Appendicular Muscle Mass per Body Weight and Waist Circumference were Appropriate Indexes for Sarcopenic Obesity

Abstract

PURPOSE:The purposes of this study were 1) to examine the association between difference of indexes for sarcopenic obesity (SO) and risk factors of metabolic syndrome (MetS) and 2) to determine the more appropriate indexes for SO in middle-aged and older Japanese men. METHODS:This study provides a cross-sectional investigation in 100 middle-aged and older Japanese men (56 ± 12 years). We used two indexes for sarcopenia: 1) Appendicular skeletal muscle mass (ASM) divided by height squared (ASM/Ht2, kg/m2) and 2) ASM as a percentage of body weight (ASM/Wt, %). ASM was measured by dual energy X-ray absorptiometry. On the other hand, we used three indexes for obesity: 1) waist circumference (WC, cm), 2) body mass index (BMI, kg/m2) and 3) body fat percentage (% fat, %). MetS risk score was derived by standardizing and then summing the following continuously-distributed variables: fasting blood glucose (FBG), serum triglyceride (TG) / HDL cholesterol (HDL-C) and mean blood pressure (MBP), to obtain the Z-score. SO risk score was derived from the difference in subtraction (ASM/Wt Z-score minus WC, BMI, % fat Z-score). RESULTS:ASM/Wt was observed significantly age-adjusted partial correlation with MetS risk score (r = -0.30, P < 0.01), but not ASM/Ht2. On the other hand, WC (r = 0.46, P < 0.001), BMI (r = 0.39, P < 0.05) and % fat (r = 0.36, P < 0.001) were observed significantly age-adjusted partial correlation with MetS risk score. Multiple regression analysis revealed that the MetS risk score was independently associated with SO risk score (derived by ASM/Wt and WC), but not with SO risk score (derived by ASM/Wt and BMI, ASM/Wt and % fat). CONCLUSIONS:These results suggest that ASM/Wt and WC are more closely related with risk factors of MetS in Japanese SO. Therefore, ASM/Wt and WC may be more appropriate indexes for the detection of SO.