Association between trace elements and cognitive function among hemodialysis patients in Turkey.

Introduction: Cognitive impairment is common among patients with hemodialysis. Hemodialysis patients have theoretical risks for both deficiency and accumulation of trace elements. We aimed to investigate the relationship between cognitive dysfunction and whole blood levels of trace elements in hemodialysis patients. We also aimed to examine the effect of baseline trace element status and cognitive dysfunction on mortality.

Methods: Maintenance hemodialysis patients and age-and sex-matched controls were included. The whole blood levels of trace elements were measured by inductively coupled plasma mass spectrometry. Cognitive impairment was defined as a score of ≤24 points on the Montreal Cognitive Assessment test. Executive dysfunction was also defined as Trails A score of more than 75 s and Trails B score of more than 180 s.

Findings: Forty-two patients and 35 controls were included. Cognitive impairment was detected in 69% of the patients and 45.7% of the controls (p = 0.039). Cognitively impaired patients had lower education years (p = 0.003) and higher whole blood levels of manganese (Mn) and lead (Pb) (p = 0.026, p = 0.019, respectively) compared to patients without cognitive impairment. Mn levels were also found statistically higher in patients with executive dysfunction compared to patients without executive dysfunction (p = 0.005). Lower education years and higher Pb levels were independent risk factors for cognitive impairment in hemodialysis patients (odds ratio [OR] 0.589 [95% confidence interval, CI 0.400-0.866, p = 0.007] and OR 1.047 [95% CI 1.001-1.096, p = 0.047, respectively]).

Discussion: Cognitive impairment, especially impaired executive function, is common among patients with hemodialysis patients. Cognitive impairment is not found to be associated in cross-sectional analysis with several modifiable end-stage renal disease- and dialysis-associated factors. The accumulation of trace elements especially Mn and Pb might exacerbate the cognitive dysfunction in hemodialysis patients.