and dismal prognoses amid the current 2019 novel coronavirus disease (COVID-19) epidemic. COVID-19 infection also aggravates sarcopenia because of the increased muscle wasting caused by systematic inflammation and the reduced physical activity and inadequate nutrient intake caused by social isolation. Notably, the interventions targeting skeletal muscle are anticipated to break the vicious circle and benefit the treatment of both conditions. We recommend sarcopenia assessment for populations with advanced age, inactivity, chronic disease, cancers, and nutritional deficiency. Patients with sarcopenia and COVID-19 infection need intensive care and aggressive treatments. The provision of at-home physical activities together with protein supplementation is anticipated to reverse sarcopenia and promote the prevention and treatment of COVID-19. The recommended protocols on nutritional support and physical activities are provided in detail.