#4596 ASSOCIATION OF LOW BLOOD SELENIUM CONCENTRATIONS WITH POOR MUSCLE MASS AND STRENGTH IN JAPANESE HEMODIALYSIS PATIENTS
Authors: Takasawa Kazuya , Takaeda Chikako , Hayashi Daiki , Ochi Masahiko , Ueda Norishi 
Published: June 2023

Abstract

Background and Aims
Trace elements play an important role in muscle function and metabolism. Little information is available of a role of trace elements for sarcopenia (i.e. low muscle mass and strength) in patients on hemodialysis (HD). We aimed to investigate association between blood levels of trace elements and nutritional status or sarcopenia in HD patients.

Method
This cross-sectional study including patients undergoing HD at our center was conducted in June 2022. Clinical/demographic data and blood samples were collected before HD sessions at start of the week. Blood levels of zinc (Zn), copper (Cu), selenium (Se), and manganese (Mn), serum levels of creatinine (Cr), total cholesterol (Tch) and albumin (Alb) and body mass index (BMI) were measured. Handgrip strength, gait speed and muscle mass (skeletal muscle index: SMI) measured using dual-energy x-ray absorptiometry were analyzed. Sarcopenia was assessed by Asian Working Group for Sarcopenia (AWGS) and nutritional status by the Nutritional Risk Index-Japanese Hemodialysis (NRI-JH), which was calculated based on serum Cr, Tch, Alb and BMI (PLoS One. 2019, 14(3):e0214524). Peason's correlation coefficient test, multivariate logistic regression analyses were performed to evaluate the relationship between trace elements and nutritional indicators.

Results
Eighty-two patients (56 males and 26 females) were included, with a median dialysis vintage of 9.1±7.1 years and an average age of 68.7±12.2 years. Severe malnourished patients as defined by the NRI-JH and sarcopenia defined by AWGS accounted for 6.0% and 37.8% of enrolled patients, respectively. In all patients, the mean levels of Zn, Cu, Se, and Mn (in μg/dL) were 65.8±11.3, 84.1±22.2, 9.2±1.5 and, 1.2±0.6. respectively. The levels of Zn, Cu, Se and Mn were lower than normal levels in 72 cases (87.8%), 18 cases (22%), 57 cases (69.5%), and 13 cases (15.9%), respectively. There was an inverse correlation between the levels of Se and age (r = -0.298 p = 0.003) but not HD vintage. No significant correlation was found between the NRI-JH scores and blood levels of trace elements in all patients. Blood trace elements have been shown to be affected by gender. Thus, we next examined whether blood levels of trace elements and the relationship between blood trace elements and SMI and strength are different between male and female HD patients. The levels of Zn and Mn did not differ between males and females. The levels of Cu were lower in males (79.8±19.3 μg/dL) than females (93.0±25.4 μg/dL, p = 0.025). In contrast, the levels of Se were higher in males (9.5±1.5 μg/dL) than females (8.6±1.2 μg/dL, p = 0.0017). The multivariate logistic regression showed that higher blood levels of Zn and Se and lower Mn levels were independently associated with grip strength (p&lt;0.01) but not gait speed in males. There was a significant positive correlation between Se and SMI (r = 0.305 p = 0.02) but not gait speed in males. In females, grip strength (r = 0.39, p = 0.048) and gait speed (r = 0.66, p&lt;0.001) were independently associated with the Se levels but not Zn, Cu and Mn. However, there was no association between SMI and blood levels of Se, Zn and Mn in females.

Conclusion
Blood levels of Se were independently associated with grip strength and SMI in male HD patients. In female HD patients, the levels of Se were positively correlated with grip power and gait speed. Se may be implicated in muscle function and metabolism in HD patients.