Skeletal muscle mass to visceral fat area ratio is associated with metabolic syndrome and arterial stiffness: The Korean Sarcopenic Obesity Study (KSOS)

https://doi.org/10.1016/j.diabres.2011.06.013Get rights and content

Abstract

Aims

Sarcopenia measured as appendicular skeletal muscle mass (ASM), and central obesity measured as visceral fat area (VFA) may act synergistically to influence metabolic syndrome and atherosclerosis. However, several previous studies reported that metabolic risk is higher in non-sarcopenic obesity groups than in sarcopenic obesity groups because of the close relationship between muscle mass and body fat. We investigated the association of the ASM to VFA ratio, which we have termed the muscle-to-fat ratio (MFR), with metabolic syndrome and arterial stiffness.

Methods

This study was performed in 526 apparently healthy adults enrolled in the Korean Sarcopenic Obesity Study, an ongoing prospective observational cohort study. ASM was evaluated with dual energy X-ray absorptiometry and VFA with computed tomography. Arterial stiffness was measured using brachial-ankle pulse wave velocity (baPWV).

Results

MFR was significantly associated with waist circumference, blood pressure, lipid profiles, glucose and baPWV. By multiple logistic regression analysis, the odds ratio for metabolic syndrome was 5.43 (lowest versus highest tertile of MFR, 95% confidence interval, 2.56–13.34). Multiple stepwise regression analysis showed that MFR was an independent determinant of baPWV (R2 = 0.57).

Conclusions

MFR, a new index of sarcopenic obesity, showed an independent negative association with metabolic syndrome and arterial stiffness.

Introduction

Aging is frequently associated with a decrease in muscle mass and/or strength, also known as sarcopenia, and a relative increase in visceral fat [1], [2]. The imbalance between skeletal muscle mass and visceral fat mass in older individuals occurs even in the absence of significant changes in body mass index (BMI) and may have synergistic effects on health outcomes including metabolic disorders, cardiovascular disease (CVD) and mortality [2], [3]. These imbalances are extreme in some individuals, producing a condition that is a combination of obesity and sarcopenia, a condition recently termed “sarcopenic obesity”. However, several previous epidemiologic studies failed to find the association between sarcopenic obesity and cardiovascular risk factors [4], [5]. In the New Mexico Aging Process Study, the prevalence of metabolic syndrome was highest in the non-sarcopenic obese group, followed by the sarcopenic obesity group, and normal group, and was lowest in the sarcopenic non-obese group [4]. Similarly, in obese postmenopausal women, sarcopenia appeared to be associated with lower CVD predisposing risk factors [5]. In the EPIDOS study, sarcopenia was not associated with physical difficulties in the absence of obesity. However, in the presence of obesity, sarcopenia tended to add difficulties in physical function [6]. Because skeletal muscle mass and total body fat are closely correlated, an increase in skeletal muscle mass is often accompanied by gain in total body fat [7]. Therefore, assessment of the effect of sarcopenia on metabolic syndrome and atherosclerosis might require simultaneous consideration of visceral obesity.

Appendicular skeletal muscle mass (ASM) is an important index of sarcopenia that can be measured by dual energy X-ray absorptiometry (DXA), a noninvasive, highly reproducible and accurate technique [8], [9], [10]. Visceral fat area (VFA) can be measured by computed tomography (CT) which is considered the gold standard method for determining visceral adiposity [11]. Although sarcopenia and visceral obesity may potentiate each other, resulting in a substantial effect on metabolic disorders and atherosclerosis in older persons, most studies thus far have investigated the role of sarcopenia and visceral obesity separately. Therefore, we present and evaluate a new surrogate index of sarcopenic obesity using the ratio of ASM-to-VFA that we call muscle-to-fat ratio (MFR).

Arterial stiffness measured as pulse wave velocity (PWV) is also known to increase with aging. PWV is an indicator of atherosclerosis and an independent predictor of cardiovascular risk in the general population [12], [13]. Brachial-ankle PWV (baPWV) can be used as a simple and reliable marker to screen the general population for the presence of CVD [14], [15]. Several proposed underlying mechanisms of sarcopenic obesity, including aging, sedentary life style, inflammation and insulin resistance, are also known to be related to atherosclerosis [3]. Recently, Ochi et al. reported that arterial stiffness is negatively related to thigh muscle volume in men but not in women [16]. However, they did not consider visceral fat in their analysis and used thigh muscle cross-sectional area as an indicator of sarcopenia.

Based upon these findings, we hypothesize that sarcopenia and obesity interact with each other to further facilitate atherosclerosis. However, there are no studies evaluating the association between surrogate index of sarcopenic obesity and atherosclerosis, indicating that a decrease in MFR is going to be related to higher baPWV.

Herein, in order to prove our hypothesis we evaluated the possible relationship between MFR, an index of skeletal muscle mass corrected by visceral obesity, and components of metabolic syndrome. We further examined the association between MFR and arterial stiffness in an apparently healthy general population.

Section snippets

Study subjects

We analyzed baseline cross-sectional data from the Korean Sarcopenic Obesity Study (KSOS), an ongoing epidemiologic study supported by Korea Science and Engineering Foundation. This prospective observational cohort study was designed to examine the prevalence of sarcopenia and sarcopenic obesity in Korean adults with (diabetic KSOS cohort) or without diabetes (non-diabetic KSOS cohort) and to evaluate their effects on metabolic disorders and health outcomes [17], [18]. In this study, eligible

Results

The age of enrolled subjects ranged from 20 to 80 years with a mean of 53.6 ± 15.6 years, and 68% were female. Anthropometric indicators such as BMI, ASM, ASM/height2, mid-thigh muscle area, and VFA, SBP, DBP, triglyceride, FPG, and baPWV were all higher in men than in women (Table 1). By contrast, SFA, total body fat percentage and HDL-cholesterol were significantly higher in women. Interestingly, there was no significant difference of MFR as well as age and LDL-cholesterol between men and

Discussion

In this study, we found that MFR was significantly decreased in subjects with metabolic syndrome and associated with all the components of metabolic syndrome. Decreased MFR was a dependent risk factor for metabolic syndrome after correction for other confounding parameters. Furthermore, MFR was independently and negatively associated with arterial stiffness even after adjusting for other risk factors.

Changes in body composition during aging are associated with important effects on health and

Conflict of interest

The authors declare that they have no conflict of interest.

Acknowledgements

This study was supported by the Korea Science and Engineering Foundation (KOSEF) grant funded by the Korea Government (R01-2007-000-20546-0) and a grant from the Korean Health 21 R&D Project, Ministry of Health and Welfare, Republic of Korea (A 050463).

References (35)

  • M. Aubertin-Leheudre et al.

    Effect of sarcopenia on cardiovascular disease risk factors in obese postmenopausal women

    Obesity (Silver Spring)

    (2006)
  • A.B. Newman et al.

    Sarcopenia: alternative definitions and associations with lower extremity function

    J Am Geriatr Soc

    (2003)
  • R.N. Baumgartner et al.

    Epidemiology of sarcopenia among the elderly in New Mexico

    Am J Epidemiol

    (1998)
  • U. Styrkarsdottir et al.

    New sequence variants associated with bone mineral density

    Nat Genet

    (2009)
  • A. Alexandersen et al.

    Prediction of driving ability after inconclusive neuropsychological investigation

    Brain Inj

    (2009)
  • W.C. Chumlea et al.

    Bioelectric impedance methods for the estimation of body composition

    Can J Sport Sci

    (1990)
  • K.J. Howden et al.

    An investigation into human pandemic influenza virus (H1N1) 2009 on an Alberta swine farm

    Can Vet J

    (2009)
  • Cited by (0)

    View full text