Effect of vitamin D on blood pressure: a systematic review and meta-analysis. J Hypertens. 2009;27:1948-1954. [PMID: 19587609 DOI: 10.1097/hjh.0b013e32832f075b]

Unveiling the benefits of Vitamin D3 with SGLT-2 inhibitors for hypertensive obese obstructive sleep apnea patients

BACKGROUND

Obstructive sleep apnea (OSA) is associated with poorer quality of life (QoL) and increased cardiovascular risks, which may be exacerbated by hypovitaminosis D. Sodium glucose transporter-2 inhibitor (SGLT2i) provides cardiovascular benefits beyond glycemic control. As vitamin D3 and SGLT2i act through different pathways with similar mechanisms in improving cardio-metabolic health, this study aimed to investigate the synergistic effects of this combination therapy in improving these parameters and QoL in hypertensive obese OSA patients.

METHODS

Patients who fulfilled the study criteria were randomized to receive: (i) Dapagliflozin, (ii) vitamin D3, (iii) Dapagliflozin plus vitamin D3, or (iv) no treatment, for 16 weeks. The parameters evaluated included anthropometric measurements, uric acid, HbA1c, lipid profile, steatotic liver disease grade, plasma aldosterone concentration, plasma renin concentration, ultrasound flow-mediated dilatation of brachial artery, hsCRP, heart rate variability (HRV), Epworth Sleepiness Scale (ESS), and QoL scores.

RESULTS

A total of 163 patients were recruited and 153 completed the study. The combination of vitamin D3 and Dapagliflozin treatment led to significant improvements in metabolic parameters and nocturnal heart rates, and prevented deterioration of HRV, with healthier HRV at the end of study visit compared to the control group. Only the combination group exhibited improvements in both ESS and QoL scores.

CONCLUSIONS

This is the first study to demonstrate beneficial effects of combining vitamin D3 and SGLT2i in cardio-metabolic outcomes and QoL in hypertensive obese OSA patients. These findings highlight the potential of this combination therapy in addressing the cardio-metabolic challenges and QoL in this patient population.

TRIALS REGISTRATION

NCT06690723. Registered 10 October 2024-Retrospectively registered, https://register.

CLINICALTRIALS

gov/prs/beta/studies/S000EWGF00000085/recordSummary.

Calcium, magnesium, and vitamin D supplementations as complementary therapy for hypertensive patients: a systematic review and meta-analysis

BACKGROUND

Hypertension, the first global modifiable risk factor for cardiovascular disease (CVD) morbidity and mortality, is a consequential and remediable threat to the health of individuals and society. Therefore, we conducted this study to explore the role of calcium (Ca++), magnesium (Mg++), and vitamin D (Vit-D) supplementation as complementary therapies for hypertension, focusing on their effects on systolic blood pressure (SBP), diastolic blood pressure (DBP), and pulse rate.

METHODS

This systematic review and meta-analysis examined relevant 6509 articles in PubMed, Scopus, Web of Science, and Cochrane CENTRAL up to October 2024. The primary outcome was the difference in blood pressure measurements (systolic and diastolic) and the pulse rate. The extracted data were analyzed using Open Meta Analyst software.

RESULTS

This systematic review and meta-analysis included 40 studies; of them, 24 studies were analyzed. Ca++ was associated with a significant drop in the DBP (MD: -2.04, 95% CI [-3.39, -0.69], P = 0.01), but not in the SBP (P = 0.34) or pulse rate (P = 0.84). Mg++ significantly reduced DBP (MD: -1.64, 95% CI [-3.19, -0.09], P = 0.04), but had no significant effect on the SBP (P = 0.16) or pulse rate (P = 0.81). The estimated effect of Vit-D showed a significant reduction in SBP (MD: -2.83, 95% CI [-5.47, -0.199], P = 0.04) and DBP (MD: -1.64, 95% CI [-2.97, -0.3], P = 0.01).

CONCLUSION

Ca++ and Mg++ significantly reduced DBP but had no significant effect on SBP or the pulse rate. Whereas, vitamin D significantly reduced SBP and DBP.

Vitamin D deficiency in Mongolian men aged 15-49 years

We aimed to estimate the prevalence of vitamin D deficiency in Mongolian men aged from 15 to 49 years at the National level as part of the Fifth National Nutrition Survey in 2016. This was a cross-sectional survey, conducted between September and November in 21 aimags of 4 economic regions of the country, and also in Ulaanbaatar. Given the regional differences in lifestyle and nutritional status, the target populations were stratified into 5 strata based on their economic region and in Ulaanbaatar, with equal samples drawn from each stratum using a cluster-randomized sampling design. A representative sample of 30 clusters [villages] was randomly selected using Probability Proportional to Size [PPS] methodology in each of the 4 regions and in Ulaanbaatar for a total of 150 cluster units. The selection of survey participants differed for the three sampling regions. Household eligibility was based on having a child 0-59 months of age, living in the household which was randomly selected from each cluster for a total of 450 households in each region. Households with a child 0-59 months of age were selected from household lists available at the kheseg or bagh level. All men 15-49 years of age who resided in the selected households were also eligible to participate in the survey. Serum concentration of 25-hydroxyvitamin D [25(OH)D] were measured using an enzyme-linked fluorescence assay in 377 men aged 15-49 years. The overall mean serum level of 25(OH)D concentration was 22.26 ± 0.48 ng/mL (95 % CI 21.31-23.21). The mean serum 25(OH)D concentrations were 19.65 ± 0.32 ng/mL (95 % CI19.01-19.82), and 33.68 ± 0.49 ng/mL (95 % CI 32.72-34.64) in vitamin D deficient, and in vitamin D sufficient subjects, respectively. The prevalence of vitamin D deficiency was 83.5 % with no significant difference in the prevalence of vitamin D deficiency by age group, economic region, area, location, education, and wealth index quintile. The prevalence of men in this study who were overweight or obese was 48.8 % and 14.6 % respectively. Although no significant difference was found between vitamin D deficiency and obesity, vitamin D deficiency was higher among men aged 30-39 and 40-49 years old by age specific analyses. The men did not take vitamin D supplements, and there is currently no vitamin D food fortification in Mongolia. The findings of this survey showed that vitamin D deficiency in men is a public health problem in Mongolia. In conclusion, vitamin D deficiency are common in Mongolian men, which indicates the need for vitamin D screening and treatment, as well as for an increased use of vitamin D supplements and for implementing vitamin D food fortification programs.

A Personalized Approach to Vitamin D Supplementation in Cardiovascular Health Beyond the Bone: An Expert Consensus by the Italian National Institute for Cardiovascular Research

Vitamin D is increasingly recognized for its role in cardiovascular health beyond its well-established effects on bone metabolism. This review synthesizes findings from observational studies, interventional trials, and meta-analyses to clarify the mechanisms through which vitamin D impacts cardiovascular health, including its influence on vascular function, inflammation, and metabolic pathways. Additionally, this review emphasizes the importance of a personalized approach to vitamin D supplementation, integrating individual cardiovascular risk profiles, baseline vitamin D levels, and comorbid conditions, such as hypertension and diabetes. While current evidence supports the association between low vitamin D levels and increased cardiovascular mortality, this work contributes novel insights by proposing tailored strategies for supplementation, particularly for high-risk subgroups. Practical recommendations for implementing these strategies in clinical practice are also discussed, providing a framework for optimizing cardiovascular outcomes through individualized vitamin D management.

Associations of Vitamin D-Related Biomarkers With Hypertension and the Renin-Angiotensin System in Men and Women

BACKGROUND

Vitamin D may prevent the development of hypertension through down-regulation of renin-angiotensin system. However, epidemiologic studies assessing the interrelation of vitamin D-related biomarkers with hypertension are sparse.

METHODS

We examined the prospective associations between vitamin D-related biomarkers and the risk of hypertension in a nested case-control study. In each of the Women's Health Study (WHS) and Physicians' Health Study (PHS) II, 500 incident hypertension cases and 500 age and race-matched controls were randomly selected. Baseline plasma 25(OH)-vitamin D [25(OH)D], parathyroid hormone (PTH), and total renin concentrations were measured.

RESULTS

Among controls, 25(OH)D and PTH were inversely correlated, but neither was correlated with total renin. In the crude model, there was a trend of association between increasing quintiles of 25(OH)D and lower risk of hypertension in women, with relative risks and 95% CIs of 1.00, 1.24 (0.84-1.83), 0.82 (0.53-1.25), 0.75 (0.48-1.16), and 0.81 (0.52-1.27) (P, trend: .07). Adjustment for body mass index and other hypertension risk factors eliminated this association (relative risk of 5th quintile: 1.03). No associations were found in men. Baseline PTH and ratio of 25(OH)D to PTH were not associated with the risk of hypertension in women or men. When men and women were included in the same model, vitamin D insufficiency (defined as 25(OH)D <20 ng/mL) also was not associated with an increased risk of hypertension. No interactions were found across subgroups.

CONCLUSIONS

Our study found no association of baseline plasma 25(OH)D or PTH with the risk of hypertension or total renin concentration in middle-aged and older men and women.

The relationship between serum 25-hydroxy vitamin D status and hypertension in Syrian population: retrospective cohort study

Introduction

Vitamin D is a liposoluble steroid hormone that plays a crucial role in the maintenance of bone metabolism and calcium homoeostasis. Many studies on the effects of vitamin D on general health have been significantly increased, driven by new findings concerning the systemic and extraskeletal effects of this hormone. This study was performed to determine whether low levels of vitamin D were associated with hypertension in Syrian people.

Materials and methods

This retrospective cohort study consisted of 207 subjects, including 83 (40.1%) patients suffering from essential hypertension and 124 (59.9%) patients with normal blood pressure. Aged older than 18 years, who was referred to the endocrinology clinic from September 2022 to September 2023. The data were analysed by using SPSS (version 25). Logistic regression analyses were performed with adjustments for age, sex, and waist circumference.

Results

Hypertension rates were 73%, 20%, and 5% in 25-hydroxyvitamin D groups less than 12 ng/ml, 12-20 ng/mL, and greater than or equal to 20 ng/ml, respectively. Odds ratios (95% CIs) for hypertension adjusting for age, sex, and waist circumference were 178.6 (30.5_1045.6), 5.13 (0.9_26.5) for 25-hydroxyvitamin D levels less than 12 ng/ml, and 12-20 ng/ml, respectively, compared with the greater than or equal to 20 ng/ml group.

Conclusions

This study has shown a high prevalence of low vitamin D levels (25OHVD/20 ng/ml) among a sample of Syrian people (78.3%). The lowest 25OHVD group was associated with a higher prevalence of hypertension, which refers to an adverse association between vitamin D level and essential hypertension. Further research is needed to confirm this relationship.

Associations between vitamin D status, VDR gene polymorphisms and echocardiographic markers in Polish patients with cardiovascular disease

Aim: This work was designed to investigate the associations between vitamin D metabolites, VDR gene polymorphisms and echocardiographic markers in a population of patients with cardiovascular disease. Methods: Echocardiographic markers for 42 patients were determined with tissue Doppler techniques. PCR-restriction fragment length polymorphism analysis identified genetic variants ApaI, TaqI, BsmI and FokI. A validated UHPLC-MS/MS method determined vitamin D metabolites. Results: Patients with the ApaI-GT genotype exhibited a lower pressure gradient across the aortic valve than ApaI-TT carriers. BMI, ApaI-GT, TaqI-TC, aortic arch diameter and maximal pressure gradient were significant univariate predictors of hypertension. Conclusion: A potential link exists between VDR gene polymorphisms and cardiovascular function.

Are There Any Pleiotropic Benefits of Vitamin D in Patients With Diabetic Kidney Disease? A Systematic Review of Randomized Controlled Trials

Background

Type 2 diabetes (T2D) and kidney disease are risk factors for vitamin D deficiency. Native forms of vitamin D have a lower risk of hypercalcemia than calcitriol, the active hormone. The enzyme responsible for activating native vitamin D is now known to be expressed throughout the body; therefore, native vitamin D may have clinically relevant effects in many body systems.

Objective

The objective of this systematic review was to examine the effect of native vitamin D supplementation on clinical outcomes and surrogate laboratory measures in patients with T2D and diabetic kidney disease (DKD).

Design

Systematic review.

Setting

Randomized controlled trials (RCTs) conducted in any country.

Patients

Adults with T2D and DKD receiving supplementation with any form of native vitamin D (eg, ergocalciferol, cholecalciferol, calcifediol).

Measurements

Clinical outcomes and surrogate clinical and laboratory measures reported in each of the trials were included in this review.

Methods

The following databases were searched from inception to January 31, 2023: Embase, MEDLINE, Cochrane CENTRAL, Web of Science, ProQuest Dissertations and Theses, and medRxiv. Only RCTs examining supplementation with a native vitamin D form with a control or placebo comparison group were included. We excluded studies reporting only vitamin D status or mineral metabolism parameters, without any other outcomes of clinical relevance or surrogate laboratory measures. Study quality was evaluated using the Cochrane risk-of-bias tool (RoB2). Results were synthesized in summary tables for each type of outcome with the P values from the original studies displayed.

Results

Nine publications were included, corresponding to 5 separate RCTs (377 participants total). Mean age ranged from 40 to 63. All trials administered vitamin D3. Intervention groups experienced improvements in vitamin D status and a reduction in proteinuria in 4 of the 5 included RCTs. There was a decrease in low-density lipoprotein and total cholesterol in the 2 trials in which they were measured. Improvements in bone mass, flow-mediated dilation, and inflammation were also reported, but each was only measured in 1 RCT. Effects on glucose metabolism, high-density lipoprotein, triglycerides, blood pressure, oxidative stress, and kidney function were mixed. No serious adverse effects were reported.

Limitations

Limitations include the small number of RCTs and lack of information on the use of drugs that affect measured outcomes (eg, proteinuria-lowering renin-angiotensin-aldosterone system inhibitors and lipid-lowering medication) in most studies. Our study is also limited by the absence of a prestudy protocol and registration.

Conclusions

Native vitamin D is a safe treatment that improves vitamin D status in patients with DKD. Vitamin D may modify proteinuria and lipid metabolism in DKD, but further well-designed trials that include well-established treatments are necessary. Overall, there is limited evidence for beneficial pleiotropic effects of vitamin D in patients with DKD.

Unveiling the molecular Culprit of arterial stiffness in vitamin D deficiency and obesity: Potential for novel therapeutic targets

Cardiovascular diseases (CVDs) are highly associated with both vitamin D deficiency and obesity, two prevalent health conditions worldwide. Arterial stiffness, an independent predictor of CVDs, is particularly elevated in both conditions, yet the molecular mechanisms underlying this phenomenon remain elusive, hindering effective management of CVDs in this population. We recruited 20 middle-aged Emiratis, including 9 individuals with vitamin D deficiency (Vit D level ≤20 ng) and obesity (BMI ≥30) and 11 individuals as control with Vit D level >20 ng and BMI <30. We measured arterial stiffness using pulse wave velocity (PWV) and performed whole transcriptome sequencing to identify differentially expressed genes (DEGs) and enriched pathways. We validated these findings using qRT-PCR, Western blot, and multiplex analysis. PWV was significantly higher in the vitamin D deficient and obese group relative to controls (p ≤ 0.05). The DEG analysis revealed that pathways related to interleukin 1 (IL-1), nitrogen metabolism, HIF-1 signaling, and MAPK signaling were over-activated in the vitamin D deficient and obese group. We found that HIF-1alpha, NOX-I, NOX-II, IL-1b, IL-8, IL-10, and VEGF were significantly upregulated in the vitamin D deficient and obese group (p < 0.05). Our study provides new insights into the molecular mechanisms of arterial stiffness in vitamin D deficiency and obesity, demonstrating the role of oxidative stress and inflammation in this process. Our findings suggest that these biomarkers may serve as potential therapeutic targets for early prevention of CVDs. Further studies are needed to investigate these pathways and biomarkers with larger cohort.

The Impact of Vitamin D Supplementation on Improving Blood Pressure: Evidence Obtained From an Umbrella Meta-analysis

PURPOSE

The results of meta-analyses regarding the effect of vitamin D on blood pressure are conflicting. The present umbrella meta-analysis was conducted to provide definite and conclusive results.

METHODS

Systematically, Scopus, EMBASE, PubMed, and Web of Science databases and Google Scholar were searched for relevant literature published up to July 2022. All meta-analyses of clinical trials addressing the effect of vitamin D on blood pressure were included. Random effects analysis was performed to obtain the overall effect size based on the standardized mean differences (SMDs) and weighted mean differences (WMDs) separately. The quality of included meta-analyses was assessed by using the Measurement Tool for Assessing Multiple Systematic Reviews 2 questionnaire.

FINDINGS

Overall, 21 meta-analyses were enrolled in the umbrella review. The results indicated that systolic blood pressure was significantly reduced after the intervention based on WMD effect size analysis (ESWMD = -0.69 mm Hg; 95% CI, -1.35 to -0.04 [P < 0.038]; I2 = 46.7%, P = 0.021); however, no considerable impact was observed based on analysis of SMD effect sizes (ESSMD = -0.05 mm Hg; 95% CI, -0.24 to 0.14; P = 0.615). Also, vitamin D supplementation indicated a significant improvement in diastolic blood pressure based on WMD effect sizes (ESWMD = -0.66 mm Hg; 95% CI, -1.05 to -0.27 [P < 0.001]; I2 = 56.4%, P = 0.004) but not SMD analysis (ESSMD = -0.04 mm Hg; 95% CI, -0.13 to 0.04 [P = 0.328]; I2 = 53.4%, P = 0.057).

IMPLICATIONS

Based on obtained evidence, vitamin D could be considered an efficient adjuvant for improving blood pressure.

Relationship between serum 25-hydroxyvitamin D concentrations and blood pressure among US adults without a previous diagnosis of hypertension: evidence from NHANES 2005-2018

Background

There are various cross-sectional studies that concluded that vitamin D is associated with blood pressure, but randomized controlled studies have not yielded consistent conclusions. Considering many limitations indeed, our study aimed to examine whether concentrations of 25(OH)D are inversely associated with blood pressure in people without a previous diagnosis of hypertension.

Method

We analyzed data from the 2005-2018 National Health and Nutrition Examination Survey. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by applying multivariable logistic regression models. The dose-response relationship was assessed by means of restricted cubic spline regression, and stratification analyses were employed to test the consistency between the subgroups.

Results

Of 17,467 participants aged ≥ 20 years without a previous diagnosis of hypertension, 4,769 had higher blood pressure. Compared with individuals whose 25(OH)D levels were in the bottom quartile (<44.3 nnol/L), adjusting for multiple confounders, the ORs for higher blood pressure were 0.90(95%CI 0.78, 1.05), 0.85(95%CI 0.72, 0.99), and 0.86(95%CI 0.72, 1.02), respectively (P for trend = 0.096). Furthermore, as a continuous variable, 25(OH)D concentrations were non-linearly associated with an increased risk of hypertension (P < 0.001). The interaction between the sleeplessness subgroup and higher blood pressure was significant (P = 0.042).

Conclusion

In adults without a previous diagnosis of hypertension in the United States, concentrations of 25(OH)D were inversely associated with higher blood pressure when it was <84 nmol/L.

A comprehensive review on the impact of calcium and vitamin D insufficiency and allied metabolic disorders in females

Calcium is imperative in maintaining a quality life, particularly during later ages. Its deficiency results in a wide range of metabolic disorders such as dental changes, cataracts, alterations in brain function, and osteoporosis. These deficiencies are more pronounced in females due to increased calcium turnover throughout their life cycle, especially during pregnancy and lactation. Vitamin D perform a central role in the metabolism of calcium. Recent scientific interventions have linked calcium with an array of metabolic disorders in females including hypertension, obesity, premenstrual dysphoric disorder, polycystic ovary syndrome (PCOS), multiple sclerosis, and breast cancer. This review encompasses these female metabolic disorders with special reference to calcium and vitamin D deficiency. This review article aims to present and elaborate on available data regarding the worldwide occurrence of insufficient calcium consumption in females and allied health risks, to provide a basis for formulating strategies and population-level scientific studies to adequately boost calcium intake and position where required.

Risk of Ischemic Stroke Associated with Calcium Supplements and Interaction with Oral Bisphosphonates: A Nested Case-Control Study

Conflicting results about the association of calcium supplements (CS) with ischemic stroke (IS) have been reported. We tested this hypothesis by differentiating between CS alone (CaM) and CS with vitamin D (CaD) and between cardioembolic and non-cardioembolic IS. We examined the potential interaction with oral bisphosphonates (oBs). A nested case-control study was carried out. We identified incident IS cases aged 40-90 and randomly sampled five controls per case matched by age, sex, and index date. Current users were compared to non-users. An adjusted odds ratios (AOR) and 95% CI were computed through conditional logistic regression. Only new users were considered. We included 13,267 cases (4400 cardioembolic, 8867 non-cardioembolic) and 61,378 controls (20,147 and 41,231, respectively). CaM use was associated with an increased risk of cardioembolic IS (AOR = 1.88; 95% CI: 1.21-2.90) in a duration-dependent manner, while it showed no association with non-cardioembolic IS (AOR = 1.05; 95% CI: 0.74-1.50); its combination with oBs increased the risk of cardioembolic IS considerably (AOR = 2.54; 95% CI: 1.28-5.04), showing no effect on non-cardioembolic. CaD use was not associated with either cardioembolic (AOR = 1.08; 95% CI: 0.88-1.31) or non-cardioembolic IS (AOR = 0.98; 95% CI: 0.84-1.13) but showed a small association with cardioembolic IS when combined with oBs (AOR = 1.35; 95% CI: 1.03-1.76). The results support the hypothesis that CS increases the risk of cardioembolic IS, primarily when used concomitantly with oBs.

Effect of lard plus soybean oil on blood pressure and other cardiometabolic risk factors in healthy subjects: a randomized controlled-feeding trial

Lard has been consumed by humans for thousands of years, but its consumption has declined substantially in the last few decades, because of negative publicity about the consumption of animal-derived saturated fats. Emerging evidence highlights that lard plus soybean oil (blend oil) could be more beneficial for body weight and liver function than the individual use of the two oils. This study aimed to evaluate the effects of blend oil on cardiometabolic risk factors in healthy subjects. This was a parallel, three-arm, randomized controlled-feeding trial. 334 healthy subjects (mean age: 33.1 years, 60% women) were randomized into three isoenergetic diet groups with three different edible oils (30 g day^-1) (soybean oil, lard, and blend oil [50% lard and 50% soybean oil]) for 12 weeks. 245 (73.4%) participants completed the study. After the 12-week intervention, reductions in both systolic blood pressure (SBP) and diastolic blood pressure (DBP) were greater in the blend oil group than in the other two groups (P = 0.023 and 0.008 for the interaction between the diet group and time, respectively). Reductions of SBP and DBP in the blend oil group were more significant than those in the soybean oil group with P = 0.008 and P = 0.026 and the lard group with P < 0.001 and P < 0.001. Changes in SBP/DBP at 12 weeks were -6.0 (95% CI: -8.6 to -3.4)/0.8 (95% CI: -1.7 to 3.2) mmHg in the blend oil group, -3.3 (95% CI: -5.7 to -0.9)/1.5 (95% CI: -1.0 to 4.0) mmHg in the soybean oil group and -1.2 (95% CI: -3.7 to 1.4)/3.3 (95% CI: 0.9 to 5.8) mmHg in the lard group. Subgroup analyses showed that blend oil significantly decreased SBP and DBP compared with the other two groups in participants with BP ≥ 130/80 mmHg and body mass index ≥25. There were no significant differences in the changes in body weight, waist circumference, serum lipids, or glucose between groups. In conclusion, our findings suggest that blend oil (lard plus soybean oil) reduces BP compared with soybean oil and lard in healthy subjects.

The association of vitamin-D level with catheter-related-thrombosis in hemodialysis patients: A data mining model

PURPOSE

This study aims to investigate the association of different risk factors including vitamin-D level with catheter-related-thrombosis in hemodialysis patients by applying data mining techniques.

METHODS

This study used the retrospectively approach and was done based on the CRISP-DM framework. The data of 1048 hemodialysis patients of Hasheminejad Kidney Center whose first catheterization was between 2014 and 2019 was used for analysis. In this study, patients with a previous history of deep venous thrombosis, thrombophilic condition, and undergone anticoagulant therapy were excluded. The decision tree J48 in WEKA software was used for modeling. The K-fold cross-validation method was also used to evaluate the classification performance. Finally, the model was evaluated by using Confusion Matrix and F-Measure.

RESULTS

The approved model was accurate in 70.3% of the predictions, and it demonstrated an association between patients' vitamin-D range and catheter-related-thrombosis.

CONCLUSION

The results indicated that in hemodialysis patients without the history of cancer or high blood pressure, vitamin-D had a significant impact on catheter related thrombosis.

Mechanisms Suggesting a Relationship between Vitamin D and Erectile Dysfunction: An Overview

Vitamin D deficiency (VDD) and erectile dysfunction (ED) heavily burden the male population. The higher prevalence of both conditions in the elderly suggests a possible relationship between the two conditions. In addition, in vitro, animal, and human studies have revealed several mechanisms that may relate VDD to ED. The main mechanism by which vitamin D might exert its action on sexual function appears to be through the regulation of endothelial function. Indeed, VDD correlates with several markers of endothelial function. The action of vitamin D on the endothelium would be exercised both indirectly through its intervention in inflammatory processes and through the production of oxygen free radicals, and directly through the regulation of vascular stiffness, the production of nitric oxide, and the regulation of vessel permeability. Furthermore, the ubiquitous distribution of the vitamin D receptor in the human body means that this hormone can also exert a beneficial effect on erectile function by interfering with those comorbidities significantly associated with ED, such as hypertension, diabetes mellitus, hypercholesterolemia, chronic kidney disease, and hypogonadism. In this review, we thoroughly and carefully presented the evidence and mechanisms that would appear to relate vitamin D levels to erectile function. Furthermore, we have summarized the meta-analytic evidence for and against this association to provide a true representation of this topic. Data published to date suggest that low levels of vitamin D could contribute to worsening erectile function through several mechanisms. Therefore, vitamin D levels should be measured in patients with ED and maintained at adequate levels by specific supplementation in case of deficiency. However, the low quality and heterogeneity of clinical trials evaluating the effects of vitamin D administration on erectile function and ED-associated comorbidities do not allow for a univocal conclusion, and indicate the need for further studies to analyze these aspects.

A Scoping Review of Vitamin D for Nonskeletal Health: A Framework for Evidence-based Clinical Practice

BACKGROUND

Low serum 25-hydroxy-vitamin D [25(OH)D] levels are prevalent worldwide. Although the benefits of vitamin D supplementation have focused on skeletal disorders (eg, rickets, osteomalacia, osteoporosis), emerging evidence for nonskeletal health merits further discussion.

PURPOSE

The purpose of this review was to critically examine the vitamin D supplementation literature pertaining to nonskeletal health to help guide clinicians.

METHODS

A scoping review that included observational studies and randomized clinical trials (RCTs) was performed. Evidence from meta-analyses and individual RCTs are discussed, and controversies and future directions are considered.

FINDINGS

25(OH)D deficiency is a ubiquitous condition associated with multiple nonskeletal diseases, including cardiometabolic (heart disease, diabetes, and kidney disease), immune (HIV/AIDS and cancer), lung (from traditional chronic disorders to coronavirus disease 2019), and gut diseases. Vitamin D deficiency also affects health across the life span (children, pregnant, and elderly), mental illness, and reproduction in both men and women. In contrast, vitamin D supplementation does not necessarily improve major medical outcomes, even when low 25(OH)D levels are treated. Screening for 25(OH)D status remains an important practice, primarily for high-risk patients (eg, elderly, women with osteoporosis, people with low exposure to sunlight). It is reasonable to supplement with vitamin D to treat 25(OH)D deficiency, such that if beneficial nonskeletal health occurs, this may be considered as a coadjutant instead of the central tenet of the disease. Furthermore, optimizing dosing regimens is an important clinical consideration.

IMPLICATIONS

Although 25(OH)D deficiency is prevalent in nonskeletal diseases, there is no uniform evidence that vitamin D supplementation improves major medical outcomes, even when low 25(OH)D levels are corrected. Findings from RCTs warrant caution due to possible selection bias. Overall, vitamin D supplementation must be guided by circulating levels as a reasonable medical practice to correct 25(OH)D deficiency.

Evidence That Increasing Serum 25(OH)D Concentrations to 30 ng/mL in the Kingdom of Saudi Arabia and the United Arab Emirates Could Greatly Improve Health Outcomes

Accumulating evidence supports the potential protective effects of vitamin D against chronic diseases such as Alzheimer's disease, autoimmune diseases, cancers, cardiovascular disease (ischaemic heart disease and stroke), type 2 diabetes, hypertension, chronic kidney disease, stroke, and infectious diseases such as acute respiratory tract diseases, COVID-19, influenza, and pneumonia, as well as adverse pregnancy outcomes. The respective evidence is based on ecological and observational studies, randomized controlled trials, mechanistic studies, and Mendelian randomization studies. However, randomized controlled trials on vitamin D supplementation have largely failed to show benefits, probably due to poor design and analysis. In this work, we aim to use the best available evidence on the potential beneficial effects of vitamin D to estimate the expected reduction in incidence and mortality rates of vitamin D-related diseases in the Kingdom of Saudi Arabia and the United Arab Emirates if minimum serum 25(OH)D concentrations were to be raised to 30 ng/mL. Estimated reductions by 25% for myocardial infarction incidence, 35% for stroke incidence, 20 to 35% for cardiovascular disease mortality, and 35% for cancer mortality rates depicted a promising potential for raising serum 25(OH)D. Methods to increase serum 25(OH)D concentrations at the population level could include food fortification with vitamin D3, vitamin D supplementation, improved dietary vitamin D intake, and sensible sun exposure.

Nonskeletal and skeletal effects of high doses versus low doses of vitamin D3 in renal transplant recipients: Results of the VITALE (VITamin D supplementation in renAL transplant recipients) study, a randomized clinical trial

Vitamin D sufficiency is associated with a reduced risk of fractures, diabetes mellitus, cardiovascular events, and cancers, which are frequent complications after renal transplantation. The VITALE (VITamin D supplementation in renAL transplant recipients) study is a multicenter double-blind randomized trial, including nondiabetic adult renal transplant recipients with serum 25-hydroxy vitamin D (25(OH) vitamin D) levels of <30 ng/mL, which is randomized 12 to 48 months after transplantation to receive high (100 000 IU) or low doses (12 000 IU) of cholecalciferol every 2 weeks for 2 months and then monthly for 22 months. The primary outcome was a composite endpoint, including diabetes mellitus, major cardiovascular events, cancer, and death. Of 536 inclusions (50.8 [13.7] years, 335 men), 269 and 267 inclusions were in the high-dose and low-dose groups, respectively. The serum 25(OH) vitamin D levels increased by 23 versus 6 ng/mL in the high-dose and low-dose groups, respectively (P < .0001). In the intent-to-treat analysis, 15% versus 16% of the patients in the high-dose and low-dose groups, respectively, experienced a first event of the composite endpoint (hazard ratio, 0.94 [0.60-1.48]; P = .78), whereas 1% and 4% of patients in the high-dose and low-dose groups, respectively, experienced an incident symptomatic fracture (odds ratio, 0.24 [0.07-0.86], P = .03). The incidence of adverse events was similar between the groups. After renal transplantation, high doses of cholecalciferol are safe but do not reduce extraskeletal complications (trial registration: ClinicalTrials.gov; identifier: NCT01431430).

Association between vitamin D and cardiovascular health: Myth or Fact? A narrative review of the evidence

Vitamin D deficiency is prevalent worldwide. Since the discovery of the expression of vitamin D receptor in ventricular cardiomyocytes, fibroblasts, and blood vessels, there has been a growing body of literature assessing the link between vitamin D status and cardiovascular health from one side, and the effect of vitamin D supplementation on prevention of cardiovascular diseases from the other side. In this review, we summarized studies highlighting the role of vitamin D on cardiovascular health, namely atherosclerosis, hypertension, heart failure, and metabolic syndrome, a recognized significant risk factor for cardiovascular diseases. Studies showed discrepancies between findings from cross-sectional and longitudinal cohorts and those from interventional trials, but also between one outcome and another. Cross-sectional studies found a strong association between low 25 hydroxyvitamin D (25(OH)D3) and acute coronary syndrome, and heart failure. These findings encouraged the promotion for vitamin D supplementation as a preventive measure for cardiovascular diseases in the elderly, namely in women. This fact, however, turned out into a myth with the results of large interventional trials that did not show any benefit from vitamin D supplementation in reducing ischemic events, heart failure or its outcomes, or hypertension. Although some clinical studies showed beneficial effect of vitamin D supplementation on insulin sensitivity and metabolic syndrome, this effect was not consistent across all studies.

Is Vitamin D Deficiency Prothrombotic? A Systematic Review

Observational studies indicate a relationship between vitamin D deficiency and an increased risk of venous and arterial thrombotic events, but the underlying mechanisms behind this association are uncertain. This systematic review explores if there is an association between decreased vitamin D levels and a prothrombotic profile. The systematic literature search initially identified 3,214 studies (published until December 21, 2021) investigating the relationship between vitamin D and numerous hemostatic parameters. After the screening process, 18 observational and intervention studies fulfilled the inclusion criteria and were included in this systematic review. Parameters of primary hemostasis, secondary hemostasis, and fibrinolysis were investigated in six, thirteen, and fifteen of these studies, respectively. Most of the eligible studies did not identify significant associations between decreased vitamin D levels and hemostatic parameters. Some conflicting results were found between decreased vitamin D levels and thrombin generation parameters and the tissue factor pathway inhibitor. Conflicting results were also found between decreased vitamin D levels and fibrinolytic parameters, although the evidence may point toward weak associations with some regulators of fibrinolysis, mostly decreased tissue type plasminogen activator. Overall, our systematic review did not identify any definitive link between vitamin D deficiency and a prothrombotic profile, which might otherwise help explain the observed association between vitamin D deficiency and increased risk of thrombotic events. Moreover, there is no clinical evidence to confirm or refute a possible antithrombotic effect of vitamin D. Larger high-quality randomized controlled trials are needed to better elucidate the link between vitamin D deficiency and a prothrombotic risk profile.

Reduced nitric oxide synthesis in winter: A potential contributing factor to increased cardiovascular risk

BACKGROUND

Nitric oxide is a key signalling molecule that elicits a range of biological functions to maintain vascular homeostasis. A reduced availability of nitric oxide is implicated in the progression of cardiovascular diseases and increases the risk of pathogenic events.

AIMS

To compare the concentration of nitric oxide metabolites in healthy adults between winter and summer months.

DESIGN

An observational study of healthy adults (age 32 ± 9 years) living in central Scotland.

METHODS

Thirty-four healthy adults (13 females) were monitored for 7 days in summer and winter to record sunlight exposure (ultraviolet-A (UV-A) radiation), diet, and physical activity. At the end of each phase, blood pressure was measured, and samples of blood and saliva collected. The samples were analysed to determine the concentrations of plasma and salivary nitrate and nitrite and serum 25-hydroxyvitamin D (25(OH)D).

RESULTS

The participants maintained similar diets in each measurement phase but were exposed to more UV-A radiation (550%) and undertook more moderate-vigorous physical activity (23%) in the summer than in winter. Plasma nitrite (46%) and serum 25(OH)D (59%) were higher and blood pressure was lower in the summer compared to winter months. Plasma nitrite concentration was negatively associated with systolic, diastolic, and mean arterial blood pressure.

CONCLUSIONS

Plasma nitrite, an established marker of nitric oxide synthesis, is higher in healthy adults during the summer than in winter. This may be mediated by a greater exposure to UV-A which stimulates the release of nitric oxide metabolites from skin stores. While it is possible that seasonal variation in nitric oxide availability may contribute to an increased blood pressure in the winter months, the overall impact on cardiovascular health remains to be determined.

Is Vitamin D Supplementation an Effective Treatment for Hypertension?

Purpose of the Review

Results from epidemiological studies suggest that vitamin D (VD) deficiency (VDD) may be a cause of hypertension (HTN). However, the results of randomized clinical trials (RCTs) designed to address the impact of VD supplementation on reducing blood pressure (BP) remain equivocal. To determine whether VD might serve as a beneficial treatment option for a specific subset of hypertensive patients, we performed a stratified analysis of RCT data and addressed problems associated with some methodological issues.

Recent Findings

HTN is caused by multiple factors. VDD may be one of the factors contributing to the development of this disorder. There are more than 70 RCTs that examined the impact of VD supplementation on BP. These RCTs can be classified into four groups based on their respective study populations, including participants who are (1) VD-sufficient and normotensive, (2) VD-deficient and normotensive, (3) VD-sufficient and hypertensive, and (4) VD-deficient and hypertensive.

Summary

Our evaluation of these studies demonstrates that VD supplementation is ineffective when used to reduce BP in VD-sufficient normotensive subjects. VD supplementation for five years or more may reduce the risk of developing HTN specifically among those with VDD. Interestingly, findings from 12 RCTs indicate that daily or weekly supplementation, as opposed to large bolus dosing, results in the reduction of BP in VD-deficient hypertensive patients. Our ongoing research focused on elucidating the mechanisms of VDD-induced HTN will ultimately provide evidence to support the development of etiology-specific prevention and treatment strategies focused on HTN in the VD-deficient population.

The Modulation of Arachidonic Acid Metabolism and Blood Pressure-Lowering Effect of Honokiol in Spontaneously Hypertensive Rats

Background: Cardiovascular diseases have consistently been the leading cause of death in the United States over the last two decades, with 30% of the adult American population having hypertension. The metabolites of arachidonic acid (AA) in the kidney play an important role in blood pressure regulation. The present study investigates the antihypertensive effect of honokiol (HON), a naturally occurring polyphenol, and examines its correlation to the modulation of AA metabolism. Methods: Spontaneously hypertensive rats (SHR) were randomly divided into four groups. Treatment groups were administered HON intraperitoneally at concentrations of 5, 20, and 50 mg/kg. Blood pressure was monitored at seven-day intervals. After a total of 3 weeks of treatment, the rats were euthanized and the kidney tissues were collected to examine the activity of the two major enzymes involved in AA metabolism in the kidney, namely cytochrome P450 (CYP)4A and soluble epoxide hydrolase (sEH). Results: Rats treated with HON did not experience the rise in blood pressure observed in the untreated SHR. High-dose HON significantly reduced blood pressure and inhibited the activity and protein expression of the CYP4A enzyme in the rat kidney. The activity of the sEH enzyme in renal cytosol was significantly inhibited by medium and high doses of HON. Conclusion: Our data demonstrate the antihypertensive effect of HON and provide a novel mechanism for its underlying cardioprotective properties.

Serum Vitamin D Levels in Relation to Hypertension and Pre-hypertension in Adults: A Systematic Review and Dose–Response Meta-Analysis of Epidemiologic Studies

Background

Findings of observational studies that evaluated the association of serum vitamin D status and high blood pressure were contradictory. This meta-analysis of epidemiologic studies assessed the relation of serum vitamin D levels to hypertension (HTN) and pre-hypertension in adults.

Methods

We conducted a systematic search of all published articles up to March 2021, in four electronic databases (MEDLINE (PubMed), Web of Science (ISI), Embase and Scopus), and Google scholar. Seventy epidemiologic studies (10 prospective cohort, one nested case–control, and 59 cross-sectional investigations) that reported relative risks (RRs), odds ratios (ORs), hazard ratios, or prevalence ratios with 95% CIs for HTN or pre-hypertension in relation to serum vitamin D concentrations in adults were included in the analysis.

Results

In prospective studies, a 16% decrease in risk of hypertension was observed in participants with high levels of serum vitamin D compared to low levels (RR: 0.84; 95%CI: 0.73, 0.96; 12 effect sizes). Dose–response analysis in prospective studies revealed that each 25 nmol/L increase in serum vitamin D concentrations resulted in 5% reduced risk of HTN (RR: 0.95; 95% CI: 0.90, 1.00). Also, a significant nonlinear relationship between serum vitamin D levels and HTN was found (P_nonlinearity < 0.001). In cross-sectional investigations, highest vs. lowest level of serum vitamin D was related to reduced odds of HTN (OR: 0.84; 95%CI: 0.79, 0.90; 66 effect sizes) and pre-hypertension (OR: 0.75; 0.95%CI: 0.68, 0.83; 9 effect sizes). Dose–response analysis in these studies showed that each 25 nmol/L increase in serum vitamin D levels was related to a significant 6% reduction in odds of hypertension in all populations (RR: 0.94; 95%CI: 0.90, 0.99) and 3% in studies with representative populations (RR: 0.97; 95%CI: 0.95, 0.99).

Conclusion

This meta-analysis of epidemiologic studies disclosed that serum vitamin D concentrations were inversely related to the risk of HTN in adults, in a dose–response manner in both prospective cohort and cross-sectional studies.

Systematic Review Registration:http://www.crd.york.ac.uk/Prospero, identifier: CRD42021251513.

Vitamin D, respiratory infections, and chronic disease: Review of meta-analyses and randomized clinical trials

BACKGROUND

Observational studies have suggested associations of vitamin D deficiency (VDD) with respiratory tract infections, impaired bone health, and myriad chronic diseases.

OBJECTIVE

To assess potential causal relationships between vitamin D supplementation and a reduced risk of these conditions, a review of the evidence across available meta-analyses of randomized control trials (RCTs) and RCTs was performed.

METHOD

PubMed, Embase, Cochrane Library, and Web of Science were searched from their inception to March 2021. We included only RCTs and meta-analyses of RCTs focusing on the association between vitamin D and respiratory disease, bone health, cardiovascular disease (CVD), diabetes mellitus, and cancer.

RESULTS

A total of 107 RCTs and 62 meta-analysis of RCTs were included. Although most RCTs did not support benefits of vitamin D supplementation, suggestive evidence for benefit was found in populations at greater risk of VDD and for acute respiratory infections, fractures in institutionalized older adults, type 2 diabetes among patients with prediabetes, and cancer mortality. In contrast, no compelling evidence for benefit was found for other respiratory conditions, fractures in community-dwelling adults, falls, cancer incidence, or CVD.

CONCLUSIONS

Current evidence from RCTs and meta-analyses of RCTs is inconsistent regarding the effects of vitamin D supplementation on respiratory infections and chronic diseases. Individuals most likely to benefit are those with baseline VDD or with selected high-risk conditions. Public health initiatives are needed to eliminate VDD globally, and future research will be enhanced by a 'precision prevention' approach to identify those most likely to benefit from vitamin D supplementation.

The influence of CYP2R1 polymorphisms and gene-obesity interaction with hypertension risk in a Chinese rural population

BACKGROUND AND AIMS

Several studies have reported that variants in CYP2R1 have been linked with an increased risk of hypertension. However, the interaction between CYP2R1 variants and environmental factors on the susceptibility of hypertension remained unclear. Therefore, this study evaluated the influence of CYP2R1 polymorphisms on hypertension susceptibility, and explored the interaction effect of CYP2R1 variations and obesity on the disease.

METHODS AND RESULTS

We included 766 incident hypertension cases matched with non-hypertension controls in a 1:1 ratio by sex, age (within 3 years). Two loci in CYP2R1 gene (rs10766197 and rs12794714) were genotyped by TaqMan probe assays. The concentration of 25-hydroxyvitamin-D was determined by human enzyme-linked immunosorbent assay (ELISA) kits. The associations of CYP2R1 polymorphisms and risks of vitamin D deficiency (VDD) were analyzed by logistic regression. Multifactor dimensionality reduction (MDR) was used to analyze the gene-environment interaction. Multiple logistic regression was used to examine the effect of CYP2R1 gene variations, and the interaction between CYP2R1 variation and obesity on hypertension susceptibility. The results showed that rs10766197 (GG vs. AA) and rs12794714 (GG vs. AA) polymorphisms were both associated with an increased risk of VDD (OR = 1.49, 95% confidence interval (CI) = 1.08-2.05 and OR = 1.63, 95% CI = 1.19-2.25, respectively), after adjustment for potential risk factors. We also found that rs12794714 polymorphism was significantly associated with elevated risk of hypertension under the dominant model (OR = 1.26, 95% CI = 1.01-1.56). In addition, the interactions between rs12794714 with both general obesity (OR = 3.93, 95% CI = 2.72-5.68) and central obesity (OR = 3.22, 95% CI = 2.29-4.52) have significant effects on hypertension susceptibility.

CONCLUSIONS

The study provided further evidence that CYP2R1 variation was associated with a higher risk of hypertension in Chinese rural population. The interaction between CYP2R1 rs12794714 and obesity may increase the risk of hypertension.

Factors affecting vitamin D status in outpatients with abdominal aortic aneurysm and peripheral artery disease- a single centre study

BACKGROUND AND AIMS

Vitamin D (VD) deficiency is considered an important risk factor for the development of atherosclerosis and aortic aneurysms. The deficiency is claimed to enhance degeneration and remodeling of collagen and elastin fibers in the artery wall, leading to its weakening and progressive dilatation. This study aimed to assess vitamin D status, in outpatients with abdominal aneurysms (AAA) and peripheral artery disease (PAD) not treated with VD, and factors affecting serum 25-OH-D levels.

METHODS AND RESULTS

This cross-sectional study involved 59 outpatients with AAA and 150 with PAD. AAA was defined as local dilation of the aorta diameter >30 mm in imaging. None of the patients was prescribed VD containing medicines. Serum 25-OH, iPTH, phosphorus and calcium levels were assessed in all study participants. VD status was categorized according to commonly used cut-offs for serum 25-OH-D (<20 ng/mL - deficiency, <30 ng/mL -insufficiency). Serum 25-OH-D levels were similar in patient with AAA and PAD [1-3Q: 26.2 (18.8-37.6) vs 21.8 (15.9-31.4) ng/mL; p = 0.30], with deficiency noted in 25.4% with AAA and 41.8% with PAD (p < 0.05). Multiple regression analysis revealed that VD deficiency was explained by past stroke episodes [OR = 2.80 (95%CI: 1.22-6.41)]. Secondary hyperparathyroidism was diagnosed in 1.7% of patients with AAA and 1.9% with PAD.

CONCLUSIONS

The frequency of VD deficiency in outpatient with AAA is not greater than in those with PAD. Past stroke episode is associated with an increased occurrence of VD deficiency in both outpatients with AAA and PAD other than sun exposure and diet.

The effect of ultraviolet irradiation compared to oral vitamin D supplementation on blood pressure of nursing home residents with dementia

Background

Observational studies have reported an inverse association between ultraviolet (UV) radiation and hypertension. The aim of this study was to assess differences in blood pressure changes between persons with dementia receiving UV light versus vitamin D (VD) supplementation.

Methods

Post-hoc analysis of randomized controlled trial data concerning nursing home residents with dementia (N = 61; 41 women, mean age 84.8 years). The participants received half-body UV irradiation, twice weekly over 6 months, at one standard erythema dose (UV group, n = 22) or 5600 international units of cholecalciferol once a week (VD group, n = 39). Short-term effects were evaluated after 1 month and long-term effects after 3 and 6 months. Differences in blood pressure changes were assessed using linear mixed models.

Results

With the VD group as a reference, the estimated difference in mean change of systolic blood pressure was − 26.0 mmHg [95% confidence interval (CI) -39.9, − 12.1, p = .000] at 1 month, 4.5 mmHg (95% CI -6.8, 15.9, p = 0.432) at 3 months, and 0.1 (95% CI -14.1, 14.3, p = 0.83) at 6 months. The estimated difference in diastolic blood pressure was − 10.0 mmHg (95% CI -19.2, − 0.7, p = 0.035) at 1 month, 3.6 mmHg (95% CI -4.1, 11.2, p = 0.358) at 3 months, and 2.7 (95% CI -6.8, 12.1, p = 0.580) at 6 months.

Conclusions

UV light had only a short-term effect but not a long-term effect on blood pressure reduction compared to VD use in this sample of normotensive to mild hypertensive nursing home residents with dementia. Future studies will be needed to determine the effect of UV light in different samples of the population and especially in a population with hypertension.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-021-02538-7.

Role of Vitamin D in Cardiovascular Diseases

Vitamin D represents a group of secosteroids involved in the calcium and phosphate metabolism. The active form of vitamin D, 1,25-dihydroxylcalciferol, exerts its biological mechanisms via the VDR (vitamin D receptor) which acts as a regulator of several target genes. Hypovitaminosis D is associated with many diseases, which are not only limited to the metabolism of the skeleton, but growing evidence links the deficit of vitamin D to cardiovascular, metabolic, immune, and neoplastic diseases. In regard to the cardiovascular system, current evidence shows the presence of VDR in endothelial cells. Moreover, both in vitro and animal experimental models demonstrated that the deficit of vitamin D can promote endothelial dysfunction and atherosclerosis development. Vitamin D can interfere with vascular functions also by affecting the production of vasodilator mediators. VDR is also expressed in left ventricle cardiomyocytes, and hypovitaminosis D can relate to cardiac hypertrophy and heart failure. Randomized clinical trials (RCT) designed to prove the therapeutic role of vitamin D supplementation have been inconclusive to date. The aim of this review is to highlight the main interactions between vitamin D metabolism and cardiovascular diseases; thus, focusing on pathogenic mechanisms and related clinical manifestations.

The Impact of Micronutrients-Calcium, Vitamin D, Selenium, Zinc in Cardiovascular Health: A Mini Review

The role of micronutrients in health and disease has increased the curiosity and interest among researchers. The prime focus of this review is the significance of trace elements- calcium, vitamin D, selenium and zinc with cardiovascular health. WHO identified cardiovascular diseases (CVD) as the leading cause of deaths globally. Identifying the risk factors that could be modified and creating new treatment strategies remains to be the main concern for CVD prevention. The data that showed the relationship between trace elements and various ways in which they may contribute to cardiovascular health and disease from clinical trials and observational studies were collected from databases such as PubMed and Embase. Based on these collected data, it shows that either high or low circulating serum levels can be associated with the development of cardiovascular diseases. Micronutrients through diet contribute to improved cardiac health. However, due to our current lifestyle, there is a huge dependency on dietary supplements. Based on the observational studies, it is evident that supplements cause sudden increase in the circulating levels of the nutrients and result in cardiovascular damage. Thus, it is advisable to restrict the use of supplements, owing to the potent risks it may cause. In order to understand the exact mechanism between micronutrients and cardiac health, more clinical studies are required.

Decreasing prevalence of vitamin D deficiency in the central region of Saudi Arabia (2008-2017)

OBJECTIVE

Widespread vitamin D deficiency (serum 25-hydroxyvitamin D < 50 nmol/L) in Saudi Arabia (SA) has been documented, yet a time trend is needed to establish where the prevalence is headed. This study aims to fill this gap.

STUDY DESIGN AND SETTING

This cross-sectional series (N = 7360) were conducted in the central region of SA from 2008 to 2017. Participants of all ages were taken from multiple cohorts that included the Biomarker Screening in Riyadh (2008-2010; N = 1460), the Osteoporosis Registry (2014-2017; N = 1225), Gestational Diabetes Mellitus cohort (2014-2017, N = 281), Vitamin D School Project (2011-2017; N = 3039) and Prediabetes cohort (2012-2017; N = 1355) master databases.

RESULTS

Vitamin D deficiency in SA has a 10-year prevalence of 73.2 %. Between 2008-2017, the prevalence of vitamin D deficiency decreased from 87.1% to 64.7% for participants aged 18-40 years (p-trend<0.001), and from 86.2% to 45.7% in participants aged > 40 years (p-trend<0.001). During this period, vitamin D deficiency in females decreased from 80.1% to 69.6% (p-trend<0.001), whereas in males, it decreased from 93.2% to 49.3% (p-trend<0.001). Serum 25(OH)D was observed to have an overall increase of 2.2 ± 0.1 nmol/l (p < 0.001) along with the seasonally adjusted annual increase of 1.3 ± 0.2 nmol/l from 2008 to 2017 (p < 0.001).

CONCLUSION

The decreasing trend in vitamin D deficiency in SA across all demographics suggests successful public health campaigns over time. It will be interesting to investigate further whether the general improvement in the vitamin D status at the community level also translated in lesser incidences of vitamin d-related diseases over time.

Identification of Adolescents with Adiposities and Elevated Blood Pressure and Implementation of Preventive Measures Warrants the Use of Multiple Clinical Assessment Tools

The burden of abdominal adiposity has increased globally, which is recognized as a key condition for the development of obesity-related disorders among youth, including type 2 diabetes, cardiovascular disease, and hypertension. High blood pressure (BP) and cardiovascular diseases increase the rates of premature mortality and morbidity substantially. Aims: to investigate the relation between abdominal adiposity and elevated BP among adolescent males in Jordan. Methods: Nationally representative sample of male adolescents was selected using multi-cluster sampling technique. Study sample included 1035 adolescent males aged 12 to 17 years. Multiple indicators were used to assess adiposity including waist circumference (WC) and total body fat (TF), truncal fat (TrF), and visceral fat (VF). Systolic blood pressure was measured to assess hypertension. Results: After adjusting for age, smoking status, and physical activity, the odds of having stage two hypertension increased 6, 7, and 8 times for adolescents who were on 90th percentile or above for Trf, VF, and WC, respectively. Conclusion: Elevated BP was significantly associated with total and abdominal adiposity among adolescent males in Jordan. Use of multiple clinical assessment tools is essential to assess abdominal obesity among adolescents.

Vitamin D Deficiency and Risk of Metabolic Syndrome in Aging Men

The elderly population is rapidly increasing; hence, the disability due to age-related diseases has become an important socioeconomic burden. Amongst age-related diseases cardiovascular ones (CVD) have a huge impact on morbidity and mortality and are associated with metabolic syndrome (MetS). Several studies investigated the role of hypovitaminosis D in the pathogenesis of MetS and of CVD, this review unravels the relationship between aging/senescence, vitamin D, gender, and pathogenesis of MetS.

Effect of 1-year oral cholecalciferol on a metabolic profile and blood pressure in poor-controlled type 2 diabetes mellitus: an open-label randomized controlled pilot study

PURPOSE

Hypovitaminosis D has been associated with many cardio-metabolic disorders, although their pathogenetic link still remains unclear. Our aim was to evaluate whether 1-year vitamin D (D) supplementation could improve glycemic control, lipid profile, systolic (SBP) and diastolic (DBP) blood pressure levels and body composition.

METHODS

In an open-label randomized-controlled pilot study, thirty poor-controlled (HbA1c > 59 mmol/mol) type 2 diabetic patients (age 71.5 ± 3.2 years, M/F 21/9, BMI 29.8 ± 3.6 kg/m²) with hypovitaminosis D (25OHD 22.0 ± 11.3 nmol/l) were randomized to cholecalciferol supplementation (500 UI/kg p.o. weekly, + D) or observation (- D) for one year. Changes in parameters of glucose, lipid and blood pressure control at 3, 6, 9 and 12 months vs. baseline were assessed.

RESULTS

One-year D supplementation restored D status and had a beneficial effect on fasting glucose (FG, mean percentage changes ± SD, - 1.8% ± 23.1 vs. + 18.8% ± 30.0), glycosylated haemoglobin (HbA1c, - 13.7% ± 14.5 vs. - 4.2% ± 14.1), SBP (- 13.4% ± 8.5 vs. - 2.4% ± 12.6) and HDL-cholesterol levels (- 2.1% ± 14.0 vs. - 10.9% ± 12.9; p < 0.05 for all comparisons) in + D vs. - D patients, respectively. In the former, a reduction in HBA1c, SBP and DBP levels, BMI, fat mass index (FMI) and ratio (FMR) was observed after 1 year (p < 0.05 for all comparisons vs. baseline). We noticed a relationship between 1-year mean percentage changes of serum 25OHD and SBP levels (R = - 0.36, p < 0.05).

CONCLUSION

One-year cholecalciferol supplementation, able to restore D status, significantly improves FG, HbA1c, SBP and HDL-cholesterol levels in patients with poor-controlled type 2 diabetes mellitus and D deficiency.

The effect of PCOS status on atherosclerosis markers and cardiovascular disease risk factors in young women with vitamin D deficiency

OBJECTIVE

To investigate whether polycystic ovary syndrome (PCOS) had further deteriorating influence on endothelial function or cardiometabolic parameters in women with vitamin D deficiency during reproductive age.

STUDY DESIGN

The study group was composed of women with PCOS and vitamin D deficiency and insufficiency between the ages of 18 and 35 years. Age and body mass index (BMI)-matched women were chosen as controls. Serum 25(OH) Vit D levels below 20 ng/mL were considered as vitamin D deficiency. The cutoff level of vitamin D insufficiency was suggested at 30 ng/mL. Serum FSH, LH, estradiol, testosterone, DHEA-S, fasting glucose, total cholesterol, HDL, LDL, triglyceride levels were analyzed. Carotid artery intima-media thickness (CIMT) was measured, and the flow-mediated vasodilation (FMD) was calculated.

RESULTS

CIMT and FMD values in both vitamin D deficiency and insufficiency subgroups showed no significant difference between PCOS and non-PCOS groups. There was a weak negative correlation between BMI, waist/hip ratio, CRP, and 25(OH) Vitamin D.

CONCLUSION

PCOS is a heterogeneous disease with different combinations of the diagnostic components. Vitamin D is an important variable for a healthy cardiovascular system. We did not find any difference in early atherosclerotic markers and cardiometabolic features between PCOS and non-PCOS group with Vitamin D deficiency.

Vitamin D status and blood pressure in children and adolescents: a systematic review of observational studies

BACKGROUND

Childhood hypertension is a growing public health problem. Simultaneously, hypovitaminosis D is widespread in this population and could be associated with hypertension. This study systematically reviewed the literature on the relationship between vitamin D status and blood pressure (BP) in children and adolescents.

METHODS

Following the PRISMA guidelines, PUBMED, MEDLINE, CINAHL, EMBASE, Cochrane Library, and ClinicalTrials.gov and the gray literature without language or time restrictions were searched. We included observational studies, assessed their risk of bias, and extracted data on population characteristics, vitamin D status and BP measurements, and the association between the two variables. A narrative analysis of the studies was performed.

RESULTS

In total, 85 studies were included. Prospective cohort studies showed no association between vitamin D and BP, and generally, they were flawed. Also, the majority of non-prospective cohort studies (cross-sectional, retrospective, case-control) did not report an association between vitamin D and BP. They were mostly flawed regarding BP measurement and adjusting to potential confounders.

CONCLUSION

The results on the relationship between vitamin D status and BP in children and adolescents varied between the studies, and mainly pointed towards lack of association.

Impact of Micronutrients on Hypertension: Evidence from Clinical Trials with a Special Focus on Meta-Analysis

Hypertension (HT) is one of the pivotal risk factors for various detrimental diseases like cardiovascular diseases (CVDs), cerebrovascular disease, and renal dysfunction. Currently, many researchers are paying immense attention to various diet formula (dietary approach) with a special focus on micro and macronutrients along with modified lifestyle and standard anti-hypertensive drugs. Micronutrients (minerals/vitamins) play a central role in the regulation of blood pressure (BP) as they aid the function of macronutrients and also improve the anti-hypertensive functions of some anti-hypertensive agents. Even though several studies have demonstrated the beneficial effects of micronutrients on controlling BP, still some ambiguity exists among the nutritionists/doctors, which combination or individual mineral (dietary approach) contributes to better BP regulation. Therefore, this critical review article was attempted to delineate the underlying role of micronutrients (minerals and vitamins) for the management and prevention or delaying of HT and their related complications with strong affirmation from clinical trials as well as its mechanism of controlling BP. Moreover, the major source and recommended daily allowance (RDA) of various micronutrients are included in this review for guiding common readers (especially HT subjects) and dieticians to choose/recommend a better micronutrient and their combinations (other nutrients and standard anti-hypertensive drugs) for lowering the risk of HT and its related co-morbid conditions like CVDs.

Efficacy of single-dose cholecalciferol in the blood pressure of patients with type 2 diabetes, hypertension and hypovitaminoses D

Observational and experimental data reinforce the concept that vitamin D is associated with the pathogenesis of arterial hypertension. We investigated the effect of a single dose of 100,000 IU of cholecalciferol, in office blood pressure (BP), and 24-h ambulatory blood pressure monitoring (ABPM) in patients with type 2 diabetes mellitus (DM), hypertension, and hypovitaminosis D. Forty-three patients were randomized to a placebo or cholecalciferol group. BP was assessed by office measurements and 24-h ABPM, before and after intervention. At week 8, a greater decrease in median ABPM values was observed in cholecalciferol supplementation than in the placebo group for systolic 24-h (− 7.5 vs. − 1; P = 0.02), systolic daytime (− 7 vs. − 1; P = 0.007), systolic nighttime (− 7.0 vs. 3; P = 0.009), diastolic 24-h (− 3.5 vs. − 1; P = 0.037), and daytime DBP (− 5 vs. 0; P = 0.01). Office DBP was also reduced after vitamin D supplementation. A single dose of vitamin D₃ improves BP in patients with type 2 diabetes, hypertension, and vitamin D insufficiency, regardless of vitamin D normalization. Vitamin D supplementation could be a valuable tool to treat patients with type 2 DM, hypertension, and hypovitaminosis D.

Trial registration: Clinicaltrials.gov NCT 02204527.

Vitamin D inhibits Tissue Factor and CAMs expression in oxidized low-density lipoproteins-treated human endothelial cells by modulating NF-κB pathway

Epidemiologic studies have clearly demonstrated the correlation existing between Vitamin D (Vit. D) deficiency and increased risk of developing cardiovascular disease, suggesting that it might have a protective role in this clinical setting. Although many experimental studies have investigated the molecular mechanisms by which Vit. D might exert these effects, its potential role in protecting against athero-thrombosis is still partially unknown. We have investigated whether Vit. D might exert anti athero-thombotic effects by preventing expression of adhesion molecules (CAMs) and Tissue Factor (TF), molecules involved in atherothrombotic pathophysiology, in oxLDL stimulated endothelial cells (HUVEC). Moreover, we have investigated whether Vit. D effects might be due to the NF-kB modulation. HUVEC cultivated in medium enriched with Vit. D (10 nM) were stimulated with oxLDL (50 μg/ml). TF gene (RT-PCR), protein (Western blot), surface expression (FACS) and procoagulant activity (FXa generation assay) were measured. Similarly, CAMs gene (RT-PCR), surface expression (FACS) and soluble values (ELISA) were measured. NF-kB translocation was also investigated. Vit. D significantly reduced TF gene as well protein expression and procoagulant activity in oxLDL-treated HUVEC. Similar effects were observed for CAMs. These effects were associated with Vit. D modulation of NF-κB pathway. This study, although in vitro, indicate that Vit. D has protective effect on endothelial cells by inhibiting expression of TF and CAMs, proteins involved in atherothrombotic pathophysiology. Further studies will be necessary to translate these findings to a clinical scenario to better define the potential therapeutical role of Vit. D supplementation in the management of cardiovascular disease in patients with Vit. D deficiency.

The Antihypertensive Effect of Quercetin in Young Spontaneously Hypertensive Rats; Role of Arachidonic Acid Metabolism

Hypertension affects almost 50% of the adult American population. Metabolites of arachidonic acid (AA) in the kidney play an important role in blood pressure regulation. The present study investigates the blood pressure-lowering potential of quercetin (QR), a naturally occurring polyphenol, and examines its correlation to the modulation of AA metabolism. Spontaneously hypertensive rats (SHR) were randomly divided into four groups. Treatment groups were administered QR in drinking water at concentrations of 10, 30, and 60 mg/L. Blood pressure was monitored at seven-day intervals. After a total of seven weeks of treatment, rats were killed and kidney tissues were collected to examine the activity of the two major enzymes involved in AA metabolism in the kidney, namely cytochrome P450 (CYP)4A and soluble epoxide hydrolase (sEH). Medium- and high-dose QR resisted the rise in blood pressure observed in the untreated SHR and significantly inhibited the activity of the CYP4A enzyme in renal cortical microsomes. The activity of the sEH enzyme in renal cortical cytosols was significantly inhibited only by the high QR dose. Our data not only demonstrate the antihypertensive effect of QR, but also provide a novel mechanism for its underlying cardioprotective properties.

Vitamin D and Cardiovascular Disease, with Emphasis on Hypertension, Atherosclerosis, and Heart Failure

Vitamin D deficiency is the most common nutritional deficiency, affecting almost one billion people worldwide. Vitamin D is mostly known for its role in intestinal calcium absorption and bone mineralization. However, the observation of seasonal changes in blood pressure and the subsequent identification of vitamin D receptor (VDR) and 1α-hydroxylase in cardiomyocytes, as well as endothelial and vascular smooth muscle cells, implicated a role of vitamin D in the cardiovascular system. Animal studies provided compelling evidence that vitamin D signaling is essential for cardiovascular integrity, especially for the regulation of vascular tone and as an antifibrotic and antihypertrophic signaling pathway in the heart. In addition, observational studies reported an association between vitamin D deficiency and risk of hypertension, atherosclerosis, and heart failure. However, recent clinical intervention studies failed to prove the causal relationship between vitamin D supplementation and beneficial effects on cardiovascular health. In this review, we aim to highlight our current understanding of the role of vitamin D in the cardiovascular system and to find potential explanations for the large discrepancies between the outcome of experimental studies and clinical intervention trials.

Effects of a multi-modal resistance exercise program and calcium-vitamin D3 fortified milk on blood pressure and blood lipids in middle-aged and older men: secondary analysis of an 18-month factorial design randomised controlled trial

PURPOSE

Physical activity and dietary interventions are recommended as front-line therapy for prevention and management of cardiovascular disease. This study investigated the independent and combined effects of low-fat, calcium-vitamin D₃ fortified milk and multi-modal exercise training on blood pressure (BP) and blood lipids in middle-aged and older men.

METHODS

This was a pre-planned secondary analysis of an 18-month, randomised controlled trial. Community-dwelling men aged 50-79 years (n = 180) were randomised into (i) exercise + fortified milk; (ii) fortified milk; (iii) exercise; or (iv) control. The low-fat milk (400 mL/day) was fortified with 1,000 mg/day calcium and 800 IU/day of vitamin-D₃, whilst the exercise intervention consisted of three sessions/week of resistance- and weight-bearing impact exercises. Resting BP and fasting lipids were assessed at baseline, 6 (lipids only), 12 and 18 months.

RESULTS

Mean ± SD serum 25(OH)D and calcium intake for the entire cohort at baseline was 86 ± 36 nmol/L and 1002 ± 397 mg/day, respectively, with 10% classified as vitamin-D insufficient and 58% reporting a calcium intake below 1000 mg/day. There were no exercise-by-fortified milk interactions, nor any main-group effects for exercise or milk on BP or lipids at any time. However, there were significant reductions from baseline to 18 months in systolic (mean change, 5-8 mmHg) and diastolic (4-6 mmHg) BP in the exercise, fortified milk and control groups. All results remained largely unchanged after adjusting for use of anti-hypertensive or lipid lowering medication, weight or fat mass, or only including men with hypertension (n = 89) or dyslipidemia (n = 130) at baseline.

CONCLUSION

Supplementation with low-fat, calcium + vitamin D₃ fortified milk and a multi-modal exercise program, alone or in combination, was not effective for improving BP or blood lipids in community-dwelling middle-aged and older men.

Effects of vitamin D supplementation on 25(OH)D levels and blood pressure in the elderly: a systematic review and meta-analysis

Background: Hypertension and vitamin D deficiency are prevalent among the elderly. This study evaluated the effects of vitamin D supplementation on changes in serum 25-hydroxyvitamin D (25(OH)D) levels and blood pressure (BP) in the elderly (age > 60 years). Methods: Randomized controlled trials from electronic databases on the elderly taking oral vitamin D, until the end of March 2019, were selected. Two reviewers independently screened the literature on the basis of specific inclusion criteria. The primary outcomes were serum 25(OH)D level, systolic BP (SBP), and diastolic BP (DBP) changes. Results: Our analysis revealed significant differences in serum 25(OH)D level changes between the vitamin D and control groups (mean difference [MD] = 13.84; 95% confidence interval [CI] = 10.21-17.47; P < 0.000). There were no significant differences in SBP and DBP changes between the vitamin D and control groups. Subgroup analysis revealed significant differences in SBP changes between the hypertensive and vitamin D-deficient subgroups (MD = -4.01; 95% CI = -7.45 to -0.57; P = 0.02 and MD = -1.91; 95% CI = -3.48 to -0.34; P = 0.02, respectively), and DBP changes only in the hypertensive subgroup (MD = -2.22; 95% CI = -4.1 to -0.34; P = 0.02). Conclusions: Vitamin D supplementation significantly increases 25(OH)D levels and seems beneficial in lowering BP, specifically in the elderly with elevated BP and vitamin D deficiency.

Effects of vitamin D supplementation on 25(OH)D levels and blood pressure in the elderly: a systematic review and meta-analysis

Background: Hypertension and vitamin D deficiency are prevalent among the elderly. This study evaluated the effects of vitamin D supplementation on changes in serum 25-hydroxyvitamin D (25(OH)D) levels and blood pressure (BP) in the elderly (age > 60 years). Methods: Randomized controlled trials from electronic databases on the elderly taking oral vitamin D, until the end of March 2019, were selected. Two reviewers independently screened the literature on the basis of specific inclusion criteria. The primary outcomes were serum 25(OH)D level, systolic BP (SBP), and diastolic BP (DBP) changes. Results: Our analysis revealed significant differences in serum 25(OH)D level changes between the vitamin D and control groups (mean difference [MD] = 13.84; 95% confidence interval [CI] = 10.21-17.47; P < 0.000). There were no significant differences in SBP and DBP changes between the vitamin D and control groups. Subgroup analysis revealed significant differences in SBP changes between the hypertensive and vitamin D-deficient subgroups (MD = -4.01; 95% CI = -7.45 to -0.57; P = 0.02 and MD = -1.91; 95% CI = -3.48 to -0.34; P = 0.02, respectively), and DBP changes only in the hypertensive subgroup (MD = -2.22; 95% CI = -4.1 to -0.34; P = 0.02). Conclusions: Vitamin D supplementation significantly increases 25(OH)D levels and seems beneficial in lowering BP, specifically in the elderly with elevated BP and vitamin D deficiency.

Effects of vitamin D supplementation on 25(OH)D concentrations and blood pressure in the elderly: a systematic review and meta-analysis

Background: Hypertension and vitamin D deficiency are prevalent among the elderly. This study evaluated the effects of vitamin D supplementation on changes in serum 25-hydroxyvitamin D (25(OH)D) concentrations and blood pressure (BP) in the elderly (age > 60 years). Methods: Randomized controlled trials from electronic databases on the elderly taking oral vitamin D, until the end of March 2019, were selected. Two reviewers independently screened the literature on the basis of specific inclusion criteria. The primary outcomes were serum 25(OH)D level, systolic BP (SBP), and diastolic BP (DBP) changes. Results: Our analysis revealed significant differences in serum 25(OH)D concentrations changes between the vitamin D and control groups (mean difference [MD] = 13.84; 95% confidence interval [CI] = 10.21-17.47; P < 0.000). There were no significant differences in SBP and DBP changes between the vitamin D and control groups. Subgroup analysis revealed significant differences in SBP changes between the hypertensive and vitamin D-deficient subgroups (MD = -4.01; 95% CI = -7.45 to -0.57; P = 0.02 and MD = -1.91; 95% CI = -3.48 to -0.34; P = 0.02, respectively), and DBP changes only in the hypertensive subgroup (MD = -2.22; 95% CI = -4.1 to -0.34; P = 0.02). Conclusions: Vitamin D supplementation significantly increases 25(OH)D concentrations and seems beneficial in lowering BP, specifically in the elderly with elevated BP and vitamin D deficiency.

Vitamin D Supplementation and Blood Pressure in Children and Adolescents: A Systematic Review and Meta-Analysis

Suboptimal vitamin D status is associated with elevated blood pressure (BP) in children and adolescents. Whether vitamin D supplementation reduces BP remains unclear. To systematically review whether vitamin D supplementation reduces BP in children and adolescents, we conducted a literature review according to the PRISMA statement. We included vitamin-D supplementation human interventions studies that reported on BP as an outcome. We searched PUBMED, MEDLINE, CINAHL, EMBASE, the Cochrane Library, and the clinical trials website. We also hand searched the references of the included articles and previous reviews of vitamin D therapy. No language or time restrictions were applied. We extracted data on population characteristics, baseline and endline vitamin D and BP values, and assessed the risk of bias of the included studies. We performed a narrative review of the findings, conducted a meta-analysis when possible, and performed sensitivity analyses to test the robustness of our results. We assessed the overall quality of the evidence produced in the meta-analysis. We included eight studies in our review and five studies in the meta-analysis, none of which included hypertensive only participants. The risk of bias was variable. In non-randomized studies, no effect of vitamin D supplementation was seen on systolic BP (SBP) (mean difference: 0.39 (95% confidence interval (CI): -0.9; 1.68) mmHg; p = 0.55; I2 = 0%). Only a significant decrease in diastolic BP (DBP) (mean difference: -1.87 (95% CI: -3.02; -0.72) mmHg; p = 0.001; I2 = 0%) was noted. Both analyses had a low quality of evidence. In randomized controlled trials (RCTs), no effect was noted on SBP (mean difference: -2.04 (95% CI: -5.12; 1.04) mmHg; p = 0.19; I2 = 71%) nor DBP (mean difference: 0.01 (95% CI: -1.09; 1.12) mmHg; p = 0.98; I2 = 0%). The final quality of evidence ranged between low and moderate. Sensitivity analyses did not affect the results. Vitamin D supplementation was found to be ineffective in lowering SBP and DBP in children and adolescents.

Role of Vitamin D in Preventing and Treating Selected Extraskeletal Diseases-An Umbrella Review

Evidence is accumulating that vitamin D may have beneficial effects on respiratory tract, autoimmune, neuro-degenerative, and mental diseases. The present umbrella review of systematic reviews (SRs) of cohort studies and randomised controlled trials (RCTs), plus single Mendelian randomisation studies aims to update current knowledge on the potential role of vitamin D in preventing and treating these extraskeletal diseases. Altogether, 73 SRs were identified. Observational data on primary prevention suggest an inverse association between vitamin D status and the risk of acute respiratory tract infections (ARI), dementia and cognitive decline, and depression, whereas studies regarding asthma, multiple sclerosis (MS), and type 1 diabetes mellitus (T1DM) are scarce. SRs of RCTs support observational data only for the risk of ARI. No respective RCTs are available for the prevention of chronic obstructive pulmonary disease (COPD), MS, and T1DM. SRs of RCTs indicate beneficial therapeutic effects in vitamin D-deficient patients with asthma and COPD, while effects on major depression and T1DM need to be further elucidated. Mendelian randomisation studies do not consistently support the results of SRs. Since several limitations of the included SRs and existing RCTs do not permit definitive conclusions regarding vitamin D and the selected diseases, further high-quality RCTs are warranted.