CST3 and sarcopenia: Prior studies utilized clinical and anthropomorphic measurements (BMI, muscle strength, skin fold thickness, etc.)as an assessment of sarcopenia and obesity, which may not as accurately reflect the body composition of muscle and adipose tissue.S9–S11 As cystatin C is secreted by nucleated cells and constitutively expressed in almost all organs,31 higher body cell mass, which correlates with a higher BMI, could lead to a higher cystatin C level independent of kidney function.