The relationships among the skeletal muscle mass index, cardiorespiratory fitness and the prevalence of coronary artery disease in the elderly population

Relationship Between Number of Cardiac Rehabilitation Exercise Training Sessions, Muscle Mass, and Cardiorespiratory Fitness in Rural Elderly Patients with Coronary Artery Disease

Purpose

This study aimed to compare the effects of a cardiac rehabilitation (CR) exercise program on skeletal muscle index (SMI) and cardiorespiratory fitness (CRF) in patients aged ≥65 years.

Patients and Methods

From January 2012 to December 2021, patients living in rural regions aged ≥65 who underwent percutaneous coronary intervention for acute myocardial infarction (AMI) and at least one CR exercise session were enrolled. We retrospectively reviewed the medical records of the patients who underwent an exercise tolerance test (ETT) at initial and 3-month follow-ups. A total of 36 patients were enrolled who underwent a mean of 6.56 exercise sessions and were divided into groups based on the number of center-based CR (CBCR) sessions: 14 in Group A (≥7 sessions) and 22 in Group B (<7 sessions). In CBCR session, we comprehensively counseled them about their nutrition, smoking cessation et al. Both groups underwent an ETT after 12 weeks. The outcomes were CRF parameters examined by a cardiorespiratory exercise test and the SMI examined by bioimpedance analysis (BIA).

Results

The number of exercise sessions was significantly correlated with the rate of SMI change. Group A showed significant increases in metabolic equivalent of task (MET), maximal oxygen uptake (VO2max), and SMI after 3 months. There were significant differences in the rates of change in MET, VO2max, and SMI between the two groups.

Conclusion

CRF significantly improved in Group A in a short period. Further studies are required to increase long-term CBCR adherence in elderly patients with AMI in rural regions.

The relationship between skeletal muscle mass and the KOSHA cardiovascular risk in obese male workers

Background

Efforts for the prevention and management of cardiovascular diseases (CVDs) in workers have been actively pursued. Obesity is one of the important risk factors related to CVDs. Obesity has various metabolic characteristics, and some individuals can be metabolically healthy. Body composition including skeletal muscle mass is known to have protective effect in obesity. The study aims to investigate the association between skeletal muscle mass and Korea Occupational Safety and Health Agency (KOSHA) CVD risk among obese male manufacturing workers in Korea and to identify appropriate indicators of skeletal muscle mass for predicting risk of CVDs.

Methods

The study was conducted on 2,007 obese male workers at a manufacturing industry aged more than 19 years. Skeletal muscle mass, skeletal muscle index (SMI), skeletal muscle mass percent (SMM%) and skeletal muscle to body fat ratio (MFR) were used to evaluate body composition and these indicators were divided into quartiles. The odds ratios (ORs) and 95% confidence intervals (CIs) for the KOSHA CVD risk groups according to quartiles of skeletal muscle mass indicators were estimated using ordinal logistic regression analysis.

Results

The OR for the KOSHA CVD risk groups in the highest quartile of SMI was 1.67 (95% CI: 1.42-1.92), while the ORs for the KOSHA CVD risk groups in the highest quartiles of SMM%, SMM/body mass index (BMI), and MFR were 0.47 (95% CI: 0.22-0.72), 0.51 (95% CI: 0.05-0.76), and 0.48 (95% CI: 0.23-0.74), respectively.

Conclusions

We found that high SMI increase the likelihood of high risk of CVDs, while high SMM%, SMM/BMI, and MFR lower the likelihood of high risk of CVDs. Accurate evaluation of skeletal muscle mass can help assess the cardiovascular risk in obese male workers.