PS-C25-12: CORRELATION OF RENAL FUNCTION AND MUSCLE MASS IN YOUNG ATHLETES

Objective: Renal function is closely associated with the development of hypertension. Creatinine is often used as a serum marker of renal function. Since creatinine is a metabolite of muscle, its concentration in serum is affected by muscle mass. Therefore, serum creatinine levels are high in individuals with high muscle mass, and renal function is underestimated. On the other hand, in elderly people with low muscle mass, serum creatinine concentration tends to be low, and there is a risk that renal function is estimated better than it actually is. Since another renal function marker, cystatin C, is produced in every cell of humans, it is considered to be unaffected by skeletal muscle mass. Therefore, cystatin C is often used as a renal function marker that is less dependent on muscle mass than creatinine. In this study, we analyzed the correlation between muscle mass and renal function in young athletes with high muscle mass. Design and Methods: The subjects are 250 first-year male students at the National Institute of Fitness and Sports in Kanoya. The impedance method was used to measure muscle mass. Serum creatinine and cystatin C levels were measured by a clinical laboratory. Grip strength was measured with a Smedley-type hand dynamometer, and isometric measurement was performed to measure the leg extension force. Results: Muscle mass showed a significant correlation with left and right grip strength and right leg extension force. These results show that the muscle mass of the whole body measured in this study reveals the skeletal muscle mass, from which serum creatinine is derived. Muscle mass showed a significant correlation with serum creatinine levels. It also showed a significant correlation with the glomerular filtration rate estimated from creatinine concentration, age, and gender. Muscle mass also showed a significant correlation with serum cystatin C levels. It also showed a significant correlation with the glomerular filtration rate estimated from cystatin C, age, and gender. Conclusion: In general, serum creatinine concentration is a renal function marker that is affected by muscle mass, and cystatin C is a renal function marker that is less affected by muscle mass. The results in this study show that muscle mass should be taken into consideration for the evaluation of renal function based on serum cystatin C level in young athletes.