<p>Attenuated serum 25-hydroxyvitamin D and vitamin D binding protein associated with cognitive impairment in patients with type 2 diabetes</p>

Abstract

PurposeClinical studies suggest that 25-hydroxyvitamin D (25[OH]D) deficiency plays a pivotal role in both type 2 diabetes mellitus (T2DM) and cognitive impairment. However, it is unclear if 25(OH)D deficiency could be a possible cause of cognitive impairment in T2DM. Vitamin-D binding protein (VDBP) acts as a major 25(OH)D transporter. Preclinical study has demonstrated improvement in cognitive function by VDBP via inhibiting synaptic degeneration. The aim of the study was to assess the association between serum 25(OH)D, VDBP and cognitive impairment in T2DM patients.Patients and methodsIn this case-control study, cognitive function was assessed using the Mini-Mental State Examination (MMSE) and serum 25(OH)D and VDBP levels were estimated using ELISA kits.ResultsA total of 88 subjects were included in the study. T2DM patients had lower serum 25(OH)D (p=0.02), VDBP levels (p=0.04) and MMSE scores (p<0.0001) than controls. T2DM patients had higher prevalence of 25(OH)D deficiency and insufficiency, aOR 0.322 (0.128–0.809), p=0.016 and cognitive impairment, aOR 4.405 (1.617–12.002); p=0.004. Cognitive impairment was associated with serum 25(OH)D, aOR 0.131 (0.027–0.638); p=0.014 and VDBP, aOR 1.008 (1.001–1.015), p=0.029. A general linear model showed a significant association of MMSE with serum 25(OH)D (p=0.022).ConclusionSerum 25(OH)D deficiency and cognitive impairment was higher in T2DM patients. Routine assessment of cognitive function is suggested to prevent further behavioral complications. The association of VDBP and cognitive impairment in T2DM needs further exploration.

Comparative assessment of cognitive impairment and oxidative stress markers among vitamin D insufficient elderly patients with and without type 2 diabetes mellitus (T2DM)

“…Contrarily, few of the previous clinical studies have shown an association between diabetes mellitus, vitamin D and cognitive dysfunctions and an increased risk of vascular dementia and Alzheimer’s disease in vitamin D deficient patients. A case control study by Parveen et al, and a cross-sectional study by Chen et al, have reported an inverse association of 25(OH)D and cognitive impairment in T2DM patients [ 34 , 35 ]. A randomized control trial by Byrn et al, found, no significant differences in cognitive outcomes between T2DM patients who received high-dose therapy and those who received low dose of vitamin D. But the study did not contain a true placebo group [ 36 ].…”

Association of serum 25-hydroxyvitamin D concentrations with risk of dementia among individuals with type 2 diabetes: A cohort study in the UK Biobank

“…The heterogeneity in these findings might be explained by limited statistical power, residual confounding, variations in 25(OH)D level measurement, and unstandardized definitions of dementia diagnosisAU : Ichangedunstandardizeddementiadiagnosest across studies. Among patientsAU : Pleasecheckthattheeditstothesentence}Amongpatients:::}captureyourmeaning:I with diabetes, who have a high prevalence of vitamin D deficiency and heightened risk of developing dementia [13][14][15][16]AU : ðOriginalÞreference30wasaduplicateofref 14; soIde , the evidence regarding vitamin D status and cognitive function is scarce [17][18][19]. A cross-sectional study found lower levels of serum 25 (OH)D among T2D patients with mild cognitive impairment assessed using the Montreal Cognitive Assessment score [17].…”

“…A cross-sectional study found lower levels of serum 25 (OH)D among T2D patients with mild cognitive impairment assessed using the Montreal Cognitive Assessment score [17]. Another 2 case-control studies showed that serum 25(OH)D levels were associated with Mini-Mental State Examination and Montreal Cognitive Assessment score among patients with T2D [18,19]. However, no study has examined the association between circulation 25(OH)D levels and dementia among patients with diabetes.…”

“…Moreover, compared with general populations, individuals with diabetes are particularly susceptible to both vitamin D deficiency [13,14] and increased risk of developing dementia [15,16]. Although several crosssectional and case-control studies have suggested an inverse association between serum 25-hydroxyvitamin D (25[OH]D) and cognitive function decline assessed using neuropsychological tests among patients with T2D [17][18][19], these studies had limitations of small sample size, low quality of study design, and insufficient adjustment for critical confounders such as apolipoprotein E (APOE) ε4AU : Ichanged"AOPEε4"to"APOEε4"throughout:Ifthisisnotcorrect; pleasee genotype, severity of diabetes, and lifestyle factors. To fill these knowledge gaps, we examined the association of serum 25(OH)D concentration with the risk of all-cause dementia, Alzheimer disease (AD), and vascular dementia (VD) among 13,486 individuals with T2D who were �60 years old in the UK Biobank study.…”

Alterations in Circulating Levels of Vitamin D Binding Protein, Total and Bioavailability of Vitamin D in Diabetes Retinopathy Patients

“…However, abnormal metabolic environmental factors like vitamin D de ciency increase the risk of developing diabetic retinopathy [6][7][8][9][10][11]. Vitamin D may have a role in the pathogenic mechanisms predisposing to diabetes complications through dysregulating in glucose homeostasis, modulating insulin resistance, and/or pancreatic β-cell function [12,13].…”