The Prevalence Rate of Adult Sarcopenic Obesity and Correlation of Appendicular Skeletal Muscle Mass Index with Body Mass Index, Percent Body Fat, Waist–Hip Ratio, Basal Metabolic Rate, and Visceral Fat Area

Background: This study aimed to investigate the prevalence rate of adult sarcopenic obesity and discuss its predisposing factors. Methods: A total of 14,608 participants including 7521 men and 7087 women aged 18-93 years were enrolled in this study. The definition of sarcopenia was based on appendicular skeletal muscle mass index (ASMI) standards (≤7.0 kg/m2 for men and ≤5.7 grams/m2 for women). The definition of obesity followed percent body fat (PBF) ≥25% for men and ≥35% for women. Sarcopenic obesity was defined as the combination of sarcopenia and obesity diagnosis. Risk factors for the onset of sarcopenic obesity were analyzed by logistic regression analysis, followed by diagnostic value assessment. Results: There were 496 cases of sarcopenic obesity, including 308 male patients and 188 female patients. The overall prevalence rate was 3.4%, with 4.10% for men and 2.65% for women. Compared with nonsarcogenic obesity group, the subjects with sarcogenic obesity showed shorter height and circumference of limbs, arm muscle, neck, chest, waist and hip, lighter weight, lower body mass index (BMI), bone mineral content (BMC), skeletal muscle mass, basal metabolic rate (BMR), body cell mass, fitness score and ASMI, and higher body fat mass, PBF, waist-hip ratio (WHR), visceral fat area (VFA), extracellular fluid/total body fat, and extracellular water/total body water (ECW/TBW; P < 0.01). Based on logistic regression analysis, BMI, BMC, PBF, WHR, BMR, VFA, fitness score, lean balance trunk, lean balance left leg, ASMI, ECW/TBW and the circumference of left arm, left leg, arm muscle, chest waist and hip were considered as risk factors for sarcogenic obesity (P < 0.05). After receiver operating characteristic (ROC) curve analysis of basic condition, muscle mass, and limb condition, ASMI [area under the curve (AUC) = 0.75] showed relatively high diagnostic value for adult sarcopenic obesity; other indicators (AUC <0.75) showed moderate diagnostic value for adult sarcopenic obesity, except for fitness score. According to joint ROC analysis, combination of BMC, PBF, VFA, and ASMI (AUC = 0.78) showed high diagnostic value for adult sarcopenic obesity. ASMI was correlated with BMI (r = 0.246, P < 0.001), BMC (r = 0.798, P < 0.001), WHR (r = 0.197, P < 0.001), BMR (r = 0.932, P < 0.001), PBF (r = -0.761, P < 0.001), and VFA (r = -0.530, P < 0.001). In adult patients with sarcopenic obesity, a decrease in ASMI indicators may be accompanied by a decrease in BMI, BMC, WHR, and BMR as well as an increase in PBF and VFA. Conclusion: The prevalence rate of adult sarcopenic obesity was 3.40%. ASMI was closely correlated with BMI, BMC, PBF, WHR, BMR, and VFA, which may serve as early indicators in the diagnosis of adult sarcopenic obesity.