Low Vitamin D level and its relation to cognitive function in chronic kidney diseases (dialysis and non-dialysis) patients

Abstract

Cognitive disability and vitamin D deficiency are mostly common in chronic kidney disease (CKD) patients. Vitamin D applies protective and controlling role in the CNS. Low level of D vitamin has been related with the weakness of muscle and bone trouble, circulatory disorders (hyperlipidemic, diabetes, and hypertension), oxidative injury, infections, immune decline and neurocognitive impedance. The level of vitamin D that is suboptimal is very common as well as to CKD. The two disorders, especially predominant in patients older than 65 years, and are known dangers for firmly connected with cognitive impairment. In spite of the fact that it is estimated that patients with CKD insufficient vitamin D level might encounter a quickened cognitive decline, and just little effectively planned studies achieved in this subject. Aim of study: Assessment of cognitive function in association with vitamin D level in patients with CKD with or without dialysis. Patients and methods: the study include two groups; 61 dialysis and 56 CKD nondialysis patients enrolled in our study, in which CKD was defined as eGFR <60 mL/min on at least two occasions during the previous study period (calculated using Modification of Diet in Renal Disease (MDRD) study). The exclusion criteria are: patients below 20 years old, pregnant ladies, deaf, blind and patients with stroke. The cognitive function had been assessed by using 1- The Mini-Mental State Examination (MMS) to asses' attention, short term and immediate recall and language2- Trail making Test B (Trails B) estimating the time needed to associate progression at succession numbered and lettered circles. Vitamin D assessed by using direct enzyme immune assay method. Results: For dialysis patients, 39.3 % had deficient 25 (OH) D levels, 34.4 % insufficient, 24.5 % had sufficient 25 (OH) D levels. Serum 25 (OH) vitamin D was significantly lower in dialysis patients compared to those with CKD, Mean MMs score was significantly lower in dialysis patients compared to CKD, while Trail B was significantly higher in dialysis patients, There was a significant correlation between various cognitive function tests (MMs, and Trials B) with vitamin D, There was a significant relation between various cognitive capacity tests (MMs, and Trials B) with creatinine. Conclusion: There is a high incidence of low 25(OH)D level in patients with CKD especially those on hemodialysis and that deficiency in vitamin D may be related to poor cognitive capacity.