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

Association between serum 25-hydroxyvitamin D3 level and cognitive impairment in older chronic kidney disease patients

This study aims to examine whether hypovitaminosis D was associated with cognitive impairment among chronic kidney patients with different level of albuminuria. This population-based cross-sectional study was conducted on elderly (over 60 years old) with urine albumin to creatinine ratio (UACR) ≥ 30 mg/g from 2011 to 2014 in the US National Health and Nutrition Examination Survey (NHANES). Cognitive function was assessed by the Consortium to Establish a Registry for Alzheimer's Disease Word List Learning (CERAD). Subjects were divided into 2 groups according to the absence or presence of cognitive impairment and a propensity score matching (PSM) was further conducted. The association was assessed with Spearman correlation and logistic regression analysis. The positive association of 25-hydroxyvitamin D3 (25(OH)D3) and cognitive score was presented. PSM analysis revealed that a higher level of 25(OH)D3 correlated to a better cognitive function in CKD patients with albuminuria, especially in patients with 30 mg/g ≤ UACR < 300 mg/g. This study indicated that a low 25(OH)D3 level was associated with poor cognitive performance, especially in patients with microalbuminuria. Thus, early diagnosis of vitamin D insufficiency and an effective intervention might be a useful therapeutic strategy to prevent cognitive decline in patients with the progression of renal dysfunction.

Association of vitamin D and cognition in people with type 2 diabetes: a systematic review

CONTEXT

There is a high prevalence of vitamin D deficiency and impaired cognitive function in people with type 2 diabetes mellitus (T2DM).

OBJECTIVE

To critically and systematically review the literature on the association between vitamin D status and cognitive performance in people with type 2 diabetes.

DATA SOURCES

This review was conducted according to PRISMA recommendations. MEDLINE, SCOPUS, the Cochrane Library, and Web of Science databases were searched using the terms "Diabetes Mellitus, Type 2", "Cognitive Function", and "Vitamin D".

DATA EXTRACTION

Eight observational and 1 randomized study were included, containing data of 14 648 adult and elderly individuals (19-74 y). All extracted data were compiled, compared, and critically analyzed.

DATA ANALYSIS

There is no strong evidence that lower serum concentrations of vitamin D and vitamin D-binding protein are associated with worsening cognitive function in individuals with T2DM. Vitamin D supplementation (12 wk) improved the scores of some executive functioning tests, although there was no difference between low doses (5000 IU/wk) and high doses (50 000 IU/wk).

CONCLUSIONS

There is no high-quality evidence demonstrating an association between vitamin D status and cognitive function, or clinical benefits on cognition from vitamin D supplementation in individuals with T2DM. Future studies are needed. Systematic Review Registration: PROSPERO registration no. CRD42021261520.

Vitamin D Deficiency Participates in Depression of Patients with Diabetic Peripheral Neuropathy by Regulating the Expression of Pro-Inflammatory Cytokines

Objective

Vitamin D deficiency is associated with patients with diabetic peripheral neuropathy (DPN), and low levels of vitamin D are common in patients with depression. Depression is common in DPN patients and the definite pathogenesis remains unclear. This study aimed to determine vitamin D deficiency in the onset of depression in DPN and evaluate the effect of vitamin D supplementation on depression.

Methods

A total of 192 patients with DPN were enrolled in this study. Clinical and laboratory information was collected. Chemiluminescent immunoassay was used to measure the level of 25(OH)D. Enzyme-linked immunosorbent assay was employed to measure the concentrations of interleukin (IL)-1β, tumor necrosis factor-α (TNF-α), and IL-17A. Subjects with low 25(OH)D received 5000IU vitamin D daily for 12 weeks. Depression scores and levels of 25(OH)D, IL-1β, TNF-α, and IL-17A were re-evaluated after supplementation.

Results

The incidence of vitamin D deficiency and depression was high in DPN patients. Compared with vitamin D sufficient participants, Hamilton Depression Rating Scale (HAMD) scores and the levels of inflammatory markers IL-1β, TNF-α, and IL-17A were significantly higher in insufficient group (all p<0.05). HAMD score, IL-1β, TNF-α, and IL-17A were negatively correlated with 25(OH)D (all p<0.05). A linear relationship existed among IL-1β, TNF-α, IL-17A, and 25(OH)D (p<0.05). HAMD scores, IL-1β, TNF-α, and IL-17A were all reduced significantly after supplementation of vitamin D (p<0.05). Binary logistic analysis revealed that vitamin D insufficiency was an independent risk factor for depression in patients with DPN. Receiver operating characteristic (ROC) curve analysis showed a high sensitivity (87.20%) of 25(OH)D in discriminating DPN patients with depression.

Conclusion

Vitamin D deficiency participated in occurrence of depression in DPN patients and could be mediated, at least in part, by upregulation of pro-inflammatory cytokines. Vitamin D supplementation may be effective in improving depressive symptoms in DPN patients.

The Impact of Vitamin D Deficiency and Insufficiency on the Outcome of Type 2 Diabetes Mellitus Patients: A Systematic Review

Vitamin D deficiency and insufficiency are public health concerns that have contributed to multiple negative health outcomes. Recent studies have revealed that vitamin D deficiency and insufficiency influence glycaemic control and the development of diabetes complications. The goal of this systematic review is to summarise the latest evidence on the impact of vitamin D deficiency and insufficiency on the outcome of Type 2 Diabetes Mellitus (T2DM) patients. In this PRISMA-guided systematic review, articles were sourced from three databases, namely, PubMed, Scopus, and Web of Science. The review only included literature published from 2012 until 2022, and 33 eligible studies met the inclusion criteria for this review. The included articles were critically appraised using the Mixed Method Appraisal Tool (MMAT). According to our findings, vitamin D deficiency or insufficiency is associated with mental health status, macrovascular and microvascular complications of T2DM, metabolic syndrome, increased risk of obesity, increased blood pressure, dyslipidaemia, glycaemic control, nerve-related disease, musculoskeletal-related complications, and reduced quality of life. Due to the diverse implications of vitamin D deficiency and insufficiency, screening for vitamin D levels in T2DM patients may be beneficial.

Consistent Inverse Associations of Total, “Bioavailable”, Free, and “Non-Bioavailable” Vitamin D with Incidence of Diabetes among Older Adults with Lower Baseline HbA1c (≤6%) Levels

Background: Serum 25-hydroxyvitamin (25(OH)D) levels are inversely associated with risk of diabetes. The “free hormone hypothesis” suggests potential effects to be mainly related to concentrations of “bioavailable” and free rather than total 25(OH)D. We assessed associations of serum concentrations of vitamin D-binding protein (VDBP), as well as total “bioavailable”, complementary “non-bioavailable”, and free 25(OH)D, with the risk of developing diabetes among non-diabetic older adults in a large population-based cohort study in Germany. Methods: We included 4841 non-diabetic older adults aged 50–75 years at the baseline exam from the ESTHER cohort conducted in Saarland, Germany, in 2001–2002. Concentrations of “bioavailable” and free 25(OH)D were derived from serum concentrations of VDBP, total 25(OH)D, and albumin. Incidence of diabetes was ascertained during up to 14 years of follow-up. Associations were quantified by multivariable Cox proportional hazards regression models with comprehensive confounder adjustment. Results: During a median follow-up of 10.6 years, 837 non-diabetic participants developed diabetes. We observed similar inverse associations with developing diabetes for VDBP (hazard ratio (HR) for lowest versus highest quintile: 1.37, 95% confidence interval (CI): 1.09, 1.72), total 25(OH)D (HR: 1.31, 95% CI: 1.03, 1.66), and “non-bioavailable” 25(OH)D (HR: 1.30, 95% CI: 1.02, 1.65). Associations were smaller and statistically insignificant for “bioavailable” and free 25(OH)D. However, associations of total “non-bioavailable”, “bioavailable”, and free 25(OH)D with incidence of diabetes were much stronger among, and essentially restricted to, participants with lower baseline HbA_1c (≤6%) levels. Conclusions: This large prospective cohort study of older Caucasian adults, in agreement with results from randomized trials and Mendelian randomization studies, supports a protective effect of vitamin D against development of diabetes. The “free hormone theory” may not be relevant in this context. However, our results underline the importance of adequate vitamin D status among those who have not yet shown any sign of impaired glucose tolerance.

Alterations in circulating levels of vitamin D binding protein, total and bioavailability of vitamin D in diabetic retinopathy patients

AIMS

This study aimed to investigate the association between circulating levels of vitamin D binding protein (VDBP) and its genotypes and diabetic retinopathy risk.

METHODS

This case-control study recruited 154 patients with type 2 diabetes mellitus; 62 with diabetic retinopathy (DR) and 92 without DR and diabetic nephropathy (DN). Circulating levels of 25-hydroxyvitamin D3 and VDBP levels were measured in the patients. The genotype and phenotype of VDBP were evaluated based on two common VDBP variations; rs7041 and rs4588.

RESULTS

Serum levels of VDBP were significantly lower in patients with DR than in patients without DR and/or DN (Ln-VDBP (μg/ml): 6.14 ± 0.92 vs. 6.73 ± 1.45, p = 0.001) even after adjustment for age, sex, body mass index, disease duration, estimated glomerular filtration rate (eGFR), HbA1C, insulin therapy profile, and serum levels of 25(OH)D. The distribution of VDBP phenotypes and genotypes in the two studied groups were nearly the same, and the distribution was similar to that of the general population.

CONCLUSIONS

In this study, we found the association between lower circulating levels of VDBP and risk of DR. However, the precise mechanism linking these two remains unknown. Further and more in-depth research is needed to find out the underlying causes of the relationship.

M. R, Madhunapantula SV, Salimath PV, K. P, M. SK, M. R. K. Comparative assessment of cognitive impairment and oxidative stress markers among vitamin D insufficient elderly patients with and without type 2 diabetes mellitus (T2DM)

BACKGROUND

Disorders of mental health are known to affect cognitive functions, hence called as cognitive disorders. Impaired glucose metabolism, insulin resistance, vitamin-D deficiency and oxidative stress are some of the key early events reported to be involved in the pathogenesis of most common cognitive disorders, which include Alzheimer's disease. Type-2 diabetes mellitus (T2DM) is one of the known contributing factors of cognitive impairment and dementia.

METHODS

A cross sectional study was carried out in 145 subjects, who were assessed for cognitive function by modified mini mental status examination (3MS). In addition, measurement of fasting blood sugar (FBS), fasting insulin, HbA1c, lipid profile, vitamin D and oxidative markers was performed. Participants were divided into different groups based on (a) vitamin D insufficiency and sufficiency; (b) diabetic and non-diabetic with and without cognitive impairment.

RESULTS

The study included a total of 145 subjects; 51 males and 94 females and the mean age was 68.24±9.70 years. Among diabetics with vitamin D insufficiency, 35 subjects (71.43%) had cognitive impairment, but, among non-diabetics with vitamin D insufficiency, 27 subjects (62.79%) had cognitive impairment. Chi square test showed no significant association between diabetes, vitamin D insufficiency and cognitive impairment. Glutathione peroxidase (GPx) and superoxide dismutase (SOD) levels were non-significantly lower in cognition-impaired subjects, when compared to cognition normal subjects in diabetics with vitamin D insufficiency.

CONCLUSION

Our study showed that cognitive impairment is more predominant in individuals with diabetes. However, our study did not find any significant relationship between T2DM, vitamin D deficiency, cognitive impairment, and oxidative stress. A significant association was found only with GPx and 3MSE score in vitamin D insufficient non-diabetics.

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

BACKGROUND

Several epidemiological studies have suggested that vitamin D status is associated with risk of dementia in general populations. However, due to the synergistic effect between diabetic pathology and neuroinflammation, and the prothrombotic profile in patients with diabetes, whether vitamin D is associated with risk of dementia among patients with diabetes is unclear. This study aimed to investigate the associations of circulating vitamin D levels with risks of all-cause dementia, Alzheimer disease (AD), and vascular dementia (VD) among adults with type 2 diabetes (T2D).

METHODS AND FINDINGS

This study included 13,486 individuals (≥60 years) with T2D and free of dementia at recruitment (2006-2010) from the UK Biobank study. Serum 25-hydroxyvitamin D (25[OH]D) concentrations were measured using the chemiluminescent immunoassay method at recruitment. Serum 25(OH)D ≥ 75 nmol/L was considered sufficient, according to the Endocrine Society Clinical Practice Guidelines. Incidence of all-cause dementia, AD, and VD cases was ascertained using electronic health records (EHRs). Each participant's person-years at risk were calculated from the date of recruitment to the date that dementia was reported, date of death, date of loss to follow-up, or 28 February 2018, whichever occurred first. Among the 13,486 individuals with T2D (mean age, 64.6 years; men, 64.3%), 38.3% had vitamin D ≥ 50 nmol/L and only 9.1% had vitamin D ≥ 75 nmol/L. During a mean follow-up of 8.5 years, we observed 283 cases of all-cause dementia, including 101 AD and 97 VD cases. Restricted cubic spline analysis demonstrated a nonlinear relationship between serum 25(OH)D and risk of all-cause dementia (Pnonlinearity < 0.001) and VD (Pnonlinearity = 0.007), and the nonlinear association reached borderline significance for AD (Pnonlinearity = 0.06), with a threshold at around a serum 25(OH)D value of 50 nmol/L for all the outcomes. Higher serum levels of 25(OH)D were significantly associated with a lower risk of all-cause dementia, AD, and VD. The multivariate hazard ratios and 95% confidence intervals for participants who had serum 25(OH)D ≥ 50 nmol/L, compared with those who were severely deficient (25[OH]D < 25 nmol/L), were 0.41 (0.29-0.60) for all-cause dementia (Ptrend < 0.001), 0.50 (0.27-0.92) for AD (Ptrend = 0.06), and 0.41 (0.22-0.77) for VD (Ptrend = 0.01). The main limitation of the current analysis was the potential underreporting of dementia cases, as the cases were identified via EHRs.

CONCLUSIONS

In this study, we observed that higher concentrations of serum 25(OH)D were significantly associated with a lower risk of all-cause dementia, AD, and VD among individuals with T2D. Our findings, if confirmed by replication, may have relevance for dementia prevention strategies that target improving or maintaining serum vitamin D concentrations among patients with T2D.

Potential role of 25(OH)D insufficiency in the dysfunction of glycolipid metabolism and cognitive impairment in patients with T2DM

PURPOSE

To investigate the changes of plasma 25(OH)D levels in type 2 diabetes mellitus (T2DM) patients and explore its role in the dysfunction of glucose and lipid metabolism and cognition.

METHODS

One hundred and thirty-two T2DM patients were enrolled and the demographic and clinical data were collected. The plasma concentration of 25(OH)D was detected and the patients were divided into two groups including a Vitamin D insufficient (VDI) group and a normal VD group according to the clinical diagnostic criterial of VDI with the plasma 25(OH)D level less than 29 ng/mL. The glycolipid metabolic and routine blood biochemical indices were detected, the plasma concentrations of C-reactive protein (CRP), interleukin-6 (IL-6), soluble myeloid soluble trigger receptor 1 (sTREM1) were measured. The cognitive function was assessed using the Behavior Rating Inventory of Executive Function-Adult Version (BRIEF-A). The depressive symptomatology was assessed using the Center for Epidemiological Survey Depression Scale (CES-D). Sleep quality was assessed using the Pittsburgh sleep quality index (PSQI).

RESULTS

There were 70 T2DM patients with VDI (70/132, 53.03%) in this study. The plasma concentrations of glycated hemoglobin (HbA1c), fasting plasma glucose (FPG), postprandial blood glucose (PBG), IL-6, and sTREM1 were remarkably increased in T2DM patients with VDI as compared with that with the normal VD, accompanied with an elevated BRIEF-A scores. There was no significant difference between groups with regard to the indices of blood lipid, liver function, and scores in CES-D and PSQI. Moreover, results of Pearson correlation test showed that the plasma 25(OH)D levels were negatively correlated with HbA1c, FPG, PBG, CRP, IL-6, sTREM1, CES-D sum scores, and PSQI sum scores, but positively correlated with the plasma levels of Serum creatinine (Scr). Furthermore, result of Receiver Operating Characteristic (ROC) curve analysis showed a predictive role of VDI levels in discriminating T2DM patients with higher cognitive impairments, with the sensitivity and specificity being 62.12% and 62.12%, respectively.

CONCLUSION

VDI is harmful for T2DM patients with a significant relation with the hyperglycosemia and cognitive dysfunction.