ABSTRACT

Obesity plays a critical role in the etiopathogenesis of insulin resistance, which is one of the risk factors for sarcopenia. We aimed to investigate the relationship between muscle mass assessed using different formulas and insulin resistance.

The patients aged between 18 and 65 years, who visited the obesity outpatient clinic between 2013-2015, were retrospectively evaluated. Based on the results of 75-g oral glucose tolerance test, patients whose fasting plasma glucose, HbA1c, and second-hour plasma glucose were within the normal limits were enrolled in the study. Appendicular lean mass (ALM) and total muscle mass were measured using bioimpedance analysis. Subsequently, the muscle mass ratio (MMR) was calculated as the percentage of total muscle mass divided by the body weight, and the skeletal muscle index (SMI) was calculated as the total muscle mass divided by the height2.

Of the 284 participants, 159 (55.99%) were female. Although a positive correlation was observed for the homeostasis model assessment as an index of insulin resistance (HOMA-IR) level with body mass index (BMI), ALM/height2, and fat percentage, a negative correlation was observed with MMR, ALM/body weight, and ALM/BMI in males (p<0.001, p=0.011, p=0.001, p=0.002, p=0.008, and p=0.004, respectively). In females, HOMA-IR was found to have a positive correlation with ALM and ALM/height2 (p=0.039 and p=0.035, respectively). When adjusted for fat percentage and BMI, no relationship was determined between HOMA-IR and relevant muscle measurements in both sexes (p>0.05 for females and males).

Although MMR and ALM/body weight were low in the participants with insulin resistance in both sexes, the difference was not statistically significant. ALM/height2 that is used in the diagnosis of sarcopenia may not be appropriate for the assessment of muscle mass in insulin resistance.