The relationship between selenium level and cognitive functions in patients undergoing dialysis for end stage renal disease

Aim: It is known that impairment in cognitive functions, which is reported to develop in 16-38% of those with chronic kidney disease (CKD), is a factor that increases morbidity and mortality. It is known that selenium inhibits cognitive impairment by preventing neuronal damage caused by free radicals with its antioxidant effect. In this study, the relationship of serum selenium level with cognitive dysfunction and depression in CKD patients was investigated. Materials and Methods: In this clinical cross-sectional study, a total of 100 participants between the ages of 20-65 [Hemodialysis treatment (HD) (n=25), peritoneal dialysis (PD) treatment (n=25), stage 3-4 CKD (n=25), control group without CKD (n=25) participants] were included. Standardized Mini Mental Test (sMMT) was used to evaluate cognitive functions and Beck Depression Inventory (BDI) was used to detect the presence of depression. Simultaneously, blood samples were taken for serum selenium level measurements. Results: In our study cognitive dysfunction was detected in 16% of the patients with CKD (n=75), 30% of the dialysis patients (n=50) and 4% of the control group without CKD. Moderate or severe depression was found in 44% of HD patients, 50% of PD patients, 40% of stage 3-4 CKD patients and 16% of the control group without CKD. In the group without CKD, sMMT scores were significantly higher than the other groups (P<0.001, P<0.001, P<0.001, respectively), while the BDI score was lower (P=0.003). In post-hoc test analyzes, serum selenium level was found to be significantly higher than HD and PD groups in patients non-dialysis CKD and controls (respectively, P=0.001, P<0.001, P<0.001, P<0.001). Conclusion: Cognitive impairment and depression are common in CKD patients, especially in dialysis patients. Our findings suggest that serum selenium deficiency may contribute to both cognitive impairment and depression in this patient population. However, our findings should be supported by more extensive research.