The Relationship Between Serum Selenium Level, Cognitive Functions, and Depression in Patients With Chronic Kidney Disease

Introduction Impairment of cognitive functions can commonly develop in patients with chronic kidney disease (CKD) and increase morbidity and mortality. The antioxidant activity of selenium reduces cognitive decline by protecting neurons from free radical damage. We aimed to explore the associations between serum selenium levels, cognitive impairment, and depression in CKD patients in this research. Methods In this prospective cross-sectional research, 100 participants between the ages of 20 and 65 were included, and four groups of 25 patients each were formed (control group, stage 3-4 CKD, peritoneal dialysis [PD], hemodialysis [HD]). The Standardized Mini Mental Test (sMMT) was used to measure cognitive skills, and the Beck Depression Inventory (BDI) was utilized to diagnose depression. Simultaneously, measurements of serum selenium levels were done from collected blood samples. Results Cognitive impairment was detected in 4% of the control group, 16% of CKD patients (n=75), and 30% of the dialysis patients (n=50). Depression was found in 16% of the control group, 40% of the stage 3-4 CKD group, 50% of the PD group, and 44% of the HD group. In the control group, sMMT scores were higher than the other groups (p<0.001 for all), while the BDI score was statistically significantly lower (p=0.003). Serum selenium levels were found to be higher than HD and PD groups in patients with non-dialysis CKD and control groups in the post hoc analyses (p=0.001, p<0.001, p<0.001, p<0.001, respectively). Conclusion Depression and cognitive impairment are particularly prevalent in CKD and dialysis patients. Our results indicate serum selenium insufficiency may be related to depression and cognitive impairment in this patient group. Nonetheless, these findings need to be confirmed by larger-scale studies.