Vitamin D, carotid intima-media thickness and bone structure in patients with type 2 diabetes

The Safety Profile of Vitamin D Supplements Using Real-World Data from 445,493 Participants of the UK Biobank: Slightly Higher Hypercalcemia Prevalence but Neither Increased Risks of Kidney Stones nor Atherosclerosis

Background: Potential calcium-related adverse events of vitamin D supplement use have not been addressed in large-scale, real-world data so far. Methods: Leveraging data from the UK Biobank, encompassing 445,493 individuals aged 40-69, we examined associations of high 25-hydroxyvitamin (25(OH)D) levels ≥ 100 nmol/L and vitamin D supplementation with hypercalcemia (serum calcium > 2.6 mmol/L), kidney stones, and atherosclerosis assessments (pulse wave arterial stiffness index and carotid intima-medial thickness). Regression models were comprehensively adjusted for 49 covariates. Results: Approximately 1.5% of the participants had high 25(OH)D levels, 4.3% regularly used vitamin D supplements, and 20.4% reported regular multivitamin use. At baseline, the hypercalcemia prevalence was 1.6%, and 1.1% was diagnosed with kidney stones during follow-up. High 25(OH)D levels were neither associated with calcium-related adverse events nor atherosclerosis assessments. Vitamin D and multivitamin supplementation were associated with an increased prevalence of hypercalcemia (odds ratios and 95% confidence intervals: 1.46 [1.32-1.62] and 1.11 [1.04-1.18], respectively) but were neither associated with atherosclerosis nor future kidney stones. Conclusions: High 25(OH)D levels observable in routine care were not associated with any adverse outcome. Vitamin D users have a slightly higher prevalence of hypercalcemia, possibly due to co-supplementation with calcium, but without a higher atherosclerosis prevalence or risk of kidney stones.

Correction of plasma fat-soluble vitamin levels by blood lipids in elderly patients with coronary heart disease

This study aims to investigate the correlation between plasma fat-soluble vitamin levels and blood lipid in elderly patients with coronary heart disease (CHD). A total of 120 participants were enrolled, including 60 CHD patients and 60 controls without CHD. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to quantify plasma levels of vitamins A, D3, E, and K. Data analysis was conducted using the statistical analysis system module of MetaboAnalyst 5.0. The CHD group showed significantly higher levels of plasma total cholesterol (TC), triglycerides (TG), and low-density lipoprotein cholesterol (LDL-C) but not high-density lipoprotein cholesterol (HDL-C) compared to controls. The CHD group exhibited significantly higher plasma levels of VA and VE, positively correlating with TC, TG, and LDL-C. After adjusted by TG levels, the CHD group had significantly lower plasma levels of VA and VE, negatively correlating with TC, TG, and LDL-C. The CHD group also had significantly lower concentrations of VD3, independent of TG modification, compared to controls. VD3 negatively correlated with TC, TG, and LDL-C. Elderly individuals with CHD display abnormal blood lipid metabolism, and fat-soluble vitamins adjusted by TG levels can more accurately and timely response to implicit fat-soluble vitamins deficiency in CHD patients.

Ultrasound Assessment of Carotid Intima-Media Thickness: Comparison between Diabetes and Nondiabetes Subjects, and Correlation with Serum Vitamin D

Methods

This multicenter cross-sectional study was performed on two groups of adults (nondiabetes and type 2 diabetes) of various ages, sexes, and body mass index (BMI). CIMT for each side was measured at three segments using high-resolution ultrasound, and the mean of both sides was determined. Comparison was made between each group, and the association of CIMT with each of age, sex, BMI, serum vitamin D status, smoking, and physical activity status was studied. The chi-square test was used to compare categorical data, and binary logistic regression was utilized to ascertain the relationship between CIMT and the study variables.

Results

A significant difference was observed between the CIMT of the diabetes and nondiabetes group, average CIMT was 0.82 ± 0.23 mm vs. 1.12 ± 0.24 mm for the nondiabetes and diabetes group, respectively, with P value <0.005. No significant correlation was observed between serum vitamin D level and CIMT neither in the study group as a whole nor in either subgroup; however, a significant association was observed between CIMT with each of age, sex, BMI, smoking, and physical activity status.

Conclusion

Ultrasound is a sensitive tool for CIMT evaluation. Diabetes has a 5.4-fold higher risk of having high CIMT. Serum vitamin D level showed no significant influence on CIMT. Smoking, BMI, and physical activity are among the modifiable risk factors with significant influence on CIMT.

Vitamin D improves vascular function and decreases monoamine oxidase A expression in experimental diabetes

The active form of vitamin D, 1,25-dihydroxycholecalciferol (1,25(OH)₂D₃), was reported to improve vascular function in patients with diabetes, yet the underlying mechanisms remain to be fully elucidated. Monoamine oxidase (MAO), a mitochondrial enzyme, with two isoforms (A and B) that generates hydrogen peroxide (H₂O₂) as by-product, has been recently reported to contribute to the pathogenesis of endothelial dysfunction in diabetes. The present study assessed the interaction between vitamin D and MAO in the vascular wall in the setting of type 1 experimental diabetes. To this aim, diabetes was induced in male Wistar rats via a single injection of streptozotocin (STZ, 50 mg/kg, IP) and 1 month later thoracic aortas were harvested and used for organ bath studies and H₂O₂ measurements. MAO expression was assessed by immunohistochemistry and RT-PCR. Endothelial function was evaluated in isolated aortic rings in the absence vs. presence of 1,25(OH)₂D₃ (100 nM, 24 h incubation). In diabetic animals, we found a significant reduction in the endothelial-dependent relaxation to acetylcholine and an increased expression of the MAO-A isoform, respectively. Vitamin D significantly improved vascular function, mitigated oxidative stress and decreased MAO-A expression in diabetic vascular preparations. In conclusion, MAO-A is induced in diabetic aortas and vitamin D can improve diabetes-induced endothelial dysfunction by modulating the MAO-A expression.

Association of Serum Vitamin D Level and Carotid Atherosclerosis: A Systematic Review and Meta-analysis

Vitamin D deficiency is associated with an increased risk of subclinical atherosclerosis. To explore the potential link of the serum vitamin D level with carotid atherosclerosis, this meta-analysis assessed the correlation between vitamin D and carotid intima-media thickness as well as carotid atherosclerotic plaque. PubMed, Embase, Web of Science, and Cochrane Library databases were searched until the end of March 2017. Clinical studies investigating the relationship between vitamin D and carotid atherosclerosis were included. The outcome data were extracted according to the inclusion criteria and pooled for an effect estimate by a random-effects model. Of the 506 initially retrieved studies, 11 studies involving a total of 16,434 participants were included in the meta-analysis. Newcastle-Ottawa Quality Assessment Scale scores suggested that the included studies were of high quality. The pooled effects estimate showed that the serum vitamin D level was negatively associated with carotid atherosclerosis (odds ratio, 0.95; 95% confidence interval [CI], 0.93-0.96), with substantial heterogeneity among the individual studies (I²  = 54%). Furthermore, a subgroup analysis suggested that hypovitaminosis D was associated with an 0.85-fold decrease in the odds of having a higher carotid intima-media thickness (95% CI, 0.76-0.96; P < .05; I²  = 69%). Additionally, the pooled analysis also indicated that the serum vitamin D level was a protective factor against increased carotid plaque (odds ratio, 0.95; 95% CI, 0.93-0.97; P < .05; I²  = 29%). Funnel plots and the Egger regression test showed the absence of a publication bias. In this meta-analysis, we comprehensively revealed a close link between vitamin D deficiency and carotid atherosclerosis. Patients with hypovitaminosis D might have extra requirements for preventive and therapeutic measures against early atherosclerosis, thus reducing the cardiovascular disease risk in the long term.

Correlation between serum 25-hydroxyvitamin D levels and carotid intima-media thickness in a Brazilian population descended from African slaves

Hypovitaminosis D has been identified as a possible new cardiovascular risk factor. However, the results of studies correlating serum vitamin D levels with markers of subclinical atherosclerosis have been conflicting. The aim of this study was to correlate serum levels of 25-hydroxyvitamin D [25(OH)D] with carotid intima-media thickness (C-IMT) and conventional cardiovascular risk factors in Afro-descendants. A cross-sectional analysis was performed on a sample of 382 individuals from a cohort of descendants of African slaves, inhabitants of “Quilombola” communities, with a mean age of 57.79 ±15.3 years, 54.5% of whom were women. Socio-demographic and clinical data were collected and biochemical tests were performed, including serum levels of 25(OH)D by electrochemiluminescence and urinary albumin excretion, evaluated by the albumin/creatinine ratio (ACR) in a spot urine sample. All participants underwent high-resolution ultrasonography for C-IMT measurement. Hypovitaminosis D was defined as serum 25(OH)D levels <30 ng/mL. The mean serum 25(OH)D levels were 50.4±13.5 ng/mL, with a low prevalence of hypovitaminosis D (4.86%). By simple linear correlation, a significant inverse association between 25(OH)D levels and C-IMT (r=-0.174, P=0.001) was observed. However, after multiple linear regression analysis, the significance of the association between serum levels of 25(OH)D and C-IMT measurement was lost (β=-0.039, P=0.318) and only male gender, age, smoking, systolic blood pressure, glucose and low density lipoprotein (LDL)-cholesterol remained significantly associated with C-IMT. Levels of 25(OH)D were independently and positively associated with HDL-cholesterol and inversely associated with age and ACR. In conclusion, no independent association between 25(OH)D levels and C-IMT was observed in this population. On the other hand, there was an inverse association with albuminuria, a marker of endothelial lesion.

Vitamin D and progression of carotid intima-media thickness in HIV-positive Canadians

OBJECTIVES

Based on a growing body of evidence implicating low vitamin D status in the development of cardiovascular disease (CVD), we hypothesized that in Canadian HIV-positive adults, low 25-hydroxyvitamin D (25(OH)D) concentration would be associated with increased subclinical vascular disease progression.

METHODS

We prospectively studied the relationship between baseline 25(OH)D and subsequent progression of carotid intima-media thickness (CIMT) between 2002 and 2011, in the Canadian HIV Vascular Study using stored blood specimens.

RESULTS

Of the 128 participants, 89.1% were men, the mean age (standard deviation [SD]) was 46.5 (8.2) years, 93.8% were white, and 36.7% were current smokers. Mean (SD) annual CIMT follow-up was 5.9 (1.8) years (maximum 8.5 years), providing approximately 750 patient-years of follow-up. Mean (SD) CIMT progression was 0.027 (0.030) mm/year. Mean (SD) 25(OH)D was 95.0 (46.9) nmol/L. Only 13.3% of participants were vitamin D deficient (25(OH)D < 50 nmol/L), whereas 61.7% had a 25(OH)D exceeding the sufficiency threshold (75 nmol/L). Vitamin D quartiles were inversely associated with body mass index (BMI) (P = 0.034), total cholesterol to high-density lipoprotein (HDL) cholesterol ratio (P = 0.001) and parathyroid hormone concentration (P = 0.003), but not efavirenz exposure (P = 0.141). In linear regression analyses, baseline 25(OH)D as a continuous variable was inversely associated with CIMT progression in univariable (P < 0.001) and multivariable (P < 0.001) models.

CONCLUSIONS

Baseline 25(OH)D was associated with CIMT progression in this relatively vitamin D replete, predominately white and male, Canadian HIV-positive population. Future research needs to establish causality as this may warrant more targeted screening or supplementation.

In Type-2 Diabetes Subjects Trabecular Bone Score is Better Associated with Carotid Intima-Media Thickness than BMD

Literature data reported that in elderly subjects, carotid intima-media thickness (IMT) was negatively associated with bone mineral density (BMD). Paradoxically, type-2 diabetes (T2DM) patients, despite having higher BMD, present an increased risk of fragility fractures and cardiovascular complications. Some studies have reported trabecular bone score (TBS), an index of trabecular bone quality, as possibly being reduced in T2DM. This study aimed to evaluate whether in T2DM subjects TBS was better associated with IMT with respect to BMD. In 131 consecutive T2DM subjects (55 men and 76 women; mean age: 60.0 ± 7.3 years) and 265 consecutive non-T2DM subjects (107 men and 158 women; mean age: 58.9 ± 7.8 years) we measured carotid IMT by high-resolution ultrasonography and BMD at lumbar spine (LS-BMD), at femoral neck FN-BMD and total hip TH-BMD; TBS was calculated using TBS iNsight software. LS-BMD, FN-BMD, and TH-BMD were all significantly higher in T2DM than in non-T2DM subjects, whereas TBS was significantly lower in T2DM subjects than in controls and inversely correlated with diabetes duration. In T2DM subjects multiple regression analysis showed that IMT was positively associated with age (b = 0.017; p < 0.001) and inversely associated with TBS (b = -0.473; p = 0.038). In non-T2DM subjects, only age was positively associated with IMT. To sum up, T2DM subjects present higher values of BMD and lower values of TBS with respect to non-diabetic controls. Moreover, in T2DM subjects TBS was found to be independently associated with carotid IMT. These findings suggest that TBS may not only capture bone fragility-related factors, but also some information associated with greater risk of developing cardiovascular diseases.

Association of Serum 25-hydroxyvitamin D in Carotid Intima-media Thickness: A Study from South India

Background:

Abnormal carotid intima-media thickness (IMT) is a marker of carotid atherosclerosis which is a risk factor for cerebrovascular and cardiovascular diseases. Recent studies have found an association of 25-hydroxyvitamin D deficiency with abnormal carotid IMT.

Purpose:

The purpose of the study was to investigate the association of serum 25-hydroxyvitamin D levels with carotid IMT in Indian participants.

Materials and Methods:

We prospectively recruited 300 participants at Yashoda Hospital, Hyderabad, during the study period between January 2012 and December 2014. All participants were assessed for fasting blood sugar, lipid profile, C-reactive protein (CRP), serum alkaline phosphatase, serum calcium, serum phosphorous, serum 25-hydroxyvitamin D levels, and carotid Doppler examination.

Results:

Among the 300 participants, men were 190 (63.3%) and mean age was 51.9 ± 7.7 years with a range from 35 to 64 years. On risk factors evaluation, 105 (35%) were hypertensive, 79 (26.3%) diabetics, 63 (21%) smokers, and 56 (18.6%) were alcoholics. On evaluation of biochemical parameters, 81 (27%) had dyslipidemia, 120 (40%) had elevated CRP levels, 119 (39.6%) had 25-hydroxyvitamin D deficiency, mean alkaline phosphatase was 93.9 ± 14.9 IU/L, serum calcium (mg/dL) was 9.2 ± 2.3, and serum phosphorous 4.4 ± 1.2 mg/dL. On carotid imaging, 121 (40.3%) had abnormal IMT. After multivariate analysis, 25-hydroxyvitamin D deficiency (odds ratio [OR]: 2.14; 95% confidence interval [CI]: 1.29–3.55), dyslipidemia (OR: 2.53; 95% CI: 1.46–4.40), elevated CRP (OR: 2.27; 95% CI: 1.37–3.76), smoking (OR: 2.09; 95% CI: 1.16–3.77), and diabetes (OR: 1.84; 95% CI: 1.05–3.21) were independently associated with abnormal IMT.

Conclusion:

In our study, we established 25-hydroxyvitamin D deficiency as an independently associated with abnormal IMT in Indian participants.

Impact of Vitamin D deficiency on subclinical carotid atherosclerosis: a pooled analysis of cohort studies

CONTEXT

Vitamin D deficiency patients have an increased cardiovascular (CV) morbidity and mortality. Carotid intima-media thickness (IMT) and carotid plaques are markers of subclinical atherosclerosis and predictors of CV events.

OBJECTIVE

To perform a meta-analysis of studies evaluating the impact of Vitamin D deficiency on common carotid artery IMT (CCA-IMT) and on the prevalence of carotid plaques.

DATA SOURCES

Studies were systematically searched in the PubMed, Web of Science, Scopus and EMBASE databases.

RESULTS

Twenty-one studies (3,777 Vitamin D deficiency patients and 4,792 controls) with data on CCA-IMT and 6 studies (1,889 Vitamin D deficiency patients and 2,883 controls) on the prevalence of carotid plaques were included. Compared to controls, Vitamin D deficiency patients showed a significantly higher CCA-IMT (mean difference [MD]: 0.043 mm; 95%CI: 0.030, 0.056; P<0.001), and an increased prevalence of carotid plaques (Odds Ratio [OR]: 2.29, 95%CI: 1.03-5.11; P=0.043) with an attributable risk of 35.9%. When selecting studies specifically including patients with diabetes, the prevalence of carotid plaques in Vitamin D deficiency patients than in controls resulted higher (OR: 3.27; 95%CI: 1,62-6.62; P=0.001). A significant difference in CCA-IMT was confirmed when comparing patients with Vitamin D insufficiency to controls (MD: 0.011; 95%CI: 0.010-0.012, P<0.001). Sensitivity analyses substantially confirmed results and regression models showed that with the exception of LDL-cholesterol, HDL-cholesterol, triglycerides and the prevalence of hypercholesterolemia, all the other clinical and demographic co-variates significantly impacted on the difference in CCA-IMT between Vitamin D deficiency patients and controls.

CONCLUSIONS

Both Vitamin D deficiency and Vitamin D insufficiency are associated with subclinical atherosclerosis, potentially suggesting an increased CV risk in these clinical settings.

Association between Micronutrients Intake/Status and Carotid Intima Media Thickness: A Systematic Review

BACKGROUND

Carotid intima media thickness (IMT) is a noninvasive marker of the extent and severity of subclinical atherosclerosis. Micronutrient intake may affect atherosclerosis and play a major role in the development of cardiovascular diseases (CVDs).

OBJECTIVE

The primary aim of this review was to synthesize the evidence regarding the association between carotid IMT and selected micronutrients.

METHOD

The authors searched PubMed, Cochrane, and EMBASE databases from inception to June 2016 for selected micronutrients, CVD, carotid IMT, and antioxidants. Thirty-five original studies met the inclusion criteria and were reviewed following preferred reporting items for systematic review and meta-analysis guidelines.

RESULTS

Although not all studies found consistent results, the weight of the evidence suggests that high intakes and/or circulatory levels of magnesium, as well as vitamin D and the vitamin B group, may be associated with lower carotid IMT or reduced progression of carotid IMT. The majority of studies did not find any significant association between vitamin E and C and carotid IMT. Less evidence was available for associations of retinol, zinc, and iron with carotid IMT.

CONCLUSIONS

In general, the current evidence concerning micronutrient intake and carotid IMT is largely inconclusive. Pragmatic clinical trials are required to determine whether dietary or supplemental intake of specific micronutrients alters carotid IMT, which is a surrogate measure of cardiovascular risk.

The Role of Vitamin D in Diabetes and Cardiovascular Disease: An Updated Review of the Literature

The dietary reference values for Vitamin D were set primarily considering its role in bone health, but with the discovery of Vitamin D receptors throughout body tissues, new links with other health conditions are now studied, such as for diabetes and cardiovascular diseases (CVD). This paper shall analyze and examine all new research studies carried out, especially in 2013–2015 regarding diabetes mellitus (DM) and cardiovascular diseases (CVD). Vast research has been carried out to establish strong relationship between Vitamin D serum levels, supplementation, diabetes, and CVD. However, the results from researches identified in this paper are disputable. Benefits of Vitamin D adequate levels were recognized from gestational period until later in disease development such as diabetes and/or CVD, but since not all studies are in agreement further investigation is suggested. Researches conducting large randomized controlled trials, exploring range of supplement doses, with variable baseline serum Vitamin D levels, and inclusion of array of associated parameters, are still required to conduct large-scale analysis and draw conclusion as a risk factor. Until then it is possible to conclude that maintenance of serum Vitamin D levels holds advantageous aspects in diabetic and cardiovascular conditions, and people should strive to attain them.