Sarcopenia refers to the decline in skeletal muscle mass and increased fragility to fall injuries in older people aged 60 years and above. Sarcopenic obesity (SO) (i.e., decrease in muscle mass and abdominal obesity) is controversially associated with cardiometabolic risk factors (CMFs). Therefore, we examined the association of SO with CMFs in Mexican-Americans by focusing on the role of adiponectin (Adp).
For the analysis, we included information from 1,127 participants from San Antonio Mexican American Family Studies (mean age: 40 (SD: 16) years, males: 32%, diabetes: 18%). Our data included serum Adp and CMFs (e.g., blood pressure, glucose, insulin, and lipid profile), including abdominal obesity (waist circumference >102 cm in men or > 88 cm in women). Sarcopenia was measured as skeletal muscle index (SMI = total muscle mass/height squared) < 1 SD of the younger group (18-to-39 years adjusted by sex). Polygenic residuals from SOLAR were inverse normalized for Mediation analysis using AMOS/SPSS.
SO was found in 12% females and 14% males. Male gender showed increased risk for obesity (OR 1.9, 95%CI: 1.5, 2.4), but not with SO (OR 1.2, 95%CI: 0.8, 1.7). SO was found to have a better metabolic profile, but abdominal obesity by itself exhibited association with fasting insulin (Cohen-d 0.39, p<0.001). Mediation analysis showed an inverse association between SMI and Adp (b=-0.32); and, Adp partially mediated effects on insulin resistance (b= -0.33), lipids (b=-0.32) and blood pressure (b=-0.12), all p-values <0.001.
In summary, Mexican-American SO has higher adiponectin levels that can explain its paradoxical association with CMFs.